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Forage selection by California bighorn sheep and the effects of grazing on an Artemisia-Agropyron community… Wikeem, Brian Michael 1984

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FORAGE SELECTION BY CALIFORNIA BIGHORN SHEEP AND THE EFFECTS OF GRAZING ON AN ARTEMISIA-AGROPYRON COMMUNITY IN SOUTHERN BRITISH COLUMBIA BY BRIAN MICHAEL WIKEEM B.Ed., U n i v e r s i t y o f C a l g a r y , 1971 B.Sc. ( A g r . ) , U n i v e r s i t y o f B r i t i s h C o l u m b i a , 1976 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY i n THE DEPARTMENT OF PLANT SCIENCE We a c c e p t t h i s t h e s i s as c o n f o r m i n g t o t h e r e q u i r e d s t a n d a r d THE UNIVERSITY OF BRITISH COLUMBIA NOVEMBER 19 84 (c) B r i a n M i c h a e l Wikeem, 1984 In presenting t h i s thes is i n p a r t i a l f u l f i l m e n t of the requirements fo r an advanced degree at the Un ivers i ty of B r i t i s h Columbia, I agree that the L ib rary s h a l l make i t f r e e l y a v a i l a b l e fo r reference and study. I fu r ther agree that permission for extensive copying of t h i s t h e s i s fo r scho la r l y purposes may be granted by the head of my department or by h i s or her representat ives . I t i s understood that copying or p u b l i c a t i o n of t h i s t h e s i s fo r f i n a n c i a l gain s h a l l not be allowed without my w r i t t e n permission. Department of Plant Science  The Un ivers i t y of B r i t i s h Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 DE-6 (3/81) ABSTRACT Th i s study was undertaken to determine the i n t e r r e l a t i o n s among forage p r o d u c t i o n and u t i l i z a t i o n , forage q u a l i t y , forage a v a i l a b i l i t y , d i e t s e l e c t i o n , and the subsequent impact of g r a z i n g by c a p t i v e C a l i f o r n i a bighorn sheep under c o n t r o l l e d e x p e r i m e n t a l c o n d i t i o n s on an A r t e m i s i a - Agropyron p l a n t community i n southern i n t e r i o r B r i t i s h Columbia. Fourteen grasses, 58 f o r b s p l u s 18 t r e e s and shrubs were a v a i l a b l e f o r g r a z i n g by the c a p t i v e h e r d w i t h i n a 42 ha experimental e n c l o s u r e . Agropyron spicatum, Bromus tectorum and A r t e m i s i a t r i d e n t a t a were the dominant s p e c i e s on the s i t e e q u a l i n g 22.1, 9.5 and 6.7% of the cover r e s p e c t i v e l y . Both annual and seasonal v a r i a t i o n s i n p l a n t s p e c i e s phen-ology, cover and b o t a n i c a l composition were e v i d e n t among p h e n o l o g i c a l groups, forage c l a s s e s and i n d i v i d u a l s p e c i e s . Cover of grasses (51.4%) and f o r b s (24.1%) was h i g h e s t i n 1978 which was the w e t t e s t year, and i t was lowest i n 1979 which was the d r i e s t year e q u a l i n g 34.2 and 12.8% f o r each group re s p e c -t i v e l y . Cover of shrubs, and both cover and b o t a n i c a l composi-t i o n of Agropyron spicatum v a r i e d l i t t l e among years. Y i e l d s f o r t o t a l s t a n d i n g crop v a r i e d from 40.83 to 62.95 g/m 2 i n 1977 and 1978 on t h e u n g r a z e d a r e a s i n r e s p o n s e t o a n n u a l weather p a t t e r n s . F a l l regrowth was p r e v a l e n t i n 1978 and 1979 e q u a l i n g 8.18 and 19.42 g/m 2 or 11.5 and 27.0% of the t o t a l herbage produced i n each year r e s p e c t i v e l y . Maximum a v a i l a b i l i t y of n u t r i e n t s occurred i n March and A p r i l each year, but from September through to November f a l l regrowth r e - e s t a b -l i s h e d n u t r i e n t l e v e l s to those recorded i n the e a r l y growth stages f o r a l l p l a n t s p e c i e s sampled. A t o t a l of 79 s p e c i e s c o n s i s t i n g of 14 grasses, 47 f o r b s and 18 shrubs were observed i n the d i e t of the experimental herd from 1977 to 1979. Grasses, f o r b s and shrubs comprised 66.6, 18.9 and 14.5% of the d i e t r e s p e c t i v e l y over the 28 month study p e r i o d . Agropyron spicatum was g e n e r a l l y the most common p l a n t found i n the bighorn d i e t i n a l l seasons, but t h i s p l a n t s p e c i e s t y p i c a l l y o c curred more f r e q u e n t l y on the range than i n the d i e t . Other grasses such as Festuca s c a b r e l l a , Festuca i d a h o e n s i s , K o e l e r i a  c r i s t a t a and S t i p a comata were p r e f e r r e d . Forbs were grazed most i n summer (26.5 and 36.2%) and s p r i n g (19.2 and 18.4%) i n 1977 and 1978 r e s p e c t i v e l y . P e r e n n i a l f o r b s were g e n e r a l l y p r e f e r r e d but annual f o r b s were s e l e c t e d a g a i n s t by the b i g h o r n sheep i n a l l s e a s o n s . Browse was u t i l i z e d most i n w i n t e r and s p r i n g each year averaging 18.7 and 17.6% of the d i e t i n each season r e s p e c t i v e l y over the two year p e r i o d . The dominant shrub, A r t e m i s i a t r i d e n t a t a was not p r e f e r r e d but most other browse s p e c i e s were. No c o n s i s t e n t r e g r e s s i o n s c o u l d be e s t a b l i s h e d between forage consumption and corresponding n u t r i t i v e q u a l i t y of s e l e c t e d forage s p e c i e s . Balsamorhiza s a g i t t a t a and Agropyron spicatum were l e a s t a f f e c t e d from g r a z i n g d e s p i t e t h e i r importance i n mountain sheep d i e t . Indeed, o n l y l e a f lengths d i f f e r e d among grazed and un-grazed Balsamorhiza s a g i t t a t a p l a n t s and no s i g n i f i c a n t d i f f e r -ences were observed i n b a s a l diameters or the number of culms produced on grazed and ungrazed Agropyron spicatum p l a n t s a f t e r three years of g r a z i n g . Reductions i n n e a r l y a l l measured para-meters were observed on grazed K o e l e r i a c r i s t a t a , Poa s a n d b e r g i i , i i i Stipa comata, C a s t i l l e j a thompsonii , Lupinus sericeus and E r i o - gonum niveum plants compared to ungrazed p lants . U t i l i z a t i o n of Amelanchier a l n i f o l i a was determined with three methods i n 1977 and f i v e methods i n 1978. I t was concluded that weight methods do not evaluate the impact of mountain sheep browsing any better than methods based on stem lengths. The long term ef fec ts of grazing by C a l i f o r n i a bighorn sheep was evaluated from 1976 to 1983. Total cover remained v i r t u a l l y the same on the grazed (71.1 and 85.0%) and ungrazed (70.3 and 86.0%) areas between these two years respect ive ly . Annual, per -o ennial and ind i v idua l plant species a l l reacted d i f f e r e n t l y to grazing by mountain sheep. Cover of perennial grasses increased only s l i g h t l y on both the grazed and protected areas between 1976 and 1983 but these d i f ferences were not s t a t i s t i c a l l y s i g n i f i c a n t . No d i f f e r -ences i n e i ther cover or botanical composition were observed between the grazed and ungrazed areas for Agropyron spicatum, Koeler ia c r i s t a t a or Poa sandbergi i . Cover and botanical composition of forbs remained the same i n 1983 compared to 1976 on the grazed areas. On the ungrazed areas, both cover and botanical composition of forbs increased over the same time per iod . Botanical composition of shrubs increased s l i g h t l y on both the grazed and' ungrazed areas over the seven year period but cover for t h i s group remained the same. Both Eriogonum niveum and Eriogonum heracleoides decl ined s i g n i f i c a n t l y on the areas grazed by bighorn sheep. Declines i n both species were a t t r ibu ted to grazing pressure by the captive herd. i v TABLE OF CONTENTS Page ABSTRACT i i LIST OF TABLES i x LIST OF FIGURES x i i ACKNOWLEDGEMENTS X V 1. INTRODUCTION AND OBJECTIVES 1 2. LITERATURE REVIEW — 4 2.1 Bighorn Sheep Food Habits and Select ive Grazing 6 2.11 D ive rs i t y and Composition of Bighorn Sheep D i e t s - 6 2.12 Seasonal Use of Forages 11 2.13 Forage S e l e c t i v i t y 18 2.2 Impacts of Bighorn Sheep on Vegetation 22 2.21 Ef fects of Grazing on Indiv idual Plants 22 2.22 Ef fects of Bighorn D i s t r i b u t i o n and Grazing on Plant Communities 24 2.23 Evaluation of Mountain Sheep Range Condition 26 3. LOCATION, HISTORY AND DESCRIPTION OF THE STUDY AREA 27 3.1 Geomorphology and S o i l s 27 3.2 Phys ical Features 28 3.3 Climate 28 3.4 Vegetation 34 4. METHODS AND PROCEDURES 36 4.1 Experimental Approach and Rationale 36 4.2 Fencing, Animal Capture and Herd Composition 36 v 4.3 F i e l d Methods, Hypotheses and Data Analyses 37 4.31 Cl imate, S o i l Moisture and S o i l Temperature 39 4.32 Forage Y ie lds and U t i l i z a t i o n 40 4.33 E f fect of Grazing on Plant Reproductive Potent ia l : 44 4.34 Shrub U t i l i z a t i o n 45 4.35 Plant Phenology 48 4.36 Botanical Composition and Cover 49 4.4 Laboratory Procedures, Hypotheses and Data Analyses 52 4.41 Forage Qual i ty 52 4.42 Diet Analysis 54 4.421 Reference Plant Co l l ec t ion 55 4.422 Fecal Analysis 59 4.423 Monthly Grazing Observations 61 4.424 Diet Data Analyses 62 4.5 Forage S e l e c t i v i t y 63 4.51 S e l e c t i v i t y Index 63 4.52 Relat ionship Between Bighorn Sheep Diet and Forage Qual i ty 65 5- RESULTS AND DISCUSSION 6 8 5.1 Bighorn Sheep Habitat Structure and Function 68 5.11 Annual Weather Patterns During the Study Period 68 5.12 Plant Community Descr ipt ion 77 5.13 Temporal Var iat ions i n Plant Species A v a i l a b i l i t y — 81 5.131 Plant Phenology 81 5.132 Cover and Botanical Composition 85 5.14 Forage Production 104 v i 5.141 Influence of Annual Weather Patterns on Forage Production 105 5.142 Forage Production i n Relat ion to S i te 116 5.143 F a l l Regrowth 119 5.15 D i s t r i b u t i o n of Nutr ients Avai lab le for Bighorn Sheep 121 5.2 C a l i f o r n i a Bighorn Sheep Diet and Forage Select ion 133 5.21 Annual, Seasonal and Monthly Diet and Forage Select ion 137 5.22 Bighorn Diet in Relat ion to Forage Qual i ty 160 5.3 Plant Community Dynamics i n Relat ion to Grazing by C a l i f o r n i a Bighorn Sheep 168 5.31 Forage U t i l i z a t i o n by C a l i f o r n i a Bighorn Sheep 169 5.32 Impact of Grazing on the Reproductive Potent ia l of Herbaceous Species : 180 5.33 Impact of Browsing on Amelanchier a l n i f o l i a 185 5.34 Impact of Grazing on Plant Community Structure 189 5.35 Potent ia l Long Term Ef fects of Grazing by C a l i f o r n i a Bighorn Sheep 215 6. MANAGEMENT IMPLICATIONS 222 7. SUMMARY AND CONCLUSIONS 22 6 8. LITERATURE CITED 234 9. APPENDICES 1. SPECIES DIVERSITY OF MOUNTAIN SHEEP DIETS 246 2. GENERA AND PLANT SPECIES IDENTIFIED IN THE DIET OF CALIFORNIA BIGHORN THROUGHOUT THEIR DISTRIBUTION — 250 3. PERCENT COMPOSITION OF MOUNTAIN SHEEP DIETS BY FORAGE CLASS FOR SELECTED NORTH AMERICAN HERDS 26 4 4. COMPOSITION OF THE CAPTIVE CALIFORNIA BIGHORN SHEEP HERD AT THE OKANAGAN GAME FARM FOLLOWING LAMBING FROM 1977 TO 1982 — 1 270 5. EXPERIMENTAL DESIGNS 272 v i i 6. PLANT SPECIES LIST FOR OKANAGAN GAME FARM STUDY SITE 277 7. PHENOLOGY OF 75 PLANT SPECIES OCCURRING ON THE OKANAGAN GAME FARM STUDY SITE IN EACH OF THREE CONSECUTIVE GROWING SEASONS (1977-1979) 281 8. PERCENT COMPOSITION OF CALIFORNIA BIGHORN DIET, BOTANICAL COMPOSITION OF THE RANGE AND SELECTIVITY INDICES FROM 19 77 TO 19 79 AT THE OKANAGAN GAME FARM 294 v i i i LIST OF TABLES Table Page 1. T o t a l number o f g e n e r a and s p e c i e s r e c o r d e d i n C a l i f o r n i a b i g h o r n sheep d i e t s t h r o u g h o u t t h e i r N o r t h A m e r i c a n d i s t r i b u t i o n 8 2. Range i n p e r c e n t d i e t c o m p o s i t i o n o f t h r e e f o r a g e c l a s s e s f o r Rocky M o u n t a i n , d e s e r t and C a l i f o r n i a b i g h o r n sheep 10 3. Range i n p e r c e n t c o m p o s i t i o n o f g r a s s e s , f o r b s , s h r u b s and c o n i f e r s i n g e s t e d by t h r e e p a i r s o f rams f r o m t h r e e v e g e t a t i o n u n i t s i n Idaho ( d a t a f r o m H i c k e y 1978) 12 4. Mean m o n t h l y r a i n f a l l (mm), s n o w f a l l (cm) and t o t a l p r e c i p i t a t i o n f o r 1977, 1978, 1979 and n o r m a l s , P e n t i c t o n , B.C. ( S o u r c e : A n n u a l Met-e r o l o g i c a l Summaries, E n v i r o n m e n t Canada 1977, 1978 , 1979) 31 5. Mean maximum, minimum and m o n t h l y t e m p e r a t u r e s (° C) f o r 1977, 1978, 1979 and n o r m a l s , P e n t i c t o n , B.C. ( S o u r c e : A n n u a l M e t e r o l o g i c a l Summaries, E n v i r o n m e n t Canada 1977,1978,1979) 32 6. M o n t h l y and a n n u a l e x t r e m e s o f r e c o r d f o r temp-e r a t u r e and p r e c i p i t a t i o n , P e n t i c t o n , B.C. ( S o u r c e : A n n u a l M e t e r o l o g i c a l Summaries, E n v i r o n m e n t Canada 1977,1978,1979) 33 7. C o m p o s i t i o n o f l a c t o p h e n o l - c o t t o n b l u e s o l u t i o n by volume 56 8. Q u a n t i t i e s and c o n s t i t u e n t s o f a c i d , a l c h o l s t a i n m i x t u r e by v o l u m e 58 9. Summary o f d e p e n d e n t and i n d e p e n d e n t v a r i a b l e s u s e d f o r 20 m u l t i p l e l i n e a r r e g r e s s i o n s c o m p a r i n g d i e t , f o r a g e q u a 1 i t y a n d c o v e r 66 10. P l a n t s p e c i e s i n c l u d e d i n t h e m o n t h l y , g r a s s , f o r b and s h r u b m u l t i p l e r e g r e s s i o n a n a l y s e s 67 11. S o i l t e m p e r a t u r e s (°C) f o r N o r t h (N), E a s t (E) and means (M) +_ t h e s t a n d a r d d e v i a t i o n (S.D.) a t two d e p t h s o v e r t h r e e g r o w i n g s e a s o n s from 1977 t o 1979 — 70 12. G r o w i n g d e g r e e d a y s above 5°C f o r P e n t i c t o n , B.C. f o r 1977, 1978, 1979, and n o r m a l s ( S o u r c e : A n n u a l M e t e r o l o g i c a l Summaries, E n v i r o n m e n t Canada 1977, 1978 , 1979) 71 i x 13. C u m u l a t i v e t o t a l p r e c i p i t a t i o n (mm) d u r i n g s e l e c t e d p e r i o d s a t P e n t i c t o n , B.C. d u r i n g 1977, 1978 and 1979 ( S o u r c e : A n n u a l M e t e r o l o g i c a l Summaries, E n v i r o n m e n t Canada 1977, 1978, 1979) 73 14. P e r c e n t s o i l m o i s t u r e f o r N o r t h (N), E a s t (E) and means (M) +_ t h e s t a n d a r d d e v i a t i o n (S.D.) a t two d e p t h s o v e r t h r e e g r o w i n g s e a s o n s f r o m 1977 t o 1979 — 75 15. Mean p e r c e n t c o v e r and b o t a n i c a l c o m p o s i t i o n +_ t h e s t a n d a r d d e v i a t i o n (S.D.) a v e r a g e d o v e r a l l s i t e s and months f r o m May t o A u g u s t 19 77 a t t h e Okanagan Game Farm 78 16. T o t a l number o f s p e c i e s r e p r e s e n t e d i n e a c h pheno-l o g i c a l g r o u p a t t h e Okanagan Game Farm s t u d y s i t e 82 17. S e a s o n a l c h a n g e s i n mean p e r c e n t c o v e r and b o t a n i c a l c o m p o s i t i o n o f p h e n o l o g i c a l g r o u p s a t t h e Okanagan Game Farm o v e r t h r e e g r o w i n g s e a s o n s 91 18. S e a s o n a l c h a n g e s i n mean p e r c e n t c o v e r and b o t a n i c a l c o m p o s i t i o n o f i m p o r t a n t C a l i f o r n i a b i g h o r n s h e e p f o r a g e p l a n t s p e c i e s a t t h e Okanagan Game Farm o v e r . t h r e e g r o w i n g s e a s o n s 92 19. S i g n i f i c a n c e o f s i n g l e d e g r e e o f f r e e d o m c o n t r a s t s f o r i n t e r a c t i o n s between y e a r and g r a z i n g on h e r b a g e y i e l d s o f 11 v e g e t a t i v e g r o u p s a t t h e Okanagan Game Farm, 1976-1979 106 20. T o t a l f o r a g e p r o d u c t i o n and r e m a i n i n g h e r b a g e y i e l d s (g/m 2) f o r 11 v e g e t a t i v e g r o u p s on a r e a s g r a z e d (G) and u n g r a z e d (UG) by C a l i f o r n i a b i g h o r n s h e e p a t t h e Okanagan Game Farm, 1976-1979 107 21. R e l a t i v e p r o d u c t i o n o f v e g e t a t i v e g r o u p s e x p r e s s e d as a p e r c e n t a g e o f t o t a l s t a n d i n g c r o p 109 22. A n n u a l f o r a g e p r o d u c t i o n f o r A g r o p y r o n s p i c a t u m a v e r a g e d o v e r a l l l e v e l s o f s i t e and g r a z i n g 110 23. F o r a g e p r o d u c t i o n (g/m 2) o f 11 v e g e t a t i v e g r o u p s on N o r t h , E a s t and Upper i n 1978 and 1979 118 24. A v e r a g e v a l u e s f o r p e r c e n t CP, ADF, Ca, P and t h e Ca/P r a t i o f o r 10 f o r a g e s p e c i e s t h r o u g h o u t t h e 1977 and 1978 g r o w i n g s e a s o n s 122 25. P e r c e n t c h e m i c a l c o m p o s i t i o n o f s i x f o r a g e s p e c i e s a v e r a g e d o v e r e i g h t months f r o m A p r i l t o O c t o b e r and i n March d u r i n g 1977 and 1978 127 x 26. Average values for percent CP, ADF, Ca, P and Ca/P r a t i o s for f a l l regrowth of four forage species i n 1978 and 1979 129 27. Monthly, seasonal and annual species d i v e r s i t y i n C a l i f o r n i a bighorn sheep d ie t over the 1977/78 and 1978/79 grazing years 134 28. Seasonal d ie t (%), botanical composition of the study s i t e (%) and s e l e c t i v i t y indices (SI) for important C a l i f o r n i a bighorn sheep forage plant species at the Okanagan Game Farm 13 8 29. S ign i f icance of s ing le degree of freedom contrasts for contr ibut ion of grass, forb and shrub plant species to C a l i f o r n i a bighorn sheep d i e t throughout the 1977/78 and 1978/79 grazing years 144 30. Monthly contr ibut ion (%) of t o t a l and important grass, forb and shrub species to C a l i f o r n i a bighorn sheep d ie t averaged over the 1977/78 and 1978/79 grazing years • 147 31. Mu l t ip le l inear and polynomial regressions r e l a t i n g C a l i f o r n i a bighorn sheep d ie t to selected n u t r i t i v e parameters and cover 163 32. Percent u t i l i z a t i o n of 11 vegetative groups by C a l i f o r n i a bighorn sheep from 1977 to 1979 170 33. Impacts of grazing by C a l i f o r n i a bighorn sheep on leaf length (mm), basal diameter (mm), culm length (mm) and the number of culms produced for eight selected forage species 181 34. Percent u t i l i z a t i o n of Amelanchier a l n i f o l i a determined with f i v e d i f f e r e n t methods 186 35. Average botanical composition (%) and cover (%) on areas grazed (G) and ungrazed (UG) by C a l i f o r n i a bighorn sheep from 1976 to 1983 195 36. Observed and expected responses of selected plant species to grazing by C a l i f o r n i a bighorn sheep at the Okanagan Game Farm 217 x i LIST OF FIGURES Figure Page 1. L o c a t i o n s o f C a l i f o r n i a b i g h o r n sheep bands' i n t h e s o u t h Okanagan, B r i t i s h C o l u m b i a (from S p a l d i n g and Bone 1969) and Okanagan Game Farm s t u d y s i t e 15 2. V i e w o f t h e low e r p o r t i o n o f t h e Okanagan Game Farm s t u d y s i t e 29 3. V i e w o f t h e up p e r 10 ha o f t h e Okanagan Game Farm s t u d y s i t e 29 4. S c h e m a t i c d i a g r a m i l l u s t r a t i n g t h e l a y o u t o f s a m p l -i n g u n i t s on t h e Okanagan Game Farm s t u d y s i t e 3 8 5. S c h e m a t i c d i a g r a m i l l u s t r a t i n g t h e a r r a n g e m e n t o f t r a n s e c t s on t h e N o r t h and E a s t s i t e s 41 6. Month by y e a r i n t e r a c t i o n f o r mean t o t a l c o v e r f r o m A p r i l t o A u g u s t i n t h r e e g r o w i n g s e a s o n s f r o m 1977 t o 1979 ( s i g n i f i c a n t a t a l p h a = 0.05) • 86 7. C o v e r o f g r a s s , f o r b s and s h r u b s f r o m A p r i l t o A u g u s t i n t h r e e g r o w i n g s e a s o n s f r o m 1977 t o 1979 88 8. B o t a n i c a l c o m p o s i t i o n o f g r a s s , f o r b s and s h r u b s f r o m A p r i l t o A u g u s t i n t h r e e g r o w i n g s e a s o n s f r o m 1977 t o 1979 89 9. The i n t e r a c t i o n between month and y e a r f o r b o t a n i c a l c o m p o s i t i o n o f Group IV f r o m A p r i l t o A u g u s t i n t h r e e g r o w i n g s e a s o n s f r o m 1977 t o 1979 ( s i g n i f i c a n t a t a l p h a = 0.05) 103 10. S c h e m a t i c p r o f i l e o f p r o t e i n p o t e n t i a l l y a v a i l a b l e t o C a l i f o r n i a b i g h o r n s h e e p t h r o u g h o u t two g r a z i n g y e a r s a t t h e Okanagan Game Farm — : 161 11. The i n t e r a c t i o n between y e a r and g r a z i n g on y i e l d s o f t o t a l s t a n d i n g c r o p (g/m sq.) f r o m 1976 t o 1979 ( s i g n i f i c a n t a t a l p h a = 0.05) 172 12. The i n t e r a c t i o n between y e a r and g r a z i n g on y i e l d s o f A g r o p y r o n s p i c a t u m (g/m sq.) f r o m 1976 t o 1979 ( s i g n i f i c a n t a t a l p h a = 0.10 between 1978 and 1979) - 173 13. The i n t e r a c t i o n between y e a r and g r a z i n g on y i e l d s o f K o e l e r i a c r i s t a t a (g/m sq.) f r o m 1977 t o 1979 ( s i g n i f i c a n t a t a l p h a = 0.05) 174 x i i 14. The i n t e r a c t i o n between y e a r and g r a z i n g on y i e l d s o f S t i p a c o m a t a (g/m sq.) f r o m 1977 t o 19,79 s i g n i -f i c a n t a t a l p h a = 0.05) 176 15. The i n t e r a c t i o n between y e a r and g r a z i n g on p e r c e n t t o t a l c o v e r f r o m 1976 t o 1983 ( s i g n i f i c a n t a t a l p h a = 0.10) 190 16. The i n t e r a c t i o n between y e a r and g r a z i n g on p e r c e n t c o v e r o f t o t a l g r a s s f r o m 1976 t o 1983 ( s i g n i f i c a n t a t a l p h a = 0.05) 192 17. The i n t e r a c t i o n between y e a r and g r a z i n g on p e r c e n t b o t a n i c a l c o m p o s i t i o n o f t o t a l g r a s s f r o m 1976 t o 1983 ( s i g n i f i c a n t a t a l p h a = 0.05) 192 18. The i n t e r a c t i o n between y e a r and g r a z i n g on p e r c e n t c o v e r o f a n n u a l g r a s s f r o m 1976 t o 1983 ( s i g n i f i c a n t a t a l p h a = 0.05) 193 19. The i n t e r a c t i o n between y e a r and g r a z i n g on p e r -c e n t b o t a n i c a l c o m p o s i t i o n o f a n n u a l g r a s s f r o m 1976 t o 1983 ( s i g n i f i c a n t a t a l p h a = 0.10) 193 20. The i n t e r a c t i o n between y e a r and g r a z i n g on p e r c e n t c o v e r o f Bromus m o l l i s f r o m 1976 t o 1983 ( s i g n i f i c a n t a t a l p h a = 0.05) 201 21. The i n t e r a c t i o n between y e a r and g r a z i n g on p e r -c e n t b o t a n i c a l c o m p o s i t i o n o f Bromus m o l l i s f r o m 1976 t o 1983 ( s i g n i f i c a n t a t a l p h a = 0.05) 201 22. The i n t e r a c t i o n between y e a r and g r a z i n g on p e r c e n t c o v e r o f S t i p a c o m a t a f r o m 1976 t o 1983 ( s i g n i f i c a n t a t a l p h a = 0.05) 204 23. The i n t e r a c t i o n between y e a r and g r a z i n g on p e r -c e n t b o t a n i c a l c o m p o s i t i o n o f S t i p a c o m a t a f r o m 1976 t o 1983 ( s i g n i f i c a n t a t a l p h a = 0.10) 204 24. The i n t e r a c t i o n between y e a r and g r a z i n g on p e r c e n t c o v e r o f t o t a l f o r b s f r o m 1976 t o 1983 ( s i g n i f i c a n t a t a l p h a = 0.10) 206 25. The i n t e r a c t i o n between y e a r and g r a z i n g on p e r -c e n t b o t a n i c a l c o m p o s i t i o n o f t o t a l f o r b s f r o m 1976 t o 1983 ( s i g n i f i c a n t a t a l p h a = 0.05) 206 26. The i n t e r a c t i o n between y e a r and g r a z i n g on p e r c e n t c o v e r o f L u p i n u s s e r i c e u s f r o m 1976 t o 1983 ( s i g n -i f i c a n t a t a l p h a = 0.10) 208 27. The i n t e r a c t i o n between y e a r and g r a z i n g on p e r -c e n t b o t a n i c a l c o m p o s i t i o n o f L u p i n u s s e r i c e u s f r o m 1976 t o 1983 ( s i g n i f i c a n t a t a l p h a = 0.10) 208 x i i i 28. The i n t e r a c t i o n between year and grazing on percent cover of A c h i l l e a m i l l e f o l i u m from 1976 to 1983 (s ign-i f i c a n t at alpha = 0.10) 210 29. The in te rac t ion between year and grazing on percent botanical composition of A c h i l l e a m i l l e f o l i u m from 1976 to 1983 ( s ign i f i cant at alpha = 0.10) 210 30. The i n t e r a c t i o n between year and grazing on percent botanical composition of t o t a l shrubs from 1976 to 1983 ( s ign i f i cant at alpha = 0.10) 212 31. The in te rac t ion between year and grazing on percent cover of Eriogonum heracleoides from 1976 to 1983 ( s i g n i f i c a n t at alpha = 0.05) 213 32. The in te rac t ion between year and grazing on percent botanical composition of Eriogonum heracleoides from 1976 to 1983 ( s ign i f i cant at alpha = 0.05) 213 33. The in te rac t ion between year and grazing on percent cover of Eriogonum niveum from 1976 to 1983 (s ign-i f i c a n t at alpha = 0.05) 214 34. The in te rac t ion between year and grazing on percent botanical composition of Eriogonum niveum from 1976 to 1983 ( s ign i f i cant at alpha = 0.05) 214 x i v ACKNOWLEDGEMENTS It gives me great pleasure to acknowledge a l l those who contr ibuted f i n a n c i a l ass is tance, d i r e c t i o n , f a c i l i t i e s , f i e l d assistance and i n t e l l e c t u a l s t imula t ion throughout t h i s study. F i r s t , I would l i k e to acknowledge g r a t e f u l l y both the National Sciences and Engineering Research Council of Canada, and the B r i t i s h Columbia F ish and W i l d l i f e Branch for f i n a n c i a l support. In p a r t i c u l a r I would l i k e to extend my grat i tude to Dr. Don Eastman who d i rected the larger research program of which th i s study was a part . I am e s p e c i a l l y g rate fu l to Dr. Michael P i t t , research advisor for t h i s pro ject , for h is ass is tance, guidance, s t i m u l a t -ing d iscuss ions , eternal patience throughout t h i s study and h is c r i t i c a l review of the manuscript. S i m i l a r l y , I wish to thank my supervis ing committee members: Drs. Les Lavku l ich , Dave Shackleton and V.C. Runeckles for t h e i r advice and guidance throughout the pro ject . Special acknowledgment i s extended to the Okanagan Game Farm whose cooperation made t h i s study poss ib le . I am p a r t i c u l a r l y indebted to the past manager Mr. Ed Lacey and h i s f a m i l y Florence, Howard, Harold and Kathy for the i r h o s p i t a l i t y during f i e l d t r i p s to the Okanagan and for the l o g i s t i c support they w i l l i n g l y supplied for the study as requested. The cooperation and assistance of Mr. Ian Robertson and Mr. Jack Bone, B.C. F ish and W i l d l i f e Branch, Pent ic ton , i n capturing the mountain sheep and providing l o g i s t i c support throughout the study was deeply appreciated. xv I would l i k e to thank Dr. George Eaton, Department of Plant Science, U.B.C., for h is advice i n plant h is to logy , microphoto-graphy, and s t a t i s t i c a l analyses. In add i t ion , h is generosity in providing laboratory space and equipment are g r a t e f u l l y acknow-ledged. Mr. Ross Eccles and Dr. Wi l l iam Kerr provided f i e l d a s s i s t -ance i n capturing mountain sheep, fencing and es tab l i sh ing f i e l d p lots for the study. Their ass is tance, often under unpleasant weather condi t ions , and the i r comments and advice are g r a t e f u l l y recognized. Our inv igorat ing discussions made long hard f i e l d days to le rab le and enjoyable. Mr. Russel l Tabata and Mr. Robert Bachman d i l i g e n t l y a s s i s t -ed i n ed i t ing data and the i r help was appreciated. Mr. Reg Newman i s espec ia l l y acknowledged for h is care fu l assistance i n e d i t i n g , programing and executing data analyses. Agr icu l ture Canada Range Research S ta t ion , Kamloops i s g r a t e f u l l y acknowledged for permit t ing access to the i r l i b r a r y and computer f a c i l i t i e s for data analyses. F i n a l l y , I would l i k e to acknowledge most g r a t e f u l l y my w i fe , Sandra who provided f i e l d and laboratory ass is tance , coded and edited data, provided moral support and continued to encour-age me i n seeing th i s study to i t s f r u i t i o n . xv i 1. 1. INTRODUCTION AND OBJECTIVES The p o p u l a t i o n s t a t u s o f C a l i f o r n i a b i g h o r n s h e e p ( O v i s  c a n a d e n s i s c a l i f o r n i a n a ) 1 i n B r i t i s h C o l u m b i a (B.C.) has been o f c o n c e r n t o w i l d l i f e managers f o r a t l e a s t t h e l a s t 25 y e a r s . U n l i k e Rocky M o u n t a i n b i g h o r n ( O v i s c a n a d e n s i s c a n a d e n s i s ) , w h i c h r e p o r t e d l y have s u s t a i n e d a minimum o f f o u r m a j o r d i e - o f f s s i n c e t h e t u r n o f t h e c e n t u r y i n b o t h B r i t i s h C o l u m b i a and A l b e r t a ( S t e l f o x 1971), C a l i f o r n i a b i g h o r n p o p u l a t i o n s w e s t o f t h e F r a s e r R i v e r have u n d e r g o n e o n l y one d e c l i n e w i t h p a r t i a l r e c o v e r y d u r i n g a p p r o x i m a t e l y t h e same p e r i o d (Sugden 1961). E a s t o f t h e F r a s e r R i v e r , i n t h e A s h n o l a r e g i o n o f s o u t h e r n B.C., p o p u l a t i o n s d e c l i n e d p r i o r t o 1900 w i t h numbers i n c r e a s i n g f r o m l e s s t h a n 100 t o 250 a n i m a l s by 1955 (Demarchi 1965). In 1954 C a l i f o r n i a b i g h o r n i n N o r t h A m e r i c a t o t a l e d l e s s t h a n 1700 w i t h a p p r o x i m a t e l y 1200 o f t h e s e a n i m a l s r e s i d i n g i n B r i t i s h C o l u m b i a . By 1970 t h e t o t a l p o p u l a t i o n was e s t i m a t e d t o be 3200 a n i m a l s ( S p a l d i n g and M i t c h e l l 1970), an i n c r e a s e o f 53% i n B r i t i s h C o l u m b i a and 153% i n t h e U n i t e d S t a t e s (Wikeem and P i t t 1979). D e s p i t e t h i s r e c o v e r y , i t was g e n e r a l l y a g r e e d t h a t b o t h t h e d i s t r i b u t i o n and numbers o f C a l i f o r n i a b i g h o r n r e m a i n e d b e l o w p r i s t i n e l e v e l s ( B l o o d 1961; S u g d e n 1961; D e m a r c h i 1965; D e m a r c h i and M i t c h e l l 1973). In an e f f o r t t o u n d e r s t a n d more f u l l y t h e e c o l o g y o f C a l i f o r n i a b i g h o r n sheep, a s e r i e s o f s t u d i e s was i n i t i a t e d i n t h e e a r l y 1960's. C o l l e c t i v e l y t h i s r e s e a r c h p r o g r a m i n v e s -1 Mammalian n o m e n c l a t u r e a f t e r Cowan and G u i g e t (1973) o r as c i t e d by a q u o t e d a u t h o r . 2 t i g a t e d numerous a s p e c t s o f r a n g e use and t h e e c o l o g y o f C a l i -f o r n i a b i g h o r n i n B.C. i n c l u d i n g : h a b i t a t components s u c h as c l i m a t e , s o i l s , v e g e t a t i o n , and p h y s i o g r a p h y ( B l o o d 1961; Sugden 1961; D e m a r c h i 1965; H a r p e r 1969; S p a l d i n g and Bone 1969; D e m a r c h i 1970; S c h e f f l e r 1972; D e m a r c h i and M i t c h e l l 1973); d i s -t r i b u t i o n , s e a s o n a l movements and m i g r a t i o n ( B l o o d 1961; Sugden 1961); b e h a v i o r ( B l o o d 1963), r a n g e c o m p e t i t i o n w i t h o t h e r ungu-l a t e s ( M o r r i s o n 1972); d i e t (Sugden 1961; D e m a r c h i 1965; B l o o d 1967); and f a c t o r s a f f e c t i n g p r o d u c t i v i t y ( B l o o d 1961; Sugden 1961). A l t h o u g h t h e s e s t u d i e s p r o v i d e d a w e a l t h o f i n f o r m a t i o n f o r management, B r i t i s h C o l u m b i a h e r d s have r e m a i n e d r e l a t i v e l y s t a b l e s i n c e 1970 w i t h a p p a r e n t low p r o d u c t i v i t y b e i n g a t t r i b -u t e d t o c o m p e t i t i o n w i t h d o m e s t i c l i v e s t o c k , a l i e n a t i o n o f w i n t e r r a n g e s , p r e d a t i o n and d i s e a s e (Wikeem and P i t t 1979). The c o m b i n a t i o n o f c o n t i n u e d low h e r d p r o d u c t i v i t y and t h e need f o r more i n f o r m a t i o n on C a l i f o r n i a b i g h o r n and t h e i r h a b i t a t p r o v i d e d t h e i m p e t u s f o r i n i t i a t i o n o f a j o i n t s t u d y among t h e B.C. F i s h and W i l d l i f e B r a n c h , t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a ( D e p a r t m e n t s o f P l a n t and A n i m a l S c i e n c e , F a c u l t y o f A g r i c u l t u r a l S c i e n c e s ) and Simon F r a s e r U n i v e r s i t y i n 1975. B a s e d on t h e a s s u m p t i o n t h a t a v a r i e t y o f p o p u l a t i o n and h a b i t a t components i n t e r a c t t o r e g u l a t e p o p u l a t i o n s i z e (Okanagan B i g h o r n Sheep R e s e a r c h Group 1978), b i g h o r n n u t r i t i o n , g e n e t i c s , b e h a v i o r , and h a b i t a t were s t u d i e d c o n c u r r e n t l y w i t h t h e o b j e c t i v e o f i n t e g r a t -i n g t h e r e s u l t s t o a s s e s s how t h e s e f a c t o r s i n t e r a c t and r e l a t e t o a n i m a l p r o d u c t i v i t y . As one p a r t o f t h i s l a r g e r r e s e a r c h p r o g r a m , t h i s t h e s i s w i l l i n v e s t i g a t e t h e i n t e r r e l a t i o n s among 3 forage production and u t i l i z a t i o n , forage q u a l i t y , forage a v a i l a b i l i t y , d ie t se lec t ion and the subsequent impact of grazing by C a l i f o r n i a bighorn on the vegetative component of the i r habi tat . The s p e c i f i c ob ject ives , fol lowed i n brackets by the sect ion where hypotheses regarding each are located, inc lude: 1. To describe the phenological development of the plant community in r e l a t i o n to forage a v a i l a b i l i t y . 2. To assess temporal changes i n cover and botanical composition i n r e l a t i o n to forage a v a i l a b i l i t y (Sect. 4.36) . 3. To determine annual herbaceous production inc lud ing f a l l regrowth i n r e l a t i o n to forage a v a i l a b i l i t y (Sect. 4.32). 4. To determine temporal changes i n forage q u a l i t y of selected plant species throughout the growing season (Sect. 4.36).' 5. To determine annual, seasonal and monthly d ie t of C a l i f o r n i a bighorn sheep (Sect. 4.424) and re la te d ie t to forage a v a i l a b i l i t y . . 6. To evaluate the re la t ionsh ip between forage se lec t ion and n u t r i t i o n a l qua l i t y of selected plant species (Sect. 4.52) . 7. To determine forage u t i l i z a t i o n and the e f fec t of grazing by C a l i f o r n i a bighorn sheep on herbage y ie lds and l i t t e r accumulation (Sect. 4.32). 8. To determine the e f fec ts of grazing by C a l i f o r n i a bighorn sheep on the v igor and reproductive potent ia l of selected p l a n t spec ies (Sect. 4 .33, Sect. 4.34). 9. To quanti fy the impact of se lec t i ve grazing by C a l i f o r n i a bighorn on the plant community (Sect 4 .36) . 10. To out l ine management impl i ca t ions r e s u l t i n g from th i s study. 4 2. LITERATURE REVIEW A n i m a l s a f f e c t v e g e t a t i o n p h y s i c a l l y and t h r o u g h s e l e c t i v e g r a z i n g . P h y s i c a l i m p a c t s o f a n i m a l s on v e g e t a t i o n may i n c l u d e : u p r o o t i n g u n e a t e n p l a n t s , b a r k wounding t h r o u g h r u b b i n g , c o v e r i n g v e g e t a t i o n w i t h dung, and t r a m p l i n g p l a n t s w h i l e w a l k i n g , r o l l i n g o r b e d d i n g . These o f t e n r e l a t e t o b e h a v i o r and s o c i a l p a t t e r n s s u c h as h e r d i n g , m i g r a t i o n , d i s t a n c e a n i m a l s w i l l t r a v e l f r o m w a t e r , and t h e need f o r o t h e r h a b i t a t components s u c h as c o v e r and e s c a p e t e r r a i n (De Vos. 1969; Heady 1975). Heady (1975) d e f i n e d f o u r g r a z i n g f a c t o r s w h i c h g o v e r n t h e r a t e and k i n d o f c h a n g e s i n d u c e d i n a f l o r a by h e r b i v o r y . T h e s e i n c l u d e : s e l e c t i v e g r a z i n g , t h e i n t e n s i t y o f g r a z i n g , t h e f r e -q u ency o f g r a z i n g and t h e s e a s o n o f use. The r o l e o f s e l e c t i v e g r a z i n g , as a s i n g l e f a c t o r i n f l u e n c i n g p l a n t c ommunity d y n a m i c s , i s n o t c l e a r a n d o f t e n c a n n o t be s e p a r a t e d f r o m t h e s e o t h e r f a c t o r s (Heady 1964; A n d e r s o n 1977). Indeed, A n d e r s o n (1977) s t a t e d t h a t " t r u e d i e t s e l e c t i v i t y p r o b a b l y t a k e s p l a c e o n l y u n d e r n a t u r a l , u n c r o w d e d c o n d i t i o n s where t h e p l a n t community i s a b u n d a n t l y i n e x c e s s o f t h a t needed t o p r o v i d e f o r a g e f o r t h e h e r b i v o r e and where t h e h e r b i v o r e i s f r e e t o roam d a i l y and s e a s o n a l l y , t h e r e b y d e m o n s t r a t i n g i t s p r e f e r e n c e f o r p l a n t s p e c i e s , p l a n t c o m m u n i t i e s and p h y s i c a l a r e a s " . A n d e r s o n (1977) s u g g e s t e d t h a t t h e f o l l o w i n g e f f e c t s m i g h t r e s u l t f r o m s e l e c t i v e g r a z i n g i n p l a n t c o m m u n i t i e s : 1. Changes i n f l o r i s t i c c o m p o s i t i o n . 2. R e d u c t i o n s i n f o l i a g e c o v e r . 3. R e d u c t i o n i n f o r a g e p r o d u c t i o n . 4. R e d u c t i o n i n r o o t g r o w t h and p r o d u c t i o n . 5. Change i n p l a n t g r o w t h f o r m . 6. R e d u c t i o n i n p l a n t v i g o r . 5 7. Changes i n p l a n t p h e n o l o g y . 8. I m p a i r e d r e p r o d u c t i o n and s e e d l i n g s u r v i v a l . 9. R e d u c t i o n o f l i t t e r and m u l c h . 10. Reduced l o n g e v i t y o f p l a n t s . 11. Reduced s t o r a g e o f p l a n t f o o d s . 12. R e d u c t i o n s i n p l a n t r e g r o w t h f o l l o w i n g g r a z i n g . 13. Changes i n n u t r i t i o n a l v a l u e o f f o r a g e c h e m i s t r y . However, i t i s l i k e l y t h a t t h e s e c h a n g e s more a p p r o p r i a t e l y s h o u l d be a t t r i b u t e d t o t h e e n t i r e g r a z i n g i n f l u e n c e i n c l u d i n g b o t h t h e p h y s i c a l and d e f o l i a t i n g e f f e c t s o f t h e a n i m a l ' s p r e -s e n c e . The s p e c i f i c i m p a c t o f any s p e c i e s o f g r a z i n g a n i m a l on a p l a n t c ommunity w i l l v a r y d e p e n d i n g upon t h e p l a n t s p e c i e s p r e s e n t , t h e s i t e , and t h e i n t e n s i t y , f r e q u e n c y and s e a s o n t h a t f o r a g e s a r e u s e d (Heady 1975). S u r p r i s i n g l y l i t t l e i s known a b o u t t h e r e l a t i o n s h i p b e t w e e n g r a z i n g by Nor (th A m e r i c a n u n g u l a t e s and t h e i r s u b s e q u e n t i m p a c t on t h e i r own h a b i t a t s . A f t e r r e v i e w i n g more t h a n 150 p a p e r s on t h i s t o p i c , A n d e r s o n (1977) c o n c l u d e d t h a t " a l t h o u g h c o n s i d e r -a b l e work has b e en done on w i l d h e r b i v o r e d i e t s and r e l a t i n g them t o v e g e t a l t y p e s , h a b i t a t s and e c o l o g i c a l c o n d i t i o n s , o r i n t e n s i -t i e s o f g r a z i n g , t h e r e a p p a r e n t l y has been l i t t l e o r n o t h i n g done t o r e l a t e w i l d h e r b i v o r e d i e t s e l e c t i v i t y t o t h e d y n a m i c s o f t h e p l a n t community". C e r t a i n l y t h i s g e n e r a l i z a t i o n h o l d s i n t h e c a s e o f m o u n t a i n sheep. A l t h o u g h s e v e r a l s t u d i e s , o v e r a w i d e g e o g r a p h i c a r e a , s u g g e s t t h a t b i g h o r n s h e e p g r a z e s e l e c t i v e l y f o r b o t h p l a n t s p e c i e s and p l a n t p a r t s (Russo 1954; Deming 1964; B l o o d 1967), l i t t l e q u a n t i t a t i v e d a t a a r e a v a i l a b l e r e l a t i n g d i e t and g r a z i n g t o p l a n t c o m m unity d y n a m i c s . T h i s i s p a r t i c u l a r l y t r u e f o r C a l i f o r n i a b i g h o r n sheep. 6 2.1 Bighorn Sheep Food Habits and Select ive Grazing Russo (1954) stated "sheep habitats i n North America vary more than for any other animal" . This i s not surpr i s ing since bighorn sheep are d i s t r ibu ted from Alaska to Mexico and occupy habitats from sea leve l to a lp ine throughout t h i s d i s t r i b u t i o n . As a r e s u l t , mountain sheep demonstrate an amazingly broad eco-l o g i c a l amplitude i n the i r d ietary habi ts . Todd (1972b) de-scribed Rocky Mountain sheep d ie t as "cosmopolitan" and c i t e d E l l i s (1941) who concluded that th i s species would eat almost every plant ava i lab le at one time or another. 2.11 D i v e r s i t y and Composition of Bighorn Sheep Diets Several studies have demonstrated the d ietary d i v e r s i t y of bighorn sheep throughout the i r North American d i s t r i b u t i o n and elsewhere. Appendix 1 summarizes the d i v e r s i t y of Rocky Mountain, desert (Ovis canadensis ne lson i ) , C a l i f o r n i a and Russian bighorn (Ovis n iv ico la ) d ie ts by forage c lass and the t o t a l species reported consumed. Unfortunately, general izat ions are somewhat dubious since methods of data c o l l e c t i o n , periods over which the data were c o l l e c t e d , and the in tens i t y of sampling var ies considerably among studies. From the data presented i n Appendix 1, forbs general ly con-t r ibuted the largest number of species represented i n Rocky Moun-t a i n sheep d ie ts fol lowed by grasses and then browse. Chernyav-s k i i (1967) reported a s i m i l a r trend for Ovis n i v i c o l a i n Russia. In contrast , Jones et a l . (1957), Deming (1964) and Brown et a l . (1977) showed browse provided the greatest number of species i n 7 d e s e r t b i g h o r n d i e t a l t h o u g h Yoakum (1964) f o u n d f o r b s d o m i n a n t i n a Nevada s t u d y . A p p e n d i x 2 l i s t s f o r a g e p l a n t s i d e n t i f i e d i n C a l i f o r n i a b i g -h o r n d i e t s f r o m C a l i f o r n i a t o B r i t i s h C o l u m b i a . Two h u n d r e d and t h i r t y two s p e c i e s have been r e c o r d e d c o n s i s t i n g o f 42 g r a s s e s / g r a s s l i k e , 128 f o r b s and 62 s h r u b s . The number o f r e p r e s e n t a -t i v e g e n e r a i n t h e i r d i e t f o l l o w s a s i m i l a r t r e n d ( T a b l e 1). Hansen (1982) r e p o r t e d t h e l a r g e s t number o f s p e c i e s consumed by an i n d i v i d u a l p o p u l a t i o n w i t h 88 t a x a r e p r e s e n t e d i n t h e a n n u a l d i e t i n Nevada. Drewek (1970) l i s t e d 44 s p e c i e s p r e s e n t i n t h e summer d i e t o f C a l i f o r n i a b i g h o r n i n Idaho. In B r i t i s h C o l u m b i a , 87 s p e c i e s have been o b s e r v e d as f o o d i t e m s c o n s i s t i n g o f 17 g r a s s e s , 44 f o r b s and 26 s h r u b s . Numerous s t u d i e s q u a n t i f i e d t h e p e r c e n t c o m p o s i t i o n o f b i g -h o r n d i e t . D i e t d e t e r m i n a t i o n t e c h n i q u e s v a r i e d f r o m e x a m i n a t i o n o f a s i n g l e o r few rumens ( B a r r e t t 1964; H i c k e y 1978) o r a few days f i e l d o b s e r v a t i o n (Cowan 1947) t o d e t a i l e d m o n t h l y and s e a s o n a l d e s c r i p t i o n s (Todd 1972b; C o n s t a n 1972; J o h n s o n 1975; S t e w a r t 1975). F u r t h e r , methods o f d a t a c o l l e c t i o n a l s o v a r i e d f r o m stem c o u n t s , snow t r a i l i n g , e x a m i n a t i o n o f f e e d i n g s i t e s , o b s e r v a t i o n s f r o m t r a n s e c t s , d i r e c t o b s e r v a t i o n s o f a n i m a l s t o rumen and f e c a l a n a l y s e s , t h u s m a k i n g c o m p a r i s o n s and g e n e r a l -i z a t i o n s d i f f i c u l t . A p p e n d i x 3 s u m m a r i z e s p e r c e n t d i e t c o m p o s i t i o n o f g r a s s e s , f o r b s and s h r u b s f o r p o p u l a t i o n s o f Rocky M o u n t a i n , d e s e r t and C a l i f o r n i a b i g h o r n s . F o l l o w i n g an e x t e n s i v e r e v i e w o f t h e l i t e r -a t u r e , Todd (1972b) c o n c l u d e d t h a t , i n g e n e r a l , g r a s s e s ( i n c l u d -8 Table 1. Total number of genera and species recorded i n C a l i f o r n i a bighorn sheep d ie ts throughout t h e i r North American d i s t r i b u t i o n Forage Class Number of Genera Number of Species Grass/Grassl ike 10 42 Forbs 77 128 Shrubs 32 62 Total 127 232 9 i n g s e d g e s and r u s h e s ) c o m p r i s e d t h e most i m p o r t a n t f o r a g e c l a s s f o r Rocky M o u n t a i n and C a l i f o r n i a b i g h o r n w h i l e , t r e e s and s h r u b s a r e t h e m a j o r f o o d i t e m s f o r d e s e r t b i g h o r n . However, A p p e n d i x 3 s u g g e s t s t h a t , w h i l e g r a s s e s o f t e n a r e p r e d o m i n a n t d i e t a r y i t e m s , t h e p e r c e n t c o m p o s i t i o n o f f o r b s and s h r u b s , as i n d i v i d u a l g r o u p s o r c o m b i n e d , o f t e n e q u a l o r s u r p a s s t h a t o f g r a s s e s . A d d i t i o n a l -l y , t h e r e i s c o n s i d e r a b l e v a r i a t i o n i n t h e r e l a t i v e p r o p o r t i o n s t h a t e a c h o f t h e s e f o r a g e c l a s s e s c o n t r i b u t e t o b i g h o r n d i e t among p o p u l a t i o n s , and even w i t h i n s u b s p e c i e s o f m o u n t a i n sheep. S u m m a r i z i n g d a t a f r o m A p p e n d i x 3, T a b l e 2 d e m o n s t r a t e s b o t h t h e v a r i a t i o n among m o u n t a i n s h e e p s u b s p e c i e s i n t h e i r d i e t com-p o s i t i o n f o r d i f f e r e n t f o r a g e c l a s s e s and t h e e x t r e m e s r e p o r t e d i n i n t a k e o f i n d i v i d u a l f o r a g e c l a s s e s w i t h i n e a c h b i g h o r n r a c e . T hese d a t a s u g g e s t t h a t d e s e r t b i g h o r n show l e s s d i e t a r y v a r i a -t i o n among f o r a g e c l a s s e s t h a n e i t h e r Rocky M o u n t a i n o r C a l i f o r -n i a b i g h o r n . F o r g r a s s e s , f o r b s and s h r u b s r e s p e c t i v e l y , t h e r a n g e i n i n t a k e among p o p u l a t i o n s w i t h i n a r a c e e q u a l s 98.0, 59.0 and 88.0; 85.3, 31.7 a n d 94.0; a n d , 92.4, 32.0 a n d 66.3 p e r c e n -t a g e p o i n t s f o r Rocky M o u n t a i n , d e s e r t and C a l i f o r n i a b i g h o r n r e s p e c t i v e l y . P e r h a p s a more a p p r o p r i a t e g e n e r a l i z a t i o n r e g a r d -i n g b i g h o r n d i e t a r y h a b i t s i s t h e i r v a r i a b i l i t y and f l e x i b i l i t y i n a c q u i r i n g a r a t i o n u n d e r a w i d e r a n g e o f h a b i t a t c o n d i t i o n s . E x t r e m e v a r i a t i o n s i n d i e t a r y c o m p o s i t i o n among f o r a g e c l a s s e s a l s o have been d e m o n s t r a t e d among i n d i v i d u a l a n i m a l s w i t h i n a s i n g l e p o p u l a t i o n . H i c k e y (1975) r e p o r t e d a mean p e r c e n t com-p o s i t i o n o f 22.6, 30.3, and 47.1 f o r g r a s s e s , f o r b s and s h r u b s r e s p e c t i v e l y when t h e c o n t e n t s o f 15 Rocky M o u n t a i n s h e e p rumens 10 Table 2. Range i n percent d i e t composition of three forage classes for Rocky Mountain, desert and C a l i f o r n i a bighorn sheep Race F o r a g e C l a s s Range P e r c e n t D i e t L o c a t i o n R e f e r e n c e G r a s s Max Min 98.0 0.0 Montana A l b e r t a P a l l i s t e r (1974) S t e l f o x (1975) Rocky M o u n t a i n F o r b Max Min 86.3 1.0 A l b e r t a Idaho S t e l f o x (1975) H i c k e y (1978) Shrub Max Min 92.4 0.0 Montana C o l o r a d o Brown (1974) B e a r (1978) G r a s s Max Mi n 94.0 35.0 Nevada Nevada B a r r e t t (1964) Brown e t a l . (1977) D e s e r t F o r b Max M i n 32.0 0.3 Nevada Nevada Yoakum (19 64) Brown e t a l . (1977) Shrub Max Min 35.0 3.0 Nevada Nevada Brown e t a l . (1977) B a r r e t t (1964) G r a s s Max Min 94.0 6.0 B.C. C a l i f o r n i a B l o o d (1967) -Jones (1950) C a l i f o r n i a F o r b s Max Min 94.0 0.0 C a l i f o r n i a B.C. J o n e s (1950) Sugden (1961) Shrub Max 66.3 B.C. Sugden (1961) Min 0.0 C a l i f o r n i a J o n e s (1950) 11 were a v e r a g e d o v e r a l l y e a r s , months and h a b i t a t s s a m p l e d i n t h e s t u d y , and 50.7, 10.5 and 38.8 f o r t h e same f o r a g e c l a s s e s when t h e c o n t e n t s o f f o u r C a l i f o r n i a b i g h o r n rumens were a v e r a g e d . However, t h e a b s o l u t e r a n g e i n i n t a k e among t h e Rocky M o u n t a i n sheep e q u a l e d 99.7, 70.5 and 100 p e r c e n t a g e p o i n t s f o r g r a s s e s , f o r b s and s h r u b s r e s p e c t i v e l y . F o r t h e C a l i f o r n i a b i g h o r n , t h e r a n g e was n o t as l a r g e e q u a l i n g 80.3, 25.0 and 79.2 p e r c e n t a g e p o i n t s f o r t h e same t h r e e f o r a g e c l a s s e s . T a b l e 3 compares t h e d i e t a r y c o m p o s i t i o n f r o m t h r e e p a i r s o f b i g h o r n sheep rumens c o l l e c t e d by H i c k e y (1978). V e r y l a r g e d i f f e r e n c e s b e t w e e n t h e p e r c e n t c o m p o s i t i o n o f i n d i v i d u a l a n i m a l d i e t s a r e n o t e d e v e n when c o m p a r i s o n s a r e made on rumens t h a t were c o l l e c t e d i n t h e same y e a r , month and f r o m t h e same v e g e t a -t i o n u n i t . A l t h o u g h d i e t a r y d i v e r s i t y and c o n s i d e r a b l e v a r i a t i o n i n d i e t a r y c o m p o s i t i o n a ppear, common f e a t u r e s o f t h e b i g h o r n f o o d n i c h e , t h e s i g n i f i c a n c e o f t h i s d i v e r s i t y t o a n i m a l n u t r i t i o n and C t o p l a n t community s t a b i l i t y u n d e r p r o l o n g e d g r a z i n g by b i g h o r n sheep r e m a i n s u n e x p l o r e d . 2.12 Seasonal Ose of Forages F o r a g e p r o d u c t i o n and p l a n t m e t a b o l i s m a r e a f f e c t e d g r e a t l y b y t h e t i m e t h a t f o r a g e i s r e m o v e d i n r e l a t i o n t o p l a n t p h e n o -l o g i c a l d e v e l o p m e n t i r r e s p e c t i v e o f t h e l e v e l o f u s e ( J a m i s o n 1963; S t o d d a r t e t a l . 1975). Whether r a n g e s a r e g r a z e d s e a s o n a l -l y o r y e a r r o u n d , g e n e r a l l y t h e most c r i t i c a l p e r i o d f r o m t h e s t a n d p o i n t o f t h e v e g e t a t i o n i s t h e e a r l y g r o w t h p e r i o d a l t h o u g h i n d i v i d u a l s p e c i e s may r e a c t d i f f e r e n t l y t o g r a z i n g ( S t o d d a r t e t Table 3. Range i n percent composition of grasses, forbs, shrubs and conifers ingested by three pairs of rams from three vegetation units i n Idaho (data from Hickey 1978) Percent Rumen Content Month and Year Race Sampled Grass Forb Shrub Conifer Rocky 9-73 0.0 34.6 65.2 0.0 Mountain 9-73 99.7 T 0.0 T Rocky 9-74 54.0 0.0 45.9 0.0 Mountain 9-74 0.0 13.3 86.6 0.0 C a l i f o r n i a 9-73 21.0 27.0 52.0 T 9-73 78.0 10.1 11.8 0.0 T= Trace 13 a l . 1 9 7 5 ) . S e a s o n a l u s e o f f o r a g e s by w i l d u n g u l a t e s r e l a t e s b o t h t o h a b i t a t use and t o f o r a g e s e l e c t i o n w i t h i n s e a s o n a l home r a n g e s . A l t h o u g h many s t u d i e s r e p o r t s e a s o n a l use o f r a n g e s by b i g h o r n , t h e s e movements v a r y c o n s i d e r a b l y among p o p u l a t i o n s . M o r e o v e r , f o r many p o p u l a t i o n s p r e c i s e s e a s o n a l movements o v e r many y e a r s a r e d i f f i c u l t t o d e f i n e b e c a u s e d a t a a r e l a c k i n g a c r o s s a r a n g e o f c l i m a t i c , f o r a g e and o t h e r e n v i r o n m e n t a l f a c t o r s w h i c h m i g h t c o n t r i b u t e t o t h e s e movements. M i g r a t i o n s , o r t h e s e a s o n a l u s e o f d i f f e r e n t p l a n t c o m m u n i t i e s o f t e n s e p a r a t e d by l a r g e d i s t a n c e s (Dasmann 1 9 6 4 ) , p r o v i d e s a mechanism f o r r e s t f r o m g r a z i n g on s p r i n g r a n g e s and d e f e r r m e n t f r o m g r a z i n g on summer r a n g e s . H e b e r t (1973) i n v e s t i g a t e d t h e s i g n i f i c a n c e o f v e r t i c a l m i g r a t i o n s f o r Rocky M o u n t a i n b i g h o r n s h e e p n u t r i t i o n b u t l i t t l e i s known a b o u t how t h e s e movements a f f e c t t h e s t r u c t u r e and f u n c t i o n o f t h e p l a n t community. M i g r a t i o n s a p p e a r common among Rocky M o u n t a i n b i g h o r n h e r d s and have been d e s c r i b e d f o r p o p u l a t i o n s i n A l b e r t a ( G e i s t 1971; J o h n s o n 1975; S t e l f o x 1975), B r i t i s h C o l u m b i a ( H e b e r t 1973; Shannon e t a l . 1975), Montana ( E r i c k s o n 1972; P a l l i s t e r 1974; S t e w a r t 1975), Idaho ( S m i t h 1954; H i c k e y 1976), Oregon ( E b e r t 1978), Wyoming (McCann 1956) and C o l o r a d o (Capp 1967). W i t h i n t h i s s p e c i e s , p o p u l a t i o n s commonly m i g r a t e v a r i a b l e d i s t a n c e s f r o m low e l e v a t i o n w i n t e r r a n g e s t o h i g h e l e v a t i o n summer r a n g e s ( S m i t h 1954; McCann 1956; H e b e r t 1973; Shannon e t a l . 1975; S t e l f o x 1975; H i c k e y 1976; E b e r t 1978) a l t h o u g h P a l l i s t e r (1974) 14 and S t e w a r t (1975) have r e p o r t e d t h e r e v e r s e f o r h e r d s i n Montana. S i m i l a r v e r t i c a l m i g r a t i o n s a l s o have been d e s c r i b e d f o r Stone's sheep ( O v i s d a l l i s t o n e i ) i n B r i t i s h C o l u m b i a ( G e i s t 1971; L u c k h u r s t 1973) f o r D a l l ' s s h e e p ( O v i s d a l l i d a l l i ) i n t h e Yukon (Hoefs 1974), f o r d e s e r t b i g h o r n i n Nevada (Deming 1964), and f o r C a l i f o r n i a b i g h o r n i n B r i t i s h C o l u m b i a ( B l o o d 1961; Sugden 1961; D e m a r c h i 1965). V e r t i c a l m i g r a t i o n s o v e r l o n g d i s t a n c e s a p p e a r l e s s common among p o p u l a t i o n s o f d e s e r t and C a l i f o r n i a b i g h o r n . P o p u l a t i o n s o f t h e s e two s u b s p e c i e s t y p i c a l l y move h o r i z o n t a l l y (Russo 1954; Drewek 1970), s e a s o n a l r a n g e s a r e n o t c l e a r l y d e f i n e d o r o v e r -l a p p e d (Brooks 1923; J o n e s 1950; J o n e s e t a l . 1957; Sugden 1961; M o r r i s o n 1972; S c h e f f l e r 1972; Van Dyke 1978; K o r n e t 1978; Ramsey 1980) o r t h e p o p u l a t i o n s a r e c o n s i d e r e d " r e s i d e n t " u s i n g t h e same h a b i t a t a l l y e a r r o u n d o r f o r some p o r t i o n o f e a c h s e a s o n (Sugden 1961; S p a l d i n g and Bone 1969; D e m a r c h i 1970; D e m a r c h i and M i t c h e l l 1973). P o p u l a t i o n s o f b i g h o r n sheep t h a t r e m a i n r e s i d e n t on a p l a n t c ommunity y e a r r o u n d , o r t h o s e t h a t r e t u r n t o t h e same h a b i t a t t h r o u g h o u t t h e g r o w i n g s e a s o n , may i n f l u e n c e p l a n t g r o w t h and p r o d u c t i o n d i f f e r e n t l y t h a n o t h e r p o p u l a t i o n s t h a t m i g r a t e . V a r i a t i o n s i n f o r a g e s e l e c t i o n by b i g h o r n sheep w i l l l i k e l y be a more i n f l u e n t i a l f a c t o r a f f e c t i n g t h e p l a n t c o m m unity i n r e s i d e n t p o p u l a t i o n s t h a n i n h a b i t a t s where b i g h o r n m i g r a t e b e c a u s e a n i m a l s have t h e o p p o r t u n i t y t o g r a z e p l a n t s a t d i f f e r e n t g r o w t h s t a g e s t h r o u g h o u t t h e i r p h e n o l o g y . 15 Figure 1. Locations of C a l i f o r n i a bighorn sheep bands i n the south Okanagan, B r i t i s h Columbia (from Spalding and Bone 1969) and the Okanagan Game Farm study s i t e . 16 Few studies evaluated u t i l i z a t i o n of ind i v idua l forage species or forage classes w i th in bighorn sheep seasonal home ranges. Todd (1972a) studied seasonal food habits of Rocky Mountain bighorn i n Colorado. Grasses, forbs and shrubs averaged 46, 9 and 45% of the year ly d ie t respect i ve ly , but considerable v a r i a t i o n was observed between seasons w i th in each forage c l a s s . Grasses ranged from 22.7% i n winter to 64.9% i n summer, forbs 2.7% i n f a l l to 10.7% i n winter , and shrubs 29.4% i n summer to 66.5% i n winter . S i m i l a r var ia t ions i n seasonal use of forage classes were reported by Smith (1954), P a l l i s t e r (1974), Johnson (1975) and Bear (1978) for Rocky Mountain bighorn i n Idaho, Montana, Alberta and Colorado respect i ve ly , and by Barrett (1964) for desert bighorn in Nevada. None of these studies re lated seasonal forage use to plant species a v a i l a b i l i t y or to plant community dynamics, however. Only Blood (1967) and Drewek (1970) reported seasonal food habits for C a l i f o r n i a bighorn i n B r i t i s h Columbia and Idaho respect ive ly . Blood (1967) showed that the percent grass com-p o s i t i o n i n the d i e t v a r i e d from 64% i n w in te r to 94% i n s p r i n g whi le the proportion of forbs i n the d ie t remained approximately constant at 4 and 3% respect ive ly during the same seasons. The composition of shrubs decl ined from 32% i n winter to 3% i n spring with most of the winter browse cons is t ing of f r inged sage (Artemisia f r i g i d a ) 2 . Drewek (1970) d id not assess d ie t composition but h is data 2. Botanical nomenclature a f te r Hitchcock and Cronquist (1978) or as c i t e d by a quoted author. 17 demonstrated that ove ra l l species d i v e r s i t y increased from nine to 44 species between winter and summer respect ive ly . S i m i l a r increases i n the number of grasses, forbs and shrubs were noted between seasons as wel l ( Appendix 1). More recent ly Hansen (1982) studied C a l i f o r n i a bighorn d iet by spec ies and forage group over a 12 month per iod i n Nevada (Appendix 3). Averaged over a l l months, grasses, forbs and shrubs equaled 42.2, 40.0 and 13.7% of the d i e t . Grass and forb use were inverse ly re lated with the highest intake of grasses occurr ing i n the f a l l and winter grazing period and the lowest i n spring and summer. Shrubs were browsed at about the same leve l in a l l months although s l i g h t peaks were recorded i n August, September and December equaling 19.0, 20.0 and 23.0% of the t o t a l d ie t i n each month respect i ve ly . Although t h i s study presented the most deta i led d ietary information for C a l i f o r n i a bighorn a v a i l a b l e , seasonal d ie t and forage u t i l i z a t i o n were not d i s -cussed i n r e l a t i o n to how these grazing patterns af fected short and long term plant species a v a i l a b i l i t y for the populat ion. Morrison (1972) provided some evidence of the potent ia l e f fec ts that C a l i f o r n i a bighorn may have on the i r own habitat by repeated use of the same plant community i n d i f f e r e n t seasons. Although a major port ion of the Ashnola herd i s considered migratory (Blood 1961; Demarchi 1965), he concluded " i t appears as though grazing by bighorn during the spring and summer i s the major b i o t i c factor a f f e c t i n g the amount of forage ava i lab le to winter ing bighorn. This i s espec ia l l y true of the bighorn which spend the major i ty of the summer on South Slope and u t i l i z e the 18 bunchgrass from the r idge areas important for winter ing bighorn". The long term e f f e c t s of t h i s g r a z i n g behavior on the p l a n t community was not evaluated however. 2-13 Forage S e l e c t i v i t y Todd (1972b) concluded that plant se lec t ion by bighorn i s re lated to forage a v a i l a b i l i t y and the type of habitat u t i l i z e d by the animal but few studies have monitored both forage and habitat factors together for most populations of mountain sheep. S i m i l a r l y , l i t t l e work has invest igated the underlying mechanisms a f f e c t i n g se lec t ion of one forage species over another at any leve l of food s e l e c t i o n . Oldemeyer et a l . (1971) ca lcu lated forage preference indices for 19 grassland plant species on three Montana Rocky Mountain bighorn ranges. Indices were determined for each taxa by d i v i d i n g percent d ie t composition by the percent cover on the range. Agropyron spicatum, the main forage species accounting for 24.5% of the t o t a l observations, var ied i n preference index from 0.7 at MacMinn Bench to 2.3 and 3.7 for Specimen Ridge and Druid Peak respect i ve ly . Other than Carex sp. , which had a preference index of 3.3, a l l other grasses and graminoids had preference rat ings less that 3.0. Those species with the highest p re fe r -ence indices were Lupinus sp. wi th rat ings of 27.0 and 22.5 at Specimen Ridge and Druid Peak respect i ve ly , and Eurot ia lanata at 5.5. Stewart (1975) determined forage preference indices for 31 plant species on spring and winter Rocky Mountain sheep habitats i n Montana. Preference indices were ca lcu lated i n t h i s study by 19 d i v i d i n g the percent "instances of use" of i nd i v idua l species at feeding s i t e s i n a habitat type by the percent canopy coverage of the same taxa i n tha t type. No c o n c l u s i o n s were drawn by the author regarding forage c lass or i nd i v idua l species p re fe r -ences. However, h is data revealed that out of the eight habitats i d e n t i f i e d , grasses and graminoids exceeded a preference ra t ing of 2.0 i n only one instance. On t h i s s i t e the preference index was 8.4 but the forage group was dominated by Carex and Agropyron  spicatum with indices of 12.0 and 7.0 respect i ve ly . Agropyron  spicatum did not exceed 2.0 on any other habi tat type. As a group, forbs had a maximum preference index of 8.0 and exceeded 3.0 on only one other habi tat type. Preference rat ings greater that 3.0 occurred on three of eight s i t e s for shrubs with a maximum ra t ing of 40.6 on a winter habitat dominated by Agro- pyron spicatum. Ar temis ia t r identa ta had an ind i v idua l p re fe r -ence index of 46.4 on t h i s s i t e . Other species with indices greater than 10.0 included Prunus v i rg in iana (29.0, 24.1, 30.6) and Artemis ia ludoviciana (20.0 and 36.8). Grasses with the highest preference rat ings included: Calamovi l fa l o n g i f o l i a (4.8 and 8.0), Festuca idahoensis (6.8) and St ipa comata (6.3) (Stewart 1975). Ste l fox (1975) evaluated forage preferences for eight grasses, s i x forbs and three shrubs on each of s i x Rocky Mountain bighorn winter ranges i n A lber ta . He concluded that none of the forage c lasses were preferred by the bighorn with average indices of 0.76, 0.43 and 0.63 for the three groups respect ive ly . Calamagrostis sp. received the highest ind i v idua l preference 20 ra t ing of 8.7 on the Sulfur winter range and Agropyron sp. was rated at 4.4 on the Disaster range. A l l other indices for grasses were less than 2.0 except for Calamagrostis sp. on the Ruby range. Other than Aster sp. on the Sulfur range which had a preference index of 6.6, i nd i v id ua l indices for forbs never exceeded 2.0. A s i m i l a r trend was noted for shrubs although P o t e n t i l l a f r u i t i c o s a rated 5.5 and 2.9 on the Sulfur and Disaster ranges respect i ve ly . Although Yoakum (1964) co l lec ted both d ie t and botanical data on the S i l v e r Peak range in Nevada, he d id not ca lcu la te forage preference indices or re la te d ie t to plant species a v a i l -a b i l i t y . Percent composition of desert bighorn d ie t was 59.5, 32.0 and 8.5 for grasses, forbs and shrubs respect i ve ly . Corres-ponding values for the range composition for these forage classes were 22.0, 4.0 and 74.0%. Div id ing percent d ie t by percent com-pos i t ion of the range y ie lds preference indices of 2.7, 8.0 and 0.01 for grasses, forbs and shrubs respect ive ly . Forage preferences have not been determined for any popula-t i on of C a l i f o r n i a bighorn. Based on a l i t e r a t u r e review, Singleton (1976) reported r e l a t i v e forage preference values for 13 plant species that occur on a number of C a l i f o r n i a bighorn ranges i n B r i t i s h Columbia. Species were c l a s s i f i e d into f i v e categories ranging from high to low. Agropyron spicatum was considered the only h ighly preferred species, Ar temis ia f r i g i d a was c l a s s i f i e d as medium and a l l other species were placed i n the medium-low or low categor ies. The c r i t e r i a for t h i s c l a s s i f i c a -t i o n were not c l e a r l y ou t l ined , however. 21 A d iscussion of the mechanisms and motivating factors under-l y ing forage se lec t ion are beyond the scope of t h i s review. Detai led reviews of t h i s process are presented by several authors (Tribe 1950; Cowlishaw and Alder 1960; Heady 1964; Arnold and H i l l 1971; E l l i s et a l . 1976). Although forage q u a l i t y was measured on bighorn sheep ranges i n several studies (McCullough and Schneegas 1966; Demarchi 1968; Demarchi 1970; Hebert 1973; Johnson 1975; Stewart 1975; Ste l fox 1975; Shannon et a l . 1975) few of them re lated n u t r i t i v e qua l i t y to forage s e l e c t i o n . Add-i t i o n a l l y , the l i t t l e data that are ava i lab le are c o n f l i c t i n g . For example, Shannon et a l . (1975) re lated forage qua l i t y to animal d i s t r i b u t i o n over f i v e periods for Rocky Mountain bighorn i n the East Kootenay Region of B r i t i s h Columbia. Based on both simple and mul t ip le regressions they concluded that mountain sheep d i s t r i b u t i o n was negatively corre lated with plant nitrogen content for a l l periods. Moreover, the highest and the only s t a t i s t i c a l l y s i g n i f i c a n t co r re la t ion occurred i n the November-December period when the sheep were on low e levat ion winter range. S i m i l a r l y , Johnson (1975) measured forage qua l i t y for 17 Rocky Mountain bighorn summer d ie t species i n Alberta concluding that " d i s t i n c t preferences were frequently observed even when there was l i t t l e apparent d i f ference between species i n chemical composition or stage of growth". In Montana, Stewart (1975) indicated that Agropyron  spicatum, which he considered as one of the most important winter forages for Rocky Mountain bighorn sheep i n the area, had the lowest nitrogen content of any of the species sampled. However, t 22 during the winter "sheep selected bluegrasses and fr inged sage-wort, which remained somewhat green a l l winter" as we l l as "the more n u t r i t i o u s terminal buds of chokecherry" suggesting that bighorn were se lec t ing plant species on the basis of n u t r i t i o n a l propert ies . Other studies postulated that sheep prefer succulent green mater ia l as w e l l (Capp 1967; Todd 1972b; Ste l fox 1975) but no quant i tat ive data were presented to v e r i f y t h i s re la t ionsh ip . 2.2 Impacts of Bighorn Sheep on Vegetation Very l i t t l e research has focussed on the inf luence of e i ther phys ical or grazing impacts by bighorn on vegetat ion. Honess and Frost (1942), Jones (1950), Simmons (1961; c i t e d in Todd 1972b) and Deming (1964) a l l reported bighorn pawing and ingest ing ent i re plants whi le grazing. Further physical in jury to i n d i -v idual plants also may occur when bighorn paw through snow for forage in winter and as a r e s u l t of "horning" on shrubs, bunch-grasses and small trees (Geist 1971). 2.21 E f fec ts of Grazing on Indiv idual Plants There i s some evidence suggesting that frequent and repeated use of i nd i v idua l plants and areas by mountain sheep may nega-t i v e l y a f fec t vegetat ion. McCann (1956) postulated that sheep on winter range may re-graze heavi ly grazed forage plants i n order to avoid deep snow i n adjacent areas. In h is Wyoming study, he observed that forage was u t i l i z e d to w i t h i n 1.27 cm of the ground on one s i t e a f te r prolonged use on the area. At a second l o c a -t i o n , an undisclosed number of sheep remained on an area "not more than s i x acres . . . .as la te as February 21, 1939, having been 23 a source of forage since the previous f a l l " (McCann 1956). Ste l fox (1975) measured forage u t i l i z a t i o n on four bighorn sheep ranges i n southern A lber ta . Average u t i l i z a t i o n of a l l vegetation equaled 47% but use on preferred forages was reported c loser to 75-100%. On three spring ranges, t o t a l forage u t i l i z a -t i on equaled 59, 63 and 48.2% respect ive ly and he concluded that "the damage to these ranges was....not so much the 57% forage u t i l i z a t i o n as the repeated use of the same ranges during May and June". Few studies have documented browse u t i l i z a t i o n by bighorn sheep although shrubby species can be used extensively on some bighorn ranges. For example, Smith (1954) reported that Rocky Mountain sheep i n Idaho u t i l i z e d 60% of the annual growth on Purshia t r identa ta and 96% of the tagged plants were browsed. S i m i l a r leve ls of use were recorded on Cercocarpus l e d i f o l i u s , Ar temis ia t r i d e n t a t a , F o r s e l l e s i a spinescens and Chrysothamnus  nauseosus with u t i l i z a t i o n equaling 60, 66, 71 and 72% for each species respect i ve ly . Deming (1964) noted intensive browsing on a desert bighorn summer range and commented that "the l i m i t e d amount of blueberry elder (Sambucus caerulea) on the Sheep Range i s so heavi ly grazed during the summer that i t seldom at ta ins more than a low shrubby growth". In C a l i f o r n i a , McCullough and Schneegas (1966) found that u t i l i z a t i o n of Purshia t r identa ta and I\_ glandulosa by C a l i f o r n i a bighorn equaled 22.5% on a S ie r ra Nevada winter range. No studies have quant i f ied u t i l i z a t i o n on Amelanchier a l n i f o l i a by bighorn sheep. 24 2.22 E f fec ts of Bighorn D i s t r i b u t i o n and Grazing on Plant Communities S e v e r a l a u t h o r s p o s t u l a t e d t h a t l o c a l o v e r g r a z i n g by m o u n t a i n sheep may be p o s s i b l e (Sugden 1961; S t e l f o x 1971; M o r r i s o n 1972; E b e r t 1978). F o r ex a m p l e , E b e r t (1978) s t a t e d : " P o p u l a t i o n c o n -t r o l and p r o p e r r a n g e management a r e more i m p o r t a n t i n t h e man-agement o f b i g h o r n s h e e p t h a n any o t h e r a n i m a l . The t r a d i t i o n a l h a b i t s o f w i n t e r i n g i n s p e c i f i c a r e a s i s so imbedded i n t h e s e a n i m a l s t h a t t h e y w i l l o f t e n o v e r u s e a t r a d i t i o n a l r a n g e w h i l e a d r a i n a g e o r two away good f o r a g i n g e x i s t s . . . . B l u e b u n c h w h e a t g r a s s i s t h e p r e f e r r e d p e r e n n i a l g r a s s f o u n d on a l l good w i n t e r r a n g e s a l t h o u g h o t h e r p e r e n n i a l g r a s s e s and f o r b s a r e u s e d t o a l e s s e r d e g r e e . O v e r g r a z e d r a n g e s e v e n t u a l l y l o s e t h e b u n c h g r a s s s t a n d s and a n n u a l g r a s s e s and f o r b s t a k e o v e r . When t h i s happens she e p numbers d e c l i n e u n t i l t h e r a n g e has r e c o v e r e d " . Numerous r e p o r t s c o n f i r m t h a t m o u n t a i n s h e e p d e m o n s t r a t e a h i g h d e g r e e o f f i d e l i t y f o r home r a n g e s , b e d d i n g g r o u n d s and e s c a p e t e r r a i n ( S m i t h 1954; Sugden 1961; D e m a r c h i , 1970; Oldemey-e r e t a l . 1971; Todd 1972b; G e i s t 1971; E r i c k s o n 1972; P a l l i s t e r 1974; Shannon e t a l . 1975; K o r n e t 1978; Hansen 1982) and t h a t t h e s e s o c i a l p a t t e r n s may a f f e c t g r a z i n g b e h a v i o r . F o r example, O l d e m e y e r e t a l . (1971) r e p o r t e d t h a t Rocky M o u n t a i n b i g h o r n i n Montana g e n e r a l l y r e m a i n e d w i t h i n 91.44 m o f e s c a p e t e r r a i n and t h a t 75% o f t h e f e e d i n g a c t i v i t i e s o c c u r r e d w i t h i n t h i s d i s t a n c e . I n t w o o t h e r M o n t a n a s t u d i e s . , 66% o f t h e s h e e p o b s e r v e d a t Sun R i v e r ( E r i c k s o n 1972) and 98, 84 and 44% o f t h o s e o b s e r v e d i n summer, f a l l and w i n t e r r e s p e c t i v e l y i n t h e B e a r t o o t h M o u n t a i n s 25 were w i t h i n 137.2 m and never f a r t h e r than 800 m from escape t e r r a i n i n any season ( P a l l i s t e r 1974). Hansen (1982) reported s i m i l a r observations for C a l i f o r n i a bighorn i n Nevada. Woolf et a l . (1970), Todd (1972a) and Kornet (1978) a l l reported mountain sheep regu lar l y returning to establ ished bed-ding grounds and that often the sheep grazed in tens i ve l y before bedding down. S i m i l a r l y , the presence of standing water a lso may inf luence bighorn d i s t r i b u t i o n espec ia l l y i n very dry areas (Jones et a l . 1957; Buechner 1960; Todd 1972b) concentrating grazing c lose to the water source (Russo 1954; Jones et a l . 1957). However, i n moister locat ions , where free water i s more read i l y ava i lab le or forage i s lush , standing water may not a f fec t grazing behavior subs tan t ia l l y (Sugden 1961). The inf luence of bighorn sheep density on vegetation has been addressed i n the l i t e r a t u r e although there i s l i t t l e quant i ta t i ve information ava i lab le r e l a t i n g the two. Ste l fox (1971), described h i s t o r i c a l f luc tuat ions of Rocky Mountain bighorn i n Alberta and B r i t i s h Columbia, concluding that numbers were not s t a t i c even i n p r i s t i n e t imes. He argued that population dens i t ies cycled over a 170 year period with ranges deter io ra t ing when population leve ls were high. Sugden (1961) maintained that population f luc tuat ions "are the ru le" for C a l i f o r n i a bighorn i n B r i t i s h Columbia. He speculated that the combined e f fec t of t r a d i t i o n a l range use and high dens i t ies of mountain sheep h i s t o r i c a l l y resul ted i n l o c a l range deter io ra t ion and may have l i m i t e d su i tab le winter range which could not support herds i n the winter . 26 2.23 Evaluat ion of Mountain Sheep Range Condit ion Although range surveys have been undertaken on a number of bighorn ranges (Smith 1954; Yoakum 1964; Capp 1967; Drewek 1970; Schef f ler 1972; Ste l fox and Spalding 1974; Ste l fox 1975), i n each case the s p e c i f i c impacts of bighorn grazing were confounded with u t i l i z a t i o n by domestic l i vestock and/or by other w i l d l i f e species. Range condit ion c lasses such as "exce l lent" , "good", " f a i r " , and "poor" a lso have been used to describe bighorn range (Stelfox and Spalding 1974; Ste l fox 1975). However, the c r i t e r i a to assess mountain sheep range condit ion are cur rent ly lacking and, as Ste l fox (1975) suggested, "the use of plant composition to evaluate sheep range requires d i f f e r e n t c r i t e r i a from those developed^ on c a t t l e ranges". Currently no data are ava i lab le to predict the response to grazing of ind i v idua l plant species or of the plant community i n any habitat type used by bighorn sheep. 27 3 . LOCATION, HISTORY AND DESCRIPTION OF THE STUDY AREA The study s i t e i s l o c a t e d at the Okanagan Game Farm, 10 km south of Pent icton, B r i t i s h Columbia on the west side of Skaha Lake (Figure 1). The experimental pasture l i e s w i th in the game farm and, p r io r to the release of the sheep, i t had received only in te rmi t tent l i g h t grazing by horses for 13 years. The s i t e i s t y p i c a l range for C a l i f o r n i a bighorn sheep i n the south Okanagan and the area formal ly supported bands of w i l d sheep (Sugden 1961). Indeed, during the study a s ing le w i l d ram approached the exc losure i n the f a l l of 1978 and as r e c e n t l y as September 1980 a band of s i x b ighorn rams was s i g h t e d i n the v i c i n i t y of the study pasture ( B o t t r e l l , pers. comm.). 3 .1 Geomorphology and S o i l s The southern end of the Okanagan Val ley i s underlain by a complex assemblage of rock formations (Kelly and Spi lsbury 1949). Dating to the lower Paleozoic and/or pre-Cambrian e ra , rocks i n the region are highly metamorphosed and f i v e phases of deforma-t i o n have been i d e n t i f i e d i n the mult i layered beds (Kel ler 1977). U p l i f t i n g of the Ter t iary erosion surface i s a dominant feature of the ent i re In ter io r Plateau and i s p a r t i c u l a r l y con-spicuous on the eastern margin i n the Okanagan highlands (Ryder 1978). During the ear ly Pleistocene the ent i re region was over-l a i n with i c e . As a r e s u l t of g l a c i a l eros ion, prominent features throughout the Okanagan are rounded mountain tops and ridge crests with steep-sided v a l l e y s . Down wasting of the stagnant Wisconsin ice i n the late Pleistocene l e f t a mantle of g l a c i a l d r i f t over the e n t i r e 28 surface of the In te r io r Plateau. In the Okanagan, the g l a c i a l ret reat was accompanied by the formation of g l a c i a l lake Penticton and l a t e r , outwash and l a t e r a l moraines (Kel ler 1977). Most s o i l s i n the Okanagan were derived from t h i s g l a c i a l t i l l which was car r ied to lower e levat ions and sorted with the act ion of water (Kelly and Spi lsbury 1949). S o i l s i n the immediate area of the Okanagan Game Farm were c l a s s i f i e d and described by Ke l l y and Spi lsbury (1949) as brown chernozems i n the Skaha Gravel ly Sandy Loam ser ies . The solum i s t y p i c a l l y brown to l i g h t brown sandy loam and approximately 45.7 cm deep. G e n e r a l l y the lower par t of the solum c o n s i s t s of a matrix of stones but the gravel and stone composition var ies from one locat ion to another (Kelley and Spi lsbury 1949). S o i l s on the immediate study area are var iab le but i n general they are shallow and course textured with bedrock often protruding. 3.2 Phys ica l Features The study area i s var iab le i n aspect, slope and e levat ion (Figure 2, Figure 3). Concave i n shape, some parts of the 42 ha s i t e are north fac ing whi le others have a more easter l y exposure. Generally the topography i s steep s lop ing , although the upper 8-10 ha i s undulating but mostly f l a t . Five deep g u l l i e s d issect the s i t e ; four from top to bottom. E levat ion i s var iab le and ranges from 550 m to a maximum of 750 m. 3.3 Climate Lying i n the rainshadow of the Coast and Cascade Mountains, low e levat ion va l l ey bottoms i n the south Okanagan are s e m i - a r i d . Figure 3. View of the upper 10 ha of the Okanagan Game Farm study s i t e . 30 Chapman (1952) described the c l imate as Middle Lat i tude Steppe (BSk) by the Koppen c l a s s i f i c a t i o n . Summaries of p r e c i p i t a t i o n , temperatures and absolute extremes are presented i n Table 4, Table 5 and Table 6, respect ive ly . Normal mean annual p r e c i p i t a t i o n at Penticton a i r p o r t , 6 km north of the research s i t e , i s 296.2 mm (Table 4). Moisture d i s -t r i b u t i o n i s bimodal with peaks i n December-January and May-June. Maximum p r e c i p i t a t i o n f a l l s i n December-January, mostly as snow but years without r a i n during t h i s period are rare . March and September are t y p i c a l l y the d r i e s t months with normal mean monthly t o t a l s of 16.3 and 18.0 mm, respect i ve ly . Both Polar Continental (in winter) and Tropical Continental (in summer) a i r masses are i n f l u e n t i a l in the south Okanagan and resu l t i n extremes of temperature (Chapman 1952). Normal maximums for the hottest months, July and August, are 28.6 and 27.3 ° C respect i ve l y , whi le the normal monthly minimum for the coldest month, January, i s -5 .6 ° C (Table 5). > The absolute extremes on record are a high of 40.6 ° C i n Ju ly , 1941 and a low of -27.2 ° C i n December, 1968 (Table 6). The inf luence of lakes i n the va l l ey bottoms moderates l oca l weather and general ly prevents extreme minimum temperatures i n winter (Chapman 1952). Normal mean annual temperature at Penticton i s 8.8 ° C (Table 5). In addi t ion to hot summers and moderate winters , Penticton enjoys 2001.4 hours of sunshine annually (Environ. Canada 1978). The growing season i s r e l a t i v e l y long with an average annual f ros t free period of 143 days although the range in extremes v a r i e s from a h igh of 172 to a low of 91 days over a 30 year Table 4. Mean monthly rainfall(mm), snowfall(cm) and t o t a l p r e c i p i t a t i o n for 1977, 1978, 1979 and normals, Penticton, B.C. (Source: Annual Meterological Summaries, Environment Canada 1977, 1978, 1979) 1977 - Monthly 1978 - Monthly 1979 - Monthly Normal - Monthly Month Rain Snow Total Rain Snow Total Rain Snow Total Rain Snow Total JAN 11.3 16.9 26.3 5.4 45.9 37.3 0.0 30.0 20.1 8.9 24.9 31.5 FEB 3.9 3.5 7.4 14.6 16.6 26.7 9.0 9.4 13.9 10.4 10.9 20.8 MAR 6.8 11.8 18.2 12.8 0.2 13.0 11.1 T 11.1 12.2 4.6 16.3 APR 14.5 T 15.3 60.4 0.0 60.4 10.5 T 10.5 22.9 0.3 23.1 MAY 61.9 0.0 61.9 21.2 T 21.2 29.2 0.0 29.2 27.7 0.0 27.7 JUN 9.3 0.0 9.3 18.5 0.0 18.5 14.6 0.0 14.6 35.6 0.0 35.6 JUL 19.9 0.0 19.9 26.0 0.0 26.0 28.0 0.0 28.0 24.6 0.0 24.6 AUG 30.5 0.0 30.5 44.9 0.0 44.9 49.2 0.0 49.2 22.4 0.0 22.4 SEP 34.0 0.0 34.0 36.8 0.0 36.8 37.2 0.0 37.2 18.0 0.0 18.0 OCT 2.7 0.0 2.7 2.3 0.0 2.3 27.1 0.0 27.1 19.8 T 19.8 NOV 21.8 9.1 32.6 18.8 3.7 24.3 5.8 T 5.8 19 .3 6.9 25.7 DEC 29.3 33.4 58.3 0.0 18.7 14.3 9.4 23.9 31.0 10.4 21.6 30.5 YEAR 245.9 74.6 316.4 228.7 85.1 325.7 231.6 63.3 278.2 232.2 69.2 296.2 T = Trace Table 5. Mean maximum, minimum and monthly temperatures (° C) f o r 1977, 1978, 1979 and normals, Penticton, B.C. (Source: Annual Meterological Summaries, Environment Canada 1977, 1978, 1979) Month 1977 1978 1979 Normal Max. Min. Month Max. Min. Month Max. M i n . Month Max. M i n . Month JAN -1.4 -6.3 -3.9 0.1 -4.2 -2.1 -5.9 -12.1 -9.0 -0.3 -5.6 -2.9 FEB 5.8 -2.0 1.9 4.1 -2.2 1.0 2.8 -5.3 -1.3 4.0 -3.3 0.3 ' MAR 9.7 -0.4 4.7 10.5 0.4 5.5 11.2 -1.3 5.0 9.0 -1.7 3.7 APR 17.6 2.5 10.1 13.9 3.3 8.6 15.3 0.9 8.1 15.6 1.9 8.9 MAY 18.2 5.8 12.0 19.2 5.9 12.6 21.4 5.8 13.6 20.8 5.9 13.4 JUN 26.4 11.1 18.8 25.5 9.0 17.3 26.3 10.5 18.4 24.5 9.7 17.1 JUL 27.3 11.5 19.4 29.3 13 .1 21.2 29.7 13.1 21.4 27.3 11.2 19.2 AUG 29.0 14.1 21.6 25.8 12.3 19.1 28.7 13.9 21.3 27.3 11.2 19.2 SEP 19.9 7.6 13.8 19.4 8.6 14.0 23.2 9.2 16.2 22.0 7.3 14.7 OCT 14.6 2.3 8.5 15.3 1.5 8.4 16.0 4.6 10.3 14.4 3.1 8.7 NOV 5.6 -1.6 2.0 3.5 -3.2 0.2 4.9 -1.7 1.6 6.4 -0.4 3.1 DEC 0.7 -4.3 -1.8 -0.8 -7.8 -4.3 5.0 -0.8 2.1 2.2 -2.9 -0.4 YEAR 14.5 3.4 8.9 13.8 3.1 8.6 14.9 3.1 9.0 14.5 3.1 8.8 Table 6. Monthly and annual extremes of record for temperature and precipitation, Penticton, B.C. (Source: Annual Meterological Summaries, Environment Canada 1977, 1978, 1979) Monthly Temperature (°C) Monthly P r e c i p i t a t i o n (mm pre c i p . , c m snow) Absol Absol Max. Min. Max. Min. Max. Month Max. Year Min. Year Mean Year Mean Year P r e c i p . Year P r e c i p . Year Snow Year JAN 13.3 1953 -26.7 1950 2.7 1953 -14.3 1950 70.6 1952 3.8 1973 64.8 1952 FEB 15.6 1947 -26.7 1950 4.1 1958 - 5.1 1949 54.4 1949 3.3 1964 51.6 1949 MAR 21.7 1966 -17.8 1955 6.9 1941 0.3 1955 40.9 1958 3.3 1944 22.9 1950 APR 28.9 1957 - 7.2 1968 10.7 1941 5.3 1948 69.6 1948 0.5 1956 4.1 1961 MAY 32.2 1969 - 5.6 1954 17.1 1958 11.1 1955 61.9 1977 4.1 1947 T 1978* JUN 36.7 1961 0.0 1962 20.3 1958 14.6 1954 73.2 1946 2.3 1974 0.0 JUL 40.6 1941 2.2 1971 22.7 1960 18.1 1948 64.5 1942 T 1960 0.0 AUG 38.9 1971 3.3 1953 22.2 1967 17.1 1964 86.1 1976 0.8 1969* 0.0 SEP 34.4 1967 - 2.8 1972* 17.4 1944 12.4 1970 55.1 1944 T 1957 T 1970 OCT 28.9 1947 - 7.8 1971 12.3 1947 6.6 1972 82.8 1945 1.3 1965 4.3 1971 NOV 16.1 1959 -18.9 1955 6.8 1954 - 1.8 1955 65.0 1973 4.1 1943 36.8 1973 DEC 14.4 1941 -27.2 1968 2.7 1966 - 5.3 1951 73.4 1949 2.5 1943 96.8 1971 Year JUL 1941 DEC 1968 JUL 1960 JAN 1950 AUG 1976 SEP 1957 DEC 1971 40.6 -27.2 22.7 -14.3 86.1 T 96.8 P e r i o d o f Record: 1941-1979 * and i n e a r l i e r years T = Trace 34 period between 1941 and 1970 (Hemmerick and Kendall 1970). 3.4 Vegetation Numerous authors described the vegetation i n the Okanagan and Similkameen regions of south centra l B r i t i s h Columbia i n d e t a i l (Spilsbury and Tisdale 1944; T isdale 1947; T isdale and McLean 1957; Demarchi 1965; Brayshaw 1970; McLean 1970; Scheff ler 1972). McLean (1970) recognized f i v e vegetation zones i n S i m i l k -ameen Val ley over an e levat iona l gradient ranging from 300 to 2100 m. D i s t r i b u t i o n of each zone i s cont ro l led by increasing moisture and decreasing temperature re f lec ted through progress-i v e l y higher e levat ions . The f i v e zones i d e n t i f i e d by McLean (1970) include the: (1) Artemis ia t r identa ta zone, (2) Pinus  ponderosa zone, (3) Pseudotsuga menzies i i zone, (4) Abies l a s i o - carpa zone, and (5) Alpine zone. Within each zone, several habitat types are recognized also based upon edaphic and topo-graphic v a r i a t i o n s . These zones also have been appl ied i n the south Okanagan (Hawes 1974). Vegetation on the study s i t e corresponds most c l o s e l y to the Pinus ponderosa - Agropyron spicatum assoc iat ion of the Pinus  ponderosa zone described by Brayshaw (1970) but perhaps i s better described as t r a n s i t i o n a l , or at the i n t e r f a c e , between McLean's (1970) Ar temis ia t r identa ta and Pinus ponderosa zones. On the lower s lopes of the study s i t e the v e g e t a t i o n i s s i m i l a r to the Ar temis ia t r identa ta - Agropyron spicatum habitat type described by McLean (1970) i n the Similkameen. Daubenmire (1970) reported s i m i l a r vegetation types i n Washington, Oregon, . 35 Idaho and Montana. Agropyron spicatum i s the dominant species i n assoc iat ion with Ar temis ia t r i den ta ta . Other plant species such as Koeler ia c r i s t a t a , St ipa comata, Balsamorhiza s a g i t a t t a , and Eriogonum niveum are present i n the plant community. Bromus  tectorum also i s found commonly on the study area perhaps r e f l e c t i n g past overuse by domestic l i ves tock . In the draws, Amelanchier a l n i f o l i a , Acer glabrum, and Prunus v i rg in iana provide an overstory for Symphoricarpos albus, Poa pratensis and mixed forbs. The upper 10 ha of the study s i t e most c l o s e l y resembles the Pinus ponderosa - Agropyron spicatum habitat type described by McLean (1970). Pinus ponderosa i s the dominant tree species although Pseudotsuga menzies i i i s present a lso . Daubenmire and Daubenmire (1968) described s i m i l a r stands i n Washington and northern Idaho. Agropyron spicatum i s the dominant understory species i n assoc iat ion with St ipa comata, Balsamorhiza s a g i t t a t a , Eriogonum niveum and numerous other forbs. Both Festuca  idahoensis and Festuca scabre l la occur on the s i t e as w e l l , although neither are described as a component of th i s habi tat type by McLean (1970). Ar temis ia t r identa ta also occurs i n openings on the upper 10 ha but not under the forest canopy. 36 4. METHODS AND PROCEDURES The methods and procedures are div ided into f i v e sections inc lud ing descr ipt ions of: (1) Experimental Approach and Rationale (2) Fencing, Animal Capture and Herd Composition, (3) Methods, Hypotheses and Data Analysis (4) Laboratory Procedures, Hypotheses and Data Analyses, and (5) Forage S e l e c t i v i t y . 4.1 Experimental Approach and Rationale Previous studies on mountain sheep i n B r i t i s h Columbia have not had the opportunity to contro l and manipulate the envi ron-ments of both animal and plant conveniently. Unfortunately, studies that are widely spaced , both temporally and s p a c i a l l y , are d i f f i c u l t to integrate into a general theory appl icable to management e s p e c i a l l y on a s i t e s p e c i f i c basis (Okanagan Bighorn Sheep Research Group 1978). I t i s essent ia l that contro l and manipulation of both the animal and i t s environment are possible for s p e c i f i c hypotheses to be tested. Despite the obvious l i m i t a t i o n s of removing some components of the animal's ecology, a captive herd, under near natural condi t ions , was considered a v iab le approach to study a complex of animal and grazing factors simultaneously. 4.2 Fencing, Animal Capture and Herd Composition During the f a l l of 1976 and ear ly winter of 1977, a 2.1 m page wire fence was constructed around the study pasture. Twenty C a l i f o r n i a bighorn sheep captured from the Vaseux winter range (Figure 1) were released into the enclosure in A p r i l , 1977. At the time of release the captive herd comprised 16 ewes, three 37 lambs, and one year l ing ram. The stocking rate for the pasture was determined by measur-ing the product iv i t y of the range and c a l c u l a t i n g the average d a i l y intake of the herd based upon metabolic body weights of the captive sheep. Bighorn numbers and herd structure were kept constant among years w i th in the constra ints of annual recruitment and mor ta l i t y (Appendix 4). Excess lambs from the previous year were removed from the study pasture i n ear ly spring each year as required to maintain herd structure and s i ze . The stocking rate was considered moderate to s l i g h t l y heavy with the in tent ion of i t being high enough to induce a change i n the vegetation but s t i l l low enough to al low the animals to express the i r forage preference. 4.3 F i e l d Methods, Hypotheses and Data Analyses The study pasture was s t r a t i f i e d into four sampling uni ts which var ied in vegetat ion, slope and aspect. These were named: (1) North with a north fac ing aspect and approximately a 45% slope; (2) East with an easter ly aspect and approximately a 45% slope; (3) Upper with a north east exposure, mostly f l a t and under a Pinus ponderosa / Pseudotsuga menzies i i canopy, and (4) Lower which had a s i m i l a r aspect and s lope as E a s t , and l i k e North and East was open range (Figure 4). The fo l low ing parameters were monitored to evaluate func-t i o n a l changes and the impact of bighorn sheep grazing on the plant community: forage production and u t i l i z a t i o n , l i t t e r accumulation, plant v igor , shrub u t i l i z a t i o n , plant phenological development, and botanical composition and cover. In add i t ion , 38 UPPER NORTH EAST LOWER Figure 4. Schematic diagram i l l u s t r a t i n g the layout of sampling units on the Okanagan Game Farm study s i t e . 39 s o i l moisture, s o i l temperature and weather data were co l lec ted to in terpret monthly and year ly va r ia t ions i n vegetal response. 4.31 C l imate, S o i l Moisture and S o i l Temperature Permanent Stephenson screens and t ipp ing bucket r a i n gauges were i n s t a l l e d w i th in the North and East exclosures i n the spring of 1977. With the in tent ion of c o l l e c t i n g s i t e s p e c i f i c data for d a i l y and monthly maximum and minimum temperatures, r e l a t i v e humidity and p r e c i p i t a t i o n , mid-monthly inspect ions of the equip-ment were maintained. However, data c o l l e c t i o n was terminated a f te r the f i r s t year because the equipment cont inua l l y malfunc-tioned . Weather data were provided by Environment Canada located at the Penticton A i rpor t 10 km north of the study loca t ion . Dai ly summaries for maximum, minimum and mean temperatures, p r e c i p i t a -t i o n (both r a i n and snow), wind speed and d i r e c t i o n , and t o t a l hours of sunl ight were provided. Dai ly normals and extremes also were a v a i l a b l e . S o i l moisture and s o i l temperature were recorded throughout the growing season w i t h i n both the North and East exclosures. Two stat ions at each exclosure were monitored for each parameter mid-monthly. Four gypsum s o i l moisture blocks were located at each of two depths at each s t a t i o n . The f i r s t group of four were set 2 cm under the s o i l su r face and the second group at a p p r o x i -mately 35 cm. Percent ava i lab le s o i l moisture was determined with a Model 59 - 10A s o i l moisture meter. Consecutive readings were co l lec ted for A p r i l to December i n 1977 and 1978 except for A p r i l , May and June i n 1977 when the moisture meter malfunc-40 t i o n e d . A d d i t i o n a l d a t a were c o l l e c t e d f r o m A p r i l t o A u g u s t 1979. S o i l t e m p e r a t u r e was m o n i t o r e d c o n s e c u t i v e l y a t m i d - m o n t h l y i n t e r v a l s f r o m A p r i l t o December i n 1977 and 1978, w i t h t h e e x c e p t i o n o f J u l y , A u g u s t , September and O c t o b e r ,1978 and f r o m A p r i l t o A u g u s t 1979. F o u r r e p l i c a t e d r e a d i n g s were d e t e r m i n e d w i t h a YSI T e l e t h e r m o m e t e r s o i l t e m p e r a t u r e m e t e r ( Model 44 TD) a t e a c h s a m p l i n g p e r i o d f o r e a c h e x c l o s u r e . S o i l t e m p e r a t u r e p r o b e s were s e t a t two d e p t h s ; a t t h e s o i l s u r f a c e ( a p p r o x i m a t e l y 1 cm) a n d a t 10 cm. 4.32 Forage Yields and U t i l i z a t i o n F o r a g e y i e l d s and u t i l i z a t i o n were d e t e r m i n e d a t t h e end o f e a c h g r o w i n g s e a s o n . S i x 1 m 2 p l o t s were r a n d o m l y l o c a t e d a l o n g p e r m a n e n t t r a n s e c t s b o t h w i t h i n and o u t s i d e two 32 X 16 m e x c l o -s u r e s i n 1976 and 1977. T h e s e e x c l o s u r e s were l o c a t e d on t h e N o r t h and E a s t s i t e s ( F i g u r e 5). T r a n s e c t s were e s t a b l i s h e d p a r a l l e l t o t h e c o n t o u r and p e r m a n e n t s t a k e s were i n s t a l l e d so t h a t i d e n t i c a l t r a n s e c t s c o u l d be r e s a m p l e d . O n l y t h e t h r e e t r a n s e c t s i m m e d i a t e l y above and b e l o w t h e e x c l o s u r e s were u s e d f o r d e t e r m i n i n g f o r a g e y i e l d s . I n 1978 t h e s a m p l e s i z e was d o u b l e d on b o t h s i t e s a n d m o n i t o r e d i n 1978 a n d 1979. T w e l v e a d d i t i o n a l 2 X 2 m 2 p o r t a b l e e x c l o s u r e s were e r e c t e d and r a n d o m l y l o c a t e d on p e r m a n e n t t r a n -s e c t s on t h e Upper s i t e . M e t e r s q u a r e p l o t s w i t h i n e a c h p o r t a b l e e x c l o s u r e and a p a i r e d p l o t o u t s i d e e a c h were m o n i t o r e d i n 1978 and 1979 t o d e t e r m i n e f o r a g e u t i l i z a t i o n . NORTH EAST I 1 I 1 I 1 I 1 I 1 I 1 I 1 i 1 i 1 i ; — i Exclosure Exclosure > : I 1 : : I 1 : I I : : I 1 I 1 i 1 I 1 I 1 I 1 I 1 I 1 i 1 I 1 I 1 Figure 5. Schematic diagram i l l u s t r a t i n g the arrangement of transects on the North and East s i t e s . 42 Above ground phytomass was hand separated and par t i t ioned into 11 groups or species. These groups were selected based on the fo l lowing c h a r a c t e r i s t i c s : (1) the group comprised a s i g n i f i c a n t proportion of the t o t a l herbage produced as potent ia l forage for C a l i f o r n i a bighorn sheep; and (2) the group was expected to , or had previously been shown to be, an important forage species. The species and groups selected included: Agropyron spicatum, Koeler ia c r i s t a t a , St ipa comata, Bromus tectorum, Poa sandberg i i , Eriogonum niveum, Balsamorhiza  s a g i t t a t a , t o t a l forbs , t o t a l annual grass, t o t a l perennial grass and t o t a l standing crop. The hypotheses that there were no di f ferences i n forage y ie lds for each species and forage groups among years, between grazed and ungrazed areas, and, that there was no i n t e r a c t i o n between year and grazing for each were tested with ANOVA (Appendix 5). The experimental design was arranged as a two factor s p l i t - p l o t i n time with subsampling (Steel and Torr ie 1980). Whole p lots were arranged i n a randomized block design i n which s i t e s were considered as "blocks" for experimental error and annually c l ipped p lots were considered as subsamples w i th in blocks. Levels of grazing were considered whole uni ts per block and year was considered the s p l i t - p l o t . Non s i g n i f i c a n t i n t e r -act ions between year and s i t e were pooled with res idual er ror . Differences among means were evaluated with Student Newman Keuls' test (alpha = 0.10). A l l other hypotheses were s i m i l a r l y tested at t h i s s ign i f i cance leve l which f a l l s w i th in an acceptable range for land use decis ions except i n l i t i g a t i o n McQuisten and 43 Gebhardt (1981). Higher leve ls of s ign i f i cance were reported when they occurred for i nd i v idua l tests however. Degrees of freedom for the main e f f e c t year and the grazing by year i n te rac t ion were subdivided and add i t iona l hypotheses were tested for each y i e l d var iab le with s ing le degree of freedom contrasts as f o l l o w s : 1. Forage production i n 1976 before grazing by bighorn sheep was not d i f f e r e n t than the average production over 1977, 1978 and 1979. 2. Forage production i n 1977 af ter one year of grazing by bighorn sheep was not d i f f e r e n t than the average production over 1977 and 1978. 3. Forage production i n 1978 was not d i f f e r e n t than production i n 1979. 4. Forage y i e l d i n 1976 was not d i f f e r e n t than the average y i e l d over 1977, 1978 and 1979, and trends were the same on both the grazed and ungrazed areas. 5. Forage y i e l d i n 1977 was not d i f f e r e n t than the average y i e l d over 1977 and 1978, and t rends were the same on both the grazed and ungrazed areas. 6. Forage y i e l d i n ' 1978 was not d i f f e r e n t than that i n 1979, and t rends were the same on both the grazed and ungrazed areas. F a l l regrowth was measured i n October, 1978 and 1979. Three meter square p lots protected from grazing on the North, East and Upper s i t e s were resampled a f te r the August sampling period to quanti fy regrowth. Total biomass was co l lec ted on each p lo t . A l l forage samples were a i r d r i e d , oven dr ied to constant weight at 70° C for 48 hours and weighed. The hypothesis that there was no d i f ference i n regrowth between years was tested with ANOVA (Appendix 5) i n a randomized block design with subsampling (Steel and Torr ie 1980). S i tes were considered as" blocks" for experimental error and c l ipped 44 p lots were considered as subsamples w i th in blocks. Forage u t i l i z a t i o n was determined at the end of August each year by the weight d i f ference technique (Brown 1954). The d i f ference i n mean weight from ins ide and outside the exclosures estimated u t i l i z a t i o n for each of the plant species and forage groups described above. 4.33 E f fec t of Grazing on Plant Reproductive Po ten t ia l The impact of grazing on the vigor and reproductive poten-t i a l of eight plant species was studied i n August, 1979. Twenty ind i v idua l plants of Agropyron spicatum, Koeler ia c r i s t a t a , Poa  sandbergi i , and Balsamorhiza sag i t ta ta were randomly located w i th in and outside exclosures on each of three s i t e s ; North, East and Upper. Eriogonum niveum, St ipa comata, Lupinus sericeus and C a s t i l l e j a thompsonii occurred inf requent ly and were widely spaced on the Upper s i t e . Therefore, 20 ind i v idua l plants of each of these spec ies were monitored on both the North and East s i t e s w i th in and outside each exclosure but Eriogonum niveum and St ipa comata were not sampled on the Upper s i t e . Sixteen C a s t i l l e j a thompsonii and s i x Lupinus sericeus plants were located and monitored on the Upper s i t e . Four parameters were measured for a l l eight taxa inc lud ing : basal diameter, number of culms or in f lo rescences , longest leaf and longest inf lorescence. The hypotheses that there were no d i f ference i n basal diameter, number of culms or in f lorescences , longest leaf and longest inf lorescence between areas ungrazed and grazed by C a l i f o r n i a bighorn were tested with ANOVA (Appendix 5) i n a 45 randomized block design with subsampling (Steel and Torr ie 1980). S i tes were considered as "blocks" for experimental error and ind i v idua l plants were considered as subsamples. 4.34 Shrub U t i l i z a t i o n Amelanchier a l n i f o l i a was chosen to monitor for browse' u t i l i z a t i o n for two reasons. F i r s t , wi th the exception of A r te - mis ia t r i d e n t a t a , t h i s taxon was the most abundant source of browse ava i lab le for the captive herd. Indeed, a l l other browse species were sporad ica l l y d i s t r i b u t e d on the s i t e and were represented by too few plants to sample adequately. Second, other studies reported that bighorn sheep u t i l i z e d t h i s species (Drewek 1970; Ste l fox and Spalding 1974; Ste l fox 1975) and work on domestic sheep indicated that i t was a preferred browse (Cook and Stoddart 1953). Percent u t i l i z a t i o n of Amelanchier a l n i f o l i a was estimated i n August, 1977 and 1978. One hundred randomly located shrubs were tagged at the i r base and numbered i n 19 77. On each shrub, two l a t e r a l branches were tagged below a height of 2 m which was bel ieved to span the zone of a v a i l a b i l i t y for mountain sheep. Because few previous attempts were made to quantify browsing by mountain sheep (Smith 1954; McCullough and Schneegas 1966), a t o t a l of f i v e methods were employed to determine u t i l i z a t i o n : three i n 1977 and two add i t iona l methods i n 1978. U t i l i z a t i o n was not evaluated i n 1979 because i t appeared that too l i t t l e forage remained ava i lab le for measurement fo l low ing the f i r s t two years of browsing. U t i l i z a t i o n was determined by the twig measurement method 46 (Aldous 1945; Dasmann 1948) which had been used previously by Smith (1954) and McCullough and Schneegas (1966) for evaluat ing browsing by mountain sheep. The average lengths of browsed and unbrowsed twigs w i th in the sampled twig c lus te rs were compared and percent u t i l i z a t i o n determined using the fo l low ing formula: Unbrowsed Length - Browsed Length % U t i l i z a t i o n = X 100. Unbrowsed Length Two add i t iona l methods were simultaneously tested on the same shrubs. The f i r s t method merely t o t a l l e d the number of tagged c lus te rs browsed to the t o t a l number of tagged c lus te rs (Cole 1959). Percent u t i l i z a t i o n was determined using the f o l l o w -ing formula: Total Clusters Browsed % U t i l i z a t i o n = X 100. Total Clusters Observed The second add i t iona l method compared the number of twigs browsed per c lus te r to the unbrowsed number (Stickney 1966). The fo l low ing formula was employed to express percent u t i l i z a t i o n : Total Twigs Browsed % U t i l i z a t i o n = X 100. Total Twigs A l l C lusters The appropriate sample s ize to determine u t i l i z a t i o n during 1978 was ca lcu lated fo l low ing the 1977 f i e l d season using the two stage formula described by Freese (1976) and the 1977 unbrowsed twig length data as an estimate of v a r i a b i l i t y . Indiv idual shrubs were treated as pr imaries and twig c lus te rs as secondaries. These ca lcu la t ions revealed that 53 pr imaries were required to y i e l d a mean w i th in 10% of the population mean at a s ign i f i cance 47 l e v e l of 0.05. For convenience i n c a l c u l a t i o n , 50 new shrubs were randomly selected and two twig c lus te rs per shrub tagged w i th in the enc lo -sure. F i f t y add i t iona l shrubs also were tagged outside the enclosure as an unbrowsed cont ro l . U t i l i z a t i o n for the f i r s t three methods was determined i n August, 19 78 on the 50 shrubs exposed to browsing fo l low ing the same methods used i n 1977. The two new methods introduced i n 1978 used both the 50 shrubs w i th in and outside the enclosure. The f i r s t new method compared d i f ferences i n weight per twig c lus te r between browsed and unbrowsed plants (Brown 1954). The t o t a l weight per twig c lus te r was s t r a t i f i e d into leaf weight, twig weight and t o t a l weight. A l l samples were a i r d r i e d , oven dr ied to constant weight at 70 o c f o r 43 hours and weighed. The fo l low ing formula was used to ca lcu la te u t i l i z a t i o n for l e a f , twig and t o t a l weight: Unbrowsed Weight - Browsed Weight % U t i l i z a t i o n = X 100. Unbrowsed Weight The second new method compared the number of buds per twig c lus te r on browsed compared to unbrowsed p lants . Percent u t i l i -zat ion was determined as f o l l o w s : No. Buds'Browsed - No. Buds Unbrowsed % U t i l i z a t i o n = X 100. No. Buds Unbrowsed The hypotheses that there were no d i f ferences i n twig length, leaf weight, twig weight, t o t a l weight and number of buds per twig on annual growth between browsed and unbrowsed shrubs of 48 Amelanchier a l n i f o l i a were tested with ANOVA (Appendix 5). An independent analys is was conducted for each var iab le i n a random-ized block design with subsampling (Steel and Torr ie 1980). Shrubs were considered "blocks" for est imat ing experimental error and twig c lus te rs were associated with subsampling error . A non s i g n i f i c a n t i n te rac t ion between grazing and shrubs was pooled with subsampling error . An F test declared s i g n i f i c a n t d i f f e r -ences between means. 4.35 Plant Phenology Phenological observations were made mid-monthly for 75 plant species from A p r i l 1977 to December 1979. Phenological develop-ment for .each taxon was determined by observing a minimum of 10 ind i v idua l plants for each species during a reconnaissance of the study area at each sampling period. Mid-monthly inspect ions were considered s u f f i c i e n t so that phenological data could be re lated to forage q u a l i t y and d ie t information which were co l lec ted concurrent ly . One of s i x growth stages, s i m i l a r to those described by Sauer and Uresk (1976), was recorded for each plant species at each sampling per iod. These included: A subject ive c l a s s i f i c a t i o n was made grouping plant taxa according to the c r i t e r i a out l ined by Tisdale (1947) with the fo l low ing modi f icat ions : 1. 2. 3 . 4. 5. 6. Growth i n i t i a t i o n F l o r a l i n i t i a t i o n F u l l flower Seed set and shatter Cured F a l l regrowth or germination. 49 Group 1 - Ear ly ephemerals which f lower before summer drought and ra re l y resprout i n f a l l . This group i s not represented i n T i s -dale's (1947) c l a s s i f i c a t i o n . Group 2 - Taxa which i n i t i a t e growth ear l y , f lower before the summer drought, may or may not cure depending upon annual weather patterns, usual ly produce s i g n i f i c a n t f a l l regrowth and occass ional ly f lower a second time. Group 3 - Plant species which i n i t i a t e growth l a t e r , f lower at the beginning and/or through the summer drought per iod , have s i g -n i f i c a n t f a l l regrowth and may f lower again i n autumn. Group 4 - Species which s ta r t l a t e , f lower i n autumn, general ly do not cure and remain "evergreen" throughout the winter . 4.36 Botanical Composition and Cover Plant community st ructure was studied from 1977 to 1979 to evaluate var ia t ions i n plant species a v a i l a b i l i t y on the area grazed by C a l i f o r n i a bighorn sheep, and from 1976 to 1983 to determine the long term ef fec ts of grazing on the plant commun-i t y . Botanical composition and cover were determined using a modi f icat ion of the Parker 3 Step Method (Parker 1951). Vegeta-t i on was sampled mid-monthly both w i th in and outside two 32 X 16 m exclosures which were located on the North and East s i t e s respect i ve l y . Using a r e s t r i c t e d randomized method, s i x transects outside and two ins ide each exclosure were establ ished p a r a l l e l to the contour (Figure 5) and permanently staked so that i d e n t i c a l t ransects could be resampled. Twenty four add i t iona l transects were located on the study s i t e i n 1977 to provide a more homo-50 geneous sampling of the area for determining forage a v a i l a b i l i t y . Four of these transects were establ ished on the North and East s i t e s , respect ive ly and the remaining 16 transects were d i s t r i -buted equal ly between the Upper and Lower s i t e s . Botanical composition and cover were sampled i n la te June 1976 to provide pre -graz ing basel ine data and then mid-monthly from May to August i n 1977, 1978, and 1979. Addi t iona l measure-ments also were taken i n March 1978 and 1979 to evaluate winter foraging preferences by the sheep. Botanical composition was assumed to remain constant from mid-August to March. Further measurements were taken i n mid-June 1980, 1981 and 1983 to assess the long term ef fec ts of grazing on the plant community. Two analyses were undertaken to assess changes i n forage a v a i l a b i l i t y and the long term ef fec ts of grazing. The hypotheses that there were no d i f ferences i n the cont r ibut ion that each plant species made to botanica l composition or cover among s i t e s , months and years and, that there were no in teract ions between year and month were tested analogously with ANOVA (Appendix 5). Each analys is was arranged as a s p l i t p lo t design with sub-sampling (Steel and Torr ie 1980). Whole p lots were arranged as randomized blocks wi th s i t e s considered as "blocks" for exper-imental error and leve ls of month were crossed with s i t e s . Year was considered as a s p l i t p lo t i n time and transects w i th in s i t e s represented subsamples. Non s i g n i f i c a n t in te ract ions between s i t e and year were pooled with res idua l er ror . Degrees of freedom for the main e f fec ts month and year, and for the month by year i n te rac t ion were subdivided and add i t iona l 51 h y p o t h e s e s were t e s t e d f o r e a c h y i e l d v a r i a b l e w i t h s i n g l e d e g r e e o f f r e e d o m c o n t r a s t s as f o l l o w s : 1. The b o t a n i c a l c o m p o s i t i o n and c o v e r o f e a c h s p e c i e s and g r o u p were n o t d i f f e r e n t i n e a r l y s p r i n g d u r i n g A p r i l and May t h a n t h e a v e r a g e b o t a n i c a l c o m p o s i t i o n and c o v e r d u r i n g t h e l a t e s p r i n g and summer p e r i o d d u r i n g June, J u l y and A u g u s t . 2. The b o t a n i c a l c o m p o s i t i o n and c o v e r o f e a c h s p e c i e s and g r o u p d u r i n g e a r l y s p r i n g were n o t d i f f e r e n t i n A p r i l t h a n i n May. 3. The b o t a n i c a l c o m p o s i t i o n and c o v e r o f e a c h s p e c i e s and g r o u p were n o t d i f f e r e n t i n e a r l y s p r i n g d u r i n g May t h a n i n l a t e s p r i n g d u r i n g J u n e . 4. The b o t a n i c a l c o m p o s i t i o n and c o v e r o f e a c h s p e c i e s and g r o u p were n o t d i f f e r e n t i n summer d u r i n g J u l y t h a n i n Au g u s t . 5. The b o t a n i c a l c o m p o s i t i o n and c o v e r o f e a c h s p e c i e s and g r o u p were n o t d i f f e r e n t i n 1977 d u r i n g t h e f i r s t y e a r o f g r a z i n g by C a l i f o r n i a b i g h o r n sheep t h a n t h e a v e r a g e b o t a n i c a l compo-s i t i o n and c o v e r d u r i n g t h e 1978 and 1979. 6. The b o t a n i c a l c o m p o s i t i o n and c o v e r o f e a c h s p e c i e s and g r o u p were n o t d i f f e r e n t i n 1978 t h a n i n 1979. 7. T r e n d s i n b o t a n i c a l c o m p o s i t i o n and c o v e r o f e a c h s p e c i e s and g r o u p were were n o t d i f f e r e n t i n e a r l y s p r i n g d u r i n g A p r i l and May t h a n t h e a v e r a g e b o t a n i c a l c o m p o s i t i o n and c o v e r d u r i n g t h e l a t e s p r i n g and summer p e r i o d d u r i n g June, J u l y and A u g u s t i n 1977 compared t o t h e a v e r a g e o f 1978 and 1979. 8. T r e n d s i n b o t a n i c a l c o m p o s i t i o n and c o v e r o f e a c h s p e c i e s and g r o u p d u r i n g e a r l y s p r i n g were n o t d i f f e r e n t i n A p r i l t h a n i n May i n 1977 compared t o t h e a v e r a g e o f 1978 and 1979. 9. T r e n d s i n b o t a n i c a l c o m p o s i t i o n and c o v e r o f e a c h s p e c i e s and g r o u p were n o t d i f f e r e n t i n e a r l y s p r i n g d u r i n g May t h a n i n l a t e s p r i n g d u r i n g J u n e i n 1977 c o m p a r e d t o t h e a v e r a g e o f 1978 and 1979. 10. T r e n d s i n b o t a n i c a l c o m p o s i t i o n and c o v e r o f e a c h s p e c i e s and g r o u p were n o t d i f f e r e n t i n summer d u r i n g J u l y t h a n i n A u g u s t i n 1977 compared t o t h e a v e r a g e o f 1978 and 1979. 11. T r e n d s i n b o t a n i c a l c o m p o s i t i o n and c o v e r o f e a c h s p e c i e s and g r o u p were were n o t d i f f e r e n t i n e a r l y s p r i n g d u r i n g A p r i l and May t h a n t h e a v e r a g e b o t a n i c a l c o m p o s i t i o n and c o v e r d u r i n g t h e l a t e s p r i n g and summer p e r i o d d u r i n g June, J u l y and A u g u s t i n 1978 t h a n i n 1979. 12. T r e n d s i n b o t a n i c a l c o m p o s i t i o n and c o v e r o f e a c h s p e c i e s and 52 group during ear ly spring were not d i f f e r e n t in A p r i l than in May i n 1978 than i n 1979. 13. Trends i n botanical composition and cover of each species and group were not d i f f e r e n t in ear ly spring during May than i n la te spring during June i n 1978 than i n 1979. 14. Trends i n botanical composition and cover of each species and group were not d i f f e r e n t i n summer during July than i n August i n 1978 than i n 1979. The hypotheses that there were no long term di f ferences i n the cont r ibut ion that each plant species made to botanical com-pos i t ion or cover among years, between grazed and ungrazed areas, and, there was no in te rac t ion between grazing and year were tested with ANOVA (Appendix 5). Each analys is was arranged as a s p l i t p lo t design with subsampling (Steel and Torr ie 1980). Whole p lots were arranged as randomized blocks with s i t e s con-sidered as "blocks" for experimental error and leve ls of grazing were crossed w i t h s i t e s . Year was cons idered as a s p l i t p l o t i n time and transects w i th in s i t e s represented subsamples. D i f f e r -ences among means were evaluated with Student Newman Keuls' tes t (alpha = .10) . 4.4 Laboratory Procedures, Hypotheses and Data Analyses Other f i e l d and n o n - f i e l d a c t i v i t i e s re lated to the develop-ment of the reference plant c o l l e c t i o n and the determination of forage se lec t ion by the captive bighorn are also included i n th i s sect ion . 4.41 Forage Qual i ty Concentration leve ls of n i t rogen, ac id detergent f i b r e , calcium and phosphorus were determined for 13 plant species over three years. Samples were co l lec ted from A p r i l to October, 53 1977, M a r ch t o November, 1978 and i n March, 1979. F a l l r e g r o w t h was s a m p l e d f r o m A u g u s t t o November, 1979 f o r f o u r t a x a . S p e c i e s c h o s e n f o r a n a l y s i s i n c l u d e d : A g r o p y r o n s p i c a t u m , K o e l e r i a c r i s t a t a , S t i p a c o m a t a , Poa s a n d b e r g i i , Bromus t e c t o r u m , B a l s a m o r h i z a s a g i t t a t a , L u p i n u s s e r i c e u s , E r i o g o n u m h e r a c l e o i d e s , E r i o g o n u m n i v e u m , A m e l a n c h i e r a l n i f o l i a , A r t e m i s i a t r i d e n t a t a , A r t e m i s i a f r i g i d a and S y m p h o r i c a r p o s a l b u s . The r a t i o n a l e f o r c h o o s i n g t h e s e s p e c i e s f o r a n a l y s e s was: (1) t h e p l a n t s p e c i e s c o n t r i b u t e d s i g n i f i c a n t l y t o f o r a g e p r o d u c t i o n o v e r t h e s t u d y a r e a , a n d / o r (2) t h e s p e c i e s was b e l i e v e d t o be p o t e n t i a l l y an i m p o r t a n t component o f t h e b i g h o r n d i e t . Ten s a m p l e s f r o m i n d i v i d u a l p l a n t s w i t h i n e a c h t a x o n were c o l l e c t e d a t e a c h s a m p l i n g d a t e , a i r d r i e d , oven d r i e d a t 70 ° C t o c o n s t a n t w e i g h t f o r 48 h o u r s a n d g r o u n d i n a W i l e y m i l l t h r o u g h a 40 mesh s c r e e n . D u p l i c a t e s a m p l e s were a n a l y s e d f o r e a c h p a r a m e t e r . N i t r o g e n was d e t e r m i n e d by t h e s t a n d a r d macro K j e l d a h l t e c h -n i q u e (A.O.A.C. 1960) a n d ADF b y t h e v a n S o e s t m e t h o d ( v a n S o e s t 1963). C a l c i u m and p h o s p h o r u s were d e t e r m i n e d by t h e a t o m i c a b s o r p t i o n s p e c t r o m e t r i c method and t h e m o l y b o d a t e - v a n a d a t e method, r e s p e c t i v e l y (Dept. o f A n i m a l S c i e n c e , U.B.C. 1979). Two a n a l y s e s o f f o r a g e q u a l i t y d a t a were u n d e r t a k e n . The h y p o t h e s e s t h a t t h e r e were no d i f f e r e n c e s i n c o n c e n t r a t i o n l e v e l s o f N, Ca, P and t h e Ca/P r a t i o among y e a r s , s p e c i e s , and months, and t h a t t h e r e was no i n t e r a c t i o n b e t w e e n s p e c i e s and month f o r a n n u a l g r o w t h were t e s t e d w i t h ANOVA (Appendix 5). The a n a l y s e s were a r r a n g e d as a r a n d o m i z e d b l o c k d e s i g n w i t h s u b s a m p l i n g ( S t e e l and T o r r i e 1980). S p e c i e s and month were f a c t o r i a l l y 54 crossed wi th in blocks. Years were considered "blocks" for experimental error and dupl icate samples were considered sub-samples. Differences among means were evaluated with Student Newman Keuls' test (alpha = 0.10). Forage q u a l i t y of Agropyron spicatum, Bromus tectorum, Koeler ia c r i s t a t a and St ipa comata were determined for f a l l regrowth. The hypotheses that there were no d i f ferences i n con-centrat ion leve ls of N, Ca, P and the Ca/P r a t i o among years, months, growth stage, and that there was no i n t e r a c t i o n between month and growth stage were tested with ANOVA (Appendix 5). Growth stages separated annual growth and f a l l regrowth for each species w i th in months. The analyses were arranged as a random-ized block design with subsampling (Steel and Torr ie 1980) for each species with a f a c t o r i a l crossing of month and growth stage wi th in blocks. Years were considered "blocks" for experimental error and dupl icate samples were considered subsamples. D i f f e r -ences among means were evaluated with Student Newman Keuls 1 tes t (alpha = 0.05). 4 . 4 2 Diet Analys is Bighorn d ie t was determined through mic roh is to log ica l analys is of feca l mate r ia l . The fo l low ing two components of animal d ie t determination w i l l be discussed i n d i v i d u a l l y : (1) development of a reference plant c o l l e c t i o n , and (2) mic roh is to -l o g i c a l analys is of feces. 4 . 4 2 1 Reference Plant C o l l e c t i o n Epidermal surfaces from 79 plant species occurr ing on the 55 study area were i s o l a t e d , mounted on microscopic s l i d e s , photo-graphed and placed in photographic albums for reference during d ie t determination. Specimens were prepared for adaxial (upper) and abaxial (lower) leaf surfaces, stems, and in some cases, f lowers . A t o t a l of 212 epidermal surfaces were photographed. Specimens for each ind i v idua l plant species were co l lec ted i n the f i e l d , numbered and pressed at the f lower ing stage for i den -t i f i c a t i o n and for preparation of epidermal samples. Voucher specimens of the plant taxa occurr ing on the study s i t e were de-posited i n the Univers i ty of B r i t i s h Columbia herbarium fo l low ing taxonomic i d e n t i f i c a t i o n . Throughout the development of the reference c o l l e c t i o n , a number of techniques were employed to obtain epidermal specimens. Fresh mater ia l was used when ava i lab le but most epidermal sec-t ions were acquired from dr ied mater ia l co l l ec ted for herbarium specimens. Approximately 86% of the voucher specimens were prepared by mechanically s t r ipp ing epidermal surfaces from leaves and stems with a razor blade. While extremely tedious, th i s method gener-a l l y produced high q u a l i t y specimens, e s p e c i a l l y for grass species. Care was taken not to remove trichomes i n the process. Dried specimens of both leaves and stems were soaked i n a lactophenol - cotton blue so lut ion (Davitt , pers. comm.) • (Table 7) u n t i l f u l l y hydrated. Hydration time var ied among species, and parts w i th in species, from a few minutes to several hours. Each specimen was placed on a microscopic s l i d e with the desired epidermal surface mounted face down. A second micro-Table 7. Composition o f l a c t o p h e n o l - c o t t o n b l u e s o l u t i o n by volume Q u a n t i t y (ml) C o n s t i t u e n t 200 l a c t i c a c i d 100 p h e n o l 100 d i s t i l l e d w a t e r 200 g l y c e r i n e 100 g l a c i a l a c i d i c a c i d 10 c o t t o n b l u e (0.35g m e t h y l b l u e i n 10 ml o f 95% a l c o h o l ) 57 scop ic s l i d e was p laced at r i g h t angles to the f i r s t to anchor the specimens whi le the intermediate plant t i ssue was scraped away. More d i f f i c u l t specimens, such as woody stems, were soaked i n an a c i d , a lcohol s t a i n mixture (Davitt , pers. comm.) for one or two days (Table 8). Fol lowing t h i s treatment, stems were sectioned i n h a l f , mounted on s l i d e s and scraped wi th a razor blade as described above. Residual plant t i ssue remaining a f te r scraping f resh specimens was removed by adding a few drops of common household bleach (5% sodium hypochlor i te) . Care must be taken i n applying t h i s t r e a t -ment however, as overexposure to bleach may r e s u l t i n the c e l l wal ls fading. Approximately 12% of the epidermal sections were prepared fo l low ing procedures out l ine by Korphage (1974) with some modi-f i c a t i o n . Af ter soaking dr ied plant mater ia l i n lactophenol , samples were t ransferred to an Oster izer C y c l o - t r o l Eight blender and blended i n water at high speed for approximately 30 seconds. Supernatent f l u i d was drained and the contents emptied into a p e t r i d i sh . Blended plant mater ia l was f loated onto a micro -scopic s l i d e and scanned under a Zeiss 62701 binocular microscope u n t i l fragments with exposed epidermal sections were located. Although the i n i t i a l stages of the blending procedure were quick and easy, considerable time was spent scanning s l i d e s microscop ica l l y . This proved to be extremely tedious and i n some instances no epidermal sections were located. A d d i t i o n a l l y , when sections were located, i t was d i f f i c u l t to d iscern whether 58 Table 8. Quant i t ies and const i tuents of a c i d , a lcohol s t a i n mixture by volume Quantity Constituent 5 ml 10% n i t r i c ac id 20 ml 95% alcohol 15-20 drops safranin 10 drops p i c r i c acid / 59 both adaxial and abaxial surfaces were recovered and trichomes often became dislodged. On the other hand, some specimens were successfu l ly obtained employing th i s technique when other methods f a i l e d . < Approximately 2% of the t o t a l epidermal sections were pre -pared using a v a r i a t i o n of the maceration technique described by Dusi (1949). Sections of plant t i ssue were placed i n a small beaker w i t h equal pa r t s of 10% chromic and 10% n i t r i c a c i d , gently heated, l e t stand for several hours and r insed i n water. Epidermal surfaces were teased apart and f loated onto micro-scopic s l i d e s . Widespread use of t h i s technique was not employ-ed however, because the epidermal layers of some f r a g i l e spec-imens were digested i n the process. Timing the removal of the botanical t i ssue from the maceration f l u i d appeared c r i t i c a l to recovering s a t i s f a c t o r y specimens. Fol lowing recovery of epidermal sections by a l l techniques, samples were mounted on standard microscopic s l i d e s i n g lycer ine . The cover s l i p was secured to the s l i d e with n a i l p o l i s h . Photo-micrographs were taken of each voucher specimen using Kodak 32 ASA Pan X f i l m at 100X magnif icat ion and a dichotomous key de-veloped (Wikeem and P i t t 1983) to a s s i s t i n the i d e n t i f i c a t i o n of plant fragments i n bighorn feca l mate r ia l . 4.422 F e c a l A n a l y s i s Fecal samples were co l lec ted mid-monthly for 28 months from May, 1977 to August, 1979. At each sampling per iod, the f i r s t 50 f resh , moist p e l l e t groups encountered on the study s i t e were co l lec ted and i n d i v i d u a l l y stored i n p l a s t i c bags. 60 Each bag was labe l led with the date and locat ion of c o l l e c t -ion and immediately frozen i n groups of 50 samples per month. Sampling was conducted on a herd, rather than on an in d i v id ua l animal , basis (Todd 1972a; Korphage 1974). In the laboratory , two p e l l e t s were subsampled from each of the 50 p e l l e t groups c o l l e c t e d , providing a s i n g l e , monthly composite sample. This sample was c a r e f u l l y washed on a 1 mm screen i n warm water to remove s o i l and botanical mater ia l adher-ing to the feca l p e l l e t s . Fol lowing washing, the composite sample was t ransferred to an Oster izer C y c l o - t r o l 8 blender and the p e l l e t s crushed at low speed for approximately 30 seconds i n two to three times t h e i r volume of 60% alcohol (Wil l iams 1969). The blended mixture was l e f t to stand for several hours to remove ch lorophy l l from the feca l plant mater ia l i n a 500 ml con ica l f l a s k . Later the f l a s k was topped with hot, but not b o i l i n g , water and the mixture l e f t standing for approximately 12 hours. The supernatant f l u i d was then decanted and the volume again brought up to 500 ml with hot water. Upon coo l ing , the contents were r insed with cold water and the water extracted with a Buchner funnel . Fecal so l ids were t ransferred to labe l led j a r s , covered with lactophenol - cotton blue so lut ion and l e f t for at l e a s t 24 hours at room temperature so that s t a i n cou ld be absorbed by the c e l l wa l l s of- the epidermal fragments. Just p r io r to mounting on microscopic s l i d e s , the feca l s o l i d s were thoroughly s t i r r e d and approximately three t a b l e -spoons of mater ia l were withdrawn and placed i n a c r u c i b l e . 61 Remaining clumps were c a r e f u l l y crushed, and the contents then washed on a 200 mesh screen. Fecal mater ia l was evenly spread over a microscopic s l i d e containing a few drops of g lycer ine . Care was taken not to deposit excessive mater ia l on each s l i d e i n order to prevent feca l fragments from overlapping. A few add i t iona l drops of g lycer ine were appl ied to the s l i d e as r e -quired to provide an even coating and the cover s l i p was mounted with n a i l p o l i s h . Ten s l i d e s were prepared for each monthly composite sample. Twenty-f ive f i e l d s of view were sampled per s l i d e t o t a l i n g 250 per sampling per iod. F ie lds of view were located using system-a t i c random sampling. Five l i nes were located randomly with the aid of a micrometer and f i v e locat ions per l i n e were s i m i l a r l y determined. Non-epidermal mater ia l i n the sample was ignored and not considered part of the sample, but detached trichomes were noted and used to a s s i s t in i d e n t i f i c a t i o n of other epidermal sections encountered. A l l sampling was undertaken at 100 X magni f icat ion . 4.423 Monthly Grazing Observations Monthly grazing observations were undertaken throughout the 28 months that feca l samples were co l lec ted for d ie t ana lys is . At each mid-monthly sampling per iod , observations were made throughout the study s i t e w i th in areas recent ly grazed by the sheep. Both the plant species and the plant parts that were grazed were recorded. Providing only q u a l i t a t i v e data, these observations provided add i t iona l information beyond the feca l 62 analys is for grazed plant taxa that did not occur i n the feca l output. 4.424 Diet Data Analyses The hypotheses that there were no d i f ferences i n the c o n t r i -bution that each plant species and forage group made to bighorn d ie t among years and months, and that there was no in te rac t ion between year and month were tested wi th ANOVA (Appendix 5). Seventy three plant species, t o t a l grass, t o t a l forbs and t o t a l shrubs were analysed. The experimental design was arranged as a randomized block design (Steel and Torr ie 1980). Years were considered as "blocks" for experimental error and r e p l i c a t e s l i d e s as subsamples. Differences among means were evaluated with Student Newman Keuls' tes t (alpha = 0.10). Degrees of freedom for the main e f fec t month were subdivided and add i t iona l hypotheses were tested for each y i e l d var iab le with s ing le degree of freedom contrast as f o l l o w s : 1. The d ietary composition of each species and group i n the summer grazing period was not d i f f e r e n t than the average of the f a l l , winter and spring seasons. 2. The d ietary composition of each species and group i n the f a l l grazing period was not d i f f e r e n t than the average of winter and spring seasons. 3. The d ietary composition of each species and group i n the winter grazing period was not d i f f e r e n t than i n the spring season. 4. The d ietary composition of each species and group i n June was not d i f f e r e n t than the average of Ju ly and August. 5. The d ietary composition of each species and group i n Sept-ember was not d i f f e r e n t than the average of October and November. 6. The d ietary composition of each species and group i n Sept-ember was not d i f f e r e n t than the average of October and 63 November. 7. The average d ietary composition of each species and group i n January and February was not d i f f e r e n t than the average of March and A p r i l . 8. The average d ietary composition of each species and group i n May and June was not d i f f e r e n t than the average of J u l y and August. 9. The average d ietary composition of each species and group i n March and A p r i l was not d i f f e r e n t than the average of May and June. 10. The d ietary composition of each species and group i n Ju ly was not d i f f e r e n t than in August. 11. The d ietary composition of each species and group i n March was not d i f f e r e n t than i n A p r i l . 12. The d ietary composition of each species and group i n May was not d i f f e r e n t than i n June. 4.5 Forage S e l e c t i v i t y Two aspects of forage se lec t ion were considered: (1) the re la t ionsh ip between forage intake and that ava i lab le i n the plant community (Se lec t i v i t y Index), and (2) the re la t ionsh ip between forage intake and forage q u a l i t y . 4.51 S e l e c t i v i t y Index Forage se lec t ion indices were ca lcu lated for 79 plant species occurr ing on the study s i t e . Paired measurements were recorded for both botanical composition of the range and and botanical composition of the d ie t for May to August, 1977, 1978 and 1979. Addi t iona l data were co l lec ted for March, 1978 and 1979 to determine la te winter forage s e l e c t i v i t y when species a v a i l a b i l i t y was considered at a minimum. Botanical composition values for each species i n the intervening months between August and March i n each year were estimated using August values. 64 August botanical composition values for each plant species and species group were compared with ANOVA (Appendix 5) to March values i n each year to v e r i f y the assumption that no further botanical changes occured on the s i t e during t h i s per iod. Forage preference indices were ca lcu lated using the f o l l o w -ing formula developed by Van Dyne and Heady (1965): % Plant i n Diet Select ion Index(SI) = . % Plant on Range Select ion indices were ca lcu lated on a species, forage c lass (grass, forbs , shrubs), and on a seasonal basis over the 28 month sampling per iod. The representative months combined for each season were: (1) Summer (June 1977, 1978, 1979; Ju ly 1977, 1978, 1979; August 1977, 1978, 1979); (2) F a l l (September 1977, 1978; October 1977, 1978; November 1977, 1978); (3) Winter (December 1977, 1978; January 1978, 1979; February 1978, 1979); (4) Spring (March 1978, 1979; A p r i l 1978, 1979; May 1978, 1979). S e l e c t i v i t y indices greater than 1.0 indicated se lec t ion for a plant species by the captive bighorn. A ca lcu lated value of 1.0 o r . l e s s than 1.0 corresponded to : (1) no se lec t ion for or against the plant species, and (2) an aversion to the t a x a by the bighorn respect i ve ly . 4.52 Relat ionship Between Bighorn Sheep Diet and Forage Qual i ty A ser ies of 20 mul t ip le l inear and polynomial regressions to the 3rd degree were undertaken to tes t the hypotheses that there 65 i s no re la t ionsh ip between forage intake (% Diet ) , as determined through the feca l ana l ys i s , and forage concentration leve ls of N, Ca, P, and the Ca/P r a t i o . The percent composition of i n d i v i d u a l p l a n t spec ies or spec ies groups present i n the d i e t were used as the dependent var iab le for each regression and forage concentra-t ions of N, ADF, Ca, P, Ca/P r a t i o were considered the indepen-dent va r iab les . Plant cover was used as an index of forage a v a i l a b i l i t y and was also included as an add i t iona l independent va r iab le . The 20 regressions analysed are summarized i n Table 9. A t o t a l of 16 plant species with coincident measurements on percent d i e t , forage q u a l i t y and cover were included i n the an-alyses. Plant species included i n the s i x monthly analyses, and the grass, forb and shrub analyses are out l ined i n Table 10. 66 Table 9. Summary of dependent and independent variables used for 20 multiple l i n e a r regressions comparing d i e t , forage q u a l i t y and cover Regression Number Dependent V a r i a b l e s Independent V a r i a b l e s (1) Q. "8 D i e t May = N + ADF + Ca + P + Ca/P + Cover (2) % D i e t June = = N + ADF + Ca + P + Ca/P + Cover (3) % D i e t J u l y = N + ADF + Ca + P + Ca/P + Cover (4) % D i e t August : = N + ADF + Ca + P + Ca/P + Cover (5) % D i e t October = N + ADF + Ca + P + Ca/P + Cover (6) % D i e t March : = N + ADF + Ca + P + Ca/P + Cover (7) Js D i e t AGSP 1 = N + ADF + Ca + P + Ca/P + Cover (8) % D i e t BRTE = N + ADF + Ca + P + Ca/P + Cover (9) % D i e t KOCR = N + ADF + Ca + P + Ca/P + Cover (10) % D i e t STCO = N + ADF + Ca + P + Ca/P + Cover (11) % D i e t BASA = N + ADF + Ca + P + Ca/P + Cover (12) % D i e t LUSE = N + ADF + Ca + P + Ca/P + Cover (13) % D i e t ERNI = N + ADF + Ca + P + Ca/P + Cover (14) % D i e t ERHE = N + ADF + Ca + P + Ca/P + Cover (15) % D i e t ARFR = N + ADF + Ca + P +Ca/P+ Cover (16) % D i e t ARTR = N + ADF + Ca + P + Ca/P + Cover (17) % D i e t Grass : = N + ADF + Ca + P + Ca/P + Cover (18) % D i e t Forbs = N + ADF + Ca + P + Ca/P + Cover (19) % D i e t Shrubs : = N + ADF + Ca + P + Ca/P + Cover (20) Q. "O D i e t A l l Species = N + ADF + Ca + P + Ca/P + Cover 1 = B o t a n i c a l names f o r coded p l a n t s p e c i e s found i n Appendix 6. 67 Table 1 0 . Plant species included i n the monthly, grass, forb and shrub multiple regression analyses Month / Forage Class Plant Species May June July Aug. Oct. Mar. Grass Forb Shrub AGSP x l X X X X X X BRTE x X X X X X X KOCR x X X X X X POSE x X X X STCO X X X X X X X FESC X X X X X X BASA X X X X LUSE X X X X X ACMI X X X X CATH X X X SAIN X X X ARFR X X X X X X X ARTR X X X X X X X ERNI X X X X X X X ERHE X X X X X X X SYAL X X X X 1. Species present i n the monthly or forage c lass a n a l y s i s . 68 5. RESULTS AND DISCUSSION 5 .1 Bighorn Sheep Habitat Structure and Function C a l i f o r n i a bighorn sheep u t i l i z e grassland ranges for some or a l l of t h e i r annual forage requirements i n B r i t i s h Columbia. In grasslands, p r e c i p i t a t i o n coupled wi th temperature, are pre -dominant factors in f luenc ing the growth, reproduction and d i s t r i -bution of forage plants for bighorn sheep p r i m a r i l y through high evapotranspirat ion rates which increase moisture d e f i c i t s (Coup-land 1958; Carder 1970). Perhaps of lesser importance, temper-ature may l i m i t plant growth as we l l (Carder 1970), i n i t i a t i n g growth in spring (Quinton et a l . 1982) and terminat ing growth i n autumn. Var iat ions i n both annual and seasonal weather condit ions can a f fec t plant community structure and funct ion. S t ructura l responses to va r ia t ions in annual weather patterns may include changes i n the d i s t r i b u t i o n , densi ty , coverage and f l o r i s t i c composition (Coupland 1958; Shimwell 1972; Stoddart et a l . 1975). S i m i l a r l y , funct iona l a t t r ibu tes of the plant community such as phenology, production, energy f low and nutr ient a v a i l a b i l i t y of forage plants may vary also (Coupland 1958). These vagaries i n plant community structure and funct ion have been shown to a l t e r the a v a i l a b i l i t y and qua l i t y of forage for deer (Anthony 1976) and a l s o may a f f e c t mountain sheep i n the same way. 5 .11 Annual Weather Patterns During the Study Period Annual weather patterns during 1977, 1978 and 1979 deviated l i t t l e from the normals reported for the Penticton area. Max-imum, minimum and mean d a i l y temperatures conformed c lose l y to 69 the long term averages i n a l l months throughout the study (Table 5). In each year, mean maximum temperatures occurred i n Ju ly and August, and mean minimums i n December, January and February. S o i l temperatures , at both the 1 and 10 cm depth, f o l l o w e d trends s i m i l a r to a i r temperatures for those months that data were ava i lab le over the three year period (Table 11). Mean maximum values at both depths occurred i n Ju ly and August i n 1977 and i n June, Ju ly and August i n 1979. Minimum s o i l temperatures could not be determined because the s o i l temperature equipment recorded pos i t i ve values only. Table 12 summarizes growing degree days above 5°C for 1977, 1978, 1979 and normals which might re la te better to plant growth than average a i r temperatures alone. Inspection of these data reveals that t o t a l growing degree days i n 1977 and 1979 were higher than the normal values and 1978 was s i g h t l y lower. During the act ive growth period from A p r i l through June, the maximum number of growing degree days occurred in 1977 (105% of normal) and the minimum i n 1978 (96% of^ normal). With the exception of 19 79, t o t a l p r e c i p i t a t i o n exceeded the normal i n each year of the study equaling 316.4, 325.7, 278.2 and 296.2 mm for 1977, 1978, 1979 and the normal respect ive ly (Table 4). Record se t t ing r a i n f a l l i n May, 1977, exceeding 223% of the normal 27.7 mm for that month, contr ibuted to s l i g h t l y above normal p r e c i p i t a t i o n i n 1977. This was somewhat o f f se t by a very dry June and October with t o t a l r a i n f a l l i n those months equaling only 9.3 and 2.7 mm or 26.1 and 13.6% of the normals respec t i ve l y . Table 11. Soil temperatures (°C) for North (N), East (E) and means (M) + the standard deviation (S.D.) at two depths over three growing seasons from 1977 to 1979 — Year 1977 1978 1979 Month Depth (cm) N n=4 E n=4 M n=8 +S.D. N n=4 E n=4 M +S.D. n=8 -N n=4 E n=4 M n=8 +S.D. March 1 ND ND ND1 5.90 11.05 8.48 + 3.09 9.13 12.38 10.75 + 2.95 10 ND ND ND 3.20 4.00 3.60 T 0.47 5.75 7.00 6.38 0.83 April 1 11.65 11.55 11.60 + 1.08 11.63 11.88 11.75 + 1.07 10.50 12.23 11.36 + 1.34 10 8.40 9.40 8.90 T 0.69 7.25 9.65 8.45 T 1.38 7.40 9.38 8.39 1.10 May 1 17.93 15.58 16.75 + 2.37 17.45 21.00 19.25 + 2.59 23.88 22.63 23.25 + 1.31 10 13.55 13.00 13.27 0.62 14.45 15.23 14.88 T 0.65 18.00 17.83 17.91 0.47 June 1 22.13 25.58 23.85 + 2.98 18.63 20.23 19.43 + 1.22 35.90 30.87 33.39 + 3.80 10 17.50 19.05 18.28 0.98 17.38 18.10 17.74 T 0.70 24.50 21.50 23.00 1.96 July 1 31.68 31.75 31.71 + 1.23 ND ND ND 25.38 33.75 29.44 + 4.97 10 23.65 25.08 24.36 T 1.37 ND ND ND 22.38 25.38 23.85 1.71 Aug. 1 31.20 36.45 33.83 + 2.97 ND ND ND 24.63 28.50 26.56 + 3.11 10 26.20 25.63 25.91 0.52 ND ND ND 20.25 21.38 20.81 T 1.19 Sept. 1 13.55 16.98 15.26 + 1.88 ND ND ND ND ND ND 10 13.18 14.53 13.85 0.78 ND ND ND ND ND ND Oct. 1 9.90 7.88 8.74 + 1.65 ND ND ND ND ND ND 10 6.33 3.93 5.13 1.68 ND ND ND ND ND ND Nov. 1 5.95 8.05 7.00 + 1.34 0.002 0.00 0.00 ND ND ND 10 4.98 5.78 5.38 0.46 0.00 0.00 0.00 ND ND ND 1. No data as a result of equipment failure except March 1977 which preceded init iation of the study. 2. 0.00 was the minimum value that the equipment was capable of recording. 71 Table 12. Growing degree days above 5oc for Penticton, B.C. for 1977, 1978, 1979, and normals (Source: Annual Meter-o l o g i c a l Summaries, Environment Canada 1977, 1978, 1979) Year Month 1977 1978 1979 Normal January 0.0 0.0 0.0 2.1 February 5.8 0.5 6.1 4.1 March 25.6 54.2 27.9 24.2 A p r i l 153.1 109.1 102.4 115.9 May 217.9 234.5 267.4 259.7 June 413 .4 368 .8 403.1 364.7 Ju ly 448.4 503.4 507.7 469.5 August 513.4 436.4 506.2 441.5 September 262.6 270.7 336.7 290.3 October 111.7 114.8 166.7 123.6 November 19.9 11.5 2.1 20.9 December 2.8 0.0 9.5 2.8 Apr i l - June 784.4 712.4 772.9 740.3 Total 2143.2 2049.2 2301.3 2088.9 72 P r e c i p i t a t i o n was d i s t r ibu ted r e l a t i v e l y evenly throughout 1978 although January, October and December were d r i e r than normal. In contrast , above average r a i n f a l l was experienced i n A p r i l , August and September equaling 263.7, 200.4 and 204.4% of the monthly normals respect ive ly (Table 4). When these values were combined wi th the more seasonally average condit ions i n other months, 1978 resul ted i n being the wettest year during the study. P r e c i p i t a t i o n was d i s t r i b u t e d e r r a t i c a l l y i n 1979. The f i r s t three months of the year were considerably d r i e r than normal. S i m i l a r l y , and more s i g n i f i c a n t l y for plant growth, both A p r i l and June also were dry recording only 45.5 and 41.0% of the normal p r e c i p i t a t i o n for each month respect i ve ly . On the other hand, moister than normal condit ions were experienced i n August, September and October, more than doubling the long term averages for the f i r s t two months and equaling 136% of the normal value for October. Cumulative t o t a l p r e c i p i t a t i o n var ied among years w i th in selected periods of plant growth (Table 13). From March to October, which might be regarded as the t o t a l growing season, p r e c i p i t a t i o n v a r i e d from a h igh of 223.1 mm i n 1978 to a low of 191.8 mm i n 1977. The normal value for p r e c i p i t a t i o n during th i s period of 187.5 mm was exceeded i n a l l three years of the study. A p r i l to June represents a period of act ive plant growth but March s o i l moisture reserves are important for growth in A p r i l when s u f f i c i e n t heat uni ts are a v a i l a b l e . During t h i s important 0 73 Table 13. Cumulative t o t a l p r e c i p i t a t i o n (mm) during selected periods at P e n t i c t o n , B.C. during 1977, 1978 and 1979 (Source: Annual Meterological Summaries, Environment Canada 1977, 1978, 1979) Period 1977 1978 1979 Normal March-October March-June August-October 191.8 104.7 64.5 223.1 113.1 81.7 206.9 65.4 86.4 187.5 102.7 40.0 74 period p r e c i p i t a t i o n patterns var ied considerably among years with cumulative t o t a l s i n 1977 and 1978 s l i g h t l y exceeding the normal of 187.5 mm. Cumulative p r e c i p i t a t i o n i n 1977 and 1978 equaled 104.7 and 113.1 mm respect ive ly . In contrast , t o t a l p r e c i p i t a t i o n during the same period i n 1979 was the lowest among the three years of study recording only 65.4 mm or 63.7% of the normal despite the fact that the March to October accumulation of moisture for 1979 was intermediate between 1978 and 1977. R a i n f a l l i n the August-October period was higher than the normal 40.0 mm i n each year of the study exceeding 200% of normal i n 1978 and 1979. In 1977 p r e c i p i t a t i o n tota led 64.5 mm or 161.3% of normal (Table 13). Although s o i l moisture was recorded i n each year of the study (Table 14) absolute values and trends i n r e l a t i o n to pre -c i p i t a t i o n patterns must be interpreted caut iously for three reasons. F i r s t , gypsum moisture blocks notor iously produce inaccurate data although they may provide some data r e f l e c t i n g trends i n s o i l moisture (Black, pers. comm.). Second, d isc rete sampling at mid-monthly in te rva l s u n l i k e l y r e f l e c t monthly average condit ions adequately, and with long in te rva l s between samples, trends may be obscured. Thi rd , equipment f a i l u r e s resul ted i n an incomplete data set over the study period espec ia l l y during c r i t i c a l periods (May and June 1977 i n par t icu lar ) which make comparisons among years dubious. In 1977 s o i l moisture d e f i c i t s were experienced by mid-July at both the surface and 35 cm depths. These condit ions pers isted u n t i l October when some s o i l moisture recharge occurred but only Table 14. Percent soi l moisture for North (N), East (E) and means (M) _+ the standard deviation (S.D.) at two depths over three growing seasons from 1977 to 1979 Year 1977 1978 1979 Depth N E M + S.D. N E M +S.D. N E M +S.D. Month (cm) n=8 n=7 n=15 n=8 n=7 n=15 n=8 n=7 n=15 March 2 ND1 ND ND 82.13 75.71 77.80 + 1.70 76.38 66.00 71.53 +11.26 35 ND ND ND 76.88 78.86 79.13 + 9.52 72.63 71.71 72.20 T 3.08 April 2 35.00 ND 35.00 + 6.78 86.63 80.00 83.53 +10.01 63.88 52.57 58.60 +14.24 35 52.75 ND 52.75 + 1.71 81.50 82.00 81.73 T 1.75 71.38 68.14 70.53 + 4.69 May 2 ND ND ND 93.63 88.28 91.13 +11.21 0.00 0.00 0.00 35 ND ND ND 86.89 87.00 86.93 + 2.23 7.38 1.43 4.60 +10.45 June 2 ND ND ND 28.86 49.00 38.26 +25.55 20.50 22.57 21.47 +13.06 35 ND ND ND 68.63 0.00 36.60 +36.08 0.00 0.00 0.00 July 2 0.00 0.00 0.00 4.15 7.00 6.45 +12.92 0.00 0.00 0.00 35 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Aug. 2 0.00 0.00 0.00 62.50 57.29 60.06 +15.56 76.50 66.43 71.80 +15.41 35 0.00 0.00 0.00 5.00 11.00 7.80 T 5.44 0.00 0.00 0.00 Sept. 2 0.00 0.00 0.00 65.25 54.71 60.33 + 9.51 ND ND ND 35 0.00 0.00 0.00 17.00 10.87 14.13 +21.02 ND ND ND Oct. 2 28.13 10.25 19.19 +11.68 0.00 0.00 0.00 3.75 0.00 2.00 + 5.61 35 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Nov. 2 34.63 43.29 38.67 +18.65 0.00 0.00 0.00 ND ND ND 35 0.00 0.00 0.00 0.00 0.00 0.00 ND ND ND 1. No data due to equipment failure. 76 at the su r face l e v e l . No s o i l moisture was detected at 35 cm i n e i ther October or November. Favorable s o i l moisture condit ions were recorded i n the spring of 1978 with maximum leve ls reaching 91.1 and 86.9% at the two and 35 cm depth respect ive ly i n May. These leve ls lagged s l i g h t l y behind the above normal r a i n f a l l that f e l l during A p r i l . S o i l moisture d e f i c i t s were not observed u n t i l Ju ly , and then only at 35 cm. Above normal p r e c i p i t a t i o n i n August and September recharged s o i l moisture u n t i l d e f i c i t s were experienced again i n October and November. • Mean s o i l moisture leve ls were general ly lower i n March and A p r i l 1979 than for the same period i n 1978 perhaps r e f l e c t i n g the condit ions of below normal p r e c i p i t a t i o n during these months. By May average s o i l moisture was reduced to 0.0 and 4.6% at 0 and 35 cm respect i ve ly . Although the surface leve l did regain some moisture i n June, d e f i c i t leve ls prevai led from June to August and i n October at the 35 cm depth. In g e n e r a l , the East s i t e was s l i g h t l y more x e r i c than the North. In most months, s o i l temperatures were higher on the East s i t e compared to the North at both the su r face and 10 cm depths (Table 11). This undoubtly contr ibuted to the corresponding trend i n s o i l moisture leve ls which general ly were lower on the East exposure than on the North (Table 14). Average snowfal l was above normal for the area from November 1977 to A p r i l 1978 e q u a l i n g 16.0 cm compared to the long term average for t h i s s i x month period of 11.5 cm. Except for .March and A p r i l 1978, snowfal l in each month exceeded the normal. 77 Absolute depths recorded for December, January and February t o t a l e d 33.4, 45.9 and 16.6 cm or 155, 184, and 152% of the normal for the three months respect ive ly (Table 4). Conversely, snow condit ions during the 1978-1979 winter were s l i g h t l y below normal for each month from November to A p r i l except for January. Average snowfal l over the s i x month period equaled 10.5 cm although snowfal l i n January tota led 30 cm which was 120.5% of the normal. 5.12 P lant Community Descr ipt ion The plant community w i th in the bighorn enclosure provided a wide d i v e r s i t y of plant species for mountain sheep grazing throughout the year. A t o t a l of 90 plant species were ava i lab le cons is t ing of 14 grasses, 58 forbs plus 18 trees and shrubs (Table 15). Averaged over a l l s i t e s and months i n 1977, grasses dominat-ed the s i t e providing 43.2% of the coverage and 68.9% of the bo-t a n i c a l composit ion. Although forbs as a group contr ibuted the largest number of i n d i v i d u a l taxa i n the f l o r a , the i r cover and botanical cont r ibut ion only equaled 10.4 and 18.0% respect ive ly . Shrubs contr ibuted s l i g h t l y less to both cover and botanical composition than forbs , equaling 9.9 and 13.2% for each respect i ve l y . Agropyron spicatum dominated the plant community providing 22.1% of the cover and 34.7% of the botanical composition. Bromus tectorum and Artemis ia t r identa ta were the most important associated species (Table 15). Other taxa that contr ibuted more than 1% to cover or botanical composition included: Bromus 78 Table 15. Mean percent cover and botanica l composition _+ the standard dev iat ion (S.D.) averaged over a l l s i t e s and months from May to August 1977 at the Okanagan Game Farm Botanical Species Cover Composition + S.D. + S.D. ANNUAL GRASS Apera inter rupta T 0.1 + 0.5 Bromus mol l i s 1.2 + 2.3 1.7 3.2 Bromus tectorum 9.5 + 10.0 15.2 + 14.0 Festuca oc to f lo ra 0.2 + 0.9 0.3 + 1.5 Total Annual Grass 10.9 + 10.7 17.3 + 14.8 PERENNIAL GRASS/GRASSLIKE Agropyron spicatum 22.1 + 12.1 34.7 + 18.7 A r i s t i d a longiseta P P Carex petasata P P Festuca idahoensis 0.2 + 1.0 0.5 + 1.7 Festuca scabre l la 0.1 + 0.6 0.2 + 1.1 Koeler ia c r i s t a t a 3.6 + 4.2 5.5 + 6.1 Poa pratensis 0.1 + 0.3 0.9 + 0.4 Poa sandbergi i 3.2 + 3.5 5.8 + 6.5 Sporobolus cryptandrus P P St ipa comata 2.9 + 4.8 4.6 + 7.7 St ipa occ identa l i s 0.2 + 1.0 0.3 + 1.4 Total Perennial Grass 32.3 + 13.5 51.6 + 18.4 ANNUAL FORBS Agoseris heterophyl la 0.1 + 0.4 0.1 + 0.6 Capsel la bursa -pastor is P P Chenopodium album P P C o l l i n s i a p a r v i f l o r a 0.1 + 0.4 0.1 + 0.7 Collomia g rand i f lo ra P P Draba verna P P Erodium cicutar ium P P Galium boreale P P Lesquerel la doug las i i P P Microser is troximoides 0.1 + 0.3 0.1 + 0.5 Montia l i n e a r i s P P Myosotis micrantha P P Plantago patagonica 0.2 + 0.6 0.3 + 0.9 Polemonium micranthum P P 79 Table 15 (continued) Botanical Species Cover Composition + S.D. + S.D. ANNUAL FORBS (continued) Polygonum doug las i i P P Sisymbrium alt issimum P P Taraxacum o f f i c i n a l e 0.1 + 0. .1 T Tragopogon dubius 0.1 + 0, .5 0.2 + 0. .8 PERENNIAL FORBS A c h i l l e a m i l l e f o l i u m 0.8 + 1, .3 1.3 + 2. .0 Antennaria dimorpha 0.4 + 0. .7 0.7 1, .3 Antennaria p a r v i f o l i a 0.2 + 0. .8 0.4 + 1, .4 Arabis h o l b o e l l i i 0.1 + 0, .4 0.2 + 0, .6 Arnica soror ia T T Asparagus o f f i c i n a l i s P P Astragalus miser T 0.1 + 0. .3 Astragalus p u r s h i i T T Balsamorhiza sag i t ta ta 2.3 + 2, .9 3.7 + 4. .0 Calochortus macrocarpus T T C a s t i l l e j a thompsonii 0.1 + 0. .4 0.5 + 0. .9 Centaurea d i f f u s a 0.1 + 0, .4 0.1 + 0. .6 Chaenactis doug las i i T T Comandra umbellata T T Crepis atrabarba P P Delphinium b ico lo r T T Dodecatheon c u s i c k i i 0.1 + 0. .5 0.2 + 0. .8 Erigeron corymbosus T 0.1 + 0. .3 Erigeron f i l i f o l i u s T T Erigeron pumilus T T F r i t i l l a r i a pudica T T G a i l l a r d i a a r i s t a t a 0.1 + 0. .5 0.2 + 0. .8 Geum t r i f l o r u m 0.1 + 0. .3 0.1 + 0. .5 Heuchera c y l i n d r i c a P P Lewisia red iv i va T T Lithophragma p a r v i f l o r a T 0.1 + 0. .7 Lithospermum ruderale T T Lomatium macrocarpum T 0.1 + 0. .4 Lomatium tr i ternatum 0.1 + 0. .3 0.2 + 0. .6 Lupinus sericeus 0.3 + 0. .8 0.4 + 1. ,2 Opuntia f r a g i l i s 0.1 + 0. ,1 T Phacel ia hastata T T Phacel ia l i n e a r i s P P Phlox l o n g i f o l i a 0.5 + 1. .0 0.7 + 1. .4 Ranunculus glaberrimus 0.1 + 0. .4 0.2 + 0. .8 80 Table 15 (continued) Botanical Species Cover Composition + S.D. + S.D. PERENNIAL FORBS (continued) Sax i f rag ia i n t e g r i f o l i a 0.1 + 0. .8 0.1 + 1. .3 S e l a g i n e l l a wa l lace i 2.9 + 7. .4 6.0 + 15. .7 Si lene n o c t i f l o r a P P Smilacina racemosa P P Verbascum thapsus P P Zigadenus venenosus 0.1 + 0, .5 0.2 + 0. .8 Total Forbs 10.4 + 8. .0 18.0 + 15. .8 FREES AND SHRUBS Acer glabrum P P Amelanchier a l n i f o l i a P P Artemisia f r i g i d a 0.2 + 0. .5 0.2 + 0. .8 Artemisia t r identa ta 6.7 + 5. .8 9.5 + 8. .5 Berberis aquifol ium P P Chrysothamnus nauseosus 0.5 + 1. .3 0.6 + 1, .4 Eriogonum heracleoides 1.1 + 1. .8 1.7 + 2. .6 Eriogonum niveum 1.4 + 1. .9 2.4 + 3. .5 Penstemon f ru t icosus P P Philadelphus l e w i s i i P P Pinus ponderosa P P Prunus v i rg in iana P P Pseudotsuga menzies i i P P Ribes cereum P P Rhus glabra P P Rosa nutkana P P Sambucus cerulea P P Symphoricarpos albus P P Total Shrubs 9.9 + 6. .5 13.2 + 9. ,3 Moss P P L i t t e r 17.5 + 9. . 8 S o i l 16.2 + 9 . ,7 Rock 3.1 + 5. .6 Feces 0.5 0. ,9 T = Trace (less than 0.05% occurence). P = Present (p|ant species occurred on the study s i t e but were not encountered on sampled t ransec ts ) . * Totals for a species group may not equal the sum of i nd i v idua l species due to Trace values and rounding. 81 m o l l i s , Koeler ia c r i s t a t a , Poa sandbergi i , St ipa comata, A c h i l l e a m i l l e f o l i u m , Balsamorhiza s a g i t t a t a , S e l a g i n e l l a w a l l - a c e i , Eriogonum heracleoides and Eriogonum niveum (Table 15). 5.13 Temporal Variations i n Plant Species A v a i l a b i l i t y Annual and seasonal va r ia t ions in plant phenology, cover and botanical composition among phenological groups, forage classes^ and ind i v idua l species may r e s u l t from vagaries i n l o c a l weather condit ions. P o t e n t i a l l y , these var ia t ions may provide oppor-t u n i t i e s for d i v e r s i t y , i n forage se lec t ion for herbivores. 5.131 Plant Phenology Appendix 7 summarizes observations on plant phenology for 75 species p o t e n t i a l l y ava i lab le for bighorn sheep u t i l i z a t i o n over three growing seasons. Data for some species are incomplete i n 1977 because observations were i n i t i a t e d i n the f i r s t year of study a f te r plant growth had s tar ted . Four phenological groups were c l a s s i f i e d (Table 16). Con-s iderable v a r i a t i o n was observed i n the l i f e forms and number of species comprising each group. Groups II and III were the l a r -gest composed of 36 and 27 plant species respect ive ly . Groups I and IV were much smal ler containing only eight and four species respect i ve l y . Phenological patterns var ied among groups espec ia l l y with respect to f l o r a l i n i t i a t i o n and regrowth patterns. Typ ica l l y , Group I species i n i t i a t e d growth ear ly i n March and completed the i r l i f e cycles by mid-May. Flowering occurred ear ly i n both 1978 and 1979, and except for Taraxacum o f f i c i n a l e , was completed 82 Table 16. Total number of species represented i n each phenological group at the Okanagan Game Farm study s i t e Forage Class Group I Group II Group II I Group IV Annual Grass 0 4 0 0 Perennial Grass 0 1 8 0 Annual Forb 2 6 4 0 Perennial Forb 6 20 13 0 Shrub 0 5 2 4 Total 8 36 27 4 83 by ear ly May i n each year. Only Sax i f rag ia i n t e g r i f o l i a and Taraxacum o f f i c i n a l e produced any f a l l growth i n both years; the former through regrowth on establ ished plant and the l a t t e r through f a l l germination of disseminated seeds. Balsamorhiza  s a g i t t a t a , the most productive forb i n th i s group and on the s i t e , did not resprout i n the autumn of any year during the study. T isdale (1947) d id not include the ephemeral species observed i n Group I of t h i s c l a s s i f i c a t i o n i n h is d iscuss ion . However, the i r l i f e c y c l e s of ear ly growth and reproduction, com-bined with v i r t u a l l y no f a l l regrowth for most species in the group, sets these species apart from other grassland taxa. The date of growth i n i t i a t i o n i s var iab le among Group II species with some emerging i n March and other at the beginning of A p r i l (Appendix 7). This group, with the largest component of annuals, general ly completed f lower ing by mid-May to ear l y June. Regrowth or f a l l germination of annuals was somewhat e r r a t i c i n t h i s group and only 11 spec ies resumed growth i n the f a l l over the three years of observation (Appendix 7). Regrowth was common on Poa sandbergi i i n each year with t i l l e r lengths reaching 8-10 cm i n 1978 and 4-6 cm i n 1979. Bromus tectorum produced substan-t i a l regrowth i n September and October of both 1978 and 1979 producing t i l l e r s from 7-10 cm i n each year respect i ve ly . Group^ II i n t h i s c l a s s i f i c a t i o n corresponds with T isdale 's (1947) Group 2 but includes an add i t iona l 33 plant species with s i m i l a r pheno-l o g i c a l patterns (Table 16) beyond the three that he i d e n t i f i e d . Comprised of mostly perennial grasses and forbs , Group III plant species general ly i n i t i a t e d vegetative growth i n March a l -84 though several inc lud ing : A r i s t i d a long iseta , Festuca  idahoensis, Calochortus macrocarpus, Philadelphus l e w i s i i , Rosa  nutkana and Symphoricarpos albus t y p i c a l l y started l a t e r i n ear ly A p r i l . F l o r a l i n i t i a t i o n was var iab le in t h i s group ranging from mid-May to mid-Ju ly although most f lower throughout June. Of the 27 species i n Group I I I , a l l but f i v e produced f a l l regrowth i n each year of the study or i n each year that o b s e r v a t -ions were taken (Appendix 7). Agropyron spicatum, Koeler ia  c r i s t a t a , and St ipa comata a l l produced s i g n i f i c a n t regrowth i n both 1978 and 1979 t i l l e r s equaling 16-18, 8-10, and 20-25. cm for each respect ive ly i n 1978 and 8-12, 6 -8 , and 10-12 cm i n 1979. Group II I i n t h i s c l a s s i f i c a t i o n corresponds to T isdale 's (1947) Group 1 and, as with Group I I , t h i s group comprised a much larger number of species than he reported. Indeed, only Agro- pyron spicatum and St ipa comata were included i n Group 1 by Tisdale (1947). This study revealed that 27 species demonstrated s i m i l a r phenologies (Appendix 7). Group IV species mostly started growth la te r in A p r i l and general ly did not f lower u n t i l we l l in to autumn i n September and October (Appendix 7). Comprised of only shrubs, t h i s group ra re l y produced any regrowth although Eriogonum niveum did f lower fo r a second t ime i n October 1979 a f t e r an e a r l i e r f l o w e r i n g i n July and August. Group IV i n t h i s study corresponds to T isdale 's (1947) Group 3. In addi t ion to Ar temis ia t r identa ta and Chry- sothamnus nauseosus reported by Tisdale (1947), Group IV was expanded i n t h i s study and also included Artemis ia f r i g i d a and Eriogonum niveum (Appendix 7). Eriogonum niveum however, has not 85 been reported i n the Lower Grassland Zone at Kamloops where Tisdale (1947) made his phenological observations. 5.132 Cover and Botanical Composition Cover and botanical composition var ied among both years and months for t o t a l cover, phenological groups, forage c lasses and i n d i v i d u a l species r e f l e c t i n g a combination of phenological development, changing weather patterns and to some extent grazing by bighorn sheep. Maximum annual t o t a l cover occurred i n 1978 and the minimum i n 1979 which corresponded with the wettest and d r i e s t growth periods from March to June during the study respect ive ly (Table 13, Figure 6). The highest percent t o t a l cover of herbaceous mater ia l on the s i t e occurred i n May and June 1978 equaling 74.1 and 74.5% for the two months respect i ve ly . This was l i k e l y i n response to the above normal p r e c i p i t a t i o n i n A p r i l and the ove ra l l moister condi t ion that year. Except i n 1977, peak cover occurred i n May and then d e c l i n e d over t h e ' r e s t of the growing season i n each year. Deviation from t h i s pattern i n 1977 was l i k e l y a r e s u l t of the record h igh r a i n f a l l i n May f o l l o w e d by a very dry June (Table 4). Fol lowing t h i s r a i n , t o t a l cover i n -creased by 3.3 percentage points i n June and then responded to the dry June condit ions by decreasing 12.6 percentage points i n Ju l y . Forage c lasses , phenological groups and ind i v idua l species a l l displayed d i f f e r e n t patterns of growth among years and months. S i g n i f i c a n t (alpha = 0.05) year by month in te rac t ions 8 6 Pi w > o o H is w u Pi w 7 0 S -601 501 40 1 V N , 8"' a 1977 V 1978 1979 APRIL MAY JUNE JULY MONTH AUGUST Figure 6. Month by year i n t e r a c t i o n for mean t o t a l cover from A p r i l to August i n three growing seasons from 1977 to 1979 ( s i g n i f i c a n t at alpha = 0.05). 87 indicated that both coverage and botanical composition for t o t a l grass and forbs as groups var ied s i g n i f i c a n t l y among years and months but no s i g n i f i c a n t in teract ions were noted for shrubs (Figure 7, Figure 8). Maximum cover of grass occurred l a t e r than forbs i n each year although these maxima var ied for both groups among years. Grass cover peaked i n June 1977 and 1978, but i n 1979 maximum coverage did not occur u n t i l July and then t h i s value did not d i f f e r s t a t i s t i c a l l y from coverage i n May. Over-r a l l , grass achieved i t s highest cont r ibut ion to cover i n the wettest year 1978 (51.4% i n June) and i t s lowest value i n the d r i e s t year 1979 (34.2% i n August). The cont r ibut ion that grass made to botanical composition fol lowed a d i s s i m i l a r trend to cover. Although s l i g h t va r ia t ions were noted among years, t y p i c a l l y grass increased in botanical contr ibut ion from A p r i l to August i n each year (Figure 8). Maximum cover and botanical composition of forbs occurred i n May each year throughout the study although absolute values var ied among years (Figure 7, Figure 8). In 1978, forbs respond-ed to above normal moisture recording 24.1% cover and 33.3% of the botanica l composition compared to the d r i e s t year 1979 i n which t h i s group's cont r ibut ion to each was only 12.8% and 21.2% respect ive ly for t h i s month. Typ ica l l y , both cover and botanical composition of forbs decl ined a f te r May in each year as s o i l moisture reserves became depleted and by August t h e i r c o n t r i -bution to cover was less than 10%. Changes i n monthly and annual weather pattern appeared to a f fec t shrubs as a group very l i t t l e . This group demonstrated 60 50 40 30 20 10 0 Pi w > o u H 53 w Pi w PH 60 50 40 30 .. 20 -10 60 50 40 30 20 10 0 GRASS FORBS SHRUBS APRIL MAY JUNE JULY AUGUST 1977 '-tn GRASS SHRUBS FORBS APRIL MAY JUNE JULY AUGUST 1978 GRASS SHRUBS •<* FORBS APRIL MAY JUNE JULY AUGUST 1979 Figure 7. Cover of grass, forbs and shrubs from A p r i l to August i n three growing seasons from 1977 to 1979. 80 70 60 50 40 30 • 20 10 0 is 80 o £ 70 CO o w u w u PM I—I o u 1-1 < H O 60 50 40 30 20 10 80 70 60 50 40 30 20 10 I 0 JBBr tn GRASS C3~'~ #— SHRUBS FORBS APRIL MAY JUNE JULY AUGUST 1977 GRASS FORBS i=# SHRUBS APRIL MAY JUNE 1978 H — ~ JULY AUGUST tn GRASS SHRUBS FORBS j. APRIL MAY JUNE 1979 JULY AUGUST Figure 8. Botanical composition of grass, forbs and shrubs from A p r i l to August i n three growing seasons from 1977 to 1979. 90 almost no v a r i a t i o n i n coverage both among years and months remaining constant at s l i g h t l y less than 10% (Figure 7). As a r e s u l t , th i s forage c lass provided a r e l a t i v e l y s tab le , although not abundant, food source for mountain sheep throughout the growing season i n each year. In contrast , a s t a t i s t i c a l l y s i g n i f i c a n t i n te rac t ion (alpha = 0.05) between year and month indicated that trends i n shrub botanical composition over the f i v e month growing period were not s i m i l a r among years. Despite th i s i n te rac t ion however, the d i f ferences among years w i th in each month were minor (Figure 8) and l i k e l y did not a f fec t a v a i l a b i l -i t y of shrubs for mountain sheep s u b s t a n t i a l l y . S i g n i f i c a n t year by month in teract ions (alpha = 0.05) i n cover and botanical composition were recorded for Group I, Group II and Group III species. Typ ica l l y Group I achieved i t s peak cover and cont r ibut ion to botanical composition by May each year (Table 17). Cover and botanical composition var ied most both among years and months for t h i s group compared to Groups I I , I I I and IV. For example, i n 1978, under higher moisture condit ions than 19 77 and 19 79, coverage of t h i s group reached i t s o v e r a l l maximum more than t r i p l i n g the respect ive values for the other two years. By June, Group I general ly contr ibuted less than 10% to cover i n each year (Table 17). Balsamorhiza s a g i t t a t a , the most predominant species i n Group I, contr ibuted most to both cover and botanical composition compared to other species (Table 18). Although t h i s species fol lowed s i m i l a r patterns to the group as a whole with respect to growth i n i t i a t i o n , f l o r a l development and the absence of r e -91 Table 17. Seasonal changes i n mean percent cover and botanical composition of phenological groups at the Okanagan Game Farm over three growing seasons Apri l May June Bot. Bot. Bot. Cover Comp. Cover Comp. Cover Comp. July Bot. Cover Comp. August Bot. Cover Comp. GROUP I 1977 3.3 5.8 4.2 6.0 3.2 4.2 1.3 2.4 1.9 3.5 1978 9.5 14.5 14.3 19.0 6.2 8.2 4.7 7.0 2.3 3.8 1979 4.0 6.5 4.6 7.1 3.6 6.5 1.4 3.0 0.6 1.4 GROUP II 1977 15.2 27.7 19.1 29.4 19.9 29.3 15.5 26.1 15.8 26.5 1978 21.4 34.-0 22.4 31.5 26.5 35.9 21.4 32.2 14.5 25.6 1979 21.3 36.9 18.0 30.8 12.2 23.4 12.8 24.3 9.5 20.8 GROUP III 1977 25.8 42.9 31.5 46.6 1978 23.3 35.4 25.8 33.5 1979 23.6 39.3 29.4 47.7 36.1 50.8 29.5 51.8 31.7 50.7 31.4 41.5 29.0 42.1 28.7 50.4 28.5 51.4 29.8 53.9 25.6 55.5 GROUP IV 1977 9.6 14.7 1978 8.2. 11.0 1979 8.4 12.5 9.0 12.2 8.2 10.0 7.4 10.6 8.3 7.9 7.7 10.5 9.2 13.1 8.5 9.3 8.0 13.6 12.0 13.4 8.6 9.3 7.8 12.7 13.7 15.4 92 Table 18. Seasonal changes i n mean percent coverage and botan-i c a l composition of important C a l i f o r n i a bighorn sheep forage plant species at the Okanagan Game Farm over three growing seasons Apr i l May June July August Bot Bot Bot Bot Bot Cover Comp Cover Comp Cover Comp Cover Comp Cover Comp GRASSES AGSP 77 21.2 35.1 21.9 32.4 24.3 33.9 20.6 36.5 22.5 35.8 78 19.3 29.0 21.9 28.4 24.3 32.1 22.6 33.1 21.9 38.6 79 19.0 31.4 21.4 34.9 21.3 38.5 24.0 43.6 21.0 45.6 BRTE 77 4.5 8.2 7.9 12.1 12.8 18.5 11.6 19.2 10.7 17.8 78 6.4 10.3 10.4 14.8 14.9 20.6 13.4 20.5 10.1 17.7 79 11.6 20.1 10.8 18.3 8.6 16.7 10.3 20.1 7.9 17.9 FESC 77 0.0 0.0 0.2 0.3 0.0 0.0 0.1 0.2 0.2 0.3 78 0.1 0.3 0.2 0.4 0.3 0.4 0.2 0.4 0.2 0.6 79 0.3 0.6 0.3 0.6 0.2 0.4 0.1 0.2 0.2 0.1 KOCR 77 2.1 3.5 3.6 5.1 4.2 5.8 3.5 6.0 4.6 7.0 78 1.3 2.0 0.4 0.6 1.5 2.0 2.1 2.6 0.2 2.8 79 0.9 1.4 1.4 2.3 1.3 2.3 0.8 1.3 0.8 1.8 POPR 77 0.0 0.0 T 0.2 T 0.4 0.0 0.0 T 0.1 78 T 0.1 0.0 0.0 T 0.4 0.0 0.0 0.1 0.2 79 0.2 1.0 T 0.4 0.0 0.0 T 0.1 0.0 0.0 POSA 77 6.3 11.8 4.5 7.6 2.0 3.4 1.3 2.5 1.8 3.5 78 7.8 12.6 5.3 7.8 2.0 3.0 2.0 3.3 1.4 2.9 79 5.5 9.4 2.4 4.4 0.4 0.8 0.3 0.5 0.2 0.4 STCO 77 0.4 0.8 1.7 2.6 5.0 7.2 4.4 7.3 3.1 5.1 78 0.8 1.2 0.4 0.5 2.4 3.2 2.0 2.8 1.4 5.5 79 1.4 2.3 3.3 5.3 3.9 7.0 4.1 7.4 3.4 7.4 OTHR 77 0.3 0.3 1.0 2.8 3.1 4.1 1.8 3.0 2.2 3.6 78 0.3 0.4 1.1 1.3 4.4 4.9 2.4 3.2 4.4 1.5 79 0.0 0.0 1.2 1.3 1.7 2.9 1.3 2.0 0.8 1.4 TOTL 77 34.8 78 36.0 .79 38.9 59.7 41.8 63.1 55.9 39.7 53.8 66.4 40.8 67.5 51.4 73.3 43.3 74.7 45.1 73.2 49.8 66.6 44.7 65.9 39.7 69.8 37.4 68.6 40.9 75.2 34.3 74.6 93 Table 18 (continued) Apr i l May June July August Bot Bot Bot Bot Bot Cover Comp Cover Comp Cover Comp Cover Comp Cover Comp FORBS ACMI 77 0.9 1.6 1.8 2.8 0.7 1.1 0.3 0.6 0.2 0.3 78 0.7 1.1 0.8 0.9 1.0 1.3 0.8 1.2 0.6 1.1 79 0.8 1.2 1.2 1.8 0.8 1.3 0.4 0.7 0.1 0.1 BASA 77 1.3 2.4 4.0 5.8 3.2 4.2 1.3 2.4 1.9 3.4 78 0.9 1.5 4.7 6.0 5.9 7.8 4.6 6.8 2.2 3.6 79 0.8 1.4 4.0 6.1 3.5 6.4 1.4 3.0 0.6 1.4 CATH 77 0.3 0.5 0.1 0.2 0.2 0.2 0.0 0.0 0.0 0.0 78 0.2 0.3 0.4 0.3 0.4 0.5 0.1 0.2 0.0 0.1 79 0.2 0.3 0.3 0.5 0.3 0.7 0.0 0.0 0.0 0.0 LUSE 77 0.2 0.3 0.8 1.2 0.3 0.4 0.1 0.1 0.1 0.1 78 0.3 0.4 0.9 1.1 1.2 1.4 0.7 0.9 0.3 0.4 79 0.2 0.3 0.4 0.6 0.1 0.2 0.0 0.0 0.0 0.0 OTHR 77 8.1 18.0 7.0 11.2 4.9 8.6 3.3 7.2 4.3 8.4 78 17.5 27.8 16.5 23.9 6.7 10.5 6.2 11.0 4.4 9.8 79 9.3 16.8 6.7 11.8 4.3 9.2 3.4 6.2 3.2 8.3 TOTL 77 12.3 22.8 13.7 21.5 9.3 14.5 5.0 10.3 6.5 12.2 78 19.6 31.1 23.3 32.2 14.7 21.5 12.4 20.1 7.5 15.0 79 11.3 20.0 12.6 20.8 9.0 17.8 5.2 10.9 3.9 9.8 TREES AND SHRUBS ARFR 77 0..3 0.4 0.3 0.4 0.2 0.2 0.0 0.0 0.0 0.1 78 0.0 0.0 0.0 0.0 0.0 T 0.1 0.1 0.1 0.1 79 0.1 0.1 0.1 0.1 0.0 T 0.0 0.0 0.0 0.0 ARTR 77 7.0 10.5 6.9 9.2 6.5 8.1 6.6 10.4 6.5 9.4 78 7.1 9.5 7.1 8.5 6.8 7.8 7.9 10.3 7.8 11.5 79 7.5 . 11.3 6.3 9.3 6.9 11.5 7.2 12.4 6.8 13.7 CHNA 77 0.6 0.8 0.5 0.5 0.5 0.6 0.5 0.5 0.5 0.6 78 0.6 0.5 0.5 0.6 0.5 0.5 0.6 0.5 0.5 0.7 79 0.5 0.5 0.5 0.4 0.5 0.9 6.5 0.5 0.6 0.9 ERHE 77 1.5 2.5 1.5 2.1 0.9 1.3 0.7 1.3 0.8 1.4 78 0.9 1.4 0.8 1.0 0.7 0.9 0.7 1.0 0.6 1.0 79 0.6 0.9 0.2 0.4 0.2 0.4 0.3 0.5 0.1 0.1 94 Table 18 (continued) Apr i l May June July August Bot Bot Bot Bot Bot Cover Comp Cover Comp Cover Comp Cover Comp Cover Comp TREES A N D SHRUBS (continued) ERNI 77 1.7 3.0 1.3 2.1 1.1 1.5 1.5 2.7 1.5 2.7 78 0.5 0.9 0.7 1.0 0.6 0.9 0.7 1.1 0.8 1.4 79 0.3 0.5 0.4 0.8 0.3 0.6 0.3 0.6 0.3 0.8 OTHR 77 0.2 0.3 0.9 1.2 0.3 0.5 0.0 0.1 0.2 0.1 78 0.3 0.7 2.0 3.0 1.4 1.8 0.7 1.0 0.3 0.5 79 0.1 0.4 0.5 0.6 0.1 0.3 0.0 0.0 0.1 0.0 TOTL 77 11.3 17.5 11.4 15.5 9.5 12.2 9.3 15.0 9.5 14.3 78 9.4 13.0 11.1 14.1 10.0 11.9 10.7 14.0 10.1 15.2. 79 9.1 13.7 8.0 11.6 8.0 13.7 8.3 13.9 7.9 15.5 T = Trace (less than 0.05% occurrence). TOTL = Total for plant species group. OTHR = Other plant species. Bryophytes are included with forbs. * Totals for a species group may not equal the sum of individual species due to Trace values and rounding. 95 growth, i t fol lowed d i s s i m i l a r trends in annual cover and botan-i c a l composition among years and months. Except for Balsamorhiza  s a g i t t a t a , Group I species are general ly shallow rooted annuals and perennials (Appendix 7) and most are quite responsive to changes in s o i l moisture. Balsamorhiza s a g i t t a t a , wi th i t s large root system, can sustain f l u c t u a t i n g s o i l moisture condit ions more read i l y than these shallow rooted species. This was re f lec ted by t h i s species' r e l a t i v e l y stable cont r ibut ion to cover and botanical composition among years. From the standpoint of forage production for C a l i f o r n i a bighorn, the potent ia l of Group I and ind i v idua l species i n the group i s p r e d i c t e d to be low because of the s m a l l s t a t u r e of most taxa i n the group, t h e i r r e l a t i v e lack of abundance compared to other groups, and the i r v a r i a b i l i t y i n a v a i l a b i l i t y depending upon annual weather condi t ions . Two exceptions should be noted however. F i r s t , these ear ly developing plant species may provide some high q u a l i t y forage for bighorn before la te r developing taxa i n i t i a t e growth. Because these species may i n i t i a t e growth as ear ly as mid-March, t h e i r importance to bighorn n u t r i t i o n should not be underestimated since other, more productive plant species, may s t i l l be of low n u t r i t i o n a l value at that t ime. Secondly, Balsamorhiza s a g i t t a t a provides s u f f i c i e n t s t a b i l i t y i n i t s con-t r i b u t i o n to both cover and botanica l composition that i t can be considered a r e l a t i v e l y ce r ta in forage resource for mountain sheep i n ear ly spr ing. Group II showed less amplitude i n f luc tuat ions of cover and botanical composition than Group I (Table 17). Trends in 96 both cover and botanical composition were s i m i l a r for t h i s group among years and months although, i n 1977, the absolute maximum recorded i n the data for cover occurred s l i g h t l y la te r i n June but for botanical composition i t occurred i n May. Differences i n mean botanical composition between May and June 1977 were not s t a t i s t i c a l l y s i g n i f i c a n t (alpha = 0.10) however. In 1979, maximum cover and botanical composition of Group II occurred much e a r l i e r than in 1977 and 1978. In contrast to those two years, both peaked simultaneously with Group I i n A p r i l . During t h i s year, cover of Group II decl ined from 21.3% in A p r i l to 9.5% i n August and botanical composition from 36.9% to 20.8% over the same months. This d i f ference compared to other years l i k e l y occurred because of the extremely dry spring which t h i s group, wi th the greatest i nc lus ion of annuals, would respond dramat ical ly t o . Indiv idual Group II species fol lowed trends i n cover and botanical composition among years and months s i m i l a r to the parent group although the magnitude of annual and seasonal changes var ied among species. For example, both cover and bo-t a n i c a l composition of Bromus tectorum, var ied considerably among years with the greatest v a r i a t i o n w i th in a s ing le month occurr ing i n A p r i l for both parameters (Table 18). Cover and botanical composition for th i s winter annual i n 1979 were 11.6% and 20.1% which nearly t r i p l e d the respective ove ra l l minimum values of 4.5 and 8.2% for each i n 1977. Maximum cover of Bromus tectorum was recorded i n June and July 1978 with t h i s species accounting for 14.9 and 13.4% of the t o t a l herbaceous cover. 97 Although large var ia t ions i n cover and botanical com-pos i t ion were apparent for Poa sandbergi i when 1977 and 1978 values were compared to those i n 1979 for June, Ju ly and August, no s t a t i s t i c a l d i f ferences for the year by month in te rac t ion were determined for e i ther . S t a t i s t i c a l l y s i g n i f i c a n t annual d i f f e r -ences (alpha = 0.05) were noted when both were averaged over a l l leve ls of s i t e and month however, with cover equaling 3.2, 3.7, and 1.7%, and botanical composition t o t a l i n g 5.8, 5.9 and 3.1% for 1977, 1978 and 1979 respect i ve ly . No s i g n i f i c a n t year by month in teract ions i n cover and botanical composition were determined for other Group II species such as C a s t i l l e j a thompsonii , Lupinus sericeus and Eriogonum  heracleoides although minor va r ia t ions were observed among year by month means (Table 18). A s t a t i s t i c a l l y s i g n i f i c a n t (alpha = 0.05) d i f ference i n both cover and botanical composition was encountered among years for Lupinus sericeus however, and as with other species i n th i s group, both recorded the i r lowest values i n 1979. When cover and botanical composition were averaged over a l l leve ls of S i te and Month i n 1977, 1978 and 1979 for th i s spec ies they equaled 0.8, 1.3 and 0.6%, and 3 .2 , 3.7 and 1.7% respect ive ly for each year. Dominated by forbs , and p a r t i c u l a r l y perennial forbs (Table 16), Group II o f fe rs a diverse but somewhat var iab le source of forage for mountain sheep. With the exceptions of Bromus  tectorum, Bromus m o l l i s , Poa sandbergi i and Eriogonum  heracleoides, i nd i v idua l members of t h i s group general ly com-pr ised less than 1% of the annual cover and botanical composition 98 (Table 15) yet c o l l e c t i v e l y they provided approximately between 9.5 and 36.9% of the botanical composition ava i lab le for grazing. This group i s l i k e l y most important for bighorn forage during the spring and ear ly summer grazing period. However, some of the browse species such as Acer glabrum, Amelanchier a l n i f o l i a , Eriogonum heracleoides and Prunus v i r g i n i a n a (Appendix 7) extend the potent ia l for use of t h i s groups to the rest of the year as wel 1. Although a s t a t i s t i c a l l y s i g n i f i c a n t i n te rac t ion (alpha = 0.05) was determined between year and month for cover and botan-i c a l composition of Group I I I , both remained r e l a t i v e l y stable among years, and months w i th in years compared to Group I and Group II (Table 17). Maximum cover occurred i n June i n both 1977 and 1978 (36.1 and 31.4%) and the minima occurred i n A p r i l (25.8 and 23.3%) i n each year respect i ve ly . Although the highest cover value i n 1979 was determined i n Ju ly (29.8%), no s t a t -i s t i c a l d i f ference was noted between t h i s value and those for May (29.4%) and June (28.5%). The dry three month period from A p r i l to June l i k e l y stagnated any further growth a f te r plants i n t h i s group, which t y p i c a l l y have deeper root systems than Group I and Group II species (Tisdale 1947), depleted res idua l s o i l moisture from spring snow melt and r a i n s . Trends i n botanical composition fol lowed a d i f f e r e n t pattern for Group III compared to cover. The highest cont r ibut ion t h i s group made to botanical composition i n 1977 occurred i n Ju ly (51.8%) and t h i s was further delayed i n 1978 and 1979 u n t i l August when i t equaled 50.4 and 55.5% respect ive ly (Table 17). 99 Minima i n botanical composition were recorded i n A p r i l for 1977 and 1979 , but i n 1978 t h i s va lue was observed i n May which a l s o was the lowest value of 33.5% recorded for t h i s group through-out the study. Not s u r p r i s i n g l y , Agropyron spicatum, which was the Group III dominant, fol lowed s i m i l a r trends i n cover and botanical composition as the overa l l group (Table 18). Although s i g n i f -icant year by month in teract ions were determined for cover (alpha = 0.10) and botanical composition (alpha = 0.05), f luc tuat ions i n both were r e l a t i v e l y minor among years, and months w i t h i n years. Maximum coverage of Agropyron spicatum was recorded i n June 1977 and June 1978 equaling 24.3% for both years, and the minimum value was observed i n A p r i l 1979 when cover tota led 19.0%. Corresponding times for the highest and lowest cont r ibut ion that t h i s species made to botanical composition occurred i n August 1979 (45.6%) and May 1978 (28.4%). To emphasize the importance of Agropyron spicatum to Group I I I , at maximum cover t h i s species represented 67.3 and 77.4% of the cover for the group i n June 1977 and June 1978 respect i ve ly . S i m i l a r l y , at i t s minimum coverage t h i s species s t i l l contr ibuted 80.5% to the t o t a l group cover. Trends i n cover and botanical composition var ied among other Group III plant species as we l l (Table 18). S i g n i f i c a n t year by month in te rac t ions (alpha = 0.05) for both were determined for St ipa comata and A c h i l l e a m i l l e f o l i u m but no s i g n i f i c a n t i n t e r -act ions were detected for Koeler ia c r i s t a t a , Festuca scabre l la or Poa pratens is . 100 Cover of St ipa comata peaked i n June 1977 (5.0%) and 1978 (2.4%) but reached i t s maximum value i n Ju ly 1979 (4.1%), although t h i s l a s t value was not s t a t i s t i c a l l y d i f f e r e n t than that recorded for June 1979 (Table 18). Minima i n coverage for th i s species occurred i n A p r i l 1977 (0.4%), May 1978 (0.4%) and A p r i l 1979 (1.4%). Trends i n botanical composition fol lowed a s i m i l a r pattern (Table 18). Although no s t a t i s t i c a l l y s i g n i f i c a n t i n te rac t ion was determined between year and month for Koeler ia c r i s t a t a , s t a t i s t i c a l d i f ferences (alpha = 0.05) were ca lcu lated among years when the year e f f e c t was averaged over a l l l e v e l s of s i t e and month. Both cover and botanical composition decl ined from 1977 to 1979 e q u a l i n g 3.6, 1.4 and 1.0%, and 5 .5 , 2.0 and 1.8% for each respect ive ly over the three year per iod. A c h i l l e a m i l l e f o l i u m , the most predominant forb i n Group I I I , d isplayed a s l i g h t l y d i f f e r e n t pattern i n i t s cont r ibut ion to cover and botanica l composition compared to other taxa i n the group. Cover and botanical compostion peaked s l i g h t l y e a r l i e r than other major species i n t h i s group with maxima for both occurr ing i n May 1977 and 1979, and i n June 1978. No c learcut pattern with respect to minimum cover or botanical composition could be discerned from the data (Table 18) although they suggested that the lowest values of both occurred i n August each year. S i m i l a r l y , no d e f i n i t e trends could be discerned for Festuca scabre l la and Poa pratensis (Table 18). Group I I I , with the largest i nc lus ion of perennial grasses, not only provides s t a b i l i t y throughout the growing season but 101 suppl ies a continued forage source for mountain sheep into the f a l l , winter and ear ly spring grazing periods. Shrubs such as Philadelphus l e w i s i i , Rosa nutkana and Symphoricarpos albus complement the herbaceous species and o f fe r the potent ia l for year round use by bighorn. Typ ica l l y these deeply rooted species tend to react less dramat ica l l y to changes i n annual and seasonal weather patterns than shallow rooted species however, there i s considerable v a r i a b i l i t y among taxa i n the i r phenological growth patterns w i th in th i s group (Appendix 7). Consequently, t h i s resu l t s i n the forage environment being s t r a t i f i e d i n a s l i g h t l y d i f f e r e n t manner than the above groups and var ia t ions among plant species may be more important to bighorn forage a v a i l a b i l i t y than annual and seasonal va r ia t ions exhibi ted by other groups. Both cover and botanica l composition of Group IV, which i s comprised e n t i r e l y of shrubs (Appendix 7), remained r e l a t i v e l y stable over each growing season (Table 17). No s i g n i f i c a n t i n te rac t ion was determined between year and month for cover but a s i g n i f i c a n t i n t e r a c t i o n was detected (alpha = 0.05) for botanica l composition of t h i s group. Although a s t a t i s t i c a l d i f ference (alpha = 0.05) i n cover was determined among months when months were averaged over a l l years and s i t e s , these d i f ferences were not of much b i o l o g i c a l s i g n i f i c a n c e . The maximum average cover age of Group IV occurred i n A p r i l 1977 (9.6%) and the minimum in May 1979 (7.4%) with a l l other values intermediate. The s i g n i f i c a n t i n te rac t ion between year and month for bo-t a n i c a l composition of Group IV indicated that seasonal c o n t r i -butions of t h i s group to t o t a l botanical composition var ied among 102 y e a r s ( F i g u r e 9). L i k e l y t h e g r e a t e s t f a c t o r a f f e c t i n g Group IV's c o n t r i b u t i o n t o b o t a n i c a l c o m p o s i t i o n i s t h e c h a n g i n g pheno-l o g i c a l p a t t e r n s o f o t h e r , more d y n a m i c p l a n t s p e c i e s s u c h as f o r b s and a n n u a l g r a s s e s whose p r e s e n c e o r a b s e n c e w o u l d a f f e c t t h e r e l a t i v e p r o p o r t i o n t h a t t h i s g r o u p c o n t r i b u t e s . However, i t s h o u l d be e m p h a s i z e d t h a t s u c h c h a n g e s i n o t h e r components o f t h e f l o r a a l t e r s t h e r e l a t i v e a v a i l a b i l i t y o f Group IV s p e c i e s f o r m o u n t a i n sheep. T y p i c a l l y , t h e b o t a n i c a l c o n t r i b u t i o n o f Group IV d e c l i n e d f r o m A p r i l t o May a n d J u n e when t h e n u m b e r o f f o r b s i n t h e s t a n d i n c r e a s e d a n d t h e n i n c r e a s e d i n J u l y a n d A u g u s t when t h e s e p l a n t s p e c i e s d i s a p p e a r e d a t t h e c o m p l e t i o n o f t h e i r l i f e c y c l e s . No s i g n i f i c a n t y e a r by month i n t e r a c t i o n s i n c o v e r were d e t e r m i n e d f o r any o f t h e i n d i v i d u a l Group IV s p e c i e s s u c h as A r t e m i s i a f r i g i d a , A r t e m i s i a t r i d e n t a t a , C h r y s o t h a m n u s n a u s e o s u s o r E r i o g o n u m n i v eum . However, a s i g n i f i c a n t y e a r and month e f f e c t ( a l p h a = 0.05) i n b o t a n i c a l c o m p o s i t i o n were o b s e r v e d f o r A r t e m i s i a t r i d e n t a t a b u t n o t f o r o t h e r s p e c i e s i n Group IV. When a v e r a g e d o v e r a l l l e v e l s o f s i t e , and month b o t a n i c a l c o m p o s i t i o n o f t h i s s p e c i e s r e m a i n e d t h e same a t 9.5% i n 1977 and 1978 b u t i n c r e a s e d t o 11.6% i n 1979. A v e r a g e m o n t h l y c o m p o s i t i o n f o l l o w e d t h e same g e n e r a l t r e n d as t h e g r o u p w i t h maximum v a l u e s o c c u r r i n g i n A p r i l ( 1 0 . 5 % ) , J u l y (11.3%) a n d A u g u s t ( 1 1 . 5 % ) , a n d m i n i m a o c c u r r i n g i n May (9.0%) and June (9.2%). A p r i l , J u l y and A u g u s t v a l u e s were d i f f e r e n t s t a t i s t i c a l l y ( a l p h a = 0.10) t h a n t h o s e f r o m May and June. E r i o g o n u m n i v e u m was t h e o n l y o t h e r s p e c i e s i n t h i s g r o u p 8 1 1 L L 1 I APRIL MAY JUNE JULY AUGUST MONTH Figure 9. The i n t e r a c t i o n between month and year f o r botanical composition of Group IV from A p r i l to August i n three growing seasons from 1977 to 1979 ( s i g n i f i c a n t at alpha = 0.05). 104 demonstrating any changes i n e i ther cover or botanical composi-t i o n . Averaged over a l l leve ls of s i t e and month, mean values for cover and botanical composition decl ined from 1.4 and 2.4% i n 1977 to 0.3 and 0.6% i n 1979 for each respect ive ly . Group IV represented the most stable potent ia l source of forage for mountain sheep on the research s i t e . This group not only was abundant during the growing season but remained exposed and ava i lab le to mountain sheep throughout the rest of the year. A d d i t i o n a l l y , a l l taxa i n t h i s group were "evergreen" providing both woody and leafy mater ia l that was p o t e n t i a l l y ava i lab le as bighorn forage i n a l l months of the year. 5.14 Forage Production Although cover and botanical composition data provide useful estimates of r e l a t i v e a v a i l a b i l i t y of i nd i v idua l species and forage groups for bighorn sheep, net primary production of above ground biomass ( total standing crop or forage production) deter -mines how much herbage i s a c t u a l l y ava i lab le . In grassland plant communities, t o t a l standing crop and that of i nd i v idua l species vary both temporal ly and s p a c i a l l y p r i m a r i l y i n response to s o i l , moisture condit ions and temperature (Coupland 1958; Stoddart et a l . 1975). Subsequent va r ia t ions i n forage y i e l d a l t e r both the grazing capacity of the range and a v a i l a b i l i t y patterns of forages both annually and throughout the grazing season. Factors a f f e c t i n g - a v a i l a b i l i t y of biomass include : (1) Growth functions of i nd i v idua l plants re lated to phenological patterns which i n turn are re lated to annual and seasonal weather condi t ions , s o i l and s i t e f a c t o r s , adaptations of component plant species i n the f l o r a , and the inf luence of previous grazing i n the plant community. 105 (2) The a b i l i t y of the plant community to respond to add i t iona l inputs into the ecosystem through increments i n p r e c i p i t a t i o n and favorable temperatures espec ia l l y i n the autumn when growth nor-mally terminates. (3) Decay rates of mature plants fo l low ing cessat ion of the current annual production which re lates to carryover of herbage throughout the rest of the grazing year. This study invest igated the inf luences of annual weather patterns, s i t e and autumn weather condit ions on forage produc-t ion . 5.141 Influence of Annual Weather Patterns on Forage Production The i n t e r a c t i o n between year and grazing was of primary i n -terest to del ineate the potent ia l e f fec ts of both annual weather and foraging by bighorn sheep on standing crop. This sect ion deals with the former, the l a t t e r w i l l be discussed l a t e r . S t a t i s t i c a l l y s i g n i f i c a n t in teract ions were observed between year, which was assumed to r e f l e c t annual weather patterns , and grazing for Koeler ia c r i s t a t a , Poa sandbergi i , St ipa comata, Bromus tectorum and t o t a l standing crop (alpha = 0.05) , and for t o t a l annual grass, t o t a l other forbs (alpha = 0.10). In ter -act ions were not s i g n i f i c a n t for Agropyron spicatum, t o t a l perennial grass, Balsamorhiza s a g i t t a t a and Eriogonum niveum (Table 19). On the ungrazed s i t e s , production for t o t a l standing crop averaged 54.43 +_ 9.85 g/m2 over a l l s i t e s and years but var ied from 41.01 to 62.95 g/m2 i n 1977 and 1978 respect ive ly (Table 20). Y ie lds in 1976 and 1979 were intermediate between these extremes equaling 60.28 and 52.30 g/m2 for the two years respec t i ve l y . 106 Table 19. Significance of single degree of freedom contrasts for interactions between year and grazing on herbage y i e l d s of 11 vegetative groups at the Okanagan Game Farm, 1976-1979 Contrasts Vegetative Group 1 2 3 Agropyron spicatum NS NS NS Koeler ia c r i s t a t a ND NS ** Poa sandbergi i ND ** ** St ipa comata ND ** ** Total Perennial Grass NS NS NS Bromus tectorum ND ** NS Total Annual Grass * NS NS Balsamorhiza s a g i t t a t a NS NS NS Total Other Forbs NS NS NS Eriogonum niveum ND NS NS Total Standing Crop ** ** ** ** S i g n i f i c a n t at alpha = 0.05 * S i g n i f i c a n t at alpha = 0.10 NS Not s i g n i f i c a n t ND No data Contrasts 1. (Grazed vs Ungrazed) (1976 vs 1977 + 1978 +1979) 2. (Grazed vs Ungrazed) (1977 vs 1978 + 1979) 3. (Grazed vs Ungrazed) (1978 vs 1979) 107 Table 20. Total forage production and remaining herbage y i e l d s (g/m2) fo r 11 vegetative groups on areas grazed (G) and ungrazed (UG) respect i ve ly by C a l i f o r n i a bighorn sheep at the Okanagan Game Farm, 1976-1979 1976 1977 1978 1979 Vegetative Group G UG G UG G UG G UG Agropyron spicatum 28.47 24.55 14.30 10.93 27.43 35.19 15.91 33.57 Koeleria cristata 1.91 2.44 1.36 • 2.81 0.62 2.49 Poa sandbergii 0.13 0.03 0.02 0.00 0.02 0.19 Stipa comata 2.05 7.83 0.05 5.17 1.18 2.26 Total Perennial Grass 32.66 29.36 18.39 21.23 28.86 43.17 17.01 38.51 Bromus tectorum 1.97 7.57 6.52 5.58 2.89 4.14 Total Annual Grass 4.76 14.97 4.78 11.12 7.02 6.23 3.43 4.59 Balsamorhiza sagittata 8.99 7.98 0.23 1.88 2.64 3.29 2.69 2.28 Total Other Forbs 15.07 7.97 0.82 4.17 1.52 7.28 1.34 5.04 Eriogonum niveum 0.45 2.61 0.21 2.98 0.27 1.88 Total Standing Crop 61.48 60.28 24.67 41.01 40.25 62.95 24.74 52.30 108 Of the 10 other v e g e t a t i v e groups s t u d i e d , only t o t a l other f o r b s , K o e l e r i a c r i s t a t a , Agropyron spicatum, and t o t a l p e r e n n i a l grass f o l l o w e d trends i n herbage p r o d u c t i o n s i m i l a r to t o t a l s t a n d i n g crop. Absolute y i e l d s of t o t a l other f o r b s v a r i e d con-s i d e r a b l y among y e a r s from a maximum o f 7.97 g/m 2 i n 1976 t o a minimum of 4.17 g/m 2 i n 1977 (Table 20). However t h e i r c o n t r i b u t i o n to t o t a l s t anding crop v a r i e d l e s s among years e q u a l i n g 13.2, 10.1, 11.6 and 9.6% of the t o t a l biomass produced i n 1976, 1977, 1978 and 1979 r e s p e c t i v e l y (Table 21). Only minor v a r i a t i o n s i n p r o d u c t i o n of K o e l e r i a c r i s t a t a were observed among years, and i n a l l years t h i s s p e c i e s c o n t r i b u t e d l i t t l e to t o t a l s t anding crop e q u a l i n g o n l y 6.0, 3.0 and 4.8% of the t o t a l above ground biomass i n 1977, 1978 and 1979 r e s p e c t i v e l y (Table 21) . The i n t e r a c t i o n between year and g r a z i n g f o r biomass produc-t i o n of Agropyron spicatum and t o t a l p e r e n n i a l grass was not s t a t i s t i c a l l y s i g n i f i c a n t , however s i g n i f i c a n t annual d i f f e r e n c e s (alpha = 0.10 and alpha = 0.05 f o r each r e s p e c t i v e l y ) were de-t e c t e d f o r both v e g e t a t i v e groups (Table 22).. Both Agropyron  spicatum and t o t a l p e r e n n i a l g r a s s , which was composed p r i m a r i l y of Agropyron spicatum, were major components of t o t a l s t anding crop i n a l l years of the study. Agropyron spicatum produced 40.7, 26.7, 55.9 and 63.0% o f the t o t a l herbage y i e l d i n 1976 , 1977, 1978, and 1979 r e s p e c t i v e l y (Table 21). Y i e l d s of t o t a l p e r e n n i a l grass exceeded 45% of the t o t a l biomass produced i n each year (Table 21). The c o n t r i b u t i o n of t h i s group to t o t a l s t a n d i n g crop v a r i e d from 48.8% i n 1976 to 73.6% i n 1979. 109 Table 21. Re lat ive production of vegetative groups expressed as a percentage of t o t a l standing crop Vegetative Group 1976 1977 1978 1979 Agropyron spicatum 40.7 26.7 55.9 63.0 Koeler ia c r i s t a t a ND 6.0 3.0 4.8 Poa sandbergi i ND 0.1 0.0 0.4 St ipa comata ND 19.0 8.2 4.3 Total Perennial Grass 48.8 51.8 68.6 73 .6 Bromus tectorum ND 18.5 8.9 7.9 Total Annual Grass 24.8 27.1 9.9 8.8 Balsamorhiza s a g i t t a t a 13.2 4.6 5.2 4.4 Total Other Forbs 13.2 10.1 11.6 9.6 Eriogonum niveum ND 6.4 4.7 3.6 Total Standing Crop 100.0 100.0 100.0 100.0 = No data a v a i l a b l e . 110 T a b l e 22. Annual f o r a g e p r o d u c t i o n f o r Ag r o p y r o n s p i c a t u m averaged o v e r a l l l e v e l s o f s i t e and g r a z i n g Species 1976 1977 1978 1979 Agropyron spicatum 26.65b 12.61a 31.31b 24.74b Means followed by d i f f e r e n t l e t t e r s i n the same row are s i g n i f i c a n t l y d i f f e r e n t by Student Newman Ke u l s 1 t e s t at alpha = 0.05. I l l Poa sandbergi i , St ipa comata, Bromus tectorum, t o t a l annual grass, Eriogonum niveum, Balsamorhiza s a g i t t a t a , and t o t a l other forbs a l l fo l lowed d i f f e r e n t trends i n annual forage production than t o t a l standing crop (Table 20). Poa sandbergii was most productive i n 1979 and y ie lded the least i n 1978. Although s t a t i s t i c a l d i f ferences were detected among years, absolute an-nual y ie lds were exiguous with th i s species only cont r ibut ing 0.1, 0.0 and 0.4% to the net primary production i n 1977, 1978 and 1979 respect ive ly (Table 21). Unlike most other vegetative groups studied, maximum and minimum herbage y i e l d s for St ipa comata occurred i n 1977 (7.83 g/m2) and 1979 (2.26 g/m2) respect i ve ly . An apparent downward trend i n absolute production was evident over the three years of study on the ungrazed p lots (Table 20). Inspection of Table 21 a f f i rms th i s trend as the proport ion of t o t a l standing crop comprised of St ipa comata decl ined from 19.0% i n 1977 to 4.3% i n 1979. Total annual grass was most productive i n 1976 and least productive i n 1979 (Table 20). L ike St ipa comata, there was a downward trend i n both the absolute y ie lds and the r e l a t i v e proportion that th i s vegetative group contr ibuted to t o t a l standing crop over the four year per iod. Bromus tectorum, which was the major const i tuent of t o t a l annual grass, was not sampled as an i n d i v i d u a l species i n 19 76. However, i t s response to annual weather from 1977 to 1979 corresponded c l o s e l y to that of t o t a l annual grass. In 1977, Bromus tectorum represented 18.5% of t o t a l standing crop^y ie ld ing 7.57 g/m2 but decl ined to 7.9% of 112 the t o t a l production (4.14 g/m2) by 1979 (Table 20). However, mean absolute y ie lds were not s t a t i s t i c a l l y s i g n i f i c a n t among years. Annual herbage production of Balsamorhiza sag i t ta ta did not d i f f e r s i g n i f i c a n t l y among years on the ungrazed areas although i t contr ibuted s u b s t a n t i a l l y to percent t o t a l standing crop i n each year (Table 20, Table 21). Balsamorhiza s a g i t t a t a was most productive i n 1976 y i e l d i n g 7.98 g/m2 or 13.2% of the t o t a l standing crop and least productive i n 1977 averaging 1.88 g/m2. Although Eriogonum niveum produced i t s maximum absolute y i e l d i n 1978 (2.98 g/m2) i t too progressively decl ined i n pro-port ion to t o t a l standing crop from 1977 to 1979. In 1977 t h i s species comprised 6.4% of the t o t a l herbage produced but by 1979 i t represented only 3.6% of the t o t a l standing crop. Y ie lds for t o t a l standing crop reported here f a l l w i t h i n the range of values for t o t a l forage production i n s i m i l a r vegetation types at approximately the same e levat ion reported by others i n the Kamloops, Okanagan and Similkameen areas. For example, T isdale (1947) reported that herbage y ie lds equaled 39 g/m2 when t o t a l standing crop was averaged on two cl imax Artemis ia  t r identa ta - Agropyron spicatum s i t e s i n the Kamloops area. Marchand (1964) studied four s i t e s near Summerland i n the Okanagan and eight add i t iona l s i t e s at Kamloops. At a l l s i tes the Ar temis ia understory was dominated by Agropyron spicatum. Average t o t a l standing crop at both locat ions were higher than those determined i n t h i s study equaling 100.5 and 80.6 g/m2 for the two locat ions respect ive ly . 113 McLean (1969) described t o t a l p roduct i v i t y for two s i t e s i n the Similkameen Val ley near Hedley. Averages for the same f i v e year period on each s i t e indicated that production between the two was markedly d i f f e r e n t ; one y i e l d i n g only 20.9 g/m2 and the other 41.5 g/m 2. A d d i t i o n a l l y , conspicuous annual va r ia t ions i n t o t a l standing crop were observed on h is s i t e s with herbage y ie lds ranging from 7.4 to 32.5 g/m2 (442%) and from 31.7 to 53.3 g/m2 (168%) on the lower and higher producing s i t e s respect i ve ly . Some data from C a l i f o r n i a bighorn range i n B r i t i s h Columbia also suggest that s i m i l a r va r ia t ions i n forage production occur on natural bighorn ranges. Demarchi (1973a), summarizing forage production values from several studies (Blood 1961; Demarchi 1965; Schef f le r 1972) i n the Ashnola and with o r i g i n a l data, demonstrated that y i e l d s on high e levat ion grassland dominated by Agropyron spicatum v a r i e d from a minimum of 77.1 g/m 2 i n 1960 to 228.0 g/m 2 i n 1972. This d i f ference over the 12 year period equaled 295.7%, however not a l l of the v a r i a t i o n could be a t t r i -buted to annual weather patterns because the range was recovering from past overuse by domestic l i ves tock (Demarchi 1973a). Re-peated measurements i n 1971 and 1972 on two of these ungrazed s i t e s indicated annual v a r i a t i o n i n production more c l e a r l y wi th one s i t e i n c r e a s i n g from 191 g/m 2 to 228 g/m 2 and the other decreas ing from 94 g/m 2 to 69 g/m 2 over the two years respec t i ve l y . In t h i s study t o t a l standing crop only var ied 154% between the extreme years of 1977 and 1979. However, these resu l t s are not su rp r i s ing considering the r e l a t i v e l y minor v a r i a t i o n i n \ 114 AN ' 3 annual weather among years, e s p e c i a l l y w i t h r e s p e c t to t o t a l p r e c i p i t a t i o n (Table 4) and growing degree days (Table 12). Maximum p r o d u c t i o n of t o t a l s t anding crop, t o t a l other f o r b s , K o e l e r i a c r i s t a t a , Agropyron spicatum and t o t a l p e r e n n i a l grass c o i n c i d e d w i t h the most f a v o r a b l e moisture c o n d i t i o n s among the three years. Accumulation of growing degree days was approx-i m a t e l y normal u n t i l June and J u l y i n 1978 which were s l i g h t l y h i gher than the long term averages f o r these months. In August however, the number of growing degree days was s l i g h t l y lower than normal and s u b s t a n t i a l l y lower than the corresponding v a l u e s f o r the same month i n 1977 and 1979. T h i s s l i g h t l y c o o l e r c o n d i -t i o n i n August, combined w i t h above normal p r e c i p i t a t i o n f o r the month, may have extended an a l r e a d y f a v o r a b l e growing season i n 1978. Although t o t a l annual p r e c i p i t a t i o n d i d not vary s u b s t a n t -i a l l y among years (Table 4), the March-October t o t a l was l e a s t i n 1977 compared to 1978 and 1979. Perhaps the most s i g n i f i c a n t f a c t o r a f f e c t i n g herbage p r o d u c t i o n i n 1977 was the heterogen-eous d i s t r i b u t i o n of moisture. In p a r t i c u l a r , r a i n f a l l i n June, one of the c r i t i c a l growing months, was on l y 9.3 mm or 26.1% of the normal 35.6 mm f o r t h a t month. U n f o r t u n a t e l y , c o r r e s p o n d i n g s o i l moisture data f o r June are l a c k i n g , but d e s p i t e near normal p r e c i p i t a t i o n i n J u l y , s o i l moisture d e f i c i t s continued from J u l y through to mid-August. The number of growing degree days from A p r i l to August was higher i n 1977 (1746.2) than 1978 (1652.2) (Table 12). Although these r e l a t i v e l y warmer c o n d i t i o n s may have a c c e l e r a t e d p l a n t growth e a r l y i n the season when s o i l moisture 115 was not l i m i t i n g , la te r i n June they may have combined with s o i l moisture d e f i c i t s r e s u l t i n g i n a t runcat ion of the growing season by about one month. The combination of above normal annual p r e c i p i t a t i o n and growing degree days i n 1979 suggest that th i s year might have been favorable for plant growth. Indeed, t o t a l standing crop i n 1979 was 83% of the 1978 production but below normal p r e c i p -i t a t i o n between March and June l i k e l y r e s t r i c t e d plant growth (Table 13). Although cumulative p r e c i p i t a t i o n during t h i s period was only 64% of normal, r a i n f a l l was.more homogeneously d i s t r i -buted throughout the act ive growing period i n 1979 than i n 1977 which l i k e l y accounts for the greater y ie lds i n forage production i n 1979. As previously mentioned, Bromus tectorum and St ipa comata both y ie lded the i r greatest herbage production i n 1977. Bromus  tectorum i s a we l l known vernal winter annual that t y p i c a l l y completes i t s l i f e h is to ry ear ly i n the growing season (Dauben-mire 1940; Klemmedson and Smith 1964). Despite 1977 being the d r i e s t of the three years, the record r a i n f a l l recorded i n May, combined with s u f f i c i e n t s o i l moisture i n A p r i l to i n i t i a t e growth, was l i k e l y responsible for the r e l a t i v e l y high produc-t i v i t y observed for t h i s species. The l i t t l e r a i n f a l l that f e l l during June occurred ear ly i n the month a l lowing t h i s species to successfu l l y complete i t s l i f e cycle under r e l a t i v e l y favorable moisture condi t ions . St ipa comata, which i s better adapted to droughty s o i l condit ions than other species such as Agropyron spicatum (Parsons 116 et a l . 1971) a lso normally develops ear ly and completes i t s phen-ology before the summer drought (Tisdale 1947). The abnormally wet May fol lowed by the unusually dry condit ions i n June may have provided t h i s species with a competit ive advantage for s o i l moisture i n 1977. By.May 26, 97.6% of the monthly p r e c i p i t a t i o n had f a l l e n , l i k e l y providing adequate s o i l moisture for a l l species on the study s i t e . From th i s date u n t i l the end of Ju ly there were 15 r a i n f a l l events but only one exceeded 4.0 mm. These i n d i v i d u a l , but s m a l l , increments of r a i n f a l l may have penetrated the s o i l s u f f i c i e n t l y to provide some moisture for continued growth of St ipa comata but l i k e l y d id not percolate far enough into the s o i l p r o f i l e to maintain growth of the more deeply rooted species. Balsamorhiza s a g i t t a t a did not respond markedly to annual f luc tuat ions in weather. This ear ly developing forb normally i n -i t i a t e s growth i n March or A p r i l and completes i t s growth and r e -production by ear ly June. I t i s possible that the large root system produced by t h i s plant species may act as a water storage organ. Although s o i l moisture (Table 14) and p r e c i p i t a t i o n (Table 4) l i k e l y were adequate to i n i t i a t e growth for t h i s plant i n each year of the s tudy , water storage i n the root system may ameliorate droughty s o i l moisture condit ions and provide for more consistent fo l iage production among years. 5.142 Forage Production i n Relat ion to S i t e Forage production was studied i n r e l a t i o n to s i t e on North, East and Upper during 1978 and 1979. Production for each of the 11 vegetative groups was averaged over a l l leve ls of year and 117 grazing (Table 23). Total standing crop averaged 49.92, 44.36 and 46.29 g/m 2 o n the North, East and Upper s i t e s respect ive ly but herbage production was not s t a t i s t i c a l l y d i f f e r e n t among s i t e s . Agropyron spicatum, Koeler ia c r i s t a t a , t o t a l perennial grass, Bromus tectorum, and t o t a l annual grass were most produc-t i v e on the North fac ing aspect and a l l , except Bromus tectorum, were least productive on the East s i t e (Table 23). Production for Agropyron spicatum on North averaged 30.23 g/m2 which nearly doubled the y i e l d on East (16.99 g/m2) but t h i s value was not s i g n i f i c a n t l y d i f f e r e n t than that on Upper (29.15 g/m2). No s t a t i s t i c a l d i f ferences were observed i n production of Bromus tectorum and t o t a l annual grass between the North and East s i t e s . However, Upper was s i g n i f i c a n t l y less productive than the North and East s i t e s for both vegetative groups. Y ie lds of Bromus tectorum averaged 6.85, 5.87 and 1.19 g/m2 for the North, East and Upper s i t e s respect i ve ly . Balsamorhiza sag i t ta ta and Poa sandbergi i were least produc-t i ve on North. For Balsamorhiza sag i t ta ta t h i s may have been more i n d i c a t i v e of the d i s t r i b u t i o n of t h i s species than simply the potent ia l of each s i t e to produce forage between the two years of study. Balsamorhiza s a g i t t a t a was infrequent on the North s i t e but i t i s unknown whether i t s present d i s t r i b u t i o n i s a r e s u l t of past graz ing, other f a c t o r s , or the long term potent ia l of the s i t e . Compared to North and Upper, t o t a l other forbs , St ipa comata and Eriogonum niveum were most productive on East. Y ie lds for 118 Table 23. Forage production (g/m2) of 11 vegetative groups on North, and 1979 East and Upper i n 1978 Vegetative Group North East Upper Agropyron spicatum 30 .23a 16 • 99b 29 .15a Koeler ia c r i s t a t a 3 .07a 0 .78b 1 • 24b Poa sandbergi i 0 .04a 0 .11a 0 .45b St ipa comata 2 .85a 3 .17a 0 .73b Total Perennial Grass 38 • 11a 21 .08b 33 .61a Bromus tectorum 6 .85a 5 .87a 1 .19b Total Annual Grass 7 .64a 6 .48a 1 .29b Balsamorhiza s a g i t t a t a ' 0 .00a 7 .29b 7 .73b Total Other Forbs 2 . 23a 4 .98b 3 .73ab Eriogonum niveum 1 • 92ab 4 .53b 0 • 00a Total Standing Crop 49 .92a 44 .36a 46 .29a Means fol lowed by the d i f f e r e n t l e t t e r s wi th in rows are s i g n i f i c a n t l y d i f f e r e n t by Student Newman Keuls ' tes t at alpha = 0 .10. 119 each vegetative group averaged 4.98, 3.17 and 4.53 g/m^ respec-t i v e l y on t h i s s i t e . Herbage y ie lds for t o t a l other forbs on East was s t a t i s t i c a l l y d i f f e r e n t (alpha = 0.05) compared to North but not d i f f e r e n t than Upper. Both St ipa comata and Eriogonum  niveum were least productive on Upper but no d i f ferences were detected between North and East (Table 23). 5.143 F a l l Regrowth Several researchers have reported f a l l regrowth on grassland ranges i n B r i t i s h Columbia (Tisdale 1947; Harper 1969; McLean and Marchand 1968) but t h i s increment i n forage production has ra re ly been quant i f ied . F a l l regrowth was f i r s t observed on 20 plant spec ies at the Okanagan Game Farm s i t e i n 1977. This was more c l o s e l y observed and quant i f ied i n 1978 and 1979. In these l a t t e r two years, 31 and 33 plant species resprouted i n ear ly September and October respect ive ly (Appendix 7). Annual production of f a l l regrowth for t o t a l standing crop between 1978 and 1979 was s t a t i s t i c a l l y s i g n i f i c a n t (alpha = 0.05) when•averaged over a l l leve ls of s i t e but considerable v a r i a b i l i t y was observed between years. For example, y ie lds i n 1978 (8.18 g/m2) were less than one ha l f those i n 1979 (19.42 g/m2) but i n both years ove ra l l y ie lds were increased from 62.95 to 71.13 g/m 2 i n 1978 and from 53.78 to 71.72 g/m 2 i n 1979. These increases equaled 11.5 and 27.0% of the t o t a l herbage produced i n each year respect i ve ly . S i m i l a r increases i n autumn herbage production were reported by Harper (19 69) i n three Agropyron spicatum communities on the Ashnola bighorn sheep range although he did not state e x p l i c i t l y that these d i f ferences 120 resul ted from regrowth. Although ind i v idua l forage species were not s t r a t i f i e d i n the above values, f i e l d observations indicated that even though numerous species resumed growth i n the f a l l only a few species made major contr ibut ions to the forage produced. Primary plant species cont r ibut ing to t h i s regrowth included the caespitose grasses such as Agropyron spicatum, Koeler ia c r i s t a t a , St ipa  comata, Festuca s c a b r e l l a , Festuca idahoensis and St ipa  o c c i d e n t a l i s , and the winter annuals such as Bromus tectorum and Bromus m o l l i s . Too few data were ava i lab le i n t h i s study to determine which a t t r ibutes of annual weather patterns contro l the amount and longevity of f a l l regrowth although August p r e c i p i t a t i o n and September and October temperatures appear to be obvious fac tors . P r e c i p i t a t i o n from August to October was r e l a t i v e l y s i m i l a r be-tween 1978 and 1979 more than doub l ing the normal va lue of 40.0 mm (Table 13). Although absolute y i e l d s of f a l l regrowth over a number of years undoubtedly cor re lates p o s i t i v e l y with r a i n f a l l during t h i s per iod, d i f ferences i n production between the two years are more l i k e l y re lated to the a v a i l a b i l i t y of heat uni ts for plant growth during la te August, September and October i n combination with t h i s moisture. Indeed, the number of growing degree days i n September and October was s l i g h t l y below normal for each month i n 1978 but considerably above normal for the same two months i n 1979. During the three year study per iod , f a l l regrowth l i k e l y af fected forage a v a i l a b i l i t y patterns for the captive mountain 121 sheep. These forage f lushes may create new grazing opportunit ies for bighorn by: (1) re - in t roduc ing plant species that may have been f u l l y u t i l i z e d e a r l i e r , (2) providing new fo l iage on ephemeral taxa such as Poa sandbergi i whose herbage from e a r l i e r growth may have deter iorated already, and (3) by a l t e r i n g the p a l a t a b i l i t y and n u t r i t i v e values of forage a l t e r n a t i v e s . 5.15 D i s t r i b u t i o n of Nutr ients Ava i lab le for Bighorn Sheep Numerous factors combine and in te rac t i n plant communities to provide var iab le and complex patterns of nutr ient a v a i l a b i l i t y for bighorn sheep. Select ion of forage c lasses , i n d i v id ua l plant species and plant parts have .been associated wi th q u a l i t a t i v e aspects of forage plants such as p ro te in , ca lc ium, phosphorus, energy, f i b r e content, sugar l e v e l s , moisture, and a n t i - q u a l i t y compounds such as tannins, coumarins and n i t ra tes (Tribe 1950; Heady 1964; Raymond 1969). Factors which a f f e c t the s t r a t i -f i c a t i o n of nutr ients i n plant communities include va r ia t ions i n plant species composit ion, plant par ts , stage of plant matur i ty , and edaphic and c l i m a t i c condit ions (Oelberg 1956; Heady 1964). Considerable va r ia t ions i n concentration leve ls of crude pro te in , ac id detergent f i b r e , ca lc ium, phosphorus and calcium/ phosphorus r a t i o s were observed among species and throughout each year i n 1977 and 1978 f o r 10 forage p l a n t spec ies sampled (Table 24). Except for Ar temis ia t r i d e n t a t a , these species c o l l e c t i v e l y accounted for more than 80% of the herbaceous b i o -mass produced'in each year (Table 20) and therefore supplied most of the nutr ients p o t e n t i a l l y ava i lab le to bighorn sheep. 122 Table 24. Average values for percent CP, ADF, Ca, P and Ca/P r a t i o s f o r 10 forage 1978 growing seasons species throughout the 1977 and Species A p r i l May June July Aug. Sept. Oct. March CP 19.36 10 .51 5.56 2.81 3.06 2.63 2.19 2.38 ADF 33.20 40 .16 43.10 46.15 47.70 49.45 50.55 55.00 1977 Ca 0.23 0 .19 0.18 0.19 0.35 0.19 0.21 0.16 P 0.35 0 .23 0.15 0.09 0.09 0.06 0.05 0.04 Ca/P 0.92 0 .84 1.24 2.33 4.19 3.09 4.75 4.00 AGSP CP 22.63 11 .91 8.35 5.60 4.93 6.25 4.50 2.80 ADF 28.70 38 .30 41.20 40.45 43.30 46.60 47.10 51.20 1978 Ca 0.40 0 .36 0.38 0.50 0.78 0.58 0.74 0.48 P 0.38 0 .27 0.19 0.13 0.12 0.13 0.11 0.08 Ca/P 1.05 1 .35 2.00 4.01 6.81 4.61 6.68 6.38 CP 12.34 9 .22 7.69 4.67 2.85 4.00 2.81 2.08 ADF 25.86 31 .54 36.85 36.75 43.95 37.85 43.90 52.95 1977 Ca 0.61 0 .32 0.80 0.20 0.14 0.12 0.15 0.04 P 0.22 0 .28 0.17 0.18 0.07 0.10 0.06 0.04 Ca/P 0.79 1 .14 4.86 1.15 2.13 1.20 2.47 1.00 BRTE CP 19.02 10 .06 5.28 5.03 4.40 5.25 3.05 3.55 ADF 19.34 30 . 55 37.25 37.90 44.20 42.30 52.25 47.85 1978 Ca 0.59 0 .45 0.30 0.23 0.22 0.24 0.24 0.19 P 0.39 0 .30 0.22 0.19 0.15 0.15 0.07 0.10 Ca/P 1.53 1 .52 1.39 1.25 1.47 1.57 3.43 1.95 CP 15.16 9 .63 5.25 2.13 2.22 2.91 3.35 3.99 ADF 31.61 37 .60 44.65 47.30 48.95 51.29 49.90 56.83 1977 Ca 0.24 0 .25 0.11 0.24 0.16 0.32 0.24 I .S. P 0.31 0 . 23 0.16 0.08 0.06 0.06 0.06 I .S. Ca/P 0.79 1 .15 0.66 2.96 2.67 5.33 4.00 I .S. KOCR CP 22.25 10 .38 7.19 6.61 6.90 I .S. I .S. I .S. ADF 25.19 37 .25 40.55 39.80 45.55 I . S . I .S. I .S. 1978 Ca 0.53 0 .42 0.52 0.55 0.56 I .S. I .S. I .S. P 0.42 0 .31 0.25 0.20 0.19 I .S. I .S. I .S. Ca/P 1.27 1 .37 2.13 2. 75 5.95 I .S. I .S. I .S. 123 Table 24 (continued) Species A p r i l May June July Aug. Sept. Oct. March CP 18.48 9.19 6.69 4.36 3.35 4.73 4.25 I .S. ADF 29.10 34.95 40.80 41.86 43.80 44.69 45.00 I .S. 1977 Ca 0.20 0.18 0.90 0.22 0.21 0.22 0.28 I .S. P 0.31 0.19 0.18 0.18 0.09 0.09 0.09 I .S. Ca/P 0.66 0.93 0.48 1.26 2.33 2.44 3.11 I .S. STCO CP 18.03 11.94 8.06 6.54 6.45 I .S. I .S. ' I .S . ADF 27.97 38.25 39.10 38.05 42.50 I .S. I .S. I .S. 1978 Ca 0.36 0.39 0.40 0.41 0.44 I .S. I .S. I .S. P 0.34 0.27 0.22 0.19 0.15 I .S. I .S . I .S. Ca/P 1.06 1.48 1.81 2.20 2.93 I .S. I .S . I .S. CP 22.94 14.63 10.69 3.62 I .S. I .S. I .S. I .S. ADF' 24.85 31.53 36.85 36.75 I .S. I .S. I .S. I .S. 1977 Ca 1.27 1.55 1.85 2.73 I .S. I .S . I .S. I .S. P 0. 65 0.38 0.34 0.30 I .S. I .S. I .S. I .S. Ca/P 1.95 4.13 5.44 9.14 I .S. I .S. I .S. I .S . BASA CP 21.59 18.25 11.38 7.55 I .S. I .S. I .S. I .S . ADF 25.60 29.95 30.75 24. 85 I .S. I .S. I .S . I .S. 1978 Ca 1.99 2.37 3.70 3.98 I .S. I .S. I .S. I .S. P 0.62 0.51 0.35 0.30 I .S. I .S. I .S. I .S. Ca/P 3.23 4.01 10.58 13.53 I .S. I .S. I .S. I .S. CP 23.78 18.75 15.97 11.48 I .S. I .S. I .S. I .S. ADF 36.10 31.10 29.55 30.02 I .S. I .S. I .S. I .S. 1977 Ca 0.76 1.67 1.57 1.68 I .S. I .S. I .S. I .S . P 0.42 0.25 0.17 0.09 I .S. I .S. I .S. I .S. Ca/P 1.82 4.66 9.23 18.61 I .S. I .S. I .S. I .S . LUSE CP 26.82 20.09 18.72 13.97 I .S. I .S . I .S. I .S. ADF 32.15 28.35 30.32 22.65 I .S. I .S. I .S . I .S. 1978 Ca 0.67 3.00 1.42 3.90 I .S. I .S. I .S. I .S . P 0.56 0.29 0.26 0.15 I .S. I .S. I .S. I .S. Ca/P 1.20 10.63 5.55 27.13 I .S. I .S. I .S. I .S. 124 Table 24 (continued) Species A p r i l May June Ju ly Aug. Sept. Oct. March CP 12 .26 9 .32 6. 60 4. 75 4 .19 5. 56 5 .41 5 .13 ADF 36 .19 32 .30 42. 80 44. 25 49 .50 43. 95 51 .50 56 .10 1977 Ca 0 .67 0 .78 0. 76 1. 00 0 .83 0. 95 . 091 1 .06 P 0 .30 0 .24 0. 17 0. 11 0 .08 0. 11 0 .12 0 .10 Ca/P 2 . 25 3 .23 4. 50 10. 20 11 .53 8. 71 8 .05 10 .55 ERNI CP 17 .97 11 .79 8. 62 5. 88 6 .40 9. 05 6 .05 6 .55 ADF 26 .25 38 .30 37. 25 36. 80 39 .25 35. 60 44 .80 55 .50 1978 Ca 0 .93 1 . 60 0. 97 1. 21 0 .80 1. 06 0 .74 0 .99 P 0 .44 0 .29 0. 24 0. 18 0 .17 0. 23 0 .17 0 .14 Ca/P 2 .11 3 .69 4. 11 7. 07 4 .71 4. 69 4 .33 7 .07 CP 11 .31 10 .19 7. 66 5. 85 5 .25 5. 88 5 .79 6 .04 ADF 34 .20 28 .55 36. 84 43. 33 52 .00 52. 50 59 .20 59 .25 1977 Ca 0 .72 0 .60 0. 80 0. 80 1 .08 1. 00 1 .11 1 .11 P 0 .30 0 .24 0. 17 0. 15 0 .09 0. 10 0 .10 0 .10 Ca/P 2 .40 2 .57 4. 86 5. 30 12 .09 10. 32 11 .99 11 .72 ERHE CP 20 .91 14 .06 10. 71 7. 83 6 .55 6." 95 8 .70 5 .55 ADF 22 .93 25 .55 25. 80 31. 05 32 .40 31. 50 33 .85 56 .60 1978 Ca 0 .82 0 .68 0. 81 0. 84 1 .15 1. 19 1 .27 1 .14 P 0 .57 0 .42 0. 30 0. 18 0 .17 0. 15 0 .23 0 .11 Ca/P 1 .44 1 .17 2. 76 4. 84 6 .25 7. 94 5 .52 10 .90 CP 10 .47 11 .03 8. 72 6. 71 7 .32 9. 63 10 .53 10 .16 ADF 40 .90 38 .45 37. 10 41. 50 37 .75 36. 50 36 .05 35 .85 1977 Ca 0 .69 0 .56 0. 70 0. 57 0 .56 0. 66 0 .73 0 .73 P 0 .21 0 . 28 0. 21 0. 16 0 .18 0. 24 0 .22 0 .18 Ca/P 3 .37 2 .02 3. 36 3. 54 3 .18 2. 74 3 .42 4 .03 ARFR CP 15 .69 11 .82 9. 06 8. 06 9 .10 11. 70 8 .50 9 .20 ADF 31 .70 40 .05 42. 30 37. 25 31 .70 35. 80 37 .35 41 .05 1978 Ca 0 .95 0 . 76 0. 56 0. 57 0 .69 0. 89 1 .00 0 .88 P 0 .28 0 .24 0. 20 0. 24 0 .24 0. 32 0 .28 0 .24 Ca/P 3 .47 3 .14 2. 80 2. 44 2 .94 2. 80 3 .65 3 .74 125 Table 24 (continued) Species A p r i l May June July Aug. Sept. Oct. March CP 10.47 10.29 9.72 8.19 7.94 9.67 8.82 10.31 ADF 27.70 30.00 23.85 25.00 24.85 31.05 31.10 24.05 1977 Ca 0.58 0.58 0.47 0.43 0.54 0.44 0.60 0.51 P 0.20 0.26 0.33 0.2.7 0.21 0.25 0.24 0.16 Ca/P 3.01 2.28 1.44 1.59 2.27 1.78 2.51 3.26 ARTR CP 18.38 14.41 10.78 8.93 8.90 8.95 9.00 12.45 ADF 19.00 30.90 33.65 24.45 32.60 31.85 29.85 22.60 1978 Ca 0.69 0.68 0.51 0.58 0.60 0.29 0.74 0.73 P 0.36 0.41 0.33 0.33 0.55 0.31 0.33 0.27 Ca/P 1.92 1.67 1.53 1.79 2.11 1.76 2.24 2.69 I .S. = I n s u f f i c i e n t sample ava i lab le to undertake analyses. 126 S i g n i f i c a n t species by month in teract ions (alpha = 0.05) in chemical composition were observed for a l l parameters measured. Typ ica l l y , over the four month period when forbs were a v a i l a b l e , species in t h i s forage c lass y ie lded higher average values of crude protein and calcium than grasses and shrubs. Averaged over a l l years and months, crude protein and calcium leve ls respect -i v e l y were 13.83 and 2.43% for Balsamorhiza s a g i t t a t a , and 18.70 and 1.77% for Lupinus ser iceus. No consistent trends were apparent among forage classes for leve ls of phosphorus or acid detergent f i b r e during t h i s per iod. Table 25 summarizes average chemical composition of s i x forage species over an eight month period i n 1977 and 1978. Single degree of freedom tests (alpha = 0.05) indicated that average pro te in , calcium and phosphorus concentrations were lower, and ac id detergent f i b r e values were higher for the grasses Agropyron spicatum and Bromus tectorum compared to the hal f shrubs Eriogonum heracleoides and Eriogonum niveum, and the shrubs Ar temis ia t r identa ta and Artemis ia f r i g i d a . However, further contrasts revealed that no s t a t i s t i c a l d i f ferences occurred w i th in each of these three groups for acid detergent f i b r e and calcium/phosphorus r a t i o . S i m i l a r l y , no d i f ferences were determined between Agropyron spicatum and Bromus tectorum, and Eriogonum niveum and Eriogonum heracleoides for calcium and phosphorus. Mean calcium and phosphorus concentrations (Table 25) were s i g n i f i c a n t l y d i f f e r e n t (alpha = 0.05) between Artemis ia  f r i g i d a and Artemis ia t r i d e n t a t a . Fibre content appeared more var iab le among species than other chemical const i tuents (Table 127 Table 25. Percent chemical composition of s i x forage species averaged over e ight months from A p r i l to October and i n March during 1977 and 1978 Species CP ADF Ca P Ca/P Agropyron spicatum 7 .21 45 .84 0 .37 0 .15 3 .39 Bromus tectorum 6 .33 41 .15 0 .30 0 .17 1 .95 Average Grass 6 .77 43 .65 0 .34 0 .16 2 .67 Eriogonum heracleoides 10 .45 28 .27 0 .58 0 .28 2 .13 Eriogonum niveum 7 .83 43 .42 0 .92 0 .19 6 .04 Average Half Shrubs 9 .14 35 .85 0 .75 0 .24 4 .09 Artemisia f r i g i d a 9 .86 37 .76 0 .71 0 .23 3 .16 Artemisia t r identa ta 8 .70 40 .60 0 .94 0 .21 6 .41 Average Shrubs 9 .28 39 .18 0 .83 0 .22 4 .74 128 25). S i g n i f i c a n t d i f ferences (alpha = 0.05) i n acid detergent f i b r e were determined between Agropyron spicatum (45.84%) and Bromus tectorum (41.15%), and Ar temis ia f r i g i d a (37.76%) and Artemis ia t r identa ta (40.60%). Conspicuous seasonal trends i n nutr ient a v a i l a b i l i t y , which resul ted from two sources, were observed throughout each year. The f i r s t and predominant f l u s h of nutr ients began i n March and A p r i l each year and, general ly by August, herbaceous species became dormant fo l low ing completion of t h e i r l i f e cycles with the onset of droughty condit ions (Table 24). A second f lush of nutr ients accompanied f a l l regrowth which general ly s tarted i n September and continued u n t i l at least November. As previously mentioned, t h i s second f lush tended to be confined p r i n c i p a l l y to a few grass species only (Table 26). However, the possib le importance of minor species supplying s p e c i f i c nutr ients should not be overlooked necessar i l y , p a r t i c u l a r l y i f mountain sheep can se lect for these plants i n the f l o r a . Both prote in and f i b r e fol lowed consistent trends throughout the year for a l l p lant species sampled although minor nuances i n these trends were observed among taxa. Typ ica l l y , crude protein was highest i n A p r i l and decl ined s tead i l y u n t i l August with concentrations remaining r e l a t i v e l y stable u n t i l March. Con-verse ly , f i b r e content increased s tead i l y as plant species matured and forage cured or decayed (Table 24). Consistent trends i n calcium and phosphorus concentration leve ls throughout the year were not d i sce rn ib le among the species sampled. These trends and observations correspond c lose l y to those reported by 129 Table 26. Average values for percent CP, ADF, Ca, P and Ca/P r a t i o s for f a l l regrowth of four forage species i n 1978 and 1979 Species September October November CP 20.18 17.14 14.71 ADF 34.65 34.06 28.85 1978 Ca 0.35 0.68 0.65 P 0.41 0.30 0.27 Ca/P 0.95 2.27 2.39 AGSP CP 19.30 16.50 11.15 ADF 33.50 33.85 35.70 1979 Ca 0.32 0.47 0.55 P 0.35 0.26 0.21 Ca/P 0.91 1.80 2.61 CP 18.30 22.60 11.66 ADF 31.30 21.50 28.44 1978 Ca 0.80 0.81 0.64 P 0.66 0.33 0.26 Ca/P 1.21 2.45 2.46 BRTE CP 23.45 14.25 11.10 ADF 22.45 25.60 26.85 1979 Ca 0.98 0.82 0.73 P 0.53 0.84 0.36 Ca/P 1.84 0.98 2.03 CP 14.01 10.32 6.77 ADF 38.00 33 .05 42.32 1978 Ca 0.47 0.47 0.48 P 0.33 0.27 0.14 Ca/P 1.42 1.74 3.43 KOCR CP 16.60 13.30 8.20 ADF 41.50 35.65 42.80 1979 Ca 0.42 0.50 0.52 P 0.37 0.27 0.21 Ca/P 1.14 1.85 2.47 o 130 Table 26 (continued) Species September October November CP 8.95 14.14 6.25 ADF 40.90 38.39 41.23 1978 Ca 0.42 0.21 0.43 P 0.21 0.26 0.17 Ca/P 2.00 0.81 2.53 STCO CP 15.30 13.20 6.64 ADF - 41.45 34.90 40.90 1979 Ca 0.39 0.46 0.59 P 0.29 0.20 0.16 Ca/P 1.34 2.30 3.69 131 other researchers i n s i m i l a r vegetation types and on other b i g -horn sheep ranges (McLean and Tisdale 1960; Demarchi 1968; Demarchi 1970; Demarchi 1973b). In general , grasses and forbs demonstrated the greatest seasonal v a r i a b i l i t y i n chemical composition and the shrubs and ha l f shrubs provided a more stable nutr ient source for bighorn over t ime. For example prote in leve ls of Agropyron spicatum var ied from 19.36 and 22.63% i n A p r i l to 2.38 and 2.80% i n March i n 1977 and 1978 respect i ve ly . In contrast , corresponding prote in leve ls for Eriogonum niveum equaled 12.26 and 17.97% i n A p r i l , and 5.13 and 6.55% in March for the same two years and values for both species of Ar temis ia var ied even less (Table 24). The expectation that discordant phenologies among species might create a d i s t r i b u t i o n i n nut r ient production with various taxa peaking i n d i f f e r e n t months could not be detected i n the data (Table 24). A broader se lec t ion of plant species for nutr ient analyses may have permitted such di f ferences to be detected. However, most of the phenological a c t i v i t y occurred i n a contracted period from mid-March to June and often more than one stage i n plant growth occurred between monthly sampling periods (Appendix 7). S i m i l a r l y , minor f luxes in forage qua l i t y r e s u l t i n g from seasonal weather patterns could not be detected adequately although they undoubtedly occur (Stoddart et a l . 1975). Conversely s i g n i f i c a n t changes i n forage qua l i t y r e s u l t i n g from f a l l regrowth were observed and quant i f ied i n 1978 and 1979. Although some changes i n chemical composition were noted 132 among the ha l f shrubs and shrubs with the onset of f a l l regrowth (Table 24), the most dramatic increases i n forage q u a l i t y occurr -ed among the grasses (Table 26). Crude protein leve ls for Agro- pyron spicatum and Bromus tectorum i n September 1978 were r e -stored to approximately the same leve ls as those i n A p r i l but corresponding values for Koeler ia c r i s t a t a and St ipa comata were s l i g h t l y lower. In a l l species however, protein leve ls decl ined less sharply from October to November than they had from May to June. S i m i l a r trends i n prote in production were noted during th i s period i n 1979 as w e l l . Although somewhat more var iab le than pro te in , f i b r e , ca lc ium, phosphorus, and the calcium/phos-phorus r a t i o a lso fol lowed s i m i l a r trends during the f a l l vege-t a t i v e period to those they respect ive ly demonstrated during spring growth i n 1978 (Table 26). Undoubtedly, the cool moist autumn condit ions suppressed rapid growth and thus maintained the s l i g h t l y elevated n u t r i t i o n a l leve ls of these species compared to the spring per iod. F a l l regrowth, when i t occurs i n these grassland ecosystems, dupl icates and extends the a v a i l a b i l i t y of high qua l i t y forage for bighorn for poss ib ly a 4-5 month period from mid-March to Ju ly to perhaps nine months i f regrowth i s i n i t i a t e d as ear ly as August and extends to November. F i e l d observations indicated that green herbage was present, although not abundant, we l l into December i n both 1977 and 1978. However, i t should be stressed once again that weather condi t ions , which appeared favorable for f a l l regrowth during the study, were unusual compared to the long term averages. 133 Var iable patterns of forage q u a l i t y have obvious i m p l i c a -t i o n s for mountain sheep n u t r i t i o n i n grassland plant commun-i t i e s . Poss ib le scenarios of extreme condit ions that might occur include a combination of cool dry springs combined with ear ly summer drought and no f a l l regrowth which could truncate the period of high q u a l i t y forage ava i lab le to bighorn into only a few short months. On the other hand, a warm moist winter , com-bined with a wet summer and warm moist f a l l could extend cond i -t ions for continued plant growth from February to November i n the Okanagan and provide qua l i t y forage over perhaps an eight to nine month period. Subsequent impacts on forage species by mountain sheep g r a z i n g w i l l depend to a la rge degree upon at what season and to what i n t e n s i t y bighorn graze these species to take advan-tage of changing forage q u a l i t y . 5.2 C a l i f o r n i a Bighorn Sheep Diet and Forage Se lect ion C a l i f o r n i a bighorn d ie t and forage se lec t ion i n r e l a t i o n to plant species a v a i l a b i l i t y was evaluated over a 28 month period from May 1977 to August 1979. During t h i s per iod, and based upon a combination of f i e l d observations and feca l analyses, a t o t a l of 79 taxa were observed i n the d ie t of the captive herd. This t o t a l consisted of 14 grasses, 47 forbs and bryophytes plus 18 browse species of which 13, 43 and 17 were detected with feca l analyses for each group respect ive ly (Appendix 8). Monthly, seasonal and annual d i v e r s i t y of grasses, forbs , browse or t o t a l species occurr ing i n the d ie t are summarized i n Table 27. Few di f ferences were observed i n the t o t a l number of representative taxa i n e i ther monthly or seasonal d i e t s . Shan-134 Table 27. Monthly, seasonal and annual species d i v e r s i t y i n C a l i f o r n i a bighorn sheep d i e t over the 1977/78 and 1978/79 grazing years Month Grass Forb Shrub Total and Season 77/78 78/79 77/78 78/79 77/78 78/79 77/78 77/7 June 9 9 12 9 11 9 32 27 July 9 7 11 15 9 11 29 33 August 9 9 10 15 7 9 26 33 SUMMER 10 10 17 21 13 9 40 40 September 11 11 9 14 9 9 29 34 October 10 10 11 10 12 5 33 25 November 10 8 7 10 12 10 29 28 FALL 11 11 18 18 14 12 43 41 December 12 9 11 11 12 7 35 27 January 8 9 8 6 6 9 22 24 February 7 8 7 8 10 6 24 22 WINTER 10 10 14 14 14 8 38 32 March 10 10 10 13 10 9 30 32 A p r i l 11 9 11 19 10 9 32 37 May 11 10 19 19 11 6 41 35 SPRING 10 10 24 31 13 10 47 51 135 non's d i v e r s i t y index and a t - t e s t for tes t ing the d i f ference between two d i v e r s i t y indices (Zar 1974) were used to determine i f species d i v e r s i t y var ied among seasons or months between the two grazing years. In both cases, no s t a t i s t i c a l d i f ferences were found i n d i c a t i n g that d i v e r s i t y i n foraging patterns r e -mained s i m i l a r between years. Although approximately the same number of species occurred i n the monthly and seasonal d ie ts between years, the actual spe-c ies encountered i n the feca l samples did vary. For example, 12 new fo rbs were grazed i n s p r i n g of the second year tha t were not detected i n the f i r s t year's d i e t . These included: Astragalus  miser, Astragalus p u r s h i i , Arabis h o l b o e l l i i , Delphinium b i c o l o r , Dodecatheon c u s i c k i i , Heuchera c y l i n d r i c a , Lomatium macrocarpum, Opuntia f r a g i l i s , Phacel ia hastata , Si lene n o c t i f l o r a , Sisymbrium  alt iss imum and Zigadenus venenosus. Conversely, Carex petasata, Crepis atrabarba, Comandra umbel lata, F r i t i l l a r i a pudica, P l a n t a - go patagonica, and Penstemon f ru t icosus and Rhus glabra were a l l grazed i n the f i r s t year but were not recorded i n the d i e t i n the second year. Three factors might expla in these d i f ferences be-tween years. F i r s t , some evidence ex i s t s ind ica t ing that animals p laced i n a new environment r e q u i r e a pe r iod of t ime to ad jus t to the new forage matrix ava i lab le (Arnold and Mai ler 1977). A l -though t h i s may have been i n f l u e n t i a l i n es tab l i sh ing ear ly search patterns for food by the captive sheep, i t was l i k e l y of minor importance because the natural habitat from which the bighorn were captured and the experimental exclosure were s i m i l a r vegetat i ve ly . 136 Second, because a l l these species were rare i n both the f l o r a and d i e t , i t i s possible that sampling i n t e n s i t i e s were i n s u f f i c i e n t to detect the i r presence. Although t h i s may be a noteworthy considerat ion expla in ing absolute d i f ferences between the two years, the t o t a l number of species and d i v e r s i t y among forage classes observed i n the d ie t of the captive herd compared c lose ly to those reported i n other studies on free ranging Rocky Mountain (Erickson 1972; Todd 1972a; Johnson 1975; Stewart 1975), desert (Deming 1964; Brown et a l . 1977) and C a l i f o r n i a bighorn populations (Drewek 1970; Hansen 1982) but are higher than those recorded previously for C a l i f o r n i a bighorn i n C a l i f o r n i a (Jones 1950; McCullough and Schneegas 1966) and B r i t i s h Columbia (Sugden 1961; Blood 1967; Ste l fox and Spalding 1974). However, only Hansen (1982) studied year round grazing by C a l i f o r n i a bighorn which might account for the lower number of species observed i n the C a l i f o r n i a and B r i t i s h Columbia studies (Appendix 1). F i n a l l y , Penstemon f ru t icosus was t r u l y unavai lable for the captive sheep i n the second year. This plant species, which occurred only inf requent ly w i th in the experimental pasture, was completely u t i l i z e d and k i l l e d by bighorn sheep grazing i n the f i r s t spr ing and summer. The greatest d ietary d i v e r s i t y was observed.in spring and the fewest species encountered i n the feces were recorded i n winter i n each year (Table 27). The number of grasses and shrubs i n the d ie t remained r e l a t i v e l y stable among both seasons and months although fewer browse species occurred i n the d ie t i n each season of the second year. In contrast to grasses and shrubs, 137 the number of forbs i n the d ie t var ied considerably among both seasons and months with maxima occurr ing i n spring (24 and 31) and summer (17 and 21) and the fewest species occurr ing i n winter (14 and 14) for the two years respect i ve ly . 5.21 Annual, Seasonal and Monthly Diet and Forage Se lect ion Averaged over a l l months i n the 1977/78 and 1978/79 grazing years, grasses comprised 66.6%, forbs 18.9% and shrubs 14.5% of the d i e t . Despite the preponderance of grass i n the d ie t th i s group was apparently selected against by the bighorn since the r e l a t i v e proport ion of grasses on the range (68.3%) exceeded that i n the d i e t . In contrast to grasses, forbs were preferred throughout the study period recording an average cont r ibut ion to botanical composition of 16.4%. Shrubs were apparently selected against since the r e l a t i v e proportion of t h i s group ava i lab le to bighorn over the two year period equaled 15.3%. However, t h i s forage c lass was dominated by Ar temis ia t r identa ta which was ra re ly eaten. Undoubtedly the predominance of t h i s species, which i n i t s e l f provided 69.2 and 77.8% of the botanical c o n t r i -bution to shrubs in each year respect i ve ly , biased t h i s i n t e r -pretat ion and had the group been assessed without t h i s species, shrubs would have been highly preferred (Table 28). Although the year e f fec t was considered as blocks for experimental e r ro r , d i f ferences between years were of in te res t and therefore analysed (Steel and Torr ie 1980). Dietary com-pos i t ion of grass, forbs , shrubs, phenological groups and i n d i -v idual species var ied among years, season and months. No s t a t i s t i c a l d i f ferences were observed i n C a l i f o r n i a b i g -Table 28. Seasonal d i e t (%), botanical composition of the study s i t e (%) and s e l e c t i v i t y indices (SI) for xmportant C a l i f o r n i a bighorn sheep forage plant species at the Okanagan Game Farm Summer F a l l Winter Spring Annual Mean Diet S i te SI Diet S i te SI Diet S i te SI Diet S i te SI Diet S i te SI GRASSES AGSP 77 78 79 15.7 18.0 24.7 33.4 32.5 38.9 0.5 0.6 0.6 18.1 17.3 33.8 36.3 0.5 0.5 26.7 30.8 33.8 36.3 0.8 0.9 18.0 19.7 30.2 30.8 0.6 0.6 19.6 21.4 26.1 34.0 0.8 0.6 BRTE 77 78 79 1.3 1.6 2.8 18.3 19.4 17.7 0.1 0.1 0.2 8.8 8.9 17.4 17.7 0.5 0.5 2.5 3.6 17.4 17.7 0.1 0.2 4.7 5.3 13.3 20.9 0.4 0.3 4.3 4.9 16.6 18.9 0.3 0.3 FESC 77 78 79 13.9 6.9 10.8 0.5 0.4 0.2 27.7 17.3 54.0 8.1 9.3 0.3 0.5 27.1 18.4 1.9 9.2 0.3 0.5 6.3 18.4 4.4 10.1 0.2 0.4 22.0 25.3 7.1 8.9 0.3 0.4 23.7 22.3 KOCR 77 78 79 12.2 14.5 13.2 6.3 2.4 1.9 1.9 6.1 7.1 12.7 19.3 7.2 2.7 1.8 7.2 13.1 14.0 7.2 2.7 1.8 5.2 10.9 14.8 1.3 1.5 8.4 9.9 12.2 15.7 5.5 2.2 2.2 7.1 POPR 77 78 79 1.9 2.9 2.8 1.3 1.1 1.8 1.4 2.4 1.6 2.9 8.5 1.0 1.4 2.9 6.1 2.9 3.2 1.0 1.4 2.9 2.3 2.3 4.0 1.0 1.7 2.3 2.4 2.5 4.7 1.1 1.4 2.3 3.4 POSA 77 78 79 0.5 0.3 0.5 2.8 2.8 0.5 0.2 0.1 1.0 2.1 1.7 3.2 2.6 0.6 0.7 0.0 0.5 3.2 2.6 0.0 0.2 5.5 2.8 10.2 7.4 0.5 0.4 2.0 1.3 4.9 3.9 0.4 0.3 STCO 77 78 79 9.2 8.3 7.1 6.5 3.9 7.0 1.4 2.1 1.0 10.7 10.5 5.2 5.4 2.1 2.0 15.2 11.5 5.2 5.4 2.9 2.1 13.1 7.1 0.6 3.1 20.4 2.2 12.1 9.2 5.1 4.5 2.4 2.1 OTHR 77 78 79 8.5 2.5 1.5 4.0 4.8 2.4 2.1 0.5 0.6 3.4 3.6 4.0 2.1 0.9 1.7 1.7 8.0 4.0 2.1 0.4 3.8 2.4 2.2 0.8 0.8 3.0 2.8 4.0 4.1 3.2 2.5 1.3 1.6 TOTL 77 78 79 63.2 55.0 63.4 73.1 67.3 70.4 0.9 0.8 0.9 67.6 79.7 72.1 68.7 0.9 1.2 64.0 76.2 72.1 68.7 0.9 1.7 61.3 66.0 57.6 66.6 1.1 1.0 64.0 69.2 68.7 67.8 0.9 1.0 Table 28 (continued) Summer F a l l Winter Spring Annual Mean Diet Si te SI Diet S i te SI Diet S i te SI Diet S i te SI Diet S i te SI FORBS ACM I 77 0.5 0.6 0.8 2 .4 0.3 8.0 78 0.8 1.2 0.7 1 .3 1.1 1.2 0 .1 0.3 0.3 0. 9 1.0 0.9 1. 0 0. 6 1.7 79 0.8 0.8 1.0 0 .3 1.1 0.3 0. 7 1.2 0.6 0. 8 1. 2 0.7 BASA 77 7.3 3.1 2.4 0 .0 3.1 0.0 78 13.9 5.6 2.5 0 .0 3.4 0.0 0 .7 3.1 0.2 4. 8 2.7 1.8 3. 2 3. 0 1.1 79 12.1 3.3 3.7 2 .3 3.4 0.7 2. 9 2.4 1.2 4. 8 3. 7 1.3 CATH 77 2.7 0.1 27.0 1 .1 0.0 NC 78 0.8 0.2 4.0 0 .0 0.1 0.0 0 .0 0.0 NC 0. 3 0.2 1.5 1. 0 0. 1 10.0 79 0.3 0.2 1.5 0 .0 0.1 0.0 0. 8 0.2 4.0 0. 4 0. 2 2.0 LUSE 77 2.5 0.2 12.5 0 .3 0.1 3.0 78 4.8 0.8 6.0 0 .1 0.3 0.3 0 .5 0.1 5.0 2. 9 0.5 5.8 1. 6 0. 2 8.0 79 5.7 0.1 57.0 0 .1 0.3 0.3 1. 9 0.3 6.3 1. 7 0. 4 4.3 OTHR 77 13.5 7.7 1.8 11 .6 8.3 1.4 78 15.9 10.8 1.5 9 .7 10.4 0.9 14 .0 7.6 1.8 10. 3 22.5 0.5 12. 4 11. 5 1.1 79 11.7 9.9 1.2 4 .0 9.0 0.4 12. 1 15.0 0.8 10. 4 11. 3 0.9 TOTL 77 26.5 11.7 2.3 15 .4 11.8 1.3 78 36.2 19.0 1.9 11 .1 15.3 0.7 15 .3 11.8 1.3 19. 2 26.9 0.7 19. 8 15. 6 1.2 79 30.6 14.3 2.1 6 .7 15.3 0.4 18. 4 19.1 1.0 18. 1 17. 2 1.1 TREES AND SHRUBS AMAL 77 2.4 T NC 1 .7 T NC 78 1.6 T NC 1 .1 T NC 2 .0 T NC 4. 3 T NC 2. 6 T NC 79 0.5 T NC 3 .7 T NC 6. 4 T NC 0. 4 T NC ARFR 77 0.1 0.1 1.0 0 .6 T NC 78 0.4 0.1 4.0 0 .6 0.1 6.0 0 .4 T NC 0. 3 0.0 NC 0. 4 T NC 79 0.1 T NC 0 .3 0.1 3.0 0. 1 0.1 1.0 0. 4 0. 1 4.0 ARTR 77 0.3 10.3 0.0 0 .4 10.7 0.0 78 0.1 10.4 0.0 1 .1 12.1 0.1 1 .7 10.7 0.2 2. 1 11.4 0.2 1. 1 10. 8 0.1 79 0.4 13.0 0.0 2 .1 12.1 0.2 0. 2 11.9 0.0 0. 9 11. 6 0.1 Table 28 (continued) Summer F a l l Winter Spring Annual Mean Diet Site SI Diet S i te SI Diet S i te SI Diet S i te SI Diet i Site SI T R E E S AND SHRUBS (continued) ERHE 77 1.1 1.2 0.9 4.3 1.2 3.3 78 0.9 0.9 1.0 2.9 0.9 3.2 7.1 1.2 5.9 2.9 1.1 2.6 3.4 1.2 2.8 79 2.0 0.3 6.7 5.7 0.9 6.3 2.8 0.6 4.7 3.1 0.8 3.9 ERNI 7 7 0.7 2.3 0.3 2.7 2.6 1.0 78 0.1 1.1 0.1 0.4 1.4 0.3 4.9 2.6 1.9 3.9 1.4 2.8 3.1 2.2 1.4 79 1.3 0.6 2.2 3.1 1.4 0.7 3.1 0.6 5.2 1.7 1.2 1.4 OTHR 77 6.0 0.6 10.0 7.2 1.0 7.2 78 3.2 0.8 4.0 3.1 1.0 3.1 4.5 1.0 4.5 5.6 1.0 5.6 5.8 0.9 6.4 79 1.4 0.8 1.2 2.1 1.0 2.1 2.7 0.6 4.5 2.8 0.9 3.1 TOTL 77 10.3 14.9 0.7 17.1 16.0 1.1 78 7.5 13.6 0.6 9.2 15.9 0.6 20.1 16.0 1.3 19.5 15.5 1.3 16.8 15.6 1.1 79 6.0 15.1 0.4 17.2 15.9 1.1 15.6 14.3 1.1 12.4 14.9 0.8 NC = Not calculated - d i v i s i o n by 0 or by Trace va lues . T = Trace (less than 0.05% occurrence). TOTL = Total for plant species group. OTHR = Other plant species. Bryophytes are included with fo rbs . * Totals for a species group may not equal the sum of i n d i v i d u a l species due to Trace values and rounding. 141 horn d ie t for grasses or forbs between grazing years even though there were large increases i n cover (Figure 7) and production (Table 20), and changes i n botanical composition (Figure 8) i n the 1978 growing season compared to 1977. Dietary composition of grass i n 1977/78 and 1978/79 equaled 64.0 and 69.2%, and forbs t o t a l l e d 19.8 and 18.1% i n each year respect i ve ly . Grasses were s l i g h t l y selected against by the captive bighorn i n the f i r s t year but s l i g h t l y selected for i n the second while forbs were preferred i n both years (Table 28). Conversely, shrubs were consumed s i g n i f i c a n t l y less (alpha = 0.05) i n 1978/79 (12.4%) compared to 1977/78 (16.8%) and the corresponding s e l e c t i v i t y indices decreased from 1.1 to 0.8 for t h i s group (Table 28). S i m i l a r l y , but with the exception of Group I I I , phenological groups were eaten i n approximately the same amounts i n each year. Average use of Group I equaled 4.5 and 5.6%, Group II 20.9 and 19.7%, and Group IV 5.0 and 4.0% f o r each year r e s p e c t i v e l y . A s t a t i s t i c a l l y s i g n i f i c a n t increase (alpha = 0.05) i n use of Group III equaling approximately 10 percentage points was observed i n 1978/79 (71.7%) compared to 1977/78 (61.6%). C a l i f o r n i a bighorn demonstrated l i t t l e v a r i a b i l i t y i n t h e i r annual se lec t ion and consumption of i n d i v id ua l forage species. Of the 15 grass species p o t e n t i a l l y ava i lab le (Appendix 6) for graz ing, s t a t i s t i c a l l y s i g n i f i c a n t (alpha = 0.05) increases in use were noted for only Koeler ia c r i s t a t a (12.2 and 15.7%) and Festuca scabre l la (7.1 and 8.9%) between 1977/78 and 1978/79. Percent d ie t compostion of Agropyron spicatum also increased from 19.6 to 21.4 % between years but th i s was s i g n i f i c a n t only at 142 alpha = 0.10. Conversely, St ipa comata (12.1 and 9.2%), Poa  sandbergi i (2.0 and 1.3%) (Table 28), and Bromus m o l l i s (0.8 and .0.4%) decl ined i n the d ie t over the same two years. No s t a t i s t i -c a l d i f ferences were observed among years for other grass species. Few di f ferences i n annual consumption of i n d i v i d u a l forb and shrub species were detected between years and most, although s t a t i s t i c a l l y s i g n i f i c a n t (alpha - 0.05), were of minor conse-quence. For example, forb species that occurred less frequently i n the d ie t i n 1977/78 than i n 1978/79 included: Antennaria  dimorpha (<0.1 and 0.1%), Astragalus miser (0.2 and 0.6%), Dodecatheon c u s i c k i i (0.0 and 0.1%), Erigeron corymbosus (0.2 and 0.6%) and Lesguerel la doug las i i (<0.1 and 0.3%) for the two years respect ive ly . Only four forb taxa occurred more frequently i n t h e v d i e t i n 1977/78 than i n 1978/79. These included: Antennaria  p a r v i f o l i a (0.3 and <0.1%), C a s t i l l e j a thompsonii (1.0 and 0.4%), Lithospermum ruderale (1.7 and 0.9%) and Lomatium tr i ternatum (0.3 and <0.1%) for each year respect i ve ly . Most browse species occurred more frequently i n the annual d ie t i n 1977/78 than 1978/79. Shrubs and trees whose average d ietary compostion decl ined s i g n i f i c a n t l y (alpha = 0.05) between the two years respect ive ly inc luded: Berberis aguifol ium (0.4 and <0.1%), Eriogonum niveum (3.1 and 1.7%), Pinus ponderosa (0.6 and 0.1%), Prunus v i r g i n i a n a (1.4 and 0.4%), Pseudotsuga m e n z i e s i i (0.7 and 0.2%) , Rhus g l a b r a (0.4 and <0.1%) and Ribes  cereum (0.3 and <0.1%). The only shrub that increased i n the d ie t was Chrysothamnus nauseosus which averaged 0.3% of the annual consumption i n 1977/78 and 1.1% i n 1978/79. 143 Forage se lec t ion indices for i nd i v idua l species w i th in a l l forage c lasses were su rp r i s ing l y s i m i l a r between grazing years and, except for Koeler ia c r i s t a t a , C a s t i l l e j a thompsonii and Lupinus ser iceus , most var ied by less than one index point (Table 28). Conversely, the captive sheep demonstrated considerable se lec t ion among plant species w i th in each year and over the two year period (Appendix 8). For example, although grass was not preferred as a forage c lass on an annual bas i s , mountain sheep did exh ib i t strong preferences for some ind i v idua l grass species such as Festuca s c a b r e l l a , Koeler ia c r i s t a t a , Poa pratensis and St ipa comata. In contrast , Agropyron spicatum, Bromus tectorum and Poa sandbergi i were not preferred over the two year per iod. Compared to grasses, nearly a l l taxa of forbs and shrubs occurred more f r e q u e n t l y i n the d i e t than on the range over the same time per iod. However, notable exceptions included: A c h i l l e a  m i l l e f o l i u m , which was preferred i n the f i r s t year but not preferred i n the second, and Ar temis ia t r identa ta which was not preferred in e i ther year (Table 28). Def in i te seasonal and monthly va r ia t ions in forage use were determined among forage c lasses and ind i v idua l species. Grasses were eaten most i n the f a l l and w i n t e r i n both years a l though , as a group, they were a major d ietary const i tuent in a l l seasons (Table 28). Averaged over both years, grasses were used least in summer (59.1%), most i n f a l l (73.7%) and at intermediate leve ls in winter (70.1%) and spring (63.7%). Differences among seasons were s t a t i s t i c a l l y s i g n i f i c a n t (Table 29). Hansen (1982) repor t -ed s i m i l a r trends on dryland C a l i f o r n i a bighorn range i n Nevada. 144 Table 29. Significance of single degree of freedom contrasts for contribution of grass, forb and shrub plant species to C a l i f o r n i a bighorn sheep d i e t throughout the 1977/78 and 1978/79 grazing years Contrasts Plant Species 1 2 3 4 5 6 7 8 9 10 11 GRASSES Agropyron spicatum ** * * * * NS NS ** NS * * NS NS NS Bromus tectorum ** * * * * NS NS * * NS * * NS * * * * Festuca scabre l la ** ** NS ** ** * * ** NS ** NS NS Koeler ia c r i s t a t a NS ** NS * * NS NS ** NS NS * NS Poa pratensis ** ** NS * * * * NS * * ** NS NS NS Poa sandbergi i ** NS ** NS NS * * * * * * NS NS * * St ipa comata * * NS * * NS NS * * NS NS NS NS NS Total Grass ** * * * * * * NS ** ** ** * * NS ** FORBS A c h i l l e a m i l l e f o l i u m NS ** NS NS ** NS NS NS NS NS NS Balsamorhiza s a g i t t a t a * * ** * * ** NS * * ** ** * * * * ** C a s t i l l e j a thompsonii ** NS NS NS ** NS NS NS * * NS ** Lupinus sericeus * * ** ** ** NS NS ** * * NS NS NS Total Forbs * * NS * * * * * * * * * * * * * * * * * * SHRUBS Amelanchier a l n i f o l i a * * ** ** NS NS ** * * * NS ** NS Artemisia f r i g i d a NS * NS NS * * NS NS NS NS NS NS Artemisia t r identa ta * * * * NS NS NS NS NS * * NS ** NS 145 Table 29 (continued) Contrast Plant Species 1 2 3 4 5 6 7 8 9 10 11 SHRUBS (continued) Chrysothamnus nauseosus NS NS ** NS NS * * NS * NS NS Eriogonum heracleoides ** * ** NS NS ** NS * NS NS NS Eriogonum niveum ** ** NS NS NS NS NS ** NS ** NS Total Shrubs ** ** NS NS ** NS NS ** NS ** NS ** S i g n i f i c a n t at alpha = 0.05 * S i g n i f i c a n t at alpha = 0.10 NS Not s i g n i f i c a n t Contrasts 1. Summer vs . Spring + F a l l + Winter 2. F a l l vs . Winter + Spring 3. Winter vs . Spring 4. June vs . Ju ly + August 5. September vs . October + November 6. January + February vs . March + A p r i l 7. May + June vs . Ju ly + August 8. March + A p r i l vs . May + June 9. Ju ly vs . August 10. March vs . A p r i l 11. May vs . June 1 4 6 Except for the summer of 1978, grasses occurred more frequently i n the d ie t for a l l seasons i n the 1978/79 grazing year than i n 1977/78 (Table 28) i n t h i s study i n d i c a t i n g that they were not preferred as a group although only s l i g h t l y so. Agropyron spicatum was the most common plant found i n the feces i n each season except i n the f a l l of 1978 when K o e l e r i a  c r i s t a t a occurred more frequently i n the d ie t (Table 28) and formed the staple of the herds d ie t throughout the study. Agropyron spicatum was used most i n winter ( 26.7 and 30.8%) and least i n summer (15.7 and 18.0%) i n each year respect ive ly but v a r i a t i o n between years was minor w i th in each season. Averaged over both years, Agropyron spicatum contr ibuted most to the d ie t i n January (29.8%) and February (33.2%). How-ever, once spring growth commenced i n March t h i s species s i g n i f i -c a n t l y (alpha = 0.05, Table 29) d e c l i n e d i n the d i e t (19.6%) as the sheep began foraging on other species. As forbs and new growth on shrubs became more prevalent on the s i t e , consumption of Agropyron spicatum continued to decl ine gradual ly u n t i l June (15.2%) and then rose s l i g h t l y , though not s t a t i s t i c a l l y s i g n i f i -cant, with the onset of summer drought. From July to November t h i s species remained at a constant leve l i n the d ie t (<19%) u n t i l December when a l l f a l l regrowth was e i ther u t i l i z e d , growth had terminated, or other forage was covered wi th snow (Table 30). Despite the r e l a t i v e importance of Agropyron spicatum as a food source for the captive bighorn, the proportion of th i s species in the d ie t never exceeded i t s a v a i l a b i l i t y on the range throughout the study except i n February 1978 when consumption (37.6%) only 147 Table 30. Monthly contribution (%) of t o t a l and important grass, f o r b and shrub species to C a l i f o r n i a b i g -horn sheep d i e t averaged over the 1977/78 and 1978/79 grazing years Month Species Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar. Apr May GRASSES AGSP 15.2 16.6 18.8 16.0 18.2 19.0 23.0 29.8 33.2 19.6 20.0 17.0 BRTE 1.2 1.0 2.2 9.0 9.0 8.6 3.4 1.8 4.0 7.0 3.2 4.8 FESC 7.0 8.0 16.2 11.2 8.6 6.4 10.0 3.4 4.2 6.8 7.0 6.4 KOCR 9.2 13.8 17.0 17.2 16.8 14.0 11.0 18.4 11.2 11.0 15.0 12.4 POPR 1.0 2..0 4.2 4.2 5.2 7.8 3.4 4.0 2.6 3.2 4.4 1.8 POSA 0.6 0.2 0.4 2.0 3.0 0.8 0.2 0.2 0.6 3.8 5.0 3.6 STCO 9.0 7.0 10.2 11.6 9.8 10.4 14.0 16.0 10.4 11.0 9.0 10.2 Others 4.4 5.4 6.8 3.8 2.4 3.7 2.6 2.2 1.0 2.4 3.2 3.4 Total 47.6 54.0 75.8 75.0 73.0 70.7 67.6 75.4 67.2 64.8 66.8 59.2 FORBS ACMI 0.6 1.0 0.4 0.6 2.2 2.8 0.0 0.2 0.4 1.2 0.4 0.8 BASA 17.6 12.0 2.2 0.0 0.0 0.0 3.4 0.4 0.6 1.0 6.8 11.2 CATH 2.2 2.4 0.6 1.6 0.0 0.0 0.0 0.0 0.0 0.6 0.6 0.4 LUSE 6.4 2.6 2.0 0.6 0.0 0.0 0.2 0.8 0.0 0.2 0.4 6.6 Others 14.4 19.8 10.0 12.8 10.0 10.2 11.6 6.4 9.4 5.2 10.0 10.6 Total 41.2 37.8 15.2 15.6 12.2 13.0 15.2 7.8 10.4 8.2 18.2 29.6 SHRUBS AMAL 3.0 1.8 1.4 0.4 2.6 1.2 2.4 2.6 3.6 8.2 5.0 2.8 148 Table 30 (continued) Month Species Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May SHRUBS (continued) ARFR 0.4 0.2 0.2 1.2 0.2 0.6 0.4 0.2 0.4 0.4 0.0 0.2 ARTR 0.4 0.2 0.0 1.2 0.0 1.0 2.2 1.6 2.0 3.0 1.0 0.2 ERHE 1.6 0.6 0.8 2.6 2.8 5.4 5.0 5.6 9.2 4.4 2.4 1.8 ERNI 0.4 0.6 0.2 1.0 1.6 2.6 3.8 3.4 4.0 6.6 2.4 1.4 Others 5.4 4.8 6.4 3.0 6.6 5.5 3.4 3.4 3.2 4.4 4.2 4.8 Total 11.2 8.2 9.0 9.4 13.8 16.3 17.2 16.8 22.4 27.0 15.0 11.2 149 s l i g h t l y surpassed a v a i l a b i l i t y (36.3%) (Appendix 8). Bromus tectorum was not a major d ietary component i n e i ther year averaging only 4.3% of the annual d ie t i n 1977/78 and 4.9% i n 1977/78 (Table 28). This species was grazed most exten-s i v e l y i n both s p r i n g (4.7 and 5.3%) and f a l l (8.8 and 8.9%) of each year respect i ve ly . F i e l d observations indicated that b i g -horn adjusted to both spring and f a l l germination of t h i s winter annual with maximum average use over both years recorded i n March ( 7 . 0 % ) , September (9.0%) and October (9.0%) (Table 3 0 ) . However, even then, and i n a l l other months, t h i s species occurred more frequently i n the plant community than in the d i e t (Appendix 8). During summer and winter Bromus tectorum was grazed spar ing ly , and averaged over both years, summer consumption was s t a t i s t i c a l -l y (alpha = 0.05) less than the combined mean of other seasons, and winter use was less than i n spring (Table 29). Both Smith (1954) and Blood (1967) reported s i m i l a r foraging patterns on t h i s species i n spring by Rocky Mountain bighorn in Idaho and C a l i f o r n i a bighorn i n B r i t i s h Columbia respect ive ly . Seasonal composition of St ipa comata and Koeler ia c r i s t a t a i n the d ie t fol lowed d i f f e r e n t trends although intake of both species was r e l a t i v e l y constant among seasons w i th in each year (Table 28). St ipa comata occurred most in the d ie t i n winter 1978 (15.2%) and was grazed least i n both spring and summer 1979 ( 7 i l % ) . Corresponding leve ls for Koeler ia c r i s t a t a were recorded i n f a l l (16.0%) and winter (13.7%) although no s t a t i s t i c a l d i f ference (alpha = 0.10) was observed between winter and spring values and therefore summer use was not s t a t i s t i c a l l y d i f f e r e n t 150 e i ther (Table 29). Both species were preferred in a l l seasons, and i n both years (Table 28) but, un l ike Koeler ia c r i s t a t a which was preferred i n a l l months, St ipa comata occurred more f r e -quently i n the plant community than the d ie t i n December, January and February 1978, and i n June and July 1979 (Appendix 8). Festuca s c a b r e l l a , which provided less than 1% of the botanical composition (Table 15), formed a su rp r i s ing l y large proportion of the annual d i e t . This highly preferred species was grazed most heavi ly i n summer (10.4%) and least i n f a l l (5.6%) over the two years. Average summer use was s t a t i s t i c a l l y greater (alpha = 0.05) than the combined'mean use throughout the rest of the g r a z i n g year , and w i n t e r use was g reater than f a l l and s p r i n g combined (Table 29). Except for summer, th i s species occurred more f r e q u e n t l y i n the d i e t i n a l l seasons dur ing 1978/79 than i n 1977/78 (Table 28). Averaged over the two years, Festuca  scabre l la contr ibuted most to bighorn d ie t i n August (16.2%) and l e a s t i n January (3.4%) (Table 30). Both the high proport ion of Festuca scabre l la i n the August d ie t compared to other months, and the d i f f e r e n t i a l use i n January and February between years may be p a r t i a l l y a t t r ibu ted to i t s d i s t r i b u t i o n r e l a t i v e to bedding preferences as much as i t s apparent p a l a t a b i l i t y (Appendix 8). This species occurs only i n the understory of Pinus ponderosa on the s i t e which was used extensively for shade during the hot August weather i n each year, and for bedding throughout the winter . Heavy snowfal ls from December 1977 to February 1978 l i m i t e d access to the Upper s i t e where both Pinus ponderosa and Festuca scabre l la occurred most 151 frequently . Consequently, the sheep were forced to bed under trees at lower elevat ions where t h i s species occured ra re l y and opportunit ies for grazing were l i m i t e d . Seasonal trends i n forb use were s t r i k i n g l y s i m i l a r to those ca lcu lated from data by Hansen (1982) i n Nevada although absolute values determined i n t h i s study were lower for a l l seasons. In contrast to grasses as a group, forbs occurred less frequently in the d i e t i n a l l seasons of 1978/79 compared to 1977/78 except i n summer. Forbs were grazed most in summer (26.5 and 36.2%) and spring (19.2 and 18.4%) of each year respect ive ly and became less important during f a l l and winter when species i n t h i s group are t y p i c a l l y senescent (Table 28, Table 29). Preference for t h i s group fol lowed a s i m i l a r trend with s e l e c t i v i t y r a t i o s equaling 1.9 or more i n summer but waning to near or below 1.0 i n other seasons (Table 28) and months (Appendix 8). In general , annual forbs were not preferred i n a l l months and years even though the i r cont r ibut ion to botanical composition inc reased more than 500% i n June and J u l y 1978 compared to the same period i n 1977. Of the 12 species represented i n t h i s group, a l l except Lesquerel la doug las i i occurred i n the feces less than 1% i n a l l months studied and even Lesquerel la doug las i i accounted for only 1.2% of the d ie t i n Ju ly and August 1979 (Appendix 8) . The seasonal importance of i n d i v id ua l forbs i n the bighorn d ie t var ied among species. Averaged over both years, use of forbs such as Balsamorhiza s a g i t t a t a , C a s t i l l e j a thompsonii , and Lupinus sericeus fol lowed s i m i l a r trends to the group with max-152 imum consumption of each occurr ing i n summer and equaling 10.6, 1.8 and 3.7% respect ive ly for the three species (Table 28). Both Balsamorhiza s a g i t t a t a and C a s t i l l e j a thompsonii also were used extensively i n f a l l averaging 3.9 and 2.4% of the d ie t respec-t i v e l y . These values were s i g n i f i c a n t l y (alpha = 0.05) higher than winter values for both species (Table 29). Other forbs preferred throughout the summer months included: Arabis  h o l b o e l l i i , Centaurea d i f f u s a (which also was p o s i t i v e l y selected by the mountain sheep from January to May 1979), Erigeron  f i l i f o l i u s , G a i l l a r d i a a r i s t a t a , Geum t r i f o l i u m , Lithospermum ' ruderale and Phlox l o n g i f o l i a (Appendix 8). A c h i l l e a m i l l e f o l i u m remained a minor component of bighorn d i e t i n a l l months and seasons and was not p r e f e r r e d by the captive herd (Appendix 8). However, un l ike other fo rbs , i t achieved i t s highest d ie tary cont r ibut ion i n f a l l averaging 1.9% over both years (Table 28) and was p o s i t i v e l y selected i n October, November and March each year. Minimum values for use were recorded i n winter of both years. Although bighorn demonstrated var iab le patterns of use and preference for most forbs , S e l a g i n e l l a wa l lace i c l e a r l y was not preferred at a l l times throughout the year. This procumbent clubmoss was recorded i n the d ie t on only f i v e occasions and only once exceeded 1% of the forage consumed even though i t c o n t r i -buted between 3 and 8% of the botanical composition (Appendix 8). However, lack of preference for t h i s species and other taxa with s i m i l a r morphologies such as Antennaria dimorpha, Antennaria  p a r v i f o l i a , Erodium c icutar ium, Astragalus p u r s h i i , Lewis ia 153 red iv i va and Ranunculus glaberrimus might be re lated p a r t i a l l y to the i r growth form since low growing plants may be less ava i lab le than t a l l species for even de l i ca te feeders such as mountain sheep. Browse, as a forage c l a s s , was most abundant i n the d i e t i n winter and spring each year. Averaged over both years, winter and spring consumption of shrubs equaled 18.7% and 17.6% for each season respect ive ly although these were not s t a t i s t i c a l l y d i f f e r e n t (alpha = 0.05) (Table 29). Shrub use i n summer was s t a t i s t i c a l l y d i f f e r e n t (alpha = 0.05) than the combined average of f a l l , winter and spring equaling less than ha l f the winter/ spring leve l or 8.9% of the d i e t . Values reported here are s i m i l a r to those observed by Hansen (1982) on C a l i f o r n i a bighorn range i n Nevada but lower than winter values recorded on other bighorn range i n B r i t i s h Columbia (Sugden 1961; Blood 1967). S i m i l a r patterns of use were recorded on member species i n t h i s group inc lud ing : Ar temis ia t r identa ta (1.9 and 1.2%), Eriogonum  heracleoides (6.4 and 2.9%) and Eriogonum niveum (4.0 and 2.4%) for winter and spring respect i ve ly . S t a t i s t i c a l d i f ferences (alpha = 0.05) between winter and spring use were determined for only Eriogonum heracleoides however (Table 29). Ar temis ia t r identa ta was not used extensively nor was i t preferred i n any season or month throughout the study despite i t s prominence i n the f l o r a (Appendix 8). Percent composition of th i s species i n the d ie t was s i m i l a r to winter values reported by Oldemeyer et a l . (1971) for Rocky Mountain bighorn i n Montana but was much lower than both the monthly and seasonal values observed 154 on two other Rocky Mountain ranges i n that s t a t e where up to 43% of the d ie t consisted of t h i s species (Stewart 1975). Hansen (1982) recorded s i m i l a r trends i n monthly consumption of Ar temis ia t r identa ta although values were general ly s l i g h t l y higher than those reported here. V a r i a b i l i t y i n the consumption of Ar temis ia t r identa ta among populations of bighorn sheep may be a t t r ibu ted to i t s d i f f e r e n t i a l p a l a t a b i l i t y among ecotypes which Plummer (1972) postulated may be associated with the chemistry and amount of essent ia l o i l s i n these ecotypes, to i t s abundance on the range r e l a t i v e to other forages (Stoddart and Smith 1955; c i t e d i n Heady 1964), or to both . Amelanchier a l n i f o l i a and Ar temis ia f r i g i d a were grazed d i s s i m i l a r l y from both the forage c lass and from each other. Maximum use of Amelanchier a l n i f o l i a occurred i n spring each year equaling 4.3 and 6.4% of the d ie t i n 1977 and 1978 respect i ve ly . Averaged over both years, t h i s species contr ibuted most to d ie t i n March (8.2%) as soon as new l e a f y growth commenced but use decl ined s i g n i f i c a n t l y (alpha = 0.05) by A p r i l (5.0%) and continued to wane throughout ,the summer as forbs and other shrubs became more a v a i l a b l e . This species contr ibuted least to bighorn d ie t i n f a l l averaging only 1.7% i n 1977 and 1.1% i n 1978 but became s l i g h t l y more prominant i n winter as bighorn browsed on woody stems (Table 28). Both Drewek (1970) and Hickey (1975) observed Amelanchier a l n i f o l i a i n C a l i f o r n i a (winter and spring) and Rocky Mountain bighorn (season unspecified) d ie ts respect i ve -l y i n Idaho but neither quant i f ied consumption. Numerous previous studies described the use of Ar temis ia 155 f r i g i d a by C a l i f o r n i a bighorn sheep i n B r i t i s h Columbia (Blood 1961,1967; Sugden 1961; Demarchi 1965; Morrison 1972) and Rocky Mountain bighorn in Idaho (Oldemeyer et a l . 1971) p a r t i c u l a r l y during the winter . Both Sugden (1961) and Blood (1967) suggested that t h i s species was preferred but neither provided enumeration of i t s r e l a t i v e a v a i l a b i l i t y on the range although both ind icate that i t was " r e l a t i v e l y abundant". Oldemeyer et a l . (1971) ranked t h i s species as s l i g h t l y preferred with a preference ra t ing of 1.1 on one winter range they studied. In t h i s study, Ar temis ia f r i g i d a was a minor const i tuent i n the d ie t among a l l seasons always averaging less than 1% of the t o t a l forage con-sumed. Although f a l l consumption was s t a t i s t i c a l l y greater (0.6%) (alpha = 0.05) than the average combined use i n winter and •spring (0.3%) (Table 29), these d i f ferences were not of much b i o l o g i c a l consequence because values were so low. Ar temis ia  f r i g i d a occurred ra re l y on the s i t e but bighorn cons is tent l y consumed t h i s species i n greater r e l a t i v e proportion than i t occurred i n the f l o r a i n a l l seasons (Table 28) supporting the above contention that i t i s a preferred forage. Several researchers described the presence of the genus Eriogonum in C a l i f o r n i a bighorn d ie ts throughout t h e i r d i s t r i -bution (Appendix 2) but l i t t l e has been reported regarding seasonal use of member species. In t h i s study, bighorn demon-strated conspicuous seasonal preferences for both species represented on the s i t e although each was grazed s l i g h t l y d i f f e r -ent ly (Table 28, Table 30). Averaged over both years, Eriogonum  heracleoides was grazed most i n winter (6.4%) and p a r t i c u l a r l y i n 156 January (5.6%) and February (9.2%). The average proportion of t h i s species i n the d ie t i n these two months was s t a t i s t i c a l l y d i f f e r e n t than the combined mean of March (4.4%) and A p r i l (2.4%). Both consumption and preference indices s tead i l y decl ined throughout the growing season as forbs, new growth on grasses and other browse became ava i lab le but throughout most of the grazing year t h i s species was highly preferred (Table 28). Eriogonum niveum was both grazed and preferred most i n spring each year (Table 28). Averaged over both years t h i s species was used most i n March (6.6%) but the sheep s i g n i f i c a n t l y (alpha = 0 . 0 5 ; Table 29) sh i f ted to other forage species i n A p r i l (2.4%) (Table 30) and, as with Eriogonum heracleoides, l i t t l e use was made on t h i s taxon u n t i l f a l l . Preference indices for Eriogonum niveum were lower i n a l l seasons and months than corresponding values for Eriogonum heracleoides except i n March and A p r i l 19 79. Other browse species preferred through the spring and summer inc lude: Acer glabrum, Philadelphus l e w i s i i , Prunus v i r g i n i a n a , Rosa nutkana and Symphoricarpos albus whi le Chrysothamnus nauseosus, Pinus ponderosa, and Pseudotsuga  menz ies i i were preferred i n f a l l and winter (Appendix 8). Despite the more favorable growing condit ions i n 1978 com-pared to 1977, the s e l e c t i v i t y r a t i o s for forage c lasses and ind i v idua l plant species var ied l i t t l e between the two years (Table 28). S e l e c t i v i t y r a t i o s for a l l three forage c lasses remained very s i m i l a r w i th in seasons between years as w e l l . Perhaps the most s i g n i f i c a n t change i n plant community structure and hence forage a v a i l a b i l i t y was that forage production changed 157 more than f l o r i s t i c composition between the two years. For example, using summer values for botanical composition (Table 28), when the greatest d i v e r s i t y i n forage was a v a i l a b l e , and August production data (Table 20), botanical composition and production of grasses i n 1978 were 92.1 and 203.8% of the 1977 values respect i ve ly . S i m i l a r l y , corresponding values for forbs as a group were 162.4 and 174.7% of the previous year for each. The importance of increased forage production i n a l t e r i n g grazing patterns of bighorn sheep i s unknown but E l l i s et a l . (1976), d iscuss ing se lec t i ve grazing i n general , suggested that "consumption general ly increases with a v a i l a b i l i t y or density of the food item up to some "saturat ion l e v e l " beyond which further increases i n food a v a i l a b i l i t y does not a f fec t consumption." This genera l i zat ion may have been true for grasses during the summer of 1978 as consumption of t h i s forage c lass decl ined to 87% of i t s leve l compared to 1979 despite the increased pro -duct ion. Conversely, d ietary composition of forbs during the same period increased to nearly 137% of t h e i r 1977 l e v e l s . Greater abundance of forbs on the s i t e might have allowed bighorn to broaden the d i v e r s i t y of t h e i r d ie t w i th in t h i s forage c lass (Table 27). Var ia t ions i n forage se lec t ion by bighorn sheep among sea-, sons, months and plant species are not surpr i s ing although the underlying mechanisms determining these responses are not known. The r e l a t i v e s t a b i l i t y of both grass and shrubs i n the d ie t l i k e l y r e f l e c t s t h e i r inherent a b i l i t i e s to provide forage year round (Oelberg 1956; Cook 1972). Grasses accomplish t h i s through 158 annual growth patterns, f a l l regrowth and the i r a b i l i t y to cure we l l although these a t t r ibu tes are not universal features of a l l species. For example, the annual grasses Apera in ter rupta and Festuca oc to f lo ra provided less than 0.5% of the botanica l com-pos i t i on i n June 1977 but more than 1% i n June 1978. Neither are p a r t i c u l a r l y productive, provide f a l l regrowth or cure w e l l . Hence both are of l i t t l e value as forage for bighorn and neither was recorded i n the feces i n any month. S i m i l a r l y , Poa  sandbergi i , which was u t i l i z e d by bighorn in spr ing , summer and f a l l , does not cure w e l l and was used l i t t l e i n the w i n t e r (Appendix 8) . Browse provides year round forage for bighorn p r i m a r i l y through annual increments i n both woody and leafy growth. In grassland plant communities various a l te rnat i ves are ava i lab le however. Deciduous species such as Acer glabrum, Amelanchier  a l n i f o l i a , Prunus v i r g i n i a n a , Philadelphus l e w i s i i , Ribes. cereum, Rosa nutkana, and Symphoricarpos albus y i e l d leafy forage throughout the growing season and woody browse that pe rs i s t s the rest of the year. Other "evergreen" taxa such as Ar temis ia  f r i g i d a , Ar temis ia t r i d e n t a t a , Chrysothamnus nauseosus, Eriogonum  heracleoides, Eriogonum niveum, Pinus ponderosa and Pseudotsuga  menz ies i i , a f ford both leaf and stem i n a l l seasons. Forbs g e n e r a l l y do not cure w e l l and o f t e n are sub jec t to losses i n forage value as senescent fo l iage deter iorates (Oelberg 1956; Cook 1972; Stoddart et a l . 1975). Undoubtedly, these changes i n forage value a f fec t the p a l a t a b i l i t y of plant species car r ied over into the f a l l and winter grazing period for bighorn. 159 S i m i l a r l y , species that decay rap id l y or were f u l l y u t i l i z e d during the growing season a l t e r the r e l a t i v e a v a i l a b i l i t y of other plant species. In tu rn , th i s might account for the greater v a r i a b i l i t y i n d ie t d i v e r s i t y and u t i l i z a t i o n of t h i s forage c lass among seasons. Although numerous plant and animal factors undoubtedly in te rac t i n determining the se lec t ion of one plant species over another (Heady 1964), morphological adaptations of bighorn l i k e l y explain the i r reputat ion for being picky and se lec t i ve grazers (Russo 1954; McCann 1956) to some degree. Jarman (1974) postu-lated that foraging habits and body s ize were re lated i n Af r ican antelope and that smaller antelope tended to be more se lec t i ve for plant species and parts than larger species. F i e l d observations i n t h i s study indicated that C a l i f o r n i a bighorn were se lec t i ve i n grazing plant parts and new growth over old growth i n grasses as i t became av a i lab le . Leaves were se -lected over stems p a r t i c u l a r l y on browse species such as Amel- anchier a l n i f o l i a , Prunus v i r g i n i a n a and Acer glabrum. Flower heads were re l i shed on forbs and shrubs as they became ava i lab le p a r t i c u l a r l y on A c h i l l e a m i l l e f o l i u m , Arnica s o r o r i a , Balsamorhiza s a g i t a t t a , G a i l l a r d i a a r i s t a t a , Sisymbrium a l t i s s - imum, Tragopogon dubius, and Chrysothamnus nauseosus. S i m i l a r l y , i t i s perhaps more than a coincidence that Agro- pyron spicatum, the largest and coarsest grass species, was not preferred but the smal le r , f i n e r species such as Koeler ia  c r i s t a t a , St ipa comata, and Festuca scabre l la were preferred. Bighorn, wi th a small mouth, seem much better adapted to grazing 160 small plants and f ine r plant parts . E l l i s o n (1954) made s i m i l a r observations on domestic sheep on subalpine range i n Utah. 5.22 Bighorn Diet i n Relat ion to Forage Qual i ty Hypothet ica l ly , the plant community can be v i s u a l i z e d as a mult i -d imensional nutr ient environment. Figure 10 schematical ly d isplays p r o f i l e s of prote in a v a i l a b i l i t y for C a l i f o r n i a bighorn sheep on the Okanagan Game Farm research s i t e in 1977 and 1978. Maximum and minimum values for these diagrams r e f l e c t only the averages of those plant species sampled w i th in each month (Table 24) and the v a r i a b i l i t y among months and years might be greater than t h a t dep ic ted here when a l l taxa i n the f l o r a are c o n s i d e r -ed. Forage se lec t ion by mountain sheep occurs w i th in t h i s range of n u t r i t i o n a l p o s s i b i l i t i e s and subsequent e f fec ts on both an-imal n u t r i t i o n and t h e i r impact on plant species depends upon the a b i l i t y of these animals to d iscern q u a l i t a t i v e d i f ferences among forage p lants . In order to f u l l y comprehend forage se lec t ion by mountain sheep i n the grassland plant community, th i s p r o f i l e must be extended to encompass a l l forage a t t r ibutes which inf luence choice. Indeed, a complete p r o f i l e would include a l l n u t r i t i o n a l aspects of forage coupled with forage production estimates which would provide a more r e a l i s t i c expression of the actual amounts of nutr ients ava i lab le per un i t area and t ime. S i m i l a r l y , other aspects of p a l a t a b i l i t y and preference which may be adjuncts to n u t r i t i o n a l propert ies , but are c o n t r o l l i n g factors i n acceptance or avoidance of a plant species or plant par ts , would also r e -quire considerat ion. 161 3 M W H O Pi PH 30 20 H W O PH M J J A S MONTH 1977 _ja MAXIMUM * * MINIMUM J I 0 N 30 _ w H PH H S3 S io Prf W PH \ - -13L \ - ^ - ^ MAXIMUM _L l_ i """^ MINIMUM M J J A S MONTH 1978 0 N Figure 10. Schematic p r o f i l e of protein poten-t i a l l y a vailable to C a l i f o r n i a b i g -horn sheep throughout two grazing years at the Okanagan Game Farm. \ 162 In a pre l iminary attempt to quantify the re la t ionsh ip be-tween forage use by bighorn sheep and nutr ient a v a i l a b i l i t y i n the plant community, consumption of forage by mountain sheep i n the captive herd was regressed against chemical propert ies and cover of potent ia l forage species throughout the study period (Table 31). Neither mul t ip le l inear or mul t ip le stepwise po ly -nomial regression to degree three could es tab l i sh any consistent re la t ionsh ips between consumption of a l l plant species sampled wi th in months, i nd i v idua l plant species, or forage c lasses and corresponding n u t r i t i v e q u a l i t y of forages. Cover was the most consistent var iab le entered i n both step-wise l inear and polynomial regression models i n each month. S t ras ia et a l . (1970) reported s i m i l a r l inear regressions between d i e t and cover fo r domest ic sheep on a l p i n e range as those p r o -duced i n th i s study but they concluded that t h e i r regressions were more evident for se lec t ion of forbs than for grasses. This parameter occurred as the only s i g n i f i c a n t var ia te remaining i n the models i n four of the s i x sampling periods and was included with calcium i n June as w e l l . Polynomial stepwise regressions general ly improved the r 2 values thus accounting for more of the v a r i a b i l i t y i n the regressions and indicated that these r e l a t i o n -ships are often both non- l inear and complex. Indeed, t h i r d order polynomials of calcium were added to the regression equations with cover i n May, June and Ju ly (Table 31). Although trends i n crude protein decl ined from May to March and ac id detergent f i b r e general ly increased over the same period i n each year (Table 24), pos i t i ve and negative re la t ionsh ips with Table 31. Multiple linear and polynomial regressions r e l a t i n g C a l i f o r n i a bighorn sheep d i e t to selected nutritxve parameters and cover Sampling Unit n S i g . r sq . Con CP ADF Ca P Ca/P Cover (XI) (X2) (X3) (X4) (X5) (X6) A. B. May 25 * * 0.51 0.29 1. 2. 50 0.56 0.17 10.52 -36 .11 - 3 . 1 5 0.39 87 0.44 C. * 0.49 Y = 10.32 - 25.59(X3) + 22.48(X3) 2 - 4 .93(X3) 3 + 0.33(X6) A. B. June 27 * * 0.57 0.35 - 1 . - 0 . 24 0.85 0.19 15.87 -42.64 - 3 . 8 5 0.36 15 0.46 0.46 C. * 0.74 Y = -32.13 + 11.58(X1) - 1.16(X1) 2 + 0.35(X1) 3 -17.90(X3) + 18.89(X3) 2 - 3.66(X3) 3 +3.05(X6) -0 .37(X6) 2 + 0 . 0 K X 6 ) 3 A. B. Ju ly 25 * * 0.53 0.20 - 1 6 . 2. 43 0.68 0.45 8.23 -20.33 - 1 . 0 2 0.52 63 0.48 C. * 0.72 Y = 14.39 - 18.74(X3) + 4.69(X3) 2 - 0.95(X5) + 0.19(X5) 2 - 0 . 0 K X 5 ) 3 + 1.65(X6) - 0.39 (X6) 2 + 0.02(X6) 3 A. B. August 25 NS * 0.28 3. 49 0.63 C. * 0.28 Y = 0.36 + 4.79(X6) - 0.66(X6) 2 + 0.02(X6) 3 A. B. C. October 11 NS NS NS A. B. C. March 16 * * * 0.72 0.36 0.36 9. 3. Y 77 -0 .84 -0 .08 -33.42 73.11 3.40 0.12 96 0.65 = 3.96 + 0.64(X6) A. B. C. AGSP 14 NS NS NS Table 31 (continued) Sampling r CP . ADF Ca P Ca/P Cover Unit n S i g . sq. Con. (XI) (X2) (X3) (X4) (X5) (X6) A. B. BRTE 14 NS 0. 80 - 3 6 . 47 0.87 0.74 1.64 19.24 - 0 . 8 1 0. 21 C. * 0. 66 Y = 24.19 - 1.45(X2) + 0.02(X2) 2 A. B. KOCR 11 NS NS C. * 0. 43 Y = - 0.14 + 25.75(X6) - 12.66(X6) 2 + 1.73(X6) 3 A. B. STCO 13 NS NS C. * 0. 79 Y = 11.98 + 17.99(X4) - 15.70(X6) + 7.84(X6) 2 - 1.03(X6) 3 A. B. C. BASA 8 NS * 0. 0. 63 63 45. Y = 13 -0 .79 45.13 - 1.13(X2) A. B. LUSE 8 * * 0. 0. 97 83 79. 64 -8 .32 0.66 11.40 205.93 -2 .09 6. 6. 34 86 C. * 0. 62 Y = -7 .08 + 8.51(X3) + 6.95(X6) - 1.8(X6) 2 A. B. ARFR 12 NS NS C. * 0. 56 Y - -4 .62 + 44.89(X4) - 99.87(X4) 2 A. B. ARTR 12 * * 0. 0. 82 40 - 1 4 . - 2 . 32 0.24 -0 .03 -22.48 29.79 5.21 19 -2 .19 0. 87 C. * 0. 84 Y = 8.19 + 0.15(X4) - 9.99(X5) + 2.57(X5) 2 A. B. ERNI 12 NS NS C. * 0. 74 Y = 34.89 - 1.79(X2) + 0.02(X2) 2 Table 31 (continued) Sampling Unit n Sig, sq. CP ADF Ca P Ca/P Cover Con. (XI) (X2) (X3) (X4) (X5) (X6) A. ERHE B. C. A. GRASS B. C. A. FORBS B. C. A. SHRUBS B. C. A. TOTAL DIET B. C. 12 63 27 57 147 NS NS NS * * * * * * * * 0.41 0.24 0.47 0.66 0.62 0.70 0.25 0.19 0.47 0.37 0.35 0.47 •26.49 4.88 1.11 0.64 5.81 -17.98 0.61 0.20 1.48 0.22 Y = 17.95 - 169 + 1.56(X5) - 2 . 6 5 0.18 0.54 .16(X2) + 810(X2)^ - 1099.47(X2) - 1 . 4 2 ( X 6 ) + 0.08(X6) 2 - 0 . 0 1 0.67 - 2 . 2 1 0.06 3.22 3.31 Y = - 3.60 + 1.28(X2) - 0.03(X2) 2 + 3.06(X6) -2 .49 0.15 0.16 0.02 1.28 - 2 . 5 7 0.24 0.08 0.27 Y = - 8.30 + 1. + 0.20(X5) 06(X2) - 0.04(X2) 2 + 0.01(X2) 3 -9 .67 -11.96 0.43 0.32 - 2.18 - 1 + 0.21(X2) - 0.19(X5) + 0.01(X6) 0.29 0.29 3.63 1.81 -11.60 - 0 . 3 9 0.52 0.55 •08(X1) + 0.13(X1) 2 - 0 .01(X1) 3 -9.73(X3) + 2.95(X3)^ + 2.02(X5) 2 + 0.01(X5) 3 + 1.05(X6) - 0.15(X6) 2 3 A. Mul t ip le l inear regression when a l l var iables forced into the regression equation B. Stepwise mult iple l inear regression only inc luding var iates making a s i g n i f i c a n t cont r ibut ion to the equation. C. Stepwise mult ip le polynomial regression equation only inc lud ing var ia tes making a s i g n i f i c a n t contr ibut ion to the equation. * S i g n i f i c a n t at (alpha = 0.05) NS Not s i g n i f i c a n t 166 these parameters respect ive ly were not establ ished. Crude pro-t e i n entered the regression model as a t h i r d order polynomial with calcium and cover i n June however. No s i g n i f i c a n t regressions (alpha = 0.05) were determined between d ie t and forage qua l i t y or cover i n October suggesting that the foraging patterns of the captive bighorn were not re lated to e i ther the qua l i t y or cover of forage despite the improved n u t r i t i v e value ava i lab le i n f a l l regrowth. Relat ionships between the intake of ind i v idua l species or forage c lasses and forage q u a l i t y were even more inconsistent than those establ ished on a monthly bas is . When a l l nutr ient var iates were "forced" into the mul t ip le regression equations, only three out of ten of these equations were s t a t i s t i c a l l y s i g n i f i c a n t (alpha = 0.05) i n d i c a t i n g that even a combination of nutr ients and cover could not expla in the foraging behavior of -the captive bighorn i n a l i near model (Table 31). General ly , stepwise l inear regression excluded a l l var ia tes when consumption of i n d i v i d u a l species was regressed against the nutr ient parameters (Table 31). Indeed, only ADF was negatively re lated to intake of Balsamorhiza s a g i t t a t a , cover was p o s i t i v e l y re lated to consumption of Lupinus sericeus and Artemis ia  t r identa ta was inverse ly re lated to the Ca/P r a t i o . Conversely, polynomial regressions improved both the amount of v a r i a t i o n explained by the regressions and the ove ra l l r e l a t i o n s h i p between consumption and qua l i t y was general ly s i g n i f i c a n t . Cover was the most consistent var iab le entering the po ly -nomial regression for i n d i v i d u a l species and forage c lasses a l -167 though not as commonly as on a monthly bas is . A d d i t i o n a l l y , re la t ionsh ips between the dependent and independent var iab les were t y p i c a l l y complex invo lv ing higher order polynomials of the f i t t e d var iates but once again no consistent forage q u a l i t y parameter could be i d e n t i f i e d for a l l species. The importance of cover i n r e l a t i o n to forage intake might imply that there i s a re la t ionsh ip between the amount of forage on o f fe r and consumption, however, Daubenmire (1968) suggested that cover often i s not a good index of production. On the other hand, coverage could be more i n d i c a t i v e of plant d i s t r i b u t i o n , and so, plant species which are common and widely d i s t r i b u t e d on the s i t e might be encountered more frequently by a grazing animal such as bighorn sheep that are constantly moving whi le grazing. Such a r e l a t i o n s h i p has been postulated for medium sized antelope in A f r i c a (Jarman 1974). The lack of any consistent q u a l i t a t i v e parameter r e l a t i n g to intake among plant species and even forage c lasses might ind icate that the "foraging strategy" of bighorn sheep i s one of n u t r i t -ional balance,(Westoby 1974) rather than the pursui t of i n d i v i -dual nut r ients . To some degree t h i s i s supported by both the mul t ip le l i near regressions where a l l the var iates were "forced" into the equations compared to the stepwise l inear regression. Typ ica l l y , when a l l var iab les were included i n the equations, higher r 2 values resul ted i n d i c a t i n g more of the v a r i a t i o n was explained by the regressions when a l l the var iates were present. S i m i l a r l y , when a l l species i n the d ie t (Total Diet) were r e -gressed against the independent var iab les i n polynomial stepwise 168 regression (Table 31), a l l parameters except phosphorus were entered although the resu l tant equation was extremely complex invo lv ing higher order polynomials of almost a l l var ia tes that were included i n the model. These regressions do not necessar i l y imply that the f i t t e d var iab les together are the determining factors i n forage s e l e c -t i on by mountain sheep. Rather i t suggests that a number of plant and animal a t t r ibu tes l i k e l y combine to determine whether or not i nd i v idua l plant species are selected or re jected by bighorn sheep and probably each plant species i s selected for a d i f f e r e n t set of fac to rs . The l i k e l i h o o d of a complex of factors being associated with forage se lec t ion has been postulated for other herbivores (Tribe 1950; Heady 1964; Raymond 1969; Al lden and Whittaker 1970; Arnold and H i l l 1971). 5.3 P lant Community Dynamics i n Relat ion to Grazing by C a l i f o r n i a Bighorn Sheep Although both E l l i s o n (1960) and Heady (1964) suggested that f l o r i s t i c changes i n a plant community more l i k e l y r e s u l t from var iab le i n t e n s i t i e s of grazing than d i r e c t l y from p a l a t a b i l i t y of forage p lants , general ly se lec t i ve grazing impairs the s u r v i -va l and growth of preferred plant species and by defaul t encour-ages less preferred taxa. Jamison (1963) argued that the meta-bolism of a l l p lant species i s measurably af fected at any leve l of grazing but deleter ious e f fec ts from grazing r e s u l t only when the phys io log ica l c a p a b i l i t i e s of the plant are exceeded or , for some species, when ap ica l buds are removed. Typ ica l l y , excessive d e f o l i a t i o n upsets normal food production, r e s p i r a t i o n and repro-169 d u c t i o n i n the p l a n t which may r e s u l t i n decreased p r o d u c t i v i t y and impaired r e p r o d u c t i v e c a p a b i l i t y of the p l a n t . S y n e c o l o g i -c a l l y , continued pressure on p r e f e r r e d taxa u l t i m a t e l y upsets e c o l o g i c a l r e l a t i o n s h i p s among p l a n t s p e c i e s and e v e n t u a l l y p a l a t a b l e s p e c i e s d e c l i n e i n abundance w h i l e l e s s p r e f e r r e d s p e c i e s become more prominent i n the f l o r a ( E l l i s o n 1960). 5.31 Forage U t i l i z a t i o n by C a l i f o r n i a Bighorn Sheep D i f f e r e n c e s i n herbage y i e l d s between grazed and ungrazed p l o t s were expected s i n c e t h i s measurement r e f l e c t s u t i l i z a t i o n more than a d e t e r m i n a t i o n of the long term e f f e c t s of g r a z i n g by mountain sheep on t h e p r o d u c t i o n of each of t h e 11 v e g e t a t i v e groups s t u d i e d (Table 32). Comparisons were not c o m p l e t e l y s a t -i s f a c t o r y f o r a l l groups s t u d i e d f o r two i n t e r r e l a t e d reasons. F i r s t , i t was assumed t h a t the average p r o d u c t i o n of a l l the v e g e t a t i v e groups was s i m i l a r on each of the r e p l i c a t e d grazed and ungrazed p a i r e d p l o t s which i s d i f f i c u l t to achieve e s p e c i a l -l y f o r r a r e s p e c i e s . Secondly, the t i m i n g and sampling i n t e n s i t y f o r p r o d u c t i o n and remaining s t a n d i n g crop may have been inade-quate to d e t e c t t r u e d i f f e r e n c e s r e s u l t i n g from g r a z i n g f o r some of the r a r e r s p e c i e s . Taxa which l i k e l y were a f f e c t e d most by these l i m i t a t i o n s i n c l u d e : Poa s a n d b e r g i i , Eriogonum niveum, S t i p a comata, and K o e l e r i a c r i s t a t a . Herbage y i e l d s f o r Poa s a n d b e r g i i were l i k e l y the most a f f e c t e d by c l i p p i n g i n August because t h i s s p e c i e s matures e a r l y i n June and some d e t e r -i o r a t i o n i s p o s s i b l e through t r a m p l i n g and weathering i n the i n t e r v a l between m a t u r i t y and harvest. Herbage y i e l d s f o r t o t a l s t anding crop were s i g n i f i c a n t l y Table 32. Percent u t i l i z a t i o n of 11 vegetative groups by C a l i f o r n i a bighorn sheep from 1977 to 1979 Vegetative Group 1977 1978 1979 Agropyron spicatum 0.001 22.05 52.60 Koeler ia c r i s t a t a 21.72 30.03 75.10 Poa sandbergi i 0.00 0.00 89.47 St ipa comata 73.81 99.03 47.79 Total Perennial Grass 13.37 33.14 55.83 Bromus tectorum 73.97 0.00 30.19 Total Annual Grass 57.10 0.00 25.27 Balsamorhiza s a g i t t a t a 87.78 19.75 0.00 Total Other Forbs 80.33 79.12 73.41 Eriogonum niveum 82.76 92.95 85.64 Total Standing Crop 39.84 36.06 52.70 1. 0.00 denotes biomass on the grazed p lots exceeded that on the ungrazed p l o t s . 171 l e s s on grazed compared to ungrazed p l o t s i n each year of the study except i n 1976 before the sheep were r e l e a s e d on the r e -search s i t e (Figure 11). Percent u t i l i z a t i o n for t o t a l standing crop v a r i e d among years rang ing from a low of 36.06% i n the wet -t e s t year (1978) to a h igh of 52.70% i n 1979 (Table 32). Non -s ign i f i cant in te ract ions (alpha = 0.10) between year and grazing were determined for Agropyron spicatum, t o t a l perennial grass and Balsamorhiza s a g i t t a t a from 1976 to 1979. However, s ingle degree of freedom contrasts indicated that there was a s t a t i s t i c a l l y s i g n i f i c a n t i n t e r a c t i o n between year and grazing for Agropyron spicatum i n the l a s t two years of the study (Figure 12). Indeed, i n the f i r s t year of graz ing, y ie lds of Agropyron  spicatum were ac tua l l y higher on the grazed (14.30 g/m2) than on the ungrazed (10.93 g/m2) p lo ts but t h i s plant species was progressively used more i n each year. U t i l i z a t i o n of Agropyron  spicatum equaled 22.05 and 52.60% i n 1977 and 1978 respect ive ly (Table 32). Although there were s i g n i f i c a n t year by grazing in teract ions for both Koeler ia c r i s t a t a and St ipa comata, trends i n y ie lds were d i f f e r e n t for each species on the grazed areas. On the ungrazed p l o t s , annual herbage production of Koeler ia c r i s t a t a var ied only s l i g h t l y remaining at a r e l a t i v e l y constant leve l between 2.0 and 3.0 g/m2 (Figure 13). Y ie lds on the grazed p lots for t h i s species decl ined over the three years equaling 1.91, 1.36 and 0.62 g/m2 i n 1977, 1978 and 1979 respect ive ly (Table 20) but l i k e l y t h i s was in response to increased consumption by the captive bighorn sheep. For example, average u t i l i z a t i o n pro-172 n 70 60 50 I 40 30 20 10 0 UNGRAZED """a GRAZED 1976 1977 1978 1979 YEAR Figure 11. The in t e r a c t i o n between year and grazing on y i e l d s of t o t a l standing crop (g/m sq.) from 1976 to 1979 (s i g n i f i c a n t at alpha = 0.05). , 1 7 3 W 40 30 20 10 0 \ t GRAZED 1976 .1977 1978 1979 YEAR Figure 12. The in t e r a c t i o n between year and grazing on y i e l d s of Agropyron  spicatum (g/m sq.) from 1976 to 1979 ( s i g n i f i c a n t at alpha = 0.10 between 1978 and 1979). 174 3.0 2.0 n w M 1.0 * UNGRAZED V GRAZED 0.0 1977 1978 1979 YEAR Figure 13. The in t e r a c t i o n between year and grazing on y i e l d s of Koeleria  c r i s t a t a (g/m sq.) from 1977 to 1979 ( s i g n i f i c a n t at alpha = 0.05). 175 gress ive ly increased equal l ing 21.72, 30.03 and 75.10% i n each of the three years respect i ve ly . Herbage production of St ipa comata decl ined progressively i n the absence of grazing but standing crops of t h i s species r e -mained r e l a t i v e l y constant on the grazed p lots from 1977 to 1979 (Figure 14). Unlike Koeler ia c r i s t a t a , the trend i n annual u t i l i z a t i o n corresponded c l o s e l y to the annual production of th i s species on the grazed p lots averaging 73.81, 99.03 and 47.79% for the three years respect ive ly (Table 32). Herbage y ie lds for both Bromus tectorum and t o t a l annual grass were higher w i th in the ungrazed exclosures than on the grazed p lots i n each year except 1978 (Table 20). Bromus  tectorum was heavi ly u t i l i z e d i n the f i r s t year of grazing by bighorn sheep (73.97%) but only moderately i n 1979 (30.19%). Total annual grass fol lowed s i m i l a r trends i n both absolute production and u t i l i z a t i o n among years, however percent u t i l i z a t i o n was lower for t h i s group than Bromus tectorum i n each year equaling 57.01 and 25.27% for 1977 and 1979 respect i ve ly . Y ie lds of both t o t a l other forbs and Eriogonum niveum did not fo l low consistent trends on the grazed p lots from 1977 to 1979 although both vegetative groups were u t i l i z e d heavi ly i n each year of the study. Percent u t i l i z a t i o n averaged 80.33, 79.12 and 73.41 f o r t o t a l other fo rbs and 82.76, 92.95 and 85.64 for Eriogonum niveum i n 1977, 1978 and 1979 respect i ve ly . Grazing i n t e n s i t y , expressed through u t i l i z a t i o n , was not homogeneously spread among the vegetative groups sampled i n t h i s study. The impact of foraging in tens i t y by C a l i f o r n i a bighorn p w 176 X , &• UNGRAZED a GRAZED 1977 1978 1979 YEAR Figure 14. The in t e r a c t i o n between year and grazing on y i e l d s of Stipa comata (g/m sq.) from 1977 to 1979 ( s i g n i f i c a n t a t alpha = 0.05). 177 over the three year p e r i o d may be p rognos t i c of the long term grazing e f fec ts on each of the vegetative groups. During the act ive growing per iod, u t i l i z a t i o n only equaled the c r i t i c a l l eve l of 50-60% (Jamison 1963) for e i ther Agropyron spicatum or t o t a l perennial grass i n 1979. In the two previous years, the i n t e n s i t y of grazing on each group was wel l below t h i s c r i t i c a l range. Should u t i l i z a t i o n remain constant or increase above those at the 1979 leve l of 52.60% for Agropyron spicatum and 55.83% for t o t a l perennial grass, both vegetative groups might be i n i m i c a l l y affected i n the future although long term reductions i n production would l i k e l y occur s lowly under the current grazing treatment. U t i l i z a t i o n of St ipa comata exceeded 70% i n both 1977 and 1978. Indeed, i n 1978 t h i s species was f u l l y u t i l i z e d (99.03%) but i n 1979 grazing removed only 47.79% of the annual f o l i a g e . U t i l i z a t i o n rates on Koeler ia c r i s t a t a increased progressively from 1977 to 1979 (Table 32) but only i n 1979 did the leve l of use exceed the c r i t i c a l range of 50-60% d e f o l i a t i o n . Continued heavy grazing on both these taxa suggest that t h e i r future pro -d u c t i v i t y may be impaired. In general , forbs are less to lerant to grazing than grasses (Jamison 1963). Balsamorhiza sag i t ta ta was the only i n d i v id ua l forb species monitored i n t h i s study. Although t h i s species was grazed heavi ly i n the ear ly spr ing of 1977 soon a f te r growth i n i t i a t e d (Wikeem and P i t t 1979) and seasonal u t i l i z a t i o n equaled 87.78%, leve ls of u t i l i z a t i o n decl ined in each of the fo l low ing years (Table 32). By 1979, herbage y ie lds of Balsamorhiza 178 sag i t ta ta were greater on the grazed p lots than the ungrazed p lots although only marginal ly so (Table 20). Balsamorhiza  sag i t ta ta appears to be r e l a t i v e l y res i s tant to d e f o l i a t i o n . In a c l i p p i n g t r i a l , B l a i s d e l l and Pechanec (1949) reported that the production of t h i s species equaled 89.7 and 40.1% of the undipped contro l plants i n the year fo l low ing intensive d e f o l i a t i o n to ground leve l when the treated plants were c l ipped at the f lower s ta lk and f u l l bloom stages respect ive ly . Timing of d e f o l i a t i o n s appears to be more important than the i n t e n s i t y for t h i s species with the plant most vunerable at the f u l l bloom stage ( B l a i s d e l l and Pechanec 1949). By th i s time the captive mountain sheep concentrated t h e i r foraging on f lower heads and made l i t t l e use of leaves. Both t o t a l other forbs and the ha l f shrub Eriogonum niveum were severely defo l ia ted i n a l l three years of study (Table 32). General izat ions regarding t o t a l other forbs must be made caut -ious ly however, because t h i s group was comprised of 57 i n d i v i d u a l species (Appendix 6) each with d i f f e r e n t l i f e h i s t o r i e s , t o l e r -ances to grazing and p a l a t a b i l i t i e s . Cer ta in ly u t i l i z a t i o n of t h i s group was s u f f i c i e n t l y intensive to suggest that continued grazing at these leve ls might u l t i m a t e l y reduce production. However, i f these leve ls of use were not homogeneously appl ied to a l l species i n th i s group, i t i s possible that compensatory production might occur among species and the ove ra l l herbage y i e l d might remain unchanged or even increase. On the other hand, a continuance of the extreme u t i l i z a t i o n on Eriogonum  niveum w i l l undoubtedly r e s u l t i n herbage production being 179 ser ious ly impaired for th i s species. Removal of herbage through grazing by mountain sheep may have secondary e f fec ts on the future product iv i t y of the i r habi tat as w e l l . The importance of mulch or l i t t e r production on nutr ient c y c l i n g , moisture i n f i l t r a t i o n , amel iorat ion of s o i l temperature, and protect ion against wind and water erosion have been long recognized (Osborn 1956; E l l i s o n 1960). L i t t e r production was measured on North, East and Upper i n 19 79 a f te r three years of grazing by mountain sheep. Averaged over a l l s i t e s , l i t t e r y i e l d s were s i g n i f i c a n t l y (alpha = 0.05) lower on the grazed (84.31 g/m2) than on the ungrazed (128.00 t g/m2) p lots i n d i c a t i n g that bighorn sheep can have an impact on muich deposi t ion. Combined herbage production and mulch t o t a l l e d 1097.8 and 1817.8 kg/ha for the grazed and ungrazed areas respect i ve ly . The potent ia l for s o i l losses through wind and water erosion appears high on most mountain sheep ranges since these animals are often associated with windswept steep slope t e r r a i n . A l -though r a i n f a l l i s t y p i c a l l y low, per iodic high i n t e n s i t y storms o do occur (Tisdale 1947). Indeed, Blood (1961) reported s i g n i f i -cant s o i l losses on the Ashnola C a l i f o r n i a bighorn sheep winter range during an intense ra instorm, although he suggested that removal of the protect ive vegetative cover resul ted from over-grazing by domestic l i ves tock . Insidious s o i l losses through erosion may reduce the inher -ent f e r t i l i t y of some bighorn ranges. Subsequent e f fec ts on forage production may be exacerbated further by the non-homo-180 geneous d i s t r i b u t i o n of feces and urine that was observed on the study s i t e with extreme concentrations of feces occurr ing around bedding areas. The rea l s ign i f i cance of mulch removal and the d i s t r i b u t i o n of excret ia cannot be assessed from t h i s study however, and warrants further research under natural condi t ions . 5.32 Impact of Grazing on the Reproductive P o ten t ia l of Herbaceous Species The impact of C a l i f o r n i a bighorn sheep grazing on leaf length, basal diameter, culm length and the number of culms pro-duced was assessed for eight forage species i n 1979 (Table 33). Relat ive e f fec ts of grazing were confounded with current seasonal use but a l l measurements for average longest leaf and culm lengths were based on ungrazed plant parts even when plants were ava i lab le for sheep grazing. Both grazed and ungrazed culms were included i n the count of the number of culms produced. Basal diameters were assumed to be least affected by the current years foraging and l i k e l y serves as the best index of long term impact on i n d i v i d u a l species. Of the four perennial grasses monitored, Agropyron spicatum was least affected by grazing despite i t s importance i n mountain sheep d i e t . Although both the longest leaf and culm lengths were s i g n i f i c a n t l y shorter on the grazed plants compared to the con-t r o l s (alpha = 0.05), leaf and culm lengths on the grazed plants were s t i l l 94.4 and 89.1% of the ungrazed for each respect i ve ly . Concurrently, basal diameters were almost i d e n t i c a l at 128.00 and 129.50 mm for the two groups respect i ve ly . Grazed plants a c t u a l -l y produced more culms on average (26.62) than the ungrazed group 181 T a b l e 3 3 . Impacts o f g r a z i n g by C a l i f o r n i a b i g h o r n sheep on l e a f l e n g t h (mm), b a s a l d i a m e t e r (mm), culm l e n g t h (mm) and t h e number o f culms produced f o r e i g h t s e l e c t e d f o r a g e s p e c i e s S p e c i e s V a r i a b l e Grazed Ungrazed S i g n i f i c a n c e L e a f L ength 390 .30 413 .50 ** Agropyron B a s a l Diameter 128 .00 129 .50 NS s p i c a t u m Culm Length 603 .00 676 .90 ** No. Culms 26 .62 25 .95 NS L e a f Length 108 .50 166 .30 ** K o e l e r i a B a s a l Diameter 33 .97 65 .45 * * c r i s t a t a Culm L e n g t h 329 .30 399 .10 * * No. Culms 2 .85 9 .50 * * L e a f L e n g t h 52 .03 60 .08 ** Poa B a s a l Diameter 25 .18 28 .90 * * s a n d b e r g i i Culm Length 225 .20 282 .58 ** No. Culms 3 .32 3 .77 NS L e a f Length 157 .20 251 .30 ** S t i p a B a s a l Diameter 32 .57 44 .85 ** comata Culm Length 307 .50 427 .40 ** No. Culms 2 .83 3 .73 ** L e a f Length 350 .00 370 .60 * B a l s a m o r h i z a B a s a l Diameter 69 .23 69 .83 NS s a g i t t a t a Culm L e n g t h 64 .98 83 .60 NS No. Culms 1 .47 1 .88 NS L e a f Length 77 .45 77 .77 NS C a s t i l l e j a B a s a l Diameter 21 .43 29 .29 * * t h o m p s o n i i Culm L e n g t h 148 .45 244 .69 ** No. Culms 1 .71 7 .19 * * L e a f Length 106 .20 318 .48 ** L u p i n u s B a s a l Diameter 34 .98 49 .48 * * s e r i c e u s Culm Length 19 .91 345 .80 * * No. Culms 0 .54 6 .36 * L e a f Length 56 .62 101 .40 ** Eriogonum B a s a l Diameter 70 .67 108 .80 ** niveum Culm Length 83 .35 212 .80 ** No. Culms 0 .93 7 .40 ** * S i g n i f i c a n t a t a l p h a = 0.10 ** S i g n i f i c a n t a t a l p h a = 0.05 NS Not s i g n i f i c a n t 182 (25.95) but the d i f ference was marginal and not s t a t i s t i c a l l y s i g n i f i c a n t . Vogel and van Dyne (1966) observed s i m i l a r e f fec ts on basal diameters, and leaf and culm lengths for t h i s species under moderate grazing by domestic sheep on dryland range i n Montana. Agropyron spicatum i s most vunerable to d e f o l i a t i o n at two phenological stages; boot to ear ly f lower ing stage (Quinton et a l . 1982; B l a i s d e l l and Pechanec 1949) and at head emergence (Mueggler 1975). Indeed, Quinton et al.(1982) concluded that repeated d e f o l i a t i o n s at the boot stage w i l l r e s u l t i n th i s species disappearing from the range. Both the i n t e n s i t y and season that Agropyron spicatum was used by b ighorn sheep dur ing t h i s study might e x p l a i n the lack of serious impact on t h i s plant species. As previously reported, u t i l i z a t i o n on Agropyron spicatum exceeded 50% only i n the t h i r d year of grazing (Table 32) and even then only s l i g h t l y . At the same t ime, grazing on t h i s species was spread r e l a t i v e l y homogen-eously over a l l seasons i n both years (Appendix 8) and i t i s u n l i k e l y that u t i l i z a t i o n leve ls were s u f f i c i e n t i n the c r i t i c a l spring period to det r imenta l l y a f fec t growth. Koeler ia c r i s t a t a , Poa sandbergi i and St ipa comata were a l l negat ively af fected by grazing. Leaf lengths, basal diameters and culm lengths were a l l s i g n i f i c a n t l y (alpha = 0.05) lower on the grazed compared to the ungrazed plants for a l l three species (Table 33). Koeler ia c r i s t a t a appeared to be affected most by grazing with the average basal diameter on grazed plants equaling only 51.9% of those on the contro l p lants . Conversely, Poa 183 sandbergi i was least af fected and di f ferences between the grazed and ungrazed plants sampled may have been more a r e f l e c t i o n of the current year's u t i l i z a t i o n i n 1979 than long term e f fec ts of grazing. For example, basal diameters on the grazed plants equaled 87.13% of the ungrazed and culm production was not s t a t i s t i c a l l y d i f f e r e n t between the two groups. Diet data for Koeler ia c r i s t a t a and St ipa comata suggest that both species were used extensively in a l l seasons, espec ia l l y i n r e l a t i o n to the i r a v a i l a b i l i t y (Appendix 8). The cont inual grazing pressure at a l l seasons, r e s u l t i n g i n o v e r u t i l i z a t i o n (Table 32) was l i k e l y most responsible for the dec l in ing v igor of both these species. Balsamorhiza s a g i t t a t a , C a s t i l l e j a thompsonii and Lupinus  sericeus a l l responded d i f f e r e n t l y to grazing with the former being least af fected and the l a t t e r the most. Although leaf lengths on grazed Balsamorhiza sag i t ta ta (350.00 mm) were s i g -n i f i c a n t l y lower than on the ungrazed (370.60 mm) (alpha = 0.10) , no s t a t i s t i c a l d i f ferences i n basal diameter, culm length and the number of culms produced were observed between the two groups. Neither the production nor reproductive c a p a b i l i t y of t h i s species appears to be threatened by mountain sheep grazing. C a s t i l l e j a thompsonii appeared to be affected only s l i g h t l y to moderately a f te r three years of grazing. Although basal diameters on grazed plants were s i g n i f i c a n t l y (alpha = 0.05) smal ler (21.43 mm) than on the controls (29.29 mm) they s t i l l remained 72.4% of the ungrazed diameters and the longest leaf lengths between the two groups were not s t a t i s t i c a l l y d i f f e r e n t (Table 33). The greatest impact on th i s species occurred on the 184 f l o r a l organs with the average culm lengths of the grazed plants equaling only 60.7% the length of t h e i r ungrazed counterparts. The number of culms produced was great ly reduced on the grazed plants averaging only 1.71 inf lorescences per plant compared to 7.19 on the cont ro ls . Although the e f fec t of past grazing was confounded with the current years u t i l i z a t i o n , i t appears l i k e l y that continued heavy grazing on the f l o r a l organs w i l l adversely a f fec t the reproductive c a p a b i l i t y of th i s species u l t i m a t e l y . Of the non-graminoids, Lupinus sericeus and Eriogonum niveum appear to be under the greatest st ress from grazing. Both s t a t -i s t i c a l and b i o l o g i c a l l y s i g n i f i c a n t d i f ferences were determined between grazed and ungrazed plants for a l l parameters measured on both species. Basal diameters were least affected by bighorn use with values for grazed plants averaging 70.7 and 65.0% of the ungrazed for Lupinus sericeus and Eriogonum niveum respect i ve ly . The greatest impacts on both taxa were reductions i n culm length and the number of culms produced. Average culm lengths on the grazed plants equaled only 5.8 and 39.2% of the contro ls for the two plant species respect ive ly (Table 33). Correspondingly, the number of inf lorescences produced on grazed plants was great ly reduced equaling only 8.5 and 12.5% of the contro l for each of the taxa respect i ve ly . L i t t l e information i s ava i lab le on the autecology of e i ther species e s p e c i a l l y i n r e l a t i o n to grazing. However, continued heavy u t i l i z a t i o n w i l l l i k e l y impair sexual reproduction at the least and probably increase mor ta l i t y among i n d i v i d u a l plants w i th in both taxa i f current bighorn grazing se lec t ion patterns p e r s i s t . The extent to which sexual repro-185 duction may be affected w i l l depend upon the importance of th i s form of propogation to each species but there i s no evidence ava i lab le i n d i c a t i n g that e i ther taxa reproduce vegetat ive ly . 5.33 Impact of Browsing on Amelanchier a l n i f o l i a During the 1977 summer grazing period u t i l i z a t i o n of Amelan- ch ier a l n i f o l i a was determined using three methods inc lud ing : twig length, t o t a l c lus te rs and the average number of twigs browsed per c l u s t e r . Percent u t i l i z a t i o n averaged 52.52, 83.83 and 63.25 for the three methods respect ive ly (Table 34). These values were unexpectedly high since any browsing by bighorn was ant ic ipated to be minimal . Observation of bighorn browsing during 1977 suggested that leaves were being selected d isproport ionate ly over stems and an .0 under estimate of the actual u t i l i z a t i o n was suspected since a l l three methods used i n 1977 involved stem determinations. A d d i t i o n a l l y , i t was noted that most buds on the l a t e r a l branches were associated with the junctions of the leaf pet io les and, wi th moderate use of the leaves, the fo l low ing year's fo l iage also might be consumed inadvertent ly . In 1978, f i v e methods were tested simultaneously to determine which could best evaluate browsing by bighorn sheep. Based on the weight d i f ference method data, leaves and stems produced 74.2 and 25.8% of the t o t a l y ie lds of the current years growth on Amelanchier a l n i f o l i a i n 1978 (Table 34). These values are s l i g h t l y lower than those reported by Cook and Stoddart (1953) and Wi l l iams (1976) for the same plant species i n two widely separated studies . Cook and Stoddart (1953) found leaves 186 Table 34. Percent u t i l i z a t i o n of Amelanchier a l n i f o l i a determined with f i v e d i f f e r e n t methods Method Year Browsed Unbrowsed S i g . % U t i l i z . Twig 1977 71.50 150.60 * 52.52 Length(mm) 1978 107.30 246.00 * 56.38 Total 1977 166 198 * 83.83 Clusters 1978 91 9 * 91.00 Average No. 1977 5.30 8.38 * 63.25 Twigs/Cluster 1978 3.69 5.00 * 73.80 Weight Difference(g) Leaves 1978 0.43 1.64 * 73.70 Twigs 1978 0.26 0.57 * 53.58 Total 1978 0.70 2.21 * 67.63 No. Buds/ Cluster 1978 3.82 8.19 * 53.35 * S i g n i f i c a n t at alpha = 0.05 o 187 comprised 80% of the t o t a l forage produced on Amelanchier a l n i - f o l i a i n northern Utah. S i m i l a r l y , Wi l l iams (1976) reported that leaves produced 81.77% of the t o t a l forage when y ie lds from s i x s i t e s i n North Dakota were averaged. However, leaf production on these s i x s i t e s ranged from 71.30 to 87.30%. U t i l i z a t i o n measurements var ied among methods again i n 1978. However, i t i s i n t e r e s t i n g to note that determination of percent u t i l i z a t i o n based upon twig length, weight of twigs and the number of buds per c l u s t e r were almost i d e n t i c a l equa l l ing 56.38, 53.58 and 53.35% respect i ve ly . Perhaps t h i s should not be sur -p r i s i n g since weight i s undoubtedly corre lated to length and probably to the number of buds produced as w e l l . In both years, u t i l i z a t i o n values ca lcu lated from the t o t a l twig c lus te r and the average number of twigs per c lus te r methods were considerably higher than other methods (Table 34). Wi l l iams (1976) noted the same e f f e c t when comparing the twig length method to the t o t a l c lus te rs browsed on mule deer winter range. Stoddart et a l . (1975) suggest that the re la t ionsh ip between the number of twigs eaten and percent u t i l i z a t i o n are not l i near and that 100% of the stems or c lus te rs may be browsed we l l before 100% u t i l i z a t i o n i s experienced. Results from t h i s study agree with the above observations. When u t i l i z a t i o n was determined by the weight d i f ference technique three d i f f e r e n t estimates were produced by p a r t i t i o n i n g the t o t a l weight into i t s component parts (Table 34). Percent u t i l i z a t i o n was highest on leaves (73.30%) and lowest on stems (53.58%) confirming the 1977 observation that more browsing 188 occurred on the leaves than on the stems. Expectedly, when per-cent u t i l i z a t i o n was based on t o t a l weight, the value produced was intermediate between those ca lcu lated for leaves and stems. On the basis of a s i x year c l i p p i n g study Payne and Young (1948) concluded that 50% u t i l i z a t i o n of the current annual stem growth of Amelanchier a l n i f o l i a i n the spring and summer w i l l decrease the fo l lowing year's production only s l i g h t l y but that 75% u t i l i z a t i o n resu l t s i n a d e f i n i t e reduction i n fo l iage y i e l d s . U t i l i z a t i o n estimates ca lcu lated from twig length, twig weights and the number of buds removed i n t h i s study a l l suggest that u t i l i z a t i o n leve ls by mountain sheep were only moderate i n both 1977 and 1978. However, by the spring of 1979 so few branches of new growth sprouted i n the 0 - 2m zone of a v a i l -a b i l i t y on Amelanchier shrubs that u t i l i z a t i o n measurements were abandoned. U t i l i z a t i o n of t h i s shrub in 1979 was l i m i t e d to the bighorn standing on t h e i r hind legs and browsing above 2m. The sheep appeared to have a g reate r impact on the p l a n t s than the u t i l i z a t i o n data ind icated . This may be par t l y e x p l a i n -ed by the unexpected but continued use of Amelanchier a l n i f o l i a into the f a l l and winter . Undoubtedly, the actual u t i l i z a t i o n on t h i s species was higher than r e f l e c t e d i n the late August sam-p l i n g . Despite bighorn s e l e c t i v e l y grazing leaves i n greater amounts than stems, i t does not appear that t h i s method evaluates the impact of mountain sheep browsing on Amelanchier a l n i f o l i a any better than stem determinations. Hypothet ica l ly , the inordinate use of leaves might a f fec t the plant most by the 189 consequential removal of buds. The resu l t s of t h i s study do not ind icate that t h i s hypothesis i s reasonable since u t i l i z a t i o n determined from more e a s i l y derived stem measurements were quant i ta t i ve l y s i m i l a r (Table 34). 5.34 Impact of Grazing on Plant Community Structure The e f fec ts of grazing by C a l i f o r n i a bighorn sheep on cover and botanical composition were monitored i n June from 1976 to 1983. In order to separate the e f fec ts of annual weather and grazing, year by grazing in teract ions were evaluated. Only 11 vegetative groups inc lud ing t o t a l cover, t o t a l grass, annual grass, Bromus m o l l i s , St ipa comata, t o t a l forbs , A c h i l l e a  m i l l e f o l i u m , Lupinus ser iceus , t o t a l shrubs, Eriogonum niveum and Eriogonum heracleoides produced s i g n i f i c a n t in teract ions between grazing and year throughout the study per iod. A l l other plant species and groups responded s i m i l a r l y on areas protected and grazed by bighorn sheep. Total cover remained v i r t u a l l y the same on the grazed (71.1 and 85.0%) and ungrazed (70.3 and 86.0%) areas between 1976 and 1983 respect ive ly (Figure 15). Although values for cover were s i m i l a r for both leve ls of grazing in 1983, herbaceous cover appeared to be increasing s l i g h t l y on the grazed areas from 1980 whi le i t was dec l in ing on those protected from grazing but these changes were not important i n absolute terms (Figure 15). Throughout t h i s period from 1980 to 1983, changes i n percent t o t a l cover undoubtedly corresponded to va r ia t ions i n cover and botanical composition of other plant species and groups i n the f l o r a (P i t t and Heady 1979). Therefore, to some extent, the 190 Figure 15. The i n t e r a c t i o n between year and grazing on percent t o t a l cover from 1976 to 1983 ( s i g n i f i c a n t at alpha = 0.10). 191 s i m i l a r i t y of t o t a l cover between the two leve ls of grazing might be a t t r ibuted to vegetative groups and species react ing d i f f e r -ent ly to grazing pressure by bighorn and, whi le one group de-c l i n e s , others increase. Woolfolk (1949) provided evidence for t h i s on domestic sheep range i n the Northern Great P l a i n s , Montana. From 1976 to 1983 cover of t o t a l grass decl ined from 46.5 to 30.8% w i th in the ungrazed exclosures but remained v i r t u a l l y un-changed increasing only from 44.7 to 48.8% under the inf luence of grazing by bighorn (Figure 16). Conversely, t h i s group's c o n t r i -bution to botanica l composition decl ined on both the grazed (63.1 and 56.6%) and ungrazed (67.3 and 37.2%) areas over the same period although t h i s decl ine was most s t r i k i n g i n the ungrazed exclosures (Figure 17). These resu l t s agree with observations on domestic sheep range which have shown that grasses often increase under moderate and heavy grazing p a r t i c u l a r l y i f these ranges are u t i l i z e d i n the spring and summer grazing seasons (Heady et a l . 1947; E l l i s o n 1954; Branson and Lommasson 1958; Vogel and van Dyne 19 66). Annual, perennial and i n d i v i d u a l grass species a l l reacted d i f f e r e n t l y to grazing. Both percent cover and botanical com-pos i t ion of annual grass as a group were reversed between 1976 and 1983 on both the grazed and protected s i t e s (Figure 18, Figure 19). In the f i r s t year of study both cover and botanical composition were greatest i n the exclosures but by 1983 t h i s group was most predominant on the grazed areas although decl ines i n absolute abundance were apparent for both treatment l e v e l s . 192 w > o u H W U Pi w PH 80 70 60 50 40 30 20 10 76 77 GRAZED 78 79 ' 80 YEAR V UNGRAZED 83 Figure 16. The in t e r a c t i o n between year and grazing on percent cover of t o t a l grass from 1976 to 1983 ( s i g n i -f i c a n t a t alpha = 0.05). o H H H !*) o S3 S W O U U PS1 PH .-4 < r H H O pq 80 70 60 50 40 .. 30 20 10 .. 76 77 V \ GRAZED UNGRAZED 78 79 YEAR 80 81 83 Figure 17. The in t e r a c t i o n between year and grazing on percent botanical com-pos i t i o n of t o t a l grass from 1976 to 1983 ( s i g n i f i c a n t at alpha = 0.05) . 193 pi w > o u 4 0 3 0 2 0 H 5 5 W £ 1 0 W P-i 76 77 78 'fe GRAZED UNGRAZED 79 8 0 81 83 YEAR Figure 18. The i n t e r a c t i o n between year and grazing on percent cover of annual grass from 1976 to 1983 ( s i g n i f i -cant a t alpha = 0.05). 5 3 O l - l H 1 | o o H c_> 5 5 W O < Pi u w M P-, AN H O PQ 4 0 , 3 0 .. 20 1 0 \ GRAZED ^ UNGRAZED J l_ 76 77 78 79 80 YEAR 83 Figure 19. The i n t e r a c t i o n between year and grazing on percent botanical compo-s i t i o n of annual grass from 1976 to 1983 ( s i g n i f i c a n t at alpha = 0.10). v 194 Although f luc tuat ions i n cover, botanical composition and production of annuals commonly vary i n response to annual weather patterns (Heady and P i t t 1979), the f l o r i s t i c changes observed i n th i s study can be at t r ibuted par t l y to grazing inf luences as component species in t h i s group responded quite d i f f e r e n t l y over the study per iod. For example, cover of Bromus m o l l i s increased nearly 170% on the grazed area (3.3 and 5.6%) but decreased subs tant ia l l y (487%) ins ide the exclosures (7.3 and 1.5%) between 1976 and 1983 respect ive ly (Table 35, Figure 20). S i m i l a r trends were evident for botanical composition of t h i s species as we l l (Figure 21). Since Bromus m o l l i s was only a minor component of the d ie t i n a l l seasons and was not preferred (Appendix 8), the observed increases i n cover and botanical composition on the unprotected area are probably only i n d i r e c t l y associated wi th grazing and more l i k e l y are re lated to changes i n s o i l surface condi t ions . For example, f i e l d observations indicated that a surface crust developed from 1977 to 1983 wi th in the exclosures i n the i n t e r -spaces between bunchgrasses and low shrubs whereas considerable s o i l disturbance was evident on the area grazed by bighorn. Some evidence suggests that formation of these crusts may i n h i b i t germination and establishment of graminoids (Pyatt 1967) which could expla in the decl ine of Bromus m o l l i s ins ide the exclosures. Conversely, the disturbed s o i l condit ions present i n the grazed environment may have provided a favorable seed bed for th i s species, and i n the absence of any grazing pressure by bighorn sheep, i t could increase i n abundance under favorable weather Table 35. Average botanical composition (%) and cover (%) on areas grazed (G) and ungrazed (UG) by C a l i f o r n i a bighorn sheep from 1976 to 1983 1976 1977 1978 1979 1980 1981 1983 Species G U G G U G G U G G U G G U G G U G G U G ANNUAL GRASS APIN Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.3 1.3 1.0 1.1 1.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 4.8 4.0 3.3 2.8 0.0 " 0.0 0.0 0.0 BRMO Bot Comp Cover 4.8 3.3 10.5 7.3 4.6 3.4 8.3 7.3 4.3 3.6 5.9 5.3 2.7 1.6 2.0 1.5 0.0 0.0 0.0 0.0 11.1 9.2 8.2 6.3 7.3 5.6 1.5 1.5 BRTE Bot Comp Cover 14.9 10.3 21.8 14.8 18.5 13.7 27.8 23.8 19.4 15.8 16.4 14.5 13.3 7.9 12.8 9.5 22.1 18.2 14.5 12.5 17.8 14.8 19.5 15.5 2.8 2.2 1.0 0.8 FEOC Bot Comp Cover 0.0 0.0 0.0 0.0 0.7 0.4 0.8 0.3 1.7 1.3 0.8 0.8 0.2 0.1 0.0 0.0 2.9 2.4 1.1 1.0 1.2 0.9 1.0 0.8 2.1 1.7 0.6 0.5 PERENNIAL GRASSES AGSP Bot Comp Cover 33.4 24.2 23.3 16.8 35.5 28.8 20.9 19.0 31.2 26.5 17.7 17.3 39.5 24.7 24.8 19.8 32.2 28.5 26.9 22.5 35.4 31.0 31.5 27.0 34.9 31.9 23.5 20.0 KOCR Bot Comp Cover 4.0 2.7 3.5 2.3 7.9 5.8 4.4 3.8 3.3 2.7 4.8 4.3 3.0 1.8 5.4 4.0 1.1 0.9 2.6 2.3 1.0 0.8 0.0 0.0 2.5 2.0 3.7 3.0 POPR Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 POSA Bot Comp Cover 2.1 1.4 1.1 0.8 1.4 1.0 2.1 1.8 2.0 1.6 1.1 1.0 0.2 0.2 0.3 0.3 4.1 3.3 1.5 1.3 0.0 0.0 0.0 0.0 1.2 1.0 0.6 0.5 STCO Bot Comp Cover 3.9 2.8 7.0 4.8 7.6 5.6 10.9 9.3 4.2 3.4 11.3 10.0 9.5 5.7 15.9 11.8 4.5 3.8 6.4 5.8 1.5 1.3 0.7 0.5 5.8 4.4 5.8 4.5 ANNUAL FORBS AGHE Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.9 0.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 0.2 0.0 0.0 0.0 0.0 0.0 0.0 COPA Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 1.9 1.5 0.9 0.8 0.0 0.0 0.0 0.0 0.7 0.6 0.6 0.5 Table 35 (continued) 1976 1977 1978 Species G U G G U G G U G ANNUAL FORBS (cxmtinued) LEDO Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.3 0.0 0.0 0.0 0.0 MITR Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 PLPA Bot Comp Cover 0.2 0.2 0.0 0.0 0.6 0.4 0.6 0.5 3.7 3.0 2.2 2.0 PODO Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 POMI Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 . 0.0 0.0 0.0 0.0 SIAL Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.9 0.8 TRDU Bot Comp Cover 0.0 0.0 0.0 0.0 0.2 0.2 0.0 0.0 0.0 0.0 0.0 0.0 TAOF Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 PERENNIAL FORBS AND BRYOPHYTES ACMI Bot Comp Cover 2.4 1.6 1.1 0.8 1.6 0.2 2.4 2.0 2.0 1.7 1.1 1.0 ANDI Bot Comp Cover 0.1 0.1 0.0 0.0 0.5 0.3 0.0 0.0 0.6 0.4 0.0 0.0 ANPA Bot Comp Cover 1.2 0.8 1.2 0.8 0.4 0.3 0.7 0.5 0.5 0.4 1.7 1.5 ARHO Bot Comp Cover 0.0 0.0 0.0 0.0 0.1 0.1 0.3 0.3 0.0 0.0 0.0 0.0 ASMI Bot Comp Cover 0.0 0.0 0.0 0.0 0.1 0.1 0.0 0.0 0.1 0.1 0.3 0.3 1979 1980 1981 1983 G U G G U G G U G G U G 0.0 0.0 0.3 0.0 0.0 0.0 0.3 0.0 0.0 0.0 0.3 0.0 0.0 0.0 0.3 0.0 1.4 0.7 2.0 0.0 0.8 0.5 1.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.6 0.0 0.0 0.0 0.5 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.3 1.8 0.0 0.3 0.3 1.5 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.6 2.7 2.7 2.9 1.0 2.0 2.2 2.5 0.3 0.4 0.5 0.9 0.2 0.3 0.4 0.8 0.7 3.4 0.8 2.8 0.4 2.5 0.6 2.3 0.0 0.0 0.3 0.0 0.0 0.0 0.3 0.0 0.0 0.7 0.2 0.9 0.0 0.5 0.2 0.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.0 0.4 0.0 0.1 0.0 0.3 0.0 1.5 0.7 1.9 0.0 1.3 0.5 1.5 0.0 0.0 1.4 0.0 1.2 0.0 1.0 0.0 1.0 0.0 0.0 0.1 0.0 0.0 0.0 0.1 0.0 0.0 0.0 0.0 0.6 0.0 0.0 0.0 0.5 0.2 0.4 0.2 1.3 0.2 0.3 0.1 1.0 0.0 0.4 0.1 0.0 0.0 0.3 0.1 0.0 2.8 4.5 2.7 6.9 2.3 3.5 2.1 5.5 0.4 0.0 0.2 0.0 0.3 0.0 0.2 0.0 0.2 1.2 0.3 1.9 0.2 1.0 0.3 1.5 0.0 0.3 0.2 0.0 0.0 0.3 0.2 0.0 0.4 0.4 0.1 0.9 0.3 0.3 0.1 1.0 Table 35 (continued) 1976 1977 1978 Species G U G G U G G U G PERENNIAL FORBS AND BRYOPHYTES (continued) BASA Bot Comp Cover 4.7 3.4 4.5 3.3 3.9 3.3 3.2 3.1 5.4 5.1 5.6 5.5 CAMA Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 0.2 0.3 0.3 CATH Bot Comp Cover 1.8 1.3 1.8 1.3 0.6 0.4 1.5 1.3 0.8 0.7 2.3 2.0 CEDI Bot Comp Cover 0.4 0.3 0.0 0.0 0.2 0.2 0.0 0.0 0.1 0.1 0.0 0.0 CHDO Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.0 0.0 COUM Bot Comp Cover 0.6 0.4 0.0 0.0 0.1 0.1 0.0 0.0 0.2 0.2 0.0 0.0 CRAT Bot Comp Cover 0.3 0.2 0.0 0.0 0.0 0.0 0.0 0.0 1.1 0.8 2.0 1.8 DEBI Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 DOCU Bot Comp Cover 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 ERGO Bot Comp Cover 0.6 0.4 0.0 0.0 0.4 0.3 0.0 0.0 0.4 0.3 0.3 0.3 ERFI Bot Comp Cover 0.2 0.2 0.8 0.5 0.1 0.1 0.0 0.0 0.3 0.3 0.3 0.3 ERPU Bot Comp Cover 0.0 0.0 0.8 0.8 0.1 0.1 0.0 0.0 0.1 0.1 0.3 0.3 GAAR Bot Comp Cover 0.4 0.3 1.3 1.0 0.2 0.2 1.2 1.0 0.7 0.6 . 1.7 1.5 GETR Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.0 0.0 1979 1980 1981 1983 G U G G U G G U G G U G 6.2 3.8 4.1 3.5 4.2 3.9 5.2 5.3 0.0 0.0 0.0 0.0 0.2 0.2 0.6 0.5 0.7 0.4 0.7 0.5 0.6 0.5 1.7 1.5 0.1 0.1 0.7 0.5 0.2 0.2 0.8 0.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.7 0.5 0.2 0.2 1.8 1.5 0.0 0.0 0.0 0.0 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.3 0.0 0.0 0.1 0.1 1.3 0.5 0.7 0.6 1.4 1.3 0.0 0.0 1.0 0.8 0.4 0.3 1.2 1.0 0.0 0.0 1.3 1.3 0.2 0.2 1.4 1.4 0.7 0.4 1.3 1.0 0.4 0.3 1.2 1.0 0.0 0.0 0.0 0.0 0.1 0.1 0.0 . 0 . 0 5.2 4.0 5.9 6.0 5.1 3.8 5.4 6.5 0.3 0.0 1.2 0.0 0.3 0.0 1.0 0.0 0.2 0.3 0.3 3.1 0.2 0.3 0.3 2.5 0.4 0.6 0.5 1.3 0.3 0.5 0.3 1.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.0 0.0 0.0 0.1 0.0 0.0 0.0 0.4 0.4 0.2 0.9 0.3 0.3 0.2 0.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 0.9 0.5 0.7 0.2 0.8 0.4 0.5 0.0 0.0 0.1 0.0 0.0 0.0 0.1 0.0 0.0 0.9 0.0 0.7 0.0 0.9 0.0 0.5 0.4 1.0 0.9 4.7 0.3 0.8 0.6 3.8 0.2 0.0 0.1 0.0 0.2 0.0 0.1 0.0 Table 35 (continued) 1976 1977 1978 Species G U G G U G G U G PERENNIAL FORBS AND BRYOPHYTES (continued) LERE Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 LOTR Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 ,0.1 0.3 0.3 LOMA Bot Comp Cover 0.4 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 LIRU Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.0 0.0 LUSE Bot Comp Cover 2.2 1.5 0.4 0.3 0.4 0.3 0.6 0.5 2.1 1.8 3.1 2.8 OPFR Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 PHHA Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.3 PHLO Bot Comp Cover 0.6 0.4 0.7 0.5 0.4 0.3 0.6 0.5 0.8 0.7 0.6 0.5 RAGL Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SAIN Bot Comp Cover 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.3 SEWA Bot Comp Cover 0.5 0.3 0.4 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 MOSS Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 UNKN Bot Comp Cover 3.6 2.3 3.4 2.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1979 1980 1981 1983 G U G G U G G U G G U G 0.0 0.0 0.0 0.0 0.1 0.1 0.0 0.0 0.0 0.0 0.3 0.3 0.0 0.0 0.6 0.5 0.1 0.1 0.0 0.0 0.1 0.1 0.0 0.0 0.0 0.0 0.7 0.5 0.2 0.2 0.0 0.0 0.3 0.2 2.3 1.8 0.5 0.4 3.0 3.0 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.7 0.4 0.7 0.5 1.1 0.9 1.7 1.5 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.8 0.6 2.0 1.8 0.2 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.2 0.3 0.3 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 0.2 0.3 0.3 0.1 0.1 0.0 0.0 0.2 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.4 0.3 0.3 0.2 2.8 2.3 0.1 0.1 3.1 2.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 0.2 0.6 0.5 0.6 0.5 1.3 1.0 0.0 0.0 0.0 0.0 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.3 1.0 0.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.3 0.3 0.3 2.4 1.8 1.6 1.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Table 35 (continued) Species 1976 1977 1978 1979 1980 1981 1983 G U G G U G G U G G U G G U G G U G G U G SHRUBS ARFR Bot Comp Cover 0.4 0.3 0.0 0.0 0.4 0.4 0.0 0.0 0.1 0.1 0.0 0.0 0.1 0.1 0.0 0.0 0.1 0.1 0.3 0.3 0.0 0.0 0.4 0.5 0.0 0.0 0.0 0.0 ARTR Bot Comp Cover 11.9 8.8 15.1 11.5 10.4 8.8 10.9 10.0 10.6 9.8 13.3 12.0 16.8 9.9 15.1 11.5 10.9 9.6 9.8 9.5 12.4 11.4 11.7 12.5 17.5 15.2 18.2 17.3 CHNA Bot Comp Cover 0.7 0.8 0.0 0.0 0.5 0.8 0.3 0.3 0.8 0.7 0.6 0.5 0.6 0.8 0.0 0.0 0.3 0.7 0.0 0.0 0.3 0.8 0.9 1.8 0.7 1.2 0.6 0.8 ERHE Bot Comp Cover 1.2 1.0 1.1 0.8 1.5 1.1 0.3 0.3 0.8 0.7 0.6 0.5 0.2 0.1 0.7 0.5 0.4 0.4 0.8 0.8 0.1 0.1 0.3 0.3 0.1 0.1 0.3 0.3 ERNI Bot Comp Cover 2.4 1.7 1.1 0.8 0.9 0.7 1.5 1.3 0.6 0.5 2.5 2.3 0.5 0.3 1.8 1.3 0.3 0.3 3.4 3.0 0.1 0.1 1.5 1.3 0.1 0.1 1.7 1.3 RICE Bot Comp Cover 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Total Annual Grass Bot Comp Cover 19.7 13.6 32.4 22.0 23.1 13.1 37.2 31.7 26.7 21.7 24.2 21.6 16.2 9.6 14.8 11.0 25.0 20.6 15.6 13.5 34.9 28.9 32.0 25.4 12.2 9.5 3.1 2.8 Total Perennial Grass Bot Comp Cover 43.4 31.1 34.9 24.7 52.4 41.2 38.3 33.9 40.8 34.3 34.9 32.6 52.2 32.4 46.4 35.9 41.9 36.5 37.4 31.9 37.9 33.1 32.2 27.5 44.4 39.3 33.6 28.0 Total Grass Bot Comp Cover 63.1 44.7 67.3 46.7 75.5 54.3 75.5 65.6 67.5 56.0 59.1 54.2 68.4 42.0 61.2 46.9 66.9 57.1 53.0 45.4 72.8 62.0 64.2 52.9 56.6 48.8 36.7 30.8 Total Forbs and Bryophytes Bot Comp Cover 20.2 14.2 16.4 11.9 9.9 6.9 12.3 10.8 19.6 17.0 23.6 21.8 13.7 8.4 23.6 18.1 19.9 17.3 33.1 30.3 14.1 12.7 21.1 17.7 20.7 19.9 38.5 33.1 Table 35 (continued) 1976 1977 1978 1979 1980 1981 1983 Species G U G G U G G U G G U G G U G G U G G U G Total Shrubs Bot Comp 16 .5 17 .3 13 .7 13.0 12.9 17 .0 ' 18 .2 17 .6 12.1 14 .3 12.9 14.8 18 .4 20.8 Cover 12 .6 13 .1 11 .8 11.9 11.8 15 .3 ^ 11 .2 13 .3 11.2 13 .6 12.4 16.4 16 .6 19.7 Rock (Cover) 0 .9 0 .3 0 .8 0.0 0.8 0 .3 1 .4 0 .3 0.7 0 .5 0.4 0.3 0 .7 0.0 Soil(Cover) 9 .3 8 .7 8 .8 5.3 6.3 3 .0 15 .6 5 .8 7.3 3 .0 4.8 0.3 3 .8 0.5 Feces (Cover) 0 .3 0 .8 0 .3 0.0 0.3 0 .0 0 .2 0 .0 0.0 0 .0 0.0 0.0 0 .3 0.0 Litter (Cover) 18 .3 20 .0 12 .0 7.3 8.0 6 .0 21 .7 17 .5 6.5 8 .6 7.6 13.3 8 .5 12.3 Total Standing Crop Cover 71 .5 71 .7 77 .0 88.3 84.8 91 .3 61 .6 78 .3 85.4 89 .3 87.1 87.0 85 .3 83.6 GRAZED UNGRAZED YEAR Figure 20. The int e r a c t i o n between year and grazing on percent cover of Bromus  moll i s from 1976 to 1983 ( s i g n i f i -cant at alpha = 0.05). § 12 H M CO O H § 55 O W CJ u PH1 w 10 PH U H O pq GRAZED UNGRAZED Figure 21. The in t e r a c t i o n between year and grazing on percent botanical com-pos i t i o n of Bromus mol l i s from 1976 to 1983 ( s i g n i f i c a n t at alpha = 0.05). 202 condi t ions . In contrast to Bromus m o l l i s , no s t a t i s t i c a l l y s i g n i f i c a n t d i f ferences (alpha = 0.10) were determined for the year by graz -ing i n t e r a c t i o n for e i ther cover or botanical compostion of Bromus tectorum ind ica t ing that trends i n both were s i m i l a r on the grazed and ungrazed areas. Despite t h i s , average values recorded for cover and botanical composition respect ive ly of Bromus tectorum were greater on the ungrazed (21.8 and 14.8%) than the grazed (14.9 and 10.3%) areas i n 1976. These apparent trends were reversed i n 1983 but the d i f ferences were small (Table 35). The expectation that Bromus tectorum would respond s i m i l a r l y to Bromus m o l l i s and increase i n abundance under grazing by bighorn sheep was not r e a l i z e d . Indeed, t h i s plant species decl ined on the grazed areas over the seven year period although there were minor f luc tuat ions i n cover and botanical composit ion, l i k e l y i n response to annual weather condi t ions . The decl ine i n Bromus tectorum on the grazed areas might be a t t r ibuted d i r e c t l y to grazing by bighorn sheep and p a r t i c u l a r l y to i t s seasonal use. For example, Daubenmire (1940) reported that ear ly spr ing grazing by domestic sheep on Bromus tectorum before anthesis in the Palouse Agropyron bunchgrass p r a i r i e of eastern Washington r e -sulted i n a substant ia l decl ine and near ex t inc t ion of t h i s species. During the short vernal season and autumn when Bromus  tectorum i s palatable for bighorn sheep, t h i s species i s heavi ly u t i l i z e d (Appendix 8). Poss ib ly the impact of th i s graz ing, p a r t i c u l a r l y i n March, A p r i l and May before f l o r a l i n i t i a t i o n 203 (Appendix 7), may have impeded seed production and thus reduced the populat ion. Cover of perennial grasses increased -only s l i g h t l y on both the grazed and protected areas between 1976 and 1983 but these di f ferences were not s t a t i s t i c a l l y s i g n i f i c a n t (alpha = 0.10) (Table 35). This s t a b i l i l t y i n perennial grass cover and b o t a n i -ca l composition might be explained by the d i f f e r e n t i a l response among member species w i th in t h i s group which may have compensated for each other to some degree. For example, under the inf luence of graz ing, cover values for Koeler ia c r i s t a t a and Poa sandbergii decl ined from 1976 to 1983. Conversely, cover and botanical composition values for both Agropyron spicatum and St ipa comata increased over the same time period (Table 35) although no s t a t i -s t i c a l l y s i g n i f i c a n t year by grazing in teract ions could be de-tected for Koeler ia c r i s t a t a , Poa sandbergi i or Agropyron  spicatum. The e a r l i e r p red ic t ion based upon u t i l i z a t i o n leve ls that St ipa comata would decl ine with continued heavy grazing by b i g -horn sheep did not m a t e r i a l i z e . Indeed, both cover and botanica l composition of t h i s species were higher on the grazed and un-grazed s i t e s a f te r seven years of treatment but these values were only s l i g h t l y d i f f e r e n t . S i g n i f i c a n t year by grazing i n t e r a c -t ions indicated that trends i n both cover and botanical composi-t i on were d i f f e r e n t on the grazed and ungrazed s i t e s (Figure 22, Figure 23) but these in teract ions l i k e l y resul ted from d i f f e r -ences i n annual weather patterns and changes in microcl imate as much as from the d i r e c t inf luence of grazing. 18 16 14 Pi 12 w > 10 o 8 5= 0 W / y 4 w 2 """ H H , v UNGRAZED GRAZED 0 I J J i i. i -76 77 78 79 80 81 83 • YEAR Figure 22. The i n t e r a c t i o n between year and grazing on percent cover of Stipa  comata from 1976 to 1983 ( s i g n i f i -cant a t alpha = 0.05). 76 77 78 79 80 81 83 YEAR Figure 23. The in t e r a c t i o n between year and grazing on percent botanical com-posi t i o n of Stipa comata from 1976 to 1983 ( s i g n i f i c a n t at alpha = 0.10). 205 The s i g n i f i c a n t in teract ions for St ipa comata resul ted p r i m a r i l y from the rapid increase i n both cover and botanica l compostion w i th in the exclosures during the f i r s t four years of study. The subsequent decl ine i n cover and abundance of t h i s species a f te r 1979 w i th in the exclosures might have resul ted from the accumulation of l i t t e r i n the absence of grazing (Sect. 5.31). Poss ib ly th i s created a more mesic environment w i t h i n the exclosure and hence sh i f ted the competit ive advantage away from t h i s drought to lerant species (Parsons et a l . 1971). Conversely,' d r ie r condit ions more l i k e l y prevai led i n the grazed environment, and by 1979 u t i l i z a t i o n of St ipa comata decl ined to 47.79% (Table 32). The combination of a more favorable environment for t h i s species and a reduction i n grazing pressure may be responsible for i t s r e l a t i v e s t a b i l i t y i n the f l o r a under grazed condi t ions . Woolfolk (1949) observed s i m i l a r trends for St ipa comata under moderate grazing by domestic sheep on bunchgrass range i n Mon-tana. However, at higher stocking ra tes , t h i s species decl ined. Numerous studies report domestic sheep preference for forbs and t h e i r subsequent decl ine r e s u l t i n g from excessive grazing on native bunchgrass ranges (Heady et a l . 1947; Teigen 1949; Mueg-g ler 1950; E l l i s o n 1954; Vogel and van Dyne 1966). Although C a l i f o r n i a bighorn sheep demonstrated strong preferences for forbs (Appendix 8) and seasonal use patterns (Table 28) suggested that t h i s group would decl ine i n abundance, both cover and botanical composition remained r e l a t i v e l y stable over the seven years of grazing (Figure 24, Figure 25). S i g n i f i c a n t in te ract ions between year and grazing for both 206 40 |-Pi 3 VE 30 i o u S NT 20 .. w u Pi w 10 .. PM UNGRAZED V j a GRAZED _l_ 76 77 78 79 ' 80 81 83 YEAR Figure 24. The in t e r a c t i o n between year and grazing on percent cover of t o t a l forbs from 1976 to 1983 ( s i g n i f i -cant a t alpha = 0.10). § 40 i—i H g 30 H O 25 U CE i-J 20 Pi <J w U PM M AN 10 H O 0 / > UNGRAZED " ^ GRAZED . X . 76 77 78 79 YEAR 80 81 83 Figure 25. The in t e r a c t i o n between year and grazing on percent botanical com-pos i t i o n of t o t a l forbs from 1976 to 1983 ( s i g n i f i c a n t at alpha = 0.05). 207 cover and botanica l composition of t o t a l forbs indicated that the most pronounced d i f ference i n the trends ins ide and outside the exclosures resul ted from t h i s group increasing i n the absence of grazing. Ind i rec t l y t h i s may support the contention that bighorn were a f f e c t i n g the forb population with the ent i re group b e n e f i t -ing from the release of grazing pressure. Furthermore, a l l species were not react ing s i m i l a r l y i n the grazed environment suggesting that compensating factors may have been operating to maintain leve ls of th i s group under grazing pressure. For example, Lupinus ser iceus , which was highly preferred (Appendix 8) and grazed severely (Table 33), decl ined on the area grazed by bighorn but increased ins ide the exclosures (Figure 26, 27). Indeed, i n 1976 both cover and botanical composition r e -spect ive ly of Lupinus sericeus were higher on the grazed areas (1.5 and 2.2%) than w i t h i n the e x c l o s u r e s (0.3 and 0.4%). How-ever, by 1983 t h i s re la t ionsh ip was reversed and Lupinus sericeus was nearly e l iminated on the grazed s i t e (0.1 and 0.1%) but had increased to account for 2.8% of the cover and 3.1% of the botan-i c a l composition on the protected areas. Lupinus sericeus and other members of t h i s genus have been reported i n both C a l i f o r n i a (Appendix 2) and i n Rocky Mountain bighorn d ie ts ( Oldemeyer et a l . 1971; Constan 1972; Erickson 1972; Stewart 1975) but there has been no previous account of i t s react ion to grazing. On the other hand, several studies on domestic sheep demonstrated that species i n t h i s genus often decl ine dramat ica l l y i n response to grazing (Teigen 1949; Mueg-g ler 1950; E l l i s o n 1954; Branson and Lommasson 1958). 208 Figure 26. The in t e r a c t i o n between year and grazing on percent cover of Lupinus  sericeus from 1976 to 1983 ( s i g n i -f i c a n t a t alpha = 0.10). UNGRAZED 76 77 78 79 80 YEAR GRAZED 81 83 Figure 27. The i n t e r a c t i o n between year and grazing on percent botanical compo-s i t i o n of Lupinus sericeus from 1976 to 1983 (s i g n i f i c a n t at alpha = 0.10). ) / 209 In contrast to Lupinus ser iceus, both cover and botanical composition of A c h i l l e a m i l l e f o l i u m increased on the grazed areas although only marginal ly (Table 35). S i g n i f i c a n t year by grazing in teract ions indicated that trends i n cover and botanical com-pos i t ion over the study period were d i s s i m i l a r on the grazed areas compared to those protected from bighorn use (Figure 28, Figure 29). L ike Lupinus ser iceus , the greatest increases i n both cover and botanica l composition occurred w i th in the e x c l o -sures, p a r t i c u l a r l y a f te r 1980 (Table 35). This increase i n A c h i l l e a m i l l e f o l i u m might be par t l y ex-plained by both the root structure of t h i s plant species and by bighorn sheep foraging behavior. Unlike most other forbs , A c h i l l e a m i l l e f o l i u m has a rhizomatous root system (E l l i son 1954) which permits vegetative i n addi t ion to sexual reproduction. Under protect ion from graz ing, both methods of reproduction could be operating. Conversely, even though the captive sheep selected against t h i s species during the spring and summer grazing periods (Table 28), f lower heads were grazed when they became ava i lab le which may have interrupted sexual reproduction. Low leve ls of grazing during the act ive growing season however, may have a l l o w -ed A c h i l l e a m i l l e f o l i u m plants to store s u f f i c i e n t nutr ients i n the i r root systems to permit vegetative reproduction to continue. The consequence of these two opposing grazing factors then may have resul ted i n a lower rate of reproduction among grazed compared to ungrazed p lants , but because grazing i n t e n s i t i e s were l i k e l y low, the population could s t i l l maintain i t s e l f in the presence of grazing. UNGRAZED 76 . 7 7 78 79 80 81 YEAR -in GRAZED 83 Figure 28. The in t e r a c t i o n between year and grazing on percent cover of A c h i l l e a  m i l l e f o l i u m from 1976 to 1983 (sig-n i f i c a n t a t alpha = 0.10). H S3 W U W PH S3 O CO o o o H O « / UNGRAZED .ft *—'—p3» -n GRAZED V 76 77 78 80 81 83 79 YEAR Figure 29. The in t e r a c t i o n between year and grazing on percent botanical compo-s i t i o n of A c h i l l e a m i l l e f o l i u m from 1976 to 1983 ( s i g n i f i c a n t at alpha = 0.10). 211 Trends i n botanical composition of low shrubs var ied s i g -n i f i c a n t l y (alpha = 0.10) between grazing treatment leve ls over the seven year period (Figure 30) but trends in cover were not s t a t i s t i c a l l y d i f f e r e n t . Shrub contr ibut ion to botanical compo-s i t i o n increased on both the grazed (16.5 and 18.4%) and ungrazed (17.3 and 20.8%) areas between 1976 and 1983 respect ive ly (Table 35). Most of t h i s i n te rac t ion was accounted for between 1976 and 1979, but a f te r 1980 trends i n shrubs response were v i r t u a l l y i d e n t i c a l i n both the presence and absence of grazing by C a l i f o r -n ia bighorn. Changes i n botanical composition of shrubs i n the f l o r a cannot be a t t r ibuted to grazing so le l y since other components of the vegetation such as annual grasses and ind i v idua l forb species were changing concurrently. However, the intensive u t i l i z a t i o n of both Eriogonum heracleoides and Eriogonum niveum undoubtedly contributed to the "apparent downward trend i n botanical composi-t i on of t h i s group from 1976 to 1978. Although numerous previous studies have reported use of t h i s genus by C a l i f o r n i a bighorn (Appendix 2), no previous research has assessed the e f fec ts of grazing on species w i th in t h i s group. Both Eriogonum heracleoides and Eriogonum niveum provided greater cover and occured more frequently on the grazed areas than the ungrazed areas i n 1976 but by 1979 these re la t ionsh ips were reversed (Figure 31, Figure 32, Figure 33, Figure 34). These highly preferred (Appendix 8) but f r a g i l e species were i n t e n s i v e -l y used by b ighorn year round but most ly i n w i n t e r and s p r i n g (Table 28). Declines i n both of these species l i k e l y re lated Figure 30. The in t e r a c t i o n between year and grazing on percent botanical compo-s i t i o n of t o t a l shrubs from 1 9 7 6 to 1 9 8 3 ( s i g n i f i c a n t at alpha = 0 . 1 0 ) . 213 1.5 Pi g i . o j o u H S3 W £0.5* w PM 0.0 V' \ /"^"""X, *•UNGRAZED V H 3 GRAZED 76 77 78 79 80 81 83 YEAR Figure 31. The i n t e r a c t i o n between year and grazing on percent cover of Eriogonum  heracleoides from 1976 to 1983 (s i g n i f i c a n t at alpha = 0.05). 2.0 YEAR Figure 32. The i n t e r a c t i o n between year and grazing on percent botanical compo-s i t i o n of Eriogonum heracleoides from 1976 to 1983 ( s i g n i f i c a n t at alpha = 0.05). 214 3 . 5 T 7 6 7 7 7 8 7 9 8 0 8 1 8 3 YEAR Figure 33. The i n t e r a c t i o n between year and grazing on percent cover of Eriogonum  niveum from 1976 to 1983 ( s i g n i f i -cant a t alpha = 0.05). o °' 5 m 0 . 0 UNGRAZED GRAZED Figure 34. The in t e r a c t i o n between year and grazing on percent botanical compo-s i t i o n of Eriogonum niveum from 1976 to 1983 (sxgnxfxcant at alpha = 0.05). 215 more to intensive grazing than to seasonal use. Indeed, as previously mentioned, u t i l i z a t i o n exceeded 80% on Eriogonum  niveum i n each year from 1977 to 1979. Furthermore, a l l plant parts were consumed inc lud ing stems, which would not only upset phys io log ica l processes w i th in the p lant , but also impair the reproductive potent ia l of these species. F i e l d observations indicated that these high leve ls of u t i l i z a t i o n continued in future years and that mor ta l i t y among plants w i th in both species was cont r ibut ing to the downward decl ine i n both cover and botan-i c a l composit ion. 5.35 Po ten t ia l Long Term Ef fec ts of Grazing by C a l i f o r n i a Bighorn Sheep Perhaps the lack of a d ramat ic change i n the f l o r a a f t e r seven years of grazing should have been expected and undoubtedly i s associated with the moderate leve ls of u t i l i z a t i o n that were recorded throughout the act ive growing season when plant species would be most affected by grazing. As previously mentioned, u t i l i z a t i o n of t o t a l standing crop and Agropyron spicatum only s l i g h t l y exceeded 50% i n 1979 and i n other years values were considerably lower (Table 32). Previous research on domestic sheep u t i l i z i n g s i m i l a r bunchgrass range suggests that f l o r i s t i c changes occur s lowly under moderate grazing (Vogel and van Dyne 1966). However, moderate stocking rates are probably more representative of the possible changes that might occur under natural condit ions i n s i m i l a r hab i ta ts . The long term ef fec ts of grazing by C a l i f o r n i a bighorn only can be in fe r red . The react ion of i n d i v id ua l plant species to 216 grazing by bighorn cannot be explained by forage preferences alone but depends upon evolved adaptations of each taxon to complete i t s l i f e cycle in a var iab le environment of grazing. The l i f e f o r m , morphological and reproductive c h a r a c t e r i s t i c s of forage plants combine to determine each species' s u s c e p t i b i l i t y to g r a z i n g and t h e i r a b i l i t y to compete w i t h each other i n the presence of grazing. Table 36 summarizes both the expected response of selected plant species to long term grazing by bighorn sheep and those observed i n t h i s study. The s ign i f i cance of observed changes i n rare plant species or speculat ion regarding t h e i r response to grazing must be evaluated c a r e f u l l y . Moreover, factors other than grazing could be c o n t r o l l i n g population leve ls or sampling i n t e n s i t i e s may be inadequate to determine the i r true response. Therefore, numerous species which occurred i n the d ie t or on the range are not included i n t h i s d iscuss ion . Koeler ia c r i s t a t a , Festuca scabre l la and Festuca idahoensis a l l were preferred forages (Appendix 8). Although the year by grazing in teract ions for Koeler ia c r i s t a t a were not s i g n i f i c a n t for e i ther cover or botanical composit ion, values for both were higher on the grazed than the protected areas i n 1976 but t h i s r e l a t i o n s h i p was reversed i n 1983. Indeed, cover and botanical composition respect ive ly equaled 2.7 and 4.0% on the grazed s i t e and 2.3 and 3.5% i n the exclosures i n 1976. By 1983 correspond-ing values i n the presence of grazing were 2.0 and 2.5% but both had decl ined i n the exclosures to 3.0 and 3.7%. These trends . might be expected to continue since both basal diameters and the 217 Table 36. Observed and expected responses of selected plant species to grazing by C a l i f o r n i a bighorn sheep at the Okanagan Game Farm L i f e Response Plant Species Preference Form Bromus tectorum NP Annual Koeler ia c r i s t a t a P Perennial Poa sandbergi i NP Perennial Festuca idahoensis P Perennial Festuca scabre l la P Perennial Decreasing Antennaria p a r v i f o l i a NP Perennial i n Artemisia f r i g i d a P Perennial Abundance C a s t i l l e j a thompsonii P Perennial Commandra umbellata P Perennial Lupinus sericeus P Perennial Eriogonum heracleoides P Perennial Eriogonum niveum P Perennial Bromus mol l i s NP Annual Festuca oc to f lo ra NP Annual Agropyron spicatum NP Perennial Increasing St ipa comata P Perennial in C o l l i n s i a p a r v i f l o r a NP Annual Abundance Plantago patagonica NP Annual A c h i l l e a mi l l e fo l ium NP Perennial Balsamorhiza sag i t ta ta P Perennial Calochortus macrocarpus NP Perennial S e l a g i n e l l a wa l lace i NP Perennial Artemisia t r identa ta NP Perennial Chrysothamnus nauseosus SP Perennial P = Prefer red , NP = Not Prefer red , SP = Seasonal Preference 218 number of inf lorescences produced were s i g n i f i c a n t l y lower (alpha = 0.05) on grazed compared to ungrazed plants a f te r three years of use (Table 33) suggesting that th i s species was under some stress and that the potent ia l for seed production was reduced. Although both Festuca scabre l la and Festuca idahoensis occurred too inf requent ly on the s i t e to monitor, f i e l d observa-t ions indicated that both plant species were in tens i ve l y u t i l i z e d and that f l o r a l production was suppressed by grazing. These ob-servations were supported by the large proportion that each species represented i n the d ie t compared to the i r r e l a t i v e a v a i l -a b i l i t y on the range (Appendix 8). Continued heavy use of both taxa can only lead to the i r eventual demise. Other plant species that may decl ine include Antennaria p a r v i f o l i a , C a s t i l l e j a  thompsonii , Commandra umbellata and Artemis ia f r i g i d a (Table 35, Table 36). Although cover of Agropyron spicatum appeared to be increasing more on the areas grazed by mountain sheep (132% increase i n 1983 compared to 1976) than on the protected s i t e s (119% increase) , no s i g n i f i c a n t year by grazing in te rac t ion was detected. The higher degree of preference exhibi ted for other small bunchgrasses, forbs and shrubs apparently defers grazing on th i s species during i t s most c r i t i c a l growth period (Appendix 8). A d d i t i o n a l l y , u t i l i z a t i o n throughout the growing season did not exceed c r i t i c a l leve ls i n any year studied (Table 32) and subsequently t h i s plant species appeared to be under no stress reproduct ively (Table 33). These factors combine to suggest that given s u f f i c i e n t time the observed trends in the data may become 219 s t a t i s t i c a l l y s i g n i f i c a n t . As preferred plant species become less ava i lab le i n the stand or are e l iminated , Agropyron spicatum w i l l l i k e l y increase i n i t s importance as a food source. As a r e s u l t , seasonal use patterns and i n t e n s i t i e s of grazing may be a l tered to the det -r iment of t h i s taxon and e v e n t u a l l y i t might be expected to de -c l i n e . No comparative data are ava i lab le for bighorn sheep but several previous studies on domestic sheep range indicated that Agropyron spicatum and other members of t h i s genus remained constant or increased i n abundance under sheep grazing (Heady et a l . 1947; E l l i s o n 1954; Vogel and van Dyne 1966). However, Daubenmire (1940) suggested that Agropyron spicatum would decrease as grazing i n t e n s i t y by domestic sheep increased on Palouse P r a i r i e grassland. Balsamorhiza s a g i t t a t a appeared unaffected by grazing even though i t was preferred throughout i t s growing season (Appendix 8). Indeed, values for both cover and botanical composition on the grazed and ungrazed areas were s l i g h t l y higher i n 1983 than in 1976 (Table 35). This plant species appears to be under l i t t l e stress from grazing by bighorn as basal diameter, the number of culms and the length of culms remained v i r t u a l l y the same af te r three years of grazing (Table 33). Under the current grazing regime, Balsamorhiza s a g i t t a t a may increase i n cover and r e l a t i v e botanical composit ion, at least i n i t i a l l y , as other plant species dec l ine . However, work on domestic sheep has indicated that under prolonged and intensive spring f a l l grazing t h i s species decl ined (Meuggler 1950). 220 V i r t u a l l y a l l species of annual forbs were not preferred (Appendix 8) and few were grazed s u f f i c i e n t l y to produce any observable changes i n the i r cover or botanical composition. I t i s u n l i k e l y that the present leve l of grazing by the captive bighorn were a f f e c t i n g populations of most of these species d i r e c t l y but, l i k e Bromus m o l l i s , they could benef i t from d i s t u r -bance and reduced competit ion as other plant species are removed from the f l o r a . Although annual weather condit ions w i l l l i k e l y contro l population leve ls of these species, annual species of both grasses and forbs should increase on the s i t e eventual ly . Ar temis ia t r identa ta was not preferred and was used sparingly i n a l l seasons (Appendix 8). Some physical damage was noted through bighorn rubbing the i r bodies and horns on t h i s shrub, but t h i s was not severe. Over the seven year period Ar temis ia  t r identa ta appeared to increase i n cover and botanical composi-t i on on both the grazed and ungrazed areas. Indeed, cover appar-ent ly increased approximately 147% between 1976 and 1983 on the grazed areas but only 120% i n the exclosures. S i m i l a r l y , b o t a n i -c a l compos i t i on i n 1983 was 173 and 150% of the 1976 va lues f o r the grazed and ungrazed s i t e s respect ive ly (Table 36) but none of the year by grazing in te rac t ions were s t a t i s t i c a l l y s i g n i f i c a n t . In the absence of any r e a l g r a z i n g pressure or p h y s i c a l damage i t i s probable that Ar temis ia t r identa ta w i l l increase on the s i t e . This l i k e l y w i l l r e s u l t from reductions i n other plant species which may reduce competit ion for moisture and nut r ients . Although both observation and the data co l lec ted on Amelanchier a l n i f o l i a suggest that t h i s species and other d e c i -221 duous browse such as Acer glabrum, Philadelphus l e w i s i i , Prunus  v i r g i n i a n a , Rosa nutkana and Symphoricarpos albus, were being u t i l i z e d heav i l y , i t i s u n l i k e l y that grazing by mountain sheep w i l l u l t i m a t e l y r e s u l t i n t h e i r mor ta l i t y under the current leve ls of grazing. Some reductions i n the i r population s izes may occur eventual ly as recruitments to the i r respect ive populations become grazed. Except for Symphoricarpos albus, v i r t u a l l y a l l of these shrubs are large enough that s u f f i c i e n t photosynthetic mater ia l i s being produced above reach of bighorn grazing to maintain these p lants . Probably the greatest impact that bighorn are exert ing on these plants i s i n reducing the browse ava i lab le to themselves through prolonged grazing. 222 6 . MANAGEMENT IMPLICATIONS Caughley (1976) st a t e d that there are only three "problems" i n w i l d l i f e management: "(1) the treatment of a population that i s at low d e n s i t y or i s d e c l i n i n g , to increase d e n s i t y and h a l t the d e c l i n e ; (2) the treatment of a population such that i t provides an optimum or maximum .sustained y i e l d ; and (3) the t r e a t m e n t of a p o p u l a t i o n t h a t i s too dense or w h ich has an unacceptably high r a t e of increase, to reduce i t s d e n s i t y or r a t e of increase." Current management of C a l i f o r n i a bighorn i n B r i t i s h Columbia i s d i r e c t e d towards the f i r s t two of these o b j e c t i v e s (Demarchi et a l . 1978) and present i n d i c a t i o n s suggest that no known cases of over s t o c k i n g e x i s t on any ranges. Good q u a l i t y h a b i t a t o f t e n has been considered as fundamen-t a l to the maintenance of productive and v i a b l e mountain sheep populations ( Buechner 1960; G e i s t 1971; Demarchi et a l . 1978) but the s p e c i f i c features of the forage component of bighorn h a b i t a t s have not been e l u c i d a t e d c l e a r l y . This i s p a r t i c u l a r l y true on s p r i n g , f a l l and summer ranges. On winter ranges, Agropyron spicatum i s o f t e n regarded as a p r i n c i p a l forage species and management g e n e r a l l y revolves around t h i s taxon. This t h e s i s confirms the importance of Agropyron  s p i c a t u m as a s t a p l e i n the year round d i e t of C a l i f o r n i a b i g h o r n and as a v i t a l w i n t e r forage. However, the importance of other taxa f o r bighorn sheep must be stressed. For example, even though Agropyron spicatum represented 21.4% of the annual d i e t i n the 1978/79 gra z i n g year (Table 28), a l l other species combined accounted f o r 78.6% of the forage consumed although they only 223 equaled approximately 46% of the forage produced (Table 20). Both t h i s study and others under natural condit ions (Appendix 1, Appendix 3) demonstrated the d ietary d i v e r s i t y of mountain sheep and suggest that f l o r i s t i c d i v e r s i t y of habitats may be equal ly important espec ia l l y on spr ing , summer and f a l l ranges. Habitat enhancement programs designed to increase the pro-d u c t i v i t y of Agropyron spicatum should be evaluated c a r e f u l l y . Evidence from t h i s study suggests that under moderate grazing by C a l i f o r n i a bighorn, Agropyron spicatum eventual ly may increase in abundance. Such increases through grazing and management i n i t i a -t i ves w i l l have ce r ta in l i a b i l i t i e s , however. For example, as the plant community becomes increas ing ly dominated by t h i s plant species, the n u t r i t i o n a l d i v e r s i t y of the habi tat i s reduced for bighorn. This w i l l be most important on winter ranges when Agropyron spicatum i s t y p i c a l l y of low n u t r i t i o n a l value but small shrubs provide better q u a l i t y forage. S i m i l a r l y , on spr ing , f a l l and summer ranges, a complement of forage species inc lud ing grasses, forbs and shrubs appears desi rable for moun-t a i n sheep by providing a d i v e r s i t y of food a l t e r n a t i v e s . Mountain sheep habitat dominated by Agropyron spicatum also imposes add i t iona l management requirements on these ranges. For example, observations i n t h i s study ind icate that even under season long grazing a l l of the current year's production of Agropyron spicatum was not removed. These condit ions w i l l undoubtedly lead to problems wi th a v a i l a b i l i t y of t h i s species and hence require d i r e c t management input. F i re i s a p r a c t i c a l and popular management pract ice recommended for bighorn habitat 224 (Demarchi 1978) but i t s e f fec ts on the maintenance and vigor of preferred plant species such as Festuca s c a b r e l l a , Festuca  idahoensis, Koeler ia c r i s t a t a , Balsamorhiza s a g i t t a t a , Lupinus  ser iceus , Eriogonum niveum, Eriogonum heracleoides and Artemis ia  f r i g i d a should be considered. At present, few quant i ta t i ve data are ava i lab le assessing the impacts of f i r e on most grassland plant species (Wikeem and Strang 1983) and add i t iona l research on the e f fec ts of f i r e on these plant species i s recommended. Opportunit ies for integrated grazing systems with c a t t l e might be considered as an a l te rna t i ve to burning i n c o n t r o l l i n g excessive buildups of l i t t e r i n Agropyron spicatum. Although overgrazing by c a t t l e has been impl icated with poor range condi -t ions on some bighorn ranges (Blood 1961; Demarchi 1965; Demarchi and M i t c h e l l 1973), some evidence suggests that they can graze sympatr ica l l y without dete r io ra t ion of the plant community (Spalding and Bone 1969). Past overuse of bighorn ranges by domestic l i ves tock may have resul ted from poor management prac -t i c e s rather than a rea l i n c o m p a t i b i l i t y between l i ves tock and mountain sheep. Any int roduct ion of c a t t l e onto bighorn range should be monitored c a r e f u l l y and proper l i ves tock management must be ensured. In natural populat ions, inherent s t a b i l i t y between bighorn sheep and the i r forage resource i s often accomplished through non-forage factors such as disease and predation. However, as management object ives to increase herd s izes are r e a l i z e d , or as other factors such as land a l i e n a t i o n , forest encroachment, and human a c t i v i t i e s reduce the area of bighorn ranges, population 225 dens i t ies w i l l increase and the p o s s i b i l i t y of mountain sheep o v e r u t i l i z i n g the i r own habitat becomes a r e a l i t y (Smith and Demarchi undated; Ebert 1978). Accurate assessment of changes i n f l o r i s t i c composition r e s u l t i n g from excessive grazing by mountain sheep w i l l provide a mechanism for determining the balance between population s ize and forage before food becomes a major factor a f f e c t i n g herd pro-d u c t i v i t y . General izat ion of the resu l t s reported here to natural mountain sheep habitats must be made caut ious ly . Indeed, i n f l o r i s t i c a l l y d i f f e r e n t habitats these resu l t s w i l l be of l i t t l e relevance. Conversely, perhaps the greatest s ign i f i cance of these resu l t s from a management perspective i s not so much the s p e c i f i c changes that occurred i n the f l o r a under these e x p e r i -mental condi t ions , but that bighorn sheep can impose changes i n the i r habi tat even at moderate grazing l e v e l s . Further research i s required on natural populations to con-f i rm the resu l t s reported here and to determine the response of d i f f e r e n t plant communities to grazing pressure by mountain sheep. S p e c i f i c a l l y , permanent exclosures should be constructed on various mountain sheep habitats such as those i n the Ashnola (Demarchi 1973a). These should be properly maintained and mon-i to red at regular f i v e year i n t e r v a l s with a consistent sampling scheme so that r e s u l t s can be compared and so t h a t long term ef fec ts of grazing can be determined. 226 7. SUMMARY AND CONCLUSIONS This study was undertaken to determine the i n t e r r e l a t i o n s among forage production and u t i l i z a t i o n , forage q u a l i t y , forage a v a i l a b i l i t y , d ie t s e l e c t i o n , and the subsequent impact of grazing by C a l i f o r n i a bighorn sheep on the i r habi tat under experimental condi t ions . S p e c i f i c a l l y , the study included inves t igat ion and determination of : (1) annual herbage production and u t i l i z a t i o n , (2) temporal v a r i a t i o n i n forage q u a l i t y , (3) the a v a i l a b i l i t y of forages i n r e l a t i o n to phenological development of plant spec ies , (4) monthly d ie t of bighorn i n r e l a t i o n to forage a v a i l a b i l i t y , (5) the re la t ionsh ip between forage qua l i t y and bighorn d i e t , and (6) the e f fec t of se lec t i ve grazing by captive mountain sheep on ind i v idua l plants and the plant community. The plant community ava i lab le for bighorn grazing i n the enclosure provided a d i v e r s i t y of plant species for mountain sheep grazing cons is t ing of 14 grasses, 58 forbs plus 18 trees and shrubs. Grasses dominated the s i t e providing 43.2% of the cover whi le forbs and shrubs contr ibuted 10.4 and 9.9% of the cover respect ive ly . Agropyron spicatum, Bromus tectorum and Artemis ia t r identa ta were the most dominant species on the s i t e representing 22.1, 9.5 and 6.7% of the cover respect i ve ly . Both annual and seasonal va r ia t ions i n plant species phen-ology, cover and botanical composition were evident among phen-o l o g i c a l groups, forage c lasses and in d i v id ua l species. Four phenological groups were c l a s s i f i e d cons is t ing of e ight , 36, 27 and four species for Groups I, I I , I I I and IV respect i ve ly . 227 Growth and development of each group fol lowed d i s s i m i l a r but overlapping trends providing bighorn with a var iab le source of forage. S i m i l a r l y , cover and botanical composition of forage c lasses and ind i v idua l species responded to annual and l o c a l weather patterns. Maximum cover of grass as a group occurred la te r than forbs i n each year but these maxima var ied for both groups among years. Both grass and forbs as groups achieved t h e i r highest cover i n 1978 (51.4 and 24.1% respect ively) which was the wettest year and t h e i r lowest values i n 1979 (34.2 and 12.8% respect ively) which was the d r i e s t year. Shrubs demonstrated almost no v a r i a t i o n among years despite changing weather patterns. S i m i l a r l y , both cover and botanical composition of Agropyron spicatum, the dominant plant on the study s i t e , remained r e l a t i v e l y stable among years. Annual weather patterns influenced forage production more than cover or botanical composition. For example, i n the ungrazed areas, y ie lds for t o t a l standing crop var ied from 41.01 to 62.95 g/m2 i n 1977 and 1978 respect ive ly . Forbs as a group demonstrated the greatest v a r i a t i o n i n y ie lds among years e q u a l i n g a maximum of 7.98 g/m 2 i n 1976 and a minimum of 4.17 g/m2 i n 1977. Agropyron spicatum made the greatest contr ibut ion to t o t a l standing crop of a l l species i n each year producing 40.7, 26.7, 55.9 and 63.7% of the t o t a l herbage y i e l d i n 1976, 1977, 1978 and 1979 respect i ve ly . F a l l regrowth was prevalent i n each year of the study equal -ing 8.18 and 19.42 g/m 2 or 11.5 and 27.0% of the t o t a l herbage 228 produced in 1978 and 1979 respect i ve ly . These increments i n herbage production increased forage a v a i l a b i l i t y for bighorn sheep during the f a l l and winter grazing periods but p r e c i -p i t a t i o n condit ions during both autumns were above the long term normals for the area. N u t r i t i v e qua l i t y of forages var ied throughout the growing season. Two conspicuous f lushes i n nutr ient a v a i l a b i l i t y were observed i n each year; the f i r s t occurr ing i n March and A p r i l with the onset of annual growth and the second i n September through to November as selected plant species responded to favorable growing condit ions and resprouted. Both prote in and f i b r e fol lowed consistent trends throughout the year for a l l plant species sampled. Maximum values for crude prote in were recorded i n A p r i l each year and these s tead i l y decl ined throughout the growing season as plant species matured. Crude f i b r e fol lowed a reverse t rend, t y p i c a l l y increasing as plants matured. No consistent trends were establ ished for ca lc ium, phosphorus or the calcium/phosphorus r a t i o however. F a l l regrowth re -es tab l i shed nutr ient leve l to those recorded i n the ear ly growth stages of a l l p lant species sampled. Captive C a l i f o r n i a bighorn demonstrated considerable d i v e r -s i t y i n t h e i r foraging behavior. A t o t a l of 79 species were observed i n t h e i r d i e t from 1977 to 1979 c o n s i s t i n g of 14 grasses, 47 forbs and bryophytes plus 18 trees and shrubs. Despite apparent changes i n forage a v a i l a b i l i t y , few di f ferences were observed i n the t o t a l number of taxa i n e i ther the monthly, seasonal or annual d i e t s . The greatest d i v e r s i t y i n the d i e t was 229 observed i n spring and the fewest species encountered i n the feces was recorded i n winter i n each year. Grasses, forbs and shrubs comprised 66.6, 18.9 and 14.6% of the d ie t respect ive ly over the 28 month study per iod. Bighorn forage preferences were s t r i k i n g l y s i m i l a r among years despite changing forage condit ions which presumably a l tered a v a i l a b i l i t y pattern. Dietary compostion of grass equaled 64.0 and 69.2%, and forbs 19.8 and 18.1% of the d ie t i n each year. S i m i l a r l y , pheno-l o g i c a l groups and i n d i v i d u a l species w i th in a l l forage classes were eaten i n approximately the same proportions between years. Agropyron spicatum was the most common plant found i n b ighorn feces i n each season except i n the f a l l of 1978 when Koeler ia c r i s t a t a occurred more frequently . Agropyron spicatum occurred most i n the d ie t i n winter (26.7 and 30.8%) and least i n summer (15.7 and 18.0%) i n 1977/78 and 1978/79 respect i ve ly . Despite i t s importance as a staple food source for the captive bighorn, Agropyron spicatum did not occur more frequently i n the d i e t than on the range i n any season or month except February 1978. Conversely, other caespitose grasses such as Festuca  s c a b r e l l a , Festuca idahoensis, Koeler ia c r i s t a t a and St ipa comata were preferred. Forbs were grazed most in summer (26.5 and 36.2%) and spring (19.2 and 18.4%) each year respect ive ly but became less important i n the d ie t as taxa in t h i s group became senescent. Annual forbs were not preferred i n a l l months and years throughout the study. Preferred forbs included Balsamorhiza s a g i t t a t a , Lupinus  ser iceus , C a s t i l l e j a thompsonii , Arabis h o l b o e l l i i , / E r i g e r o n 230 f i l i f o l i u s , G a i l l a r d i a a r i s t a t a , Geum t r i f l o r u m , Lithospermum  ruderale and Phlox l o n g i f o l i a . Browse was u t i l i z e d most i n winter and spring each year averaging 18.7 and 17.6% of the d ie t i n each season respect ive ly over the two year per iod. The dominant shrub, Ar temis ia  t r identa ta was strongly selected against by the captive bighorn i n a l l seasons and months but most other shrubs such as Acer glabrum, Amelanchier a l n i f o l i a , Ar temis ia f r i g i d a , Eriogonum  niveum, Eriogonum heracleoides, Philadelphus l e w i s i i , Prunus  v i r g i n i a n a , Rosa nutkana and Symphoricarpos albus were preferred. Neither mul t ip le l inear or mul t ip le stepwise polynomial regression could e s t a b l i s h any consistent re la t ionsh ip between forage consumption of a l l p lant species sampled w i th in months, i nd i v idua l plant species, or forage classes and corresponding n u t r i t i v e q u a l i t y of forages. Conversely, cover was f i t cons is tent l y i n both suggesting that forage ingest ion by the captive bighorn may re la te to the abundance and d i s t r i b u t i o n of ava i lab le plant species. As expected, bighorn a l te red forage y ie lds on the grazed area compared to the contro l but t h i s l i k e l y resul ted more from annual u t i l i z a t i o n than from d i r e c t impact on forage p lants . U t i l i z a t i o n rates var ied among both plant species and years. Agropyron spicatum was not heavi ly grazed i n each year of the study and u t i l i z a t i o n rates exceeded 50% only i n 1979. Forage groups and plant species that were cons is tent l y grazed heavi ly over the three year period included: St ipa comata, t o t a l other forbs , and Eriogonum niveum. Continual use of forages by bighorn 231 reduced l i t t e r production on the grazed areas (84.31 g/m2) compared to the ungrazed areas (128.0 g/m2). Grazing by C a l i f o r n i a bighorn d i r e c t l y af fected the .reproductive potent ia l of selected plant species. Balsamorhiza  s a g i t t a t a and Agropyron spicatum were least af fected from grazing despite t h e i r importance i n mountain sheep d i e t . Indeed, only leaf lengths d i f f e r e d among grazed and ungrazed Balsamorhiza  sag i t ta ta plants and no s i g n i f i c a n t d i f ferences were observed i n basal diameters or the number of culms produced on grazed and ungrazed Agropyron spicatum plants a f te r three years of grazing. Conversely, reductions i n v i r t u a l l y a l l measured parameters were observed on grazed Koeler ia c r i s t a t a , Poa sandbergi i , St ipa  comata, C a s t i l l e j a thompsonii , Lupinus sericeus and Eriogonum  niveum plants compared to ungrazed p lants . U t i l i z a t i o n of Amelanchier a l n i f o l i a was determined with three methods i n 1977 and f i v e methods in 1978. Considerable v a r i a b i l i t y was observed i n the percent u t i l i z a t i o n determined by each method but a l l methods estimated use over 50%. Although estimates of u t i l i z a t i o n based on s t r a t i f i c a t i o n of leaf and stem weight indicated that leaves were grazed d isproport ionate ly compared to stems, i t was concluded that weight methods do not evaluate the impact of mountain sheep browsing any better than methods based on stem lengths. The long term e f fec ts of grazing by C a l i f o r n i a bighorn sheep was evaluated from 1976 to 1983. Total cover remained v i r t u a l l y the same the grazed (71.1 and 85.0%) and ungrazed (70.3 and 86.0%) areas between these two years respect ive ly . Cover of 232 t o t a l grass decl ined from 46.5 to 30.8% with the ungrazed exclosures but increased form 44.7 to 48.8% under the inf luence of grazing over the same per iod. Annual, perennial and ind i v idua l plant species a l l reacted d i f f e r e n t l y to grazing by mountain sheep. Bromus m o l l i s increased i n both cover and botanical composition on the grazed areas but deceased w i th in the exclosures. In contrast to Bromus m o l l i s , Bromus tectorum decreased on both the grazed and ungrazed areas. Cover of perennial grasses increased only s l i g h t l y on both the grazed and protected areas between 1976 and 1983 but these d i f ferences were not s i g n i f i c a n t s t a t i s t i c a l l y . No di f ferences in e i ther cover or botanical composition were observed between the grazed and ungrazed areas for Agropyron spicatum, Koeler ia  c r i s t a t a , or Poa sandbergi i . Although captive bighorn demonstrated strong preference for forbs as a group and seasonal use patterns suggested that t h i s group would decl ine i n abundance, cover of t h i s group increased s l i g h t l y and botanical composition remained the same i n 1983 compared to 1976 on the grazed area. The greatest changes i n cover and botanical composition occurred w i th in the exclosures where both increased s u b s t a n t i a l l y . However, more conspicuous changes were observed among i n d i v i d u a l species. Lupinus  ser iceus , for example, increased in the absence of grazing but was v i r t u a l l y e l iminated on the grazed areas. In contrast to Lupinus ser iceus , A c h i l l e a m i l l e f o l i u m increased marginal ly on the grazed areas. Botanical composition of shrubs increased on both the grazed 233 and ungrazed areas over the seven year period but cover for t h i s group remained unchanged. Changes i n botanical composition of shrubs i n the f l o r a was a t t r ibuted to changes i n other components of the vegetation such as annual grasses and in d i v id ua l forb species which were changing concurrently . Both Eriogonum niveum and Eriogonum heracleoides decl ined s i g n i f i c a n t l y on the areas grazed by bighorn sheep. Declines i n both species were a t t r ibuted to intensive grazing pressure by the captive herd. 234 8. LITERATURE CITED Aldous, S.E. 1945. 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J . 620 p. 246 APPENDIX 1 SPECIES DIVERSITY OF MOUNTAIN SHEEP DIETS Source Location/ (Site) Season Number of Species i n Diet Grass Forb Shrub Total Ovis canadensis canadensis Smith 1954 Idaho 8 8 15 31 Schallenberger 1966 Montana 8 14 15 37 Capp 1967 Colorado 4 6 3 13 Oldemeyer et a l . 19 71 Montana 7 8 4 19 Constan 1972 Montana 9 10 8 27 Erickson 1972 Montana 6 28 8 42 Todd 1972a Colorado 14 16 12 42 P a l l i s t e r 1974 Montana (West Rose Bud) Summer F a l l Winter 8 2 2 16 2 2 00 o o 32 4 4 (St i l lwater ) F a l l Winter 8 4 11 4 3 2 22 10 Johnson 1975 Alberta 10 38 21 69 Ste l fox 1975 Alberta 11 19 6 36 Stewart 1975 Montana (West Rose Bud) (St i l lwater ) 18 21 53 35 13 15 84 71 Ovis canadensis c a l i f o r n i a n a Jones 1950 C a l i f o r n i a 5 18 6 29 Sugden 1961 B.C. 9 7 8 24 248 Appendix 1 (continued) Number of Species i n Diet Location/ (Site) Source Season Grass Forb Shrub Total McCullough and Schneegas 1966 C a l i f o r n i a 8 0 18 26 Blood 1967 B.C. Winter 6 2 2 10 Spring 6 3 3 12 Ste l fox and Spalding 1974 B.C. 5 15 7 27 Drewek 1970 Idaho Winter 2 0 7 9 Spring 10 19 15 44 Hansen 1982 Nevada 20 57 11 88 Ovis canadensis n e l s o n i i Barrett 1964 Nevada 41 19 15 38 Deming 1964 Arizona 43 34 53 130 Yoakum 19 64 Nevada 3 13 9 25 Brown et a l . 1977 Nevada (Pintwater Range) 7 11 19 37 (Las Vegas Range) 6 14 3 23 (Sheep Range) 14 20 31 65 (Eldorado Mtn.) 10 11 14 35 (Highland Range) 7 3 13 23 (McCullough Mtn.) 3 5 10 18 (River Mtn.) 5 4 8 17 (Black Mtn.) 6 8 14 28 (Muddy Mtn.) 10 4 13 27 (Mormon Mtn.) 6 5 9 20 (Meadow Val ley) 8 7 16 31 (Potose Mtn.) 3 1 11 15 (Dev i l ' s Peak) 5 4 3 12 Total A l l S i tes 17 42 61 120 2 3 249 Appendix 1 (continued) Number of Species i n Diet Location/ (Site) Source Season Grass Forb Shrub Total Ovis n i v i c o l a Chernyavskii 1967 Russia 13 70 8 91 1. Combination of plants i d e n t i f i e d to genus only and to species . 2. Synthesis of data from 1945-1953. 3. Total i nd i v idua l species from a l l s i t e s sampled inc lud ing some not reported above. 250 A P P E N D I X 2 GENERA AND P L A N T S P E C I E S I D E N T I F I E D I N THE D I E T OF C A L I F O R N I A BIGHORN THRODGHODT T H E I R D I S T R I B U T I O N 251 Plant Species Location Source GRASS/GRASSLIKE Agropyron s p . l Nevada Hansen 1982 Agropyron spicatum B.C. Idaho Oregon Blood 1961; Sugden 1961; Demarchi 1965; Ste l fox and Spalding 1974; Wikeem and P i t t 1979 Drewek 19 70 Kornet 1978 Agropyron trachycaulum B.C. Sugden 1961 Agrost is exarata Nevada Hansen 1982 Agrost is sp. * B.C. Idaho Sugden 1961 Drewek 19 70 Bromus inermis Idaho Drewek 1970 Bromus sp. Nevada Hansen 1982 Bromus tectorum C a l i f o r n i a B.C. Idaho Jones 1950 Blood 1961 Wikeem and P i t t 1979 Drewek 19 70 Calamagrostis sp. B.C. Sugden 1961 Carex sp. B.C. Nevada Sugden 19 61 Hansen 1982 Carex breweri C a l i f o r n i a Jones 1950 Carex congdonii C a l i f o r n i a Jones 1950 Carex exserta C a l i f o r n i a Jones 1950 Carex phaeocephala C a l i f o r n i a Jones 1950 Echinochloa c r u s g a l l i Idaho Drewek 1970 Elymus cinereus C a l i f o r n i a Idaho Oregon Nevada McCullough and Schneegas 1966 Drewek 1970 Kornet 1978 Hansen 1982 252 Appendix 2 (continued) Plant Species Location Source GRASS/GRASSLIKE (continued) Elymus t r i t i c o i d e s Nevada Eragrost is sp. Nevada Festuca idahoensis B.C. Idaho Nevada Festuca scabre l la B.C. Hordeum brachyantherum Nevada Juncus sp. Koeler ia c r i s t a t a Koeler ia n i t i d a  Oryzopsis hymenoides Panicum sp. Pha lar i s arundinacea  Poa sp. Poa nevadensis  Poa pratensis  Poa scabre l la Poa secunda Poa sandbergi i B.C. Nevada B.C. Nevada B.C. C a l i f o r n i a Nevada Nevada Nevada B.C. Nevada B.C. C a l i f o r n i a B.C. Idaho Nevada Hansen 1982 Hansen 1982 Blood 1961; Demarchi 1965; Morrison 1972; Ste l fox and Spalding 1974 Drewek 1970 Hansen 1982 Wikeem and P i t t 1979 Hansen 1982 Sugden 19 61 Hansen 1982 Blood 1961; Sugden 1961; Demarchi 1965; Morrison 1972; Wikeem and P i t t 1979 Hansen 1982 Sugden 1961 McCullough and Schneegas 19 66 Hansen 1982 Hansen 1982 Hansen 1982 Sugden 19 61 Hansen 1982 Blood 1961 McCullough and Schneegas 1966 Blood 1961; Demarchi 1965; Morrison 1972; Ste l fox and Spalding 1974 Drewek 19 70 Hansen 1982 253 Appendix 2 (continued) Plant Species Location Source GRASS/GRASSLIKE (continued) Sitanion hys t r i x St ipa columbiana St ipa coronata  St ipa comata St ipa r i c h a r d s o n i i  St ipa sp. St ipa speciosa  St ipa thurberiana C a l i f o r n i a Idaho Nevada B.C. C a l i f o r n i a B.C. B.C. Nevada C a l i f o r n i a Nevada McCullough and Schneegas 1966 Drewek 1970 Hansen 1982 Blood 1961; Sugden 1961 Demarchi 1965 McCullough and Schneegas 19 66 Stel fox and Spalding 1974 Wikeem and P i t t 1979 Blood 1961 Hansen 1982 McCullough and Schneegas 1966 Hansen 1982 FORBS AND BRYOPHYTES A c h i l l e a borea l i s B.C. A c h i l l e a lanulosa Nevada A c h i l l e a mi l l e fo l ium B.C. A l l ium cernuum B.C. Amsinckia t e s s e l l a t a Neveda Anemone sp. B.C. Antennaria sp. B.C. Antennaria d i o i c a or a lp ina Antennaria lanata B.C. Antennaria racemosa B.C. Sugden 1961 Hansen 1982 Blood 1961; Demarchi 1965 Morrison 1972 Wikeem and P i t t 1979 Blood 1961 Hansen 1982 Sugden 19 61 Sugden 19 61 C a l i f o r n i a Jones 1950 B.C. F ish and W i l d l . Br . 1967 B.C. F ish and W i l d l . Br . 1967 254 Appendix 2 (continued) Plant Species Location Source FORBS AND BRYOPHYTES (continued) Arabis cobrensis Nevada Hansen 1982 Arabis h o l b o e l l i i B.C. Ste l fox and Spalding 1974 Arabis n u t a l l i i Idaho Drewek 1970 Arabis puberula Nevada Hansen 1982 Artemisia michauxiana B.C. Morrison 1972 Astragalus alpinus B.C. Ste l fox and Spalding 1974 Astagalus curvicarpus Nevada Hansen 1982 Astragalus malacus Nevada Hansen 1982 Astragalus miser B.C. Morrison 1972 Astragalus p u r s h i i Nevada Hansen 1982 Astragalus serotinus B.C. Sugden 19 61 Aster occ identa l i s Nevada Hansen 1982 Aster scopulerum Nevada Hansen 1982 Aster sp. B.C. Sugden 1961 Balsamorhiza hookeri Idaho Drewek 19 70 Balsamorhiza sag i t ta ta B.C. Ste l fox and Spalding Wikeem and P i t t 1979 1974; Balsamorhiza serrata Nevada Hansen 1982 Camissonia t a n a c e t i f o l i a Nevada Hansen 1982 C a s t i l l e j a chromosa Nevada Hansen 1982 Centaurea d i f f u s a B.C. B.C.- F ish and W i l d l . ' Br . 1967 Chenopodium sp. Idaho Drewek 19 70 Chaenactis doug las i i Nevada Hansen 1982 255 Appendix 2 (continued) Plant Species Location Source F O R B S A N D B R Y O P H Y T E S (continued) Cirsium sp. B.C. Sugden 1961 Idaho Drewek 1970 Cirsium vulgare Nevada Hansen 1982 Crepis acuminata Idaho Drewek 1970 Crepis modocensis Nevada Hansen 1982 Cryptantha humil is Nevada Hansen 1982 Delphinium pauciflorum C a l i f o r n i a Jones 1950 Descurania pinnata Nevada Hansen 1982 Descurania sp. Idaho Drewek 19 70 Draba doug las i i Nevada Hansen 1982 Draba lemmonii C a l i f o r n i a Jones 1950 Epilobium sp. B.C. Sugden 19 61 Equisitum arvense B.C. B.C. F ish and W i l d l . Br . 1967 Equisitum hyemale Idaho Drewek 19 70 Eriastrum w i l c o x i i Nevada Hansen 1982 Erigeron sp. C a l i f o r n i a B.C. Nevada Jones 1950 Blood 1961 Hansen 1982 Erigeron caespitosus B.C. Ste l fox and Spalding 1974 Erigeron caespitosum Nevada Hansen 1982 (sic) Erigeron compositus B.C. Ste l fox and Spalding 1974 Eriogonum nudum var . scapigerum C a l i f o r n i a Jones 19 50 Eriogonum ova l i fo l ium C a l i f o r n i a Nevada Jones 1950 Hansen 1982 256 Appendix 2 (continued) Plant Species Location Source FORBS AND BRYOPHYTES (continued) Eriogonum umbellatum Nevada Hansen 1982 Erodium cicutar ium Nevada Hansen 1982 Eupatorium occidentale Nevada Hansen 1982 Galium boreale B.C. Sugden 1961 Galium mult i f lorum Nevada Hansen 1982 Geum macrophyllum Nevada Hansen 1982 Glycyr rh iza lepidota Idaho Drewek 1970 Haplopappus acau l i s Nevada Hansen 1982 Haplopappus cuneatus C a l i f o r n i a McCullough and Schneegas Haplopappus stenophyllus Nevada Hansen 1982 Heuchra c y l i n d r i c a B.C. -Stelfox and Spalding 1974 Hulsea a lg ida C a l i f o r n i a Jones . 1950 Ivesia pygmaea C a l i f o r n i a Jones 1950 Ivesia santol inoides C a l i f o r n i a Jones : 1950 Lappula redowskii B.C. Nevada Morrison 1972 Hansen 1982 Lithospermum ruderale B.C. Nevada Ste l fox and Hansen 1982 Spalding 1974 Lesquerel la k i n g i i Nevada Hansen 1982 L e w i s i i pygmaea C a l i f o r n i a Jones : 1950 L e w i s i i red iv i va B.C. Ste l fox and Spalding 1974 Lomatium macrocarpum Idaho Drewek 1970 Lupinus argenteus Nevada Hansen 1982 257 Appendix 2 (continued) Plant Species Location Source FORBS AND BRYOPHYTES (continued) Lupinus lepidus  Lupinus sericeus Lupinus sp. Lychnis sp. Machaeranthera  canescens Mentha arvensis Mertensia o b l o n g i f o l i a Microser is a l p e s t r i s Mic ros ter i s g r a c i l i s Monardella odoratissima subsp. p a r v i f o l i a Oenothera biennis Oenothera caespitosa Opuntia f r a g i l i s Oreocarya c o n f e r t i f o l i a Oxyria digyna Phacel ia l i n e a r i s Phacel ia sp. Plox dispersa Plox hoodi i C a l i f o r n i a Nevada B.C. B.C. B.C. Nevada Nevada Nevada B.C. Nevada C a l i f o r n i a Idaho Idaho B.C. C a l i f o r n i a C a l i f o r n i a Nevada B.C.' C a l i f o r n i a Nevada Jones 1950 Hansen 1982 Blood 1961; Demarchi 1965; Morrison 1972; Wikeem and P i t t 1979 Sugden 1961; Morrison 1972 Ste l fox and Spalding 1974 Hansen 1982 Hansen 1982 Hansen 1982 Morrison 1972 Hansen 1982 Jones 1950 Drewek 1970 Drewek 1970 Ste l fox and Spalding 1974 Jones 1950 Jones 1950 Hansen 1982 Blood 1961 Jones 1950 Hansen 1982 258 Appendix 2 (continued) Plant Species Location Source FORBS AND BRYOPHYTES (continued) Phoenicaul is cheiranthoides Nevada Hansen 1982 Phyllodoce impetr i formis B.C. B.C. F ish and W i l d l . Br . 1967 Plantago major Idaho Drewek 1970 P l e c t r i t u s macrocera Nevada Hansen 1982 Penstemon humil is Nevada Hansen 1982 Penstemon sp. Nevada Hansen 1982 Penstemon speciosus Nevada Hansen 1982 Polemonium eximium C a l i f o r n i a Jones 1950 Polytrichum sp. B.C. B.C. F ish and W i l d l . Br . 1967 P o t e n t i l l a r i v u l a r i s Nevada Hansen 1982 P o t e n t i l l a sp. B.C. Ste l fox and Spalding 1974 Ranunculus cymbalaria Nevada Hansen 1982 Ranunculus e s c h s c h o l t z i i var . oxynotus C a l i f o r n i a Jones 1950 Rumex cr ispus Idaho Drewek 1970 Rumex s a l i c i f o l i u s Idaho Drewek 1970 Rumex t r a n g u l i v a l v i s Nevada Hansen 1982 Scenecio canus Nevada Hansen 1982 Scenecio sp. Idaho Drewek 19 70 S e l a g i n e l l a sp. B.C. Ste l fox and Spalding 1974 S e l a g i n e l l a wa l lace i B.C. B.C. F ish and W i l d l . Br . 1967 Si lene s a r g e n t i i C a l i f o r n i a Jones 1950 259 Appendix 2 (continued) Plant Species Location Source FORBS AND BRYOPHYTES (continued) Si lene scaposa Nevada Si lene s c o u l e r i B.C. Smilacina s t e l l a t a Nevada Solidago sp. Idaho Solidago s p e c t a b i l i s Nevada Taraxacum o f f i c i n a l e B.C. Thelypodium laciniatum Idaho Tortula princeps B.C. Tragopogon dubius B.C. Tragopogon pratensis B.C. T r i fo l ium wormskjoldi i Nevada Verbascum thapsus B.C. V i o l a n u t t a l l i i V i o l a sp. Xanthium strumarium Nevada B.C. Idaho Hansen 1982 Morrison 1972 Hansen 1972 Drewek 19 70 Hansen 1982 Morrison 1972 Drewek 1970 B.C. F ish and W i l d l . Br . 1967 B.C. F ish and W i l d l . Br . 1967 Sugden 19 61 Ste l fox and Spalding 1974 Hansen 1982 Stel fox and Spalding 1974 Hansen 1982 Morrison 1972 Drewek 19 70 TREES AND SHRUBS Acer glabrum Acer nigrans Amelanchier a l n i f o l i a Idaho B.C. B.C. Idaho Drewek 19 70 Ste l fox and Spalding 1974 B.C. F ish and W i l d l . Br. 1967 Ste l fox and Spalding 1974 Wikeem and P i t t 1979 Drewek 19 70 Arctostaphylos patula C a l i f o r n i a McCullough and Schneegas 1966 260 Appendix 2 (continued) Plant Species Location Source TREES AND SHRUBS (continued) Arctostaphylos uva ursa B.C, Artemisia arbuscula Artemisia dracunculoides Artemisia f r i g i d a Artemisia ludovic iana Artemisia t r identa ta Berberis sp. Ceanothus greggi  Cercocarpus l e d i f o l i u s Chamaebatiaria m i l l i f o l i u m Chrysothamnus  nauseosus Chrysothamnus . v i s c i d i f l o r u s Elaeagnus commutata Ephedra nevadensis Ephedra v i r i d i s Eriogonum fasciculatum Idaho Nevada B.C. B.C. Idaho Nevada B.C. Idaho Nevada B.C. C a l i f o r n i a C a l i f o r n i a Nevada Nevada B.C. C a l i f o r n i a Blood 1961; Sugden 1961; B.C. F ish and W i l d l . Br . 1967 Drewek 1970 Hansen 1982 Blood 1961; Ste l fox and Spalding 1974 Blood 1961; Sugden 1961; Demarchi 1965; B.C. F ish and W i l d l . Br . 1967 Drewek 1970 Hansen 1982 B.C. F ish and W i l d l . Br . 1967 Ste l fox and Spalding 1974; Wikeem and P i t t 1979 Drewek 1970 Hansen 1982 B.C. F ish and W i l d l . B r . 1967 McCullough and Schneegas 1966 McCullough and Schneegas 1966 Hansen 1982 Hansen 1982 Sugden,1961 McCullough and Schneegas 1966 C a l i f o r n i a McCullough and Schneegas 1966 B.C. C a l i f o r n i a C a l i f o r n i a C a l i f o r n i a Sugden 1961 McCullough and Schneegas 19 66 McCullough and Schneegas 1966 McCullough and Schneegas 19 6 6 261 c Appendix 2 (continued) Plant Species Location Source TREES AND SHRDBS (continued) Eriogonum heracleoides B.C. Blood 1961; Demarchi Morrison 1972; Ste l fox and Spalding Wikeem and P i t t 1979 1965; 1974; Eriogonum niveum B.C. Ste l fox and Spalding Wikeem and P i t t 1979 1974 Eriogonum nudum var . scapigerum C a l i f o r n i a Jones 1950 Eriogonum sphaerocephalum Idaho Drewek 19 70 Eriogonum str ic tum Idaho Drewek 1970 Eriogonum w r i g h t i i var . subscaposum C a l i f o r n i a Jones 1950 Grayia spinosa Idaho Drewek 19 70 Holodiscus dumosus Oregon Nevada Kornet 1978 Hansen 1982 Juniperus sp. B.C. Sugden 1961 Juniperus h o r i z o n t a l i s B.C. B.C. F ish and W i l d l . Br . 1967 LeptodactyIon pungens Idaho Drewek 1970 Penstemon b r e v i f l o r u s C a l i f o r n i a McCullough and Schneegas 1966 Penstemon f ru t icosus B.C. B.C. F ish and W i l d l . Br . 1967 Penstemon menziesi i var . dav idsoni i C a l i f o r n i a Jones 1950 Philadelphus l e w i s i i B.C. Ste l fox and Spalding 1974 Pinus contorta B.C. Blood 1961 Pinus monophylla C a l i f o r n i a McCullough and Schneegas 19 66 Pinus ponderosa B.C. B.C. F ish and W i l d l . Br . 1967 262 Appendix 2 (continued) Plant Species Location Source TREES AND SHRUBS (continued) Populus tremuloides B.C. Prunus andersoni i Prunus v i r g i n i a n a Sugden 1961 C a l i f o r n i a McCullough and Schneegas 1966 Idaho Oregon B.C. Pseudotsuga menziesi i B.C. Purshia glandulosa  Purshia t r identa ta  Rhamnus c a l i f o r n i c a  Ribes aureum  Ribes cereum Ribes niveum Ribes sp. Rosa sp. Rosa woodsi S a l i x sp. Sa l i x las iadra Sa l i x exigua Sambucus caerulea Sarcobatus vermiculatus Shepherdia canadensis Symphoricarpos albus C a l i f o r n i a C a l i f o r n i a C a l i f o r n i a Idaho B.C. Nevada Idaho Nevada B.C. Idaho B.C. Idaho Idaho C a l i f o r n i a Oregon B.C. B.C. Drewek 19 70 Kornet 1978 Wikeem and P i t t 1979 Sugden 19 61; B.C. F ish and W i l d l . B r . 1967; Morrison 1972; Ste l fox and Spalding 1974 McCullough and Schneegas 19 66 McCullough and Schneegas 1966 McCullough and Schneegas 1966 Drewek 19 70 Blood 1961 Hansen 1982 Drewek 19 70 Hansen 1982 Blood 1961; Sugden 1961 Drewek 19 70 Blood 1961 Drewek 19 70 Drewek 1970 McCullough and Schneegas 1966 Kornet 1978 B.C. F ish and W i l d l . Br . 1967 Sugden 1961; B.C. F ish and W i l d l . Br . 1967 263 Appendix 2 (continued) Plant Species Location Source TREES AND SHRUBS (continued) Symphoricarpos Oregon oreophilus Symphoricarpos sp. Nevada Tetradymia canescens Nevada Vaccinium scoparium B.C. Kornet 19 78 Hansen 1982 Hansen 1982 Blood 1961 1. Taxonomic nomenclature based on author's o r i g i n a l document and synonyms may occ.ur for the same species . 264 APPENDIX 3 PERCENT COMPOSITION OF MOUNTAIN SHEEP DIETS BY FORAGE CLASS FOR SELECTED NORTH AMERICAN HERDS 265 Percent Composition Diet Location/ (Site) Source Season Grass Forb Shrub Ovis canadensis canadensis Cowan 19 47 c Alberta 83 .0 10 .0 7 .0 Smith 1954 Idaho Winter 56 . o i 39 .0 Spring 77 .0 22 .0 Summer 86 .0 14 .0 F a l l 70 .0 27 .0 Schallenberger 1966 Montana 36 .0 21 .0 43 .0 Oldenmeyer et a l . 1971 Montana (MacMinn) 55 .2 6 .1 36 .22 (Specimen) 70 .5 10 .4 12 .4 (Druid) 62 .4 24 .2 2 .9 Constan 1972 Montana 72 .0 17 .0 8 .0 Erickson 1972 Montana (Old Burn) 10 .0 69 .0 21 .0 (Bunchgrass) 45 .0 22 .0 41 .0 (Rocky Reef) 16 .0 78 .0 6 .0 Todd 1972a Colorado Winter 22 .77 10 .73 66 .50 Spring 56 .88 10 .26 32 .86 Summer 64 .89 5 .86 29 .43 F a l l 53 .93 2 .17 43 .90 Ent i re Period 46 .00 9 .00 45 .00 Claar 1973 c i t e d Idaho 57 .0 3 .0 40 .0 in Hickey 1975 Brown 1974 c i t e d Montana i n Hickey 1975 June/July 3 .0 4 .6 92 .4 Sept./Nov. 89 .0 2 .0 9 .0 266 Appendix 3 (continued) Percent Composition Diet Location/ (Site) Source Season Grass Forb Shrub Ovis canadensis canadensis (continued) P a l l i s t e r 1974 Montana (W.Rose Bud) Summer F a l l Winter 12.0 98.0 98.0 55.0 2.0 2.0 32.0 0.0 0.0 (St i l lwater ) F a l l Winter 85.0 35.0 11.0 28.0 3.0 38.0 Johnson 1975 Alberta 79.2 10.2 10.6 Hickey 1975 Idaho 22.6 30.3 47.1 Ste l fox 1975 Alberta (Galaway) (Ruby) (Pa l l i se r ) (Bourgeau) (Sulfur) (Disaster) 92.2 90.9 0.0 0.0 19.4 52.1 2.1 7.5 77.7 86.3 13.0 15.2 4.9 0.0 22.2 4.5 46.4 28.2 Average 42.4 33.6 17.7 Stewart 1975 Montana (W. Rose Bud) (St i l lwater ) 58.6 54.8 29.1 22.1 12.3 2 2 . 8 3 Bear 1978 Colorado June/July August October February/March/May 52.0 73.0 87.0 88.3 48.0 27.0 13.0 11.7 0.0 0.0 0.0 0.0 267 Appendix 3 (continued) Percent Composition Diet Location/ (Site) Source Season Grass Forb Shrub Ovis canadensis canadensis (continued) Hickey 1978 Idaho (Middle Fork) 12.0 (Proctor Ck.) 34.0 1.0 3.0 86.0 63.0 Ovis canadensis c a l i f o r n i a n a Jones 1950 Sugden 19 61 C a l i f o r n i a Alpine 6.0 Low Elevat ion 68.0 B.C. (Big Basin) 25.1 (Churn Ck.) 33.7 Total A l l S i tes 32.9 Demarchi 1965 Blood 1967 Hickey 1978 Wikeem and P i t t Hansen 1982 B.C. B.C. Winter Spring Idaho 1979 B.C. May June July August Nevada July August Sept. Oct. Nov. Dec. 88.1 6 4 . 0 4 94.0 50.7 42.0 47.0 58.5 77.0 1 5 . 0 5 37.0 36.0 59.0 80.0 58.0 94.0 32.0 17.7 0.0 6.3 5.9 4.0 3.0 10.5 40.0 41.5 29.0 14.5 72.0 37.0 36.0 26.0 9.0 14.0 0.0 0.0 57.2 66.6 60.8 6.0 32.0 3.0 38.8 18.0 11.5 12.5 8.5 9.0 19.0 20.0 10.0 9.0 23.0 Appendix 3 (continued) Percent Composition Diet Location/ (Site) Source Season Grass Forb Shrub Ovis canadensis c a l i f o r n i a n a (continued) Nevada (continued) Hansen 1982 Jan. Feb. March A p r i l May-June Annual Total 68.0 57.0 62.0 18.0 9, 7, 42.0 15.0 25.0 22.0 72.0 80.0 74.0 40.0 14.0 15.0 14.0 7. 9 15.0 13.7 Ovis canadensis n e l s o n i i Barrett 1964 Nevada1 Winter Spring Summer F a l l 81.0 67.0 94.0 48.0 2.0 25.0 3.0 8.0 17.0 8.0 3.0 44.0 Yoakum 1964 Average 72 . 6 • 9 .5 18 .0 Nevada 59 .5 32 .0 8 .5 7 Nevada (Pintwater Range) 71 .0 5 .0 24 .0 (Las Vegas Range) 63 .0 4 .0 33 .0 (Sheep Range) 65 .0 3 .0 42 .0 (Eldorado Mtn.) 62 .0 13 .0 25 .0 (Highland Range) 54 .0 9 .0 37 .0 (McCullough Mtn.) 52 .0 1 .0 42 .0 (River Mtn.) 35 .0 21 .0 44 .0 (Black Mtn.) 55 .0 18 .0 27 .0 (Muddy Mtn.) 83 .0 5 .0 12 .0 (Mormon Mtn.) 40 .0 5 .0 55 .0 (Meadow Val ley) 54 .0 9 .0 37 .0 (Potose Mtn.) 49 .0 6 .0 ' 45 .0 (Dev i l ' s Peak) 76 .0 11 .0 13 .0 Total A l l S i t e s 7 54 .7 7 .6 30 .4 269 Appendix 3 (continued) Percent Composition Diet Source Location/ (Site) Season Grass Forb Shrub Ovis d a l l i s tonei Luckhurst 1973 B.C. Winter 87.6 3.0 8.5 1. Grasses and forbs combined for a l l seasons. 2. Author's data do not t o t a l 100% 3. Author's data do not t o t a l 100%. 4. Grass category includes g rass l ike species . 5. Forage c lasses for months and annual t o t a l do not equal 100% because unknowns not inc luded. 6. Summary of data from 1957-1961. 7. Summary of data for f a l l / w i n t e r period over 20 years from 17 geographic regions. 270 APPENDIX 4 COMPOSITION OF THE CAPTIVE CALIFORNIA BIGHORN SHEEP HERD AT THE OKANAGAN GAME FARM FOLLOWING LAMBING FROM 1977 TO 1982 271 Adult Adult Year Ewes Rams Yearl ings Lambs Total 1977 15 2 3 18 38 1978 12 • 0 6 4 22 1979 15 . 3 3 10 31 1980 16 0 10 11 37 1981 14 1 9 2 26 1982 11 1 1 7 20 1983 10 3 7 9 29 APPENDIX 5 EXPERIMENTAL DESIGNS 273 1. Forage Production (Section 4.32) SOURCE DF ERROR S i t e (S) 1 E r r o r A G r a z i n g (G) 1 E r r o r A ERROR A (S*G) 1 Year (Y) 3 E r r o r B Y*G 3 E r r o r B ERROR B 86 T o t a l 95 Main E f f e c t C o n t r a s t s (YEAR) a. b. c. 1976 1977 1978 vs. vs, vs, 1977 1978 1979 1978 + 1979 1979 I n t e r a c t i o n C o n t r a s t s (YEAR * GRAZING) a. (Grazed v s . b. (Grazed v s . c. (Grazed v s . Ungrazed) Ungrazed) Ungrazed) (1976 (1977 (1978 v s . v s . v s . 1977 1978 1979) 1978 + 1979) 1979) 2. F a l l Regrowth (Section 4.32) SOURCE DF ERROR S i t e (S) Year (Y) ERROR A (S*Y) Subsampling E r r o r T o t a l 2 1 2 12 17 E r r o r A E r r o r A 3. Plant Reproductive Potential (Section 4.33) SOURCE DF ERROR A l B2 C3 D 4 S i t e (S) 2 1 2 2 E r r o r A G r a z i n g (G) 1 1 1 1 E r r o r A ERROR A (S*G) 2 1 2 2 Subsampling E r r o r 114 76 106 86 T o t a l 119 79 111 91 274 Appendix 5 (continued) 3. Plant Reproductive Potential (continued) 1 A - Degrees of freedom for Agropyron spicatum, Koeler ia  c r i s t a t a , Poa sandbergi i and Balsamorhiza s a g i t t a t a . B - Degrees of freedom for Eriogonum niveum and St ipa comata. 3 C - Degrees of freedom for C a s t i l l e j a thompsonii. 4 D - Degrees of freedom for Lupinus ser iceus . 4. Shrub U t i l i z a t i o n (Section 4.34) SOURCE DF ERROR Shrubs (S) 49 Grazing (G) , 1 ERROR A (S*G) 49 ERROR B (Subsampling Error) 100 Total 199 Error A Error A 5. Annual and Seasonal Variations i n Botanical Composition and Cover (Sections 4.36) SOURCE Si te (S) Month (M) ERROR A (S*M) Year (Y) M * Y ERROR B (Subsampling Error) Total DF 3 4 12 2 8 420 479 ERROR Error A Error A Error B Error B Main E f fec t Contrasts (SITE) a . Upper vs . Others b. North vs . East + Lower c . East vs . Lower Main E f fec t Contrast (MONTH) a . A p r i l + May vs . June + July + August b. A p r i l vs . May c . May vs . June d. Ju ly vs . August 275 Appendix 5 (continued) 5. Annual and Seasonal V a r i a t i o n s i n B o t a n i c a l Composition and Cover (continued) Main E f f e c t Contrasts (YEAR) a. 1977 vs. 1978 + 1979 b. 1978 vs. 1979 I n t e r a c t i o n Contrasts (MONTH ^  YEAR) a. ( A p r i l + May vs. June + J u l y + August) (1977 vs. 1978 + 1979) b. ( A p r i l + May vs. June + J u l y + August) (1978 vs. 1979) c. ( A p r i l vs. May) (1977 vs. 1978 + 1979) d. ( A p r i l vs. May) (1978 vs. 1979) e. (May vs. June) (1977 vs. 1978 + 1979) f. (May vs. June) (1978 vs. 1979) g. ( J u l y vs. August) (1977 vs. 1978 + 1979) h. (July vs. August) (1978 vs. 1979) 6. Long Term E f f e c t s of Grazing on Botanical Composition and Cover SOURCE DF ERROR S i t e (S) 1 E r r o r A Grazing (G) 1 E r r o r A ERROR A (S*G) 1 Year (Y) 6 Err o r B G * Y 6 Er r o r B ERROR B 12 (Subsampling Error) 84 Total 111 7. Forage Quality (Sections 4.41) SOURCE DF ERROR A n a l y s i s 1 A n a l y s i s 2 Year (Y) 1 1 Err o r A Species (S) 5 11 Error A Month (M) 7 3 Err o r A S * M 35 33 Err o r A ERROR A 47 47 ERROR B (Subsampling Error) 96 96 Total * 191 191 276 Appendix 5 (continued) 8. Forage Quality of F a l l Regrowth (Section 4.41) SOURCE DF ERROR Year (Y) Month (M) Growth Stage (G) M * G ERROR A ERROR B (Subsampling Error) Total 1 2 1 2 5 12 23 Error A Error A Error A Error A 9. Diet Analysis (4.424) SOURCE Year (Y) Month (M) ERROR A (Y * M) ERROR B (Subsampling Error) Total DF 1 11 11 216 239 Main E f fec t Contrasts (MONTH) a. Summer vs. Others b. F a l l vs . Winter + Spring c . Winter vs . Spring d. June vs . Ju ly + August e. September vs . October + November f . January + February vs . March + A p r i l g . May + June vs . Ju ly + August h. March + A p r i l vs . May + June i . Ju ly v s . August j . March vs . A p r i l k. May vs . June ERROR Error A Error A 277 APPENDIX 6 PLANT SPECIES LIST FOR OKANAGAN GAME FARM STUDY SITE 278 Species Plant Species Family Code ANNUAL GRASS Apera in ter rupta (L.) Beauv. Gramineae APIN Bromus m o l l i s ' L. Gramineae BRMO Bromus tectorum L. Gramineae BRTE Festuca oc to f lo ra Walt. Gramineae FEOC PERENNIAL GRASS/GRASSLIKE Agropyron spicatum (Pursh.) Scr ibn . & Smith Gramineae AGSP A r i s t i d a longiseta Steud. Gramineae ARLO Dacty l i s glomerata L. Gramineae DAGL Carex petasata Dewey Gramineae CAPE Festuca idahoensis Elmer Gramineae FEID Festuca scabre l la Torr. Gramineae FESC Koeler ia c r i s t a t a Pers. Gramineae KOCR Poa pratensis L. Gramineae POPR Poa sandbergi i Vasey Gramineae POSA St ipa comata T r in . & Rupr. Gramineae STCO St ipa occ identa l i s var . minor (Vasey) H i tchc . Gramineae STOC Sporobolus cryptandrus (Torr. ) Gray Gramineae SPCR ANNUAL FORBS Agoseris heterophyl la (Nutt.) Greene Compositae AGHE Capsel la bursa pastor is (L.) Medic. Cruciferae CAPA Chenopodium album L. Chenopodiaceae CHAL C o l l i n s i a p a r v i f l o r a L i n d l . Scrophulariaceae COPA Collomia g rand i f lo ra Dougl. Polemoniaceae COGR Draba verna L. Cruciferae DRVE Erodium cicutar ium (L.) L'Her Geraniaceae ERCI Galium boreale L. Rubiaceae GABO Lesquerel la doug las i i Wats. Cruciferae LEDO Microser is troximoides Gray Compositae MITR Montia l i n e a r i s (Dougl.) Green Portulacaceae MOL I Myosotis micrantha P a l l . Boraginaceae MYMI Plantago patagonica Jacq. Plantaginaceae PLPA Polemonium micranthum Benth. Polemoniaceae POMI Polygonum doug las i i Greene Polygonaceae PODO Sisymbrium altissimum L. Cruciferae SIAL Taraxacum o f f i c i n a l e Weber Compositae TAOF Tragopogon dubius Scop. Compositae TRDU Appendix 6 (continued) Plant Species Family Code PERENNIAL FORBS A c h i l l e a m i l l e f o l i u m L. Compositae ACM I Antennaria dimorpha (Nutt.) T. & G. Compositae AND I Antennaria p a r v i f o l i a Nutt . Compositae ANPA Arabis h o l b o e l l i i Hornem. Cruciferae ARHO Arnica soror ia Greene Compositae ARSO Asparagus o f f i c i n a l i s L. L i l i a c e a e ASOF Astragalus miser var . serot inus (Gray) Barneby Leguminosae ASMI Astragalus p u r s h i i var . p u r s h i i Dougl. Leguminosae ASPU Balsamorhiza sag i t ta ta (Pursh.) Nutt . Compositae BASA Calochortus macrocarpus Dougl. L i l i a c e a e CAMA C a s t i l l e j a thompsonii Pennell Scrophulariaceae CATH Centaurea d i f f u s a Lam. Compositae CEDI Chaenactis doug las i i (Hook.) H. & A. Compositae CHDO Comandra umbellata var . p a l l i d a (DC.) Jones Santalaceae COUM Crepis atrabarba Hel ler Compositae CRAT Delphinium b ico lo r Nutt . Ranunculaceae DEBI Dodecatheon c u s i c k i i Greene Primulaceae DOCU Erigeron corymbosus Nutt . Compositae ERCO Erigeron f i l i f o l i u s Nutt . Compositae ERFI Erigeron pumilus Nutt . Compositae ERPU F r i t i l l a r i a pudica (Pursh) Spreng. L i l i a c e a e FRPU G a i l l a r d i a a r i s t a t a Pursh. Compositae GAAR Geum t r i f l o r u m Pursh Rosaceae GETR Heuchera c y l i n d r i c a Dougl. Saxifragaceae HECY Lewisia red iv i va Pursh Portulacaceae LERE Lithophragma p a r v i f l o r a (Hook.) Nutt . Saxifragaceae LIPA Lithospermum ruderale Dougl. Boraginaceae LIRU Lomatium macrocarpum (Nutt.) Coul t . & Rose Umbelliferae LOMA Lomatium tr i ternatum (Pursh) Coul t . & Rose Umbelliferae LOTR Lupinus sericeus Pursh Leguminoseae LUSE Medicago sat i va L. Leguminoseae MESA * Opuntia f r a g i l i s (Nutt.) Haw. Cactaceae OPFR Phacel ia hastata Dougl. Hydrophyllaceae PHHA Phacel ia l i n e a r i s (Pursh) Holz . Hydrophy1laceae PHLI Phlox l o n g i f o l i a Nutt . Polemoniaceae PHLO Ranunculus glaberrimus Hook. Ranunculaceae RAGL Sax i f rag ia i n t e g r i f o l i a Hook. Saxifragaceae SAIN S e l a g i n e l l a wa l lace i Hieron. Selaginel laceae SEWA Si lene n o c t i f l o r a L. Caryophyllaceae SINO 2 8 0 Appendix 6 (continued) Plant Species Family Species Code PERENNIAL FORBS (CONTINUED) Smilacina racemosa (L.) Desf. Verbascum thapsus L. Zigadenus venenosus Wats. L i l i a c e a e SMRA Scrophulariaceae VETH L i l i a c e a e ZIVE TREES AND SHRUBS Acer glabrum var . doug las i i (Hook.) Dippel Amelanchier a l n i f o l i a Nutt . Artemisia f r i g i d a W i l l d . Artemisia t r identa ta Nutt . Berberis aquifol ium Pursh Chrysothamnus nauseosus ( P a l l . ) B r i t t . Eriogonum heracleoides Nutt . Eriogonum niveum Dougl. Penstemon f rut icosus (Pursh) Greene Philadelphus l e w i s i i Pursh. Pinus ponderosa Dougl. Prunus v i r g i n i a n a L. Pseudotsuga menziesi i (Mirbel) Franco. Rhus glabra L. Ribes cereum Dougl. Rosa nutkana Pres l Sambucus cerulea Raf. Symphoricarpos albus (L.) Blake Aceraceae ACGL Rosaceae AMAL Compositae ARFR Compositae ARTR Berberidaceae BEAQ Compositae CHNA Polygonaceae ERHE Polygonaceae ERNI Scrophulariaceae PEFR Hydrangeaceae PHLE Pinaceae PIPO Rosaceae PRVI Pinaceae PSME Anacardiaceae RHGL Grossulariaceae RICE Rosaceae RONU Capr i fo l iaceae SACE Capr i fo l iaceae SYAL * = Introduced on the s i t e as forage i n hay. 281 APPENDIX 7 PHENOLOGY OF 75 PLANT SPECIES OCCURRING ON THE OKANAGAN GAME FARM STDDY SITE IN EACH OF THREE SUCCESSIVE GROWING SEASONS (1977-1979) Group/ Species Forage Class Year GROUP I Balsamorhiza  sagittata Collinsia parviflora Dodecatheon cusickii F r i t i l l a r ia  pudica Lomatium tritermatum Ranunculus glaberrimus Saxifragia integrifolia 1977 FORB 1978 1979 1977 FORB 1978 1979 1977 FORB 1978 1979 1977 FORB 1978 1979 1977 FORB 1978 1979 1977 FORB 1978 1979 1977 FORB 1978 1979 Month F . M . A . M . J . J . A . S . O . N . D . [ » » » » » > 4 5 1 2,3 3 4 4,5 1.2 3,4 4 5 [ » » » » » » » » » » » » » » > 5 1,2 3 3,4 4 5 1 2,3 3,4 5 [ » » » » » » » » » » » » » » > 5 1 2,3 3,4 4 5 2.3 4 5 [ » » » » » » » » » » » » » » > 5 1,2 3 4 4 5 1 2,3 4 5 [ » » » » » » » » » » » » » » > 5 1 1,2 3,4 4 5 1 2,3 3,4 4 5 [ » » » » » » » » » » » » » » > 5 1,2 2,3 4 5 1,2 3 4,5 [ » » » » » » » » » » » » » » > 5 1,2 2,3 4,5 6 5 1,2 1,2 3,4,5 6 6 5 oo to Appendix 7 (continued) Month Group/ Forage Species Class Year J . F . M . A . M . J . J . A . S . O . N . D GROUP I (continued) Taraxacum officinale FORB 1977 1978 1979 [ » » » » » » » » » » » » » » > 5 1 1 1,2,3-3,4 5 6 3 3 5 1 1,3 3 4 4,5 6 6 5 GROUP II Apera interrupta GRASS 1977 1978 1979 [»»»»»»»»»»»>] 1 2 3,4 5 [ » » NO GERMINATION » > ] Bromus mollis GRASS 1977 1978 1979 [ » » » » » > 2 3 5 6 6 1 1 1 2,3 5 6 6 6 1 1 2,3 4 5 6 6 Bromus tectorum GRASS 1977 1978 1979 2,3,4-5 1 1 1,2 3,4 5-1 - -1 ,2 3 4 5 -6--6--6 -6 -5 Festuca octoflora GRASS 1977 1978 1979 1,2,3-4,5 -1,2 3,4,5 1,2,3-4,5 Poa sandbergii GRASS 1977 1978 1979 [ » » » » » > 3 , 4 5 1 2 3,4 4,5 1 1,2 3,4 5 6--6--6-6— -6 -5 -5 Appendix 7 (continued) Month Group/ Forage Species Class Year J . F . M . A . M . J . J . A . S . O . N . D . GROUP II (continued) Agoseris 1977 [ » » » » » > 3 4 5 heterophylla FORB 1978 1 2 f 3 3 4,5 1979 1,2 3,4 5 Antennaria 1977 [ » » » » » > 3 5 dimorpha FORB 1978 1 1 2,3 4 4 4 6 —6 6 5 1979 1 1,2 3 4 5 . 6 —6 6 Antennaria 1977 [ » » » » » » » » > 3 — 4  — 5 parvifolia . FORB 1978 1 1 2,3 3,4 4 4 6,2- —6 6 5 1979 1 1,2 3 4 4 4 6,3- —6,3 6,3 5 Arabis 1977 [ » » » » » > 2 , 3 3 4 5 6 6 5 holboelli i FORB 1978 1 1 2,3 3,4 4,5 6 —6 5 1979 1 1,2 3,4 5 6 6 Arnica 1977 [ » » » » » » » » » » » > 5 sororia FORB 1978 1 1,2 3,4 5 1979 1 2,3 4,5 Astragalus 1977 [ » » » » » > 4 5 miser FORB 1978 1 1 2,3 4 4 — — 5 1979 1,2 3 4— 5 6 5 Astragalus 1977 [ » » » » » » » » » » » » » » > 5 purshii FORB 1978 1 1 2,3 4 4 4 — — 5 6 5 1979 1 1,2 3 4 5 Appendix 7 (continued) Month Group/ Forage Species Class Year J . F . M . A . M . J . J . A . S . O . N . D . GROOP II (continued) Castilleja thompsonii FORB 1977 1978 1979 [ » » » » » > 3 5 1 1,2 3 3 4 5 1 1,2 3 4 5 6 6,3 5 6,3 5 Chaenactis douglasii FORB 1977 1978 1979 [ » » » » » » » » » » » > ] 1 1 2,3 4 5 -Comandra umbellata FORB 1977 1978 1979 [ » » » » » » » » » » » > 4 — 1 2,3 3 4 4 — 1,2 3 4 4 4 — — 4 5 — 4 4 5 — 4 5 5 Crepis atrabarba FORB 1977 1978 1979 [ » » » » » » » » » » » > 5 1,2 3 4 5 1 2 3,4 5 Delphinium bicolor FORB 1977 1978 1979 [ » » » » » > 3 4 5 1,2 3- 4,5 Galium boreale FORB 1977 1978 1979 [ » » » » » » » » » » » > 5 [ > » » 2 3 4 5 1 2,3 4 5 Lesguerella douglasii FORB 1977 1978 1979 [ » » > 3 3,4 5 1 2,3 3,4 5 [ » » > 3 4 4 5 6 6 -6 5 6 6 6 5 Appendix 7 (continued) Month Group/ Forage Species Class Year J . F . M . A . M . J . J . A . S . O . N . D . GROUP II (continued) Lewis ia 1977 [ » » » » » > 3 4 5 rediviva FORB 1978 1 1 2,3 3,4 5 1979 1 1 2,3,4-5 Lithophragma 1977 [ » » » » » » » » » » » » » » > 5 parviflora FORB 1978 1 1,2 3 4 5 1979 1 1,2 3,4 5 Lithospermum 1977 [ » » » » » » » » » » » » » » » » » > 4 , 5 ruderale FORB 1978 1 1 1,2 3,4 4 4 4 5 1979 1,2 3 4 4 4 5 Lomatium 1977 [ » » » » » » » » » » » » » » > 5 macrocarpum FORB 1978 1 1,2 3,4 4 5 1979 1,2 1,2 3 4 5 Lupinus 1977 [ » » » » » > 2 , 3 4 5 sericeus FORB 1978 1 1,2 2,3 4 5 1979 1 1,2 3 4 4 5 5 6 5 Microseris 1977 [ » » > 3 4 5 troximoides FORB 1978 1,2 3 4 5 1979 1,2 3,4 5 Myosotis 1977 [ » » » » » » » » » » » » » » > 5 micrantha FORB 1978 [ » » » » » > 3 4 5 1979 [ » » » » » > 3 , 4 5 Appendix 7 (continued) Month Group/ Forage Species Class Year J . F . M . A ' . M . J . J . A . S . O . N . D . GROUP II (continued) Phacelia linearis FORB 1977 1978 1979 [ » » » » » > 3 4 5 1,2 3 3 4,5 1,2 3,4 5 Plantago patagonica FORB 1977 1978 1979 [ » » > 3 4 5 1,2 3 4 5 1,2 3 3,4 4 5 Silene noctiflora FORB 1977 1978 1979 [ » » > 3 3 4 5 1 1,2 2,3 4 4 5 1 2,3 4 5 Smilacina racemosa FORB 1977 1978 1979 [ » » » » » » » » » » » > 5 1,2 3 4 5 1,2 3 4 5 Zigadenus venenosus FORB 1977 1978 1979 [»»»»»»»»»»»»»»>] 1,2 3 3,4 5 1 1 2,3,4-5 Acer glabrum SHRUB 1977 1978 1979 [ » » » » » » » » > 4 5 1 2,3 4 4 4 5 1 1,2 3 4 4 4 A-Amelanchier alnifol ia SHRUB 1977 1978 1979 [ » » » » » > 3 , 4 4 4 4 4 1 1,2 3,4 4 4 4 A-1 1,2 3,4 4 4 4 A-Appendix 7 (continued) Month Group/ Forage Species Class Year J . F . M . A . M . J . J . A . S . O . N . D . GROUP II (continued) Eriogonium heracleoides SHRUB 1977 1978 1979 [ » » > 3 4 4 5 1 1,2 3 4 4 4 4 4 5 1 2 3,4 4 4 4 3 4 5 Prunus virginianna SHRUB 1977 1978 1979 [ » » » » » » » » » » » » » » » » » » » » > 5 1 2,3 3,4 4 4 4 5 Ribes cereum SHRUB 1977 1978 1979 [ » » » » » > 3 4-1 1,2 3 4- .4 4 4 5 1,2 3 4 4 4 4 4 5 Group III Agropyron  spicatum GRASS 1977 1978 1979 [ » » » » » > 2 3 4,5 6 6 6 1 1 1,2 2,3 4 4,5 6 6 6 5 1 1 1,2,3-4 5 6 6 6 5 Aristida longiseta GRASS 1977 1978 1979 [ » » > 1 5 [ » » » » » » » » > 4 4 1 2 2,3,4-5 6 — 5 Festuca idahoensis GRASS 1977 1978 1979 [ » » » » » > 4 5 6 6 1 2,3 4 4,5 6 6 — 6 5 Appendix 7 (continued) Month Group/ Forage Species Class Year J . F . M . A . M . J . J . A . S . O . N . D . GROUP III (continued) Festuca -scabrella Koeleria cristata Poa pratensis Stipa comata Stipa occidentalis Achillea millefolium Calachortus macrocarpus GRASS GRASS GRASS GRASS GRASS FORB FORB 1977 1978 1979 1977 1978 1979 1977 1978 1979 1977 1978 1979 1977 1978 1979 1977 1978 1979 1977 1978 1979 [ » » » » » > 3 1 1 1,2 2,3-1 1 2 3,4-[ » » » » » > 2 3 — 1 1 1,2 3 — 1 1 2,3 4 — [ » » » » » > 3 1 1 1,2 3-1 1 2,3 3-[ » » » » » > 2 3-1 1 1,2 3-1 1 2,3 4 : [ » » » » » » » » > 3 -1 1 2,3 4-[ » » » » » > 2 3-1 1 1,2 3-1 2 3-- 4 — -4 -4 -4 -4,5 -4,5 -5 - 4 — - 4 — - 4 — -4 -4,5 -4 -4 -4 - 4 — -4,5--4,5-[ » » » » » » » » > 3 , 4 -1 1 1,2 3,4-1 1 1,2 3,4-- 5 — -4,5 -5 -5 6 — -4,5 -5 -5 -4,5 -4 -5 -5 -4,5 -4,5 -5 -5 -5 -5 6-6--6-6-6-6-6-6-6-6--5 6-6-6-6-6-6--6--6-6--6--6--6--6--6 -6--6--6 -6 -5 -6 -5 -6--6--6-6--6--6--6--6--6--6 -6--6 -6--6--6 -6--6--6 -6 -5 -6 -5 Appendix 7 (continued) Month Group/ Forage Species Class Year J . F . M . A . M . J . J . A . S . O . N . D GROUP III (continued) Centaurea diffusa FORB 1977 1978 1979 [ » » » » » > 1 1 2,3,4-5 1 1 1 1 2,3 3 — 1 1 1 1,2 3 4 6 6 6 5 — 4 6,3 5 6,3 6,3 6,3 Erigeron corymbosus FORB 1977 1978 1979 [ » » » » » » » » > 2 , 3 4 5 1 ! 1,2 3 3,4 5 1 1 1,2 3 4— 5 6,3 6,3 5 6 6,3 5 Erigeron f i l i f o l i u s FORB 1977 1978 1979 [ » » » » » » » » > 2 , 3 4 5 1 1 1,2 3 3,4 5 1 1,2 3 3 4 5 6 6 5 Erigeron pumilus FORB 1977 1978 1979 [ » » » » » » » » > 2 , 3 — 4 5 1 1,2 3- 3 4 5 6 6 6 6 6 6,3 5 6 6,3 6 5 Erodium cicutarium FORB 1977 1978 1979 [ » » > 3 4 5 1 1,2 2,3 3 4 6 — 1,2 3 3,4 4,5 6 6 5 — 6 6 6 5 6 6,3 6 5 Gaillardia aristata FORB 1977 1978 1979 [ » » » » » > 2 3 3,4 4,5 1 1 1,2 3 3,4 4 I 1 2 3,4 4,5 6 6 6 6,3 6,3 6,3 5 6,3 6,4 6 5 Geum triflorum FORB 1977 1978 1979 [ > » » » » » 3 4 5 1 1 2,3 4 4,5 6 — 1 1,2 3 4 4,5 6 — 6 6 6 6 — 6 6 6 5 — 6 6 6 6 Appendix 7 (continued) Month Group/ Forage Species Class Year J . F . M . A . M . J . J . A . S . O . N . D . GROUP III (continued) Heuchera cylindrica FORB 1977 1978 1979 [ » » » » » » » » > 4 6 1 1 2,3 3 4 4 1 1,2 3 4 4— 5 — 6 6 6 — 6 — — 6 — — 6 — Opuntia tragi l is FORB 1977 1978 1979 [ » » » » » > 2 3 4 4 1 1 1,2 3 4— 4 — 4 — 4 — — 4 — — 4 — — 4 _ _ . — 4 _ _ . Phacelia hastata FORB 1977 1978 1979 [ » » » » » > 2 3 5 1 1 1,2 3 4 4 1 1 2,3 3 4 4 6 — 6 — 6 — — 6 — — 6 — — 6 — Phlox longifolia FORB 1977 1978 1979 [ » » » » » > 3 3,4 5 1 1 2,3 3,4 4 6 1 1,2 3 4 4 5 6 — —6,3 -— 6 — Polygonum douglasii FORB 1977 1978 1979 [ » » » » » » » » > 5 1 2,3-1 -2 3,4 5 — 4 , 5 Sisymbrium altissimum FORB 1977 1978 1979 [ » » » » » » » » » » » » » » > 5 1 1,2,3-3 3,4 5 6 — 6 — — 6 — — 6 Tragopogon dubius FORB 1977 1978 1979 [ » » » > » » 2 3 4 5 1 1 1,2 2,3 4 5 1 2 3,4 4 5 6,3-6 — — 6 — —6,2 --5 -6—--6 -4 -4 -4 -6 -6 -6 6 -6,3--6,3 -5 -6 -5 -5 -5 -5 -5 -5 — 5 -5 -5 Appendix 7 (continued) Month Group/ Forage Species Class Year J . F . M . A . M . J . J . A . S . O . N . D . GROUP III (continued) Philadelphus lewisii FORB 1977 1978 1979 [ » » » » » » » » > 3 4 4 4--5 -5 Rosa nutkana SHRUB 1977 1978 1979 [ » » » » » » » » » » » » » » > 4 4-1 1,2 3 3,4 4 4-1 2,3 4 4 4 4--5 -5 4 4 5 Symphoricarpos albus SHRUB 1977 1978 1979 [ » » » » » » » » » » » > 4 5 1 1,2 3 4 4 4 5 1 2 3,4 4 4 4 5 Group IV Artemisia  frigida Artemisia tridentata Chrysothamnus nauseosus SHRUB SHRUB SHRUB 1977 1978 1979 1977 1978 1979 1977 1978 1979 [ » » » » » » » » > 1 — — 1 — — 2 — 3 — — 4 —4— — 4 1 1 1 - — 2 — — 2 , 3 - — 3 — — 3 — — 4 — _ _ 4 — — 4 — 4 [ » » > 1 — — 2 — o _ 3 — — 4 — 2 — 4 / — 1—— 1 1 _ _1 1 2 9 . —^ 9 ——4—~ • — — £J / —±— z z ft [ » » > 1 — ——— 1"— — —1""" ' "~2::: :~ 2 : : : — 3 — 7 4_ — 4 — 4 — 5 e. — 3 — —4— — 4 Appendix 7 (continued) Month Group/ Forage Species Class Year J . F . M . A . M . J . J . A . S . O . N . D . GROUP IV (continued) Eriogonum niveum SHRUB 1977 1978 1979 [ » » » » » » » » » » » > 3 4 5 ! 1 1 2 -3 3 3,4 4 5 1 2 2 3 3,4 6,3 6,3 6 5 [ » » » = No Observations; 1= Growth init iation; 2= Floral init iat ion; 3= Full flower; A- Seed set and shatter; 5= Cured; 6= Fall regrowth or germination. K3 VO LO 294 APPENDIX 8 PERCENT COMPOSITION OF CALIFORNIA BIGHORN DIET, BOTANICAL COMPOSITION OF THE RANGE AND SELECTIVITY INDICES FROM 1977 TO 1979 AT THE OKANAGAN GAME FARM JUNE JULY AUGUST DIET SITE SI DIET SITE SI DIET SITE SI ANNUAL GRASS APBSJ 77 78 79 0.0 0.2 0.0 0.0 1.7 0.0 0.0 0.0 NC 0.0 0.1 0.0 0.0 1.9 0.0 0.0 T NC 0.0 0.1 0.0 0.0 1.2 0.0 0.0 0.0 NC BEND 77 78 79 1.2 3.4 0.0 3.7 0.4 2.5 0.4 0.0 0.2 BRTE 77 1.2 18.4 0.1 78 1.2 20.8 0.1 79 2.8 16.5 0.2 0.4 2.4 0.4 1.7 0.0 2.1 0.2 0.2 0.0 1.6 19.0 0.1 0.4 20.3 0.0 3.6 19.2 0.2 1.2 2.4 0.0 0.9 0.0 1.8 1.2 17.4 3.2 17.2 2.0 17.4 0.5 0.0 0.0 0.1 0.2 0.1 FECC 77 0.0 0.3 0.0 78 0.0 1.2 0.0 79 0.0 0.3 0.0 0.0 0.1 0.0 0.0 0.4 0.0 0.0 0.0 NC 0.0 0.2 0.0 0.0 0.0 NC 0.0 0.0 NC TOTL 77 2.4 22.1 0.1 78 1.2 27.4 0.0 79 3.2 19.3 0.2 2.0 21.3 0.1 0.8 24.1 0.0 3.6 21.3 0.2 2.4 20.1 0.1 3.2 19.3 0.2 2.0 19.2 0.1 DECEMBER JANUARY FEBRUARY DIET SITE SI DIET SITE SI DIET SITE SI APIN 77 78 79 0.0 0.0 0.1 1.2 0.0 0.0 0.0 0.0 1.1 1.2 0.0 NC 0.0 0.0 0.1 1.2 0.0 NC BRMO 77 0.8 2.4 0.3 78 0.8 0.9 0.9 0.4 2.4 6.0 0.0 2.4 0.0 79 0.0 0.9 0.0 0.0 0.9 0.0 SEPTEMBER OCTOBER NOVEMBER DIET SITE SI DIET SITE SI DIET SITE SI 0.0 0.1 0.0 0.0 0.1 0.0 0.0 0.1 0.0 0.0 1.2 0.0 0.0 1.2 0.0 0.0 1.2 0.0 0.4 2.4 0.2 2.0 2.4 0.8 1.2 2.4 0.5 0.8 0.9 0.9 0.0 0.9 0.0 1.2 0.9 1.3 7.2 17.4 0.4 10.0 17.4 0.6 9.2 17.4 0.5 10.8 17.7 0.6 8.0 17.7 0.5 8.0 17.7 0.5 0.0 0.2 0.0 0.0 0.2 0.0 0.0 0.2 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 7.6 20.1 0.4 12.0 20.1 0.6 10.4 20.1 0.5 11.6 19.3 0.6 8.0 19.3 0.4 9.2 19.3 0.5 MARCH APRIL MAY DIET SITE SI DIET SITE SI DIET SITE SI 0.0 0.0 NC 0.0 0.0 ISC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.2 0.0 0.0 0.0 NC 0.0 0.0 NC ^ CO 1.6 1.6 1.0 0 1 1.2 0.9 1.3 0.8 0.4 2.0 0.4 0.4 1.0 0.4 0.6 0.7 0.0 0.2 0.0 0.8 0.3 2.7 Appendix 8 (ocntinued) DECEMBER JANUARY FEBRUARY MARCH APRIL MAY DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI ANNUAL GRASS (ccntinaed) BRTE 77 78 79 2.8 17.4 4.0 17.7 0.2 0.2 2.0 1.6 17.4 17.7 0.1 0.1 2.8 17.4 5.2 17.7 0.2 0.3 6.0 14.1 8.0 25.1 0.4 0.3 3.2 10.1 3.2 19.5 0.3 0.2 1.6 12.0 4.8 15.6 4.8 18.1 0.1 0.3 0.3 FECC 77 78 79 0.0 0.2 0.0 0.0 0.0 NC 0.0 0.0 0.2 0.0 NC NC 0.0 0.2 0.0 0.0 NC NC 0.0 0.0 0.0 0.0 NC NC 0.0 0.1 0.0 0.0 0.0 NC 0.0 1.0 0.0 0.8 0.0 1.2 0.0 0.0 0.0 TOTL 77 78 79 3.6 20.1 4.8 19.3 0.2 0.2 2.4 1.6 20.1 19.3 0.1 0.1 2.8 20.1 5.2 19.3 0.1 0.3 7.2 15.0 8.4 25.7 0.5 0.3 4.0 10.6 3.2 19.7 0.4 0.2 3.2 14.6 5.2 16.8 5.6 19.6 0.2 0.2 0.3 PERENNIAL GRASS/GRASSLIKE JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI AGSP 77 78 79 11.2 32.1 19.2 30.0 28.4 35.7 0.3 0.6 0.8 17.6 15.6 22.8 34.4 31.4 39.5 0.5 0.5 0.6 18.4 33.8 19.2 36.2 22.8 41.5 0.5 0.5 0.5 20.4 33.8 11.6 36.3 0.6 0.3 15.2 33.8 21.2 36.3 0.4 0.6 18.8 33.8 19.2 36.3 0.6 0.5 ARID 77 78 79 0.0 0.0 0.0 0.0 0.0 0.0 NC NC NC 0.0 0.0 0.4 0.0 0.0 0.0 NC NC NC 0.0 0.0 0.0 0.0 0.0 0.0 NC NC NC 0.0 0.0 0.4 0.0 NC NC 0.0 0.0 0.0 0.0 NC NC 0.0 0.0 0.0 0.0 NC NC CAPE 77 78 79 0.0 0.0 0.0 0.0 0.0 0.0 NC NC NC 0.0 0.0 0.0 0.0 0.0 0.0 NC NC NC 0.0 0.0 0.0 0.0 0.0 0.0 NC NC NC 0.0 0.0 0.0 0.0 NC NC 0.4 0.0 0.0 0.0 NC NC 0.0 0.0 0.0 0.0 NC NC Appendix 8 (continued) JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI PERENNQAL GRASS/GRASSLIKE (cmtinued) DAGL 77 0.0 * NC 78 0.0 * NC 79 0.0 * NC FEID 77 0.4 0.7 0.6 78 . 2.0 0.1 20.0 79 0.4 0.3 1.3 FESC 77 8.8 0.0 NC 78 5.2 0.3 17.3 79 3.6 0.3 12.0 KCCR 77 8.8 5.7 1.5 78 9.6 1.9 5.1 79 11.2 2.4 4.7 POPR 77 1.2 1.6 0.8 78 0.8 1.0 0.8 79 2.4 1.3 1.8 POSA 77 0.8 3.2 0.3 78 0.4 2.8 0.1 79 0.4 0.7 0.6 STCO 77 8.4 6.8 1.2 78 9.6 3.2 3.0 79 6.0 6.5 0.9 STOC 77 0.0 0.8 0.0 78 0.4 0.4 1.0 79 0.0 0.3 0.0 0.0 0.0 0.0 2.8 0.0 1.6 * * 7.6 7.4 6.4 3.2 6.8 7.1 1.2 0.4 0.8 0.3 0.4 0.2 NC NC NC 0.5 5.6 0.3 0.0 0.2 8.0 12.0 0.2 60.0 4.0 0.3 13.3 9.2 0.1 92.0 12.4 6.0 2.1 15.2 2.6 5.8 14.0 1.3 10.8 2.8 1.2 2.3 1.2 1.0 1.2 4.0 2.0 2.0 0.4 2.3 0.2 0.0 3.0 0.0 0.4 0.5 0.8 1.0 2.0 0.9 3.0 2.7 2.0 0.0 0.0 0.0 1.6 1.2 0.0 NC NC NC 2.8 0.8 3.5 2.8 0.1 28.0 1.6 0.1 16.0 20.8 0.3 69.3 11.6 0.5 23.2 19.6 0.1 196.0 15.2 7.2 18.8 2.7 14.4 1.9 1.6 1.0 6.8 1.4 2.0 1.0 0.4 3.0 0.4 2.6 0.8 0.3 11.6 5.2 8.8 5.4 8.4 7.4 0.5 0.5 0.1 2.1 7.0 7.6 1.6 4.9 2.0 0.1 0.2 2.7 2.2 1.6 1.1 3.2 2.4 0.0 0.0 * NC 0.0 * NC 2.0 0.8 2.5 0.8 0.1 8.0 10.8 0.3 36.0 11.6 0.5 23.2 16.0 7.2 2.2 18.4 2.7 6.8 2.4 1.0 2.4 6.0 1.4 4.3 2.0 3.2 0.6 2.0 2.6 0.8 13.6 5.2 2.6 9.6 5.4 1.8 1.2 0.5 2.4 1.6 0.5 3.2 0.0 0.0 * * NC NC 1.2 0.8 1.5 1.6 0.1 16.0 9.2 0.3 30.7 8.0 0.5 16.0 12.0 7.2 1.7 21.6 2.7 8.0 2.8 1.0 2.8 7.6 1.4 5.4 3.6 3.2 1.1 2.4 2.6 0.9 7.2 5.2 1.4 12.4 5.4 2.3 2.0 0.5 4.0 2.4 0.5 4.8 0.0 0.0 * * NC NC 1.2 0.8 1.5 0.4 0.1 4.0 4.4 0.3 14.7 8.4 0.5 16.8 10.0 7.2 1.4 18.0 2.7 6.7 3.6 1.0 3.6 12.0 1.4 8.6 0.8 3.2 0.3 0.8 2.6 0.3 11.2 5.2 2.2 9.6 5.4 1.8 0.8 0.5 1.6 2.8 0.5 5.6 Appendix 8 (cx)ntdnued) JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI PEREttOAL GRASS/GRASSLIKE (continued) OTHR 77 4.8 0.0 NC 5.2 0.0 NC 4.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC TOTL 77 44.4 51.1 0.9 62.0 52.7 1.2 76.4 52.0 1.5 68.4 52.0 1.3 53.6 52.0 1.0 50.8 52.0 1.0 78 47.2 39.7 1.2 43.0 42.1 1.0 69.6 49.4 1.4 62.0 49.4 1.2 77.2 49.4 1.6 71.2 49.4 1.4 79 52.4 47.5 1.1 59.6 51.9 1.2 69.6 52.2 1.3 DECEMBER JANUARY FEBRUARY MARCH APRIL MAY DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI AGSP 77 23.2 33.8 0.7 11.6 31.2 0.4 78 23.2 36.3 0.6 28.0 33.8 0.8 28.8 33.8 0.9 21.6 35.8 0.6 15.6 27.1 0.6 16.8 27.8 0.6 79 31.6 36.3 0.9 37.6 36.3 1.0 17.6 31.1 0.6 24.4 29.2 0.8 17.2 32.2 0.5 ARLO 77 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC CAPE 77 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC DAGL 77 0.4 * NC 0.0 * NC 78 0.0 * NC 0.0 * NC 0.0 * NC 0.0 * NC 0.0 * NC 0.0 * NC 79 0.0 * NC 0.0 * NC 0.0 * NC 0.0 * NC 0.0 * NC FEID 77 0.8 0.8 1.0 2.4 0.2 12.0 78 0.4 0.1 4.0 2.4 0.8 3.0 0.0 0.8 0.0 0.8 0.0 NC 1.6 0.0 NC 1.2 0.1 12.0 79 0.8 0.1 8.0 1.6 0.1 16.0 1.2 0.0 NC 2.0 0.1 20.0 2.4 0.1 24.0 Appendix 8 (cmtinued) DECEMBER JANUARY FEBRUARY MARCH APRIL MAY DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI PEREtCHAL GRASS/GRASSLIKE (coitinued) FESC 77 3.2 0.3 10.7 78 16.8 0.5 33.6 1.2 0.3 79 4.4 0.5 POPR 77 78 79 POSA 77 78 79 1.6 1.0 5.2 1.4 0.4 3.2 0.0 2.6 STCO 77 14.4 5.2 78 13.6 5.4 79 STCC 77 78 79 OTHR 77 78 79 1.2 0.5 0.4 0.5 0.0 0.0 0.0 0.0 TOTL 77 53.2 52.0 78 73.6 49.4 79 1.6 3.7 0.1 0.0 2.8 2.5 2.4 0.8 NC NC 1.0 1.5 1.6 1.0 6.4 1.4 19.2 5.2 12.8 5.4 0.0 0.0 0.0 0.0 71.6 52.0 75.2 49.4 4.0 8.8 KOCR 77 8.0 7.2 1.1 78 14.0 2.7 5.2 18.4 7.2 2.6 79 18.4 2.7 6.8 1.6 4.6 0.0 3.2 0.0 0.4 2.6 0.2 3.7 2.4 0.8 0.5 1.6 0.4 0.5 0.8 NC NC 1.4 1.5 1.2 0.3 4.0 2.8 0.0 NC 4.8 0.2 24.0 6.4 0.5 12.8 10.8 0.3 36.0 9.2 0.5 18.4 12.8 7.2 1.7 11.6 1.7 6.8 15.2 1.8 8.4 9.6 2.7 5.1 10.4 0.8 13.0 14.8 1.3 11.4 2.0 1.0 2.0 1.2 0.8 1.5 4.4 1.4 3.1 3.6 1.4 2.6 5.2 1.1 4.7 4.4 2.1 2.1 0.0 3.2 0.0 4.8 11.1 0.4 6.0 11.1 0.5 1.2 2.6 0.5 2.8 8.8 0.3 4.0 8.8 0.4 12.8 8.0 0.8 0.0 5.2 5.4 0.0 0.0 0.0 0.0 2.5 1.5 1.6 0.0 NC NC 58.4 52.0 1.1 68.0 49.4 1.4 14.4 0.4 36.0 11.6 1.1 10.5 7.6 2.0 3.8 6.4 2.2 2.9 0.8 0.0 NC 1.2 0.0 NC 0.4 0.0 NC 0.8 0.1 8.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 ISC 58.0 49.8 1.2 60.4 42.7 1.4 56.0 44.1 1.3 66.0 44.3 1.5 9.6 0.3 32.0 4.4 0.3 14.7 8.4 0.5 16.8 6.0 5.2 1.2 6.0 0.5 12.0 19.2 2.3 8.3 0.0 1.5 0.0 1.2 0.8 1.5 2.4 1.8 1.3 1.2 7.0 5.6 7.9 1.6 3.9 0.2 0.7 0.4 4.4 2.5 1.8 13.2 0.5 26.4 7.2 5.3 1.4 1.2 0.1 12.0 0.8 0.1 8.0 0.4 0.1 4.0 4.4 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 40.8 48.0 0.9 49.2 38.0 1.3 58.8 46.2 1.3 ApparifiLx 8 (continued) JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI ANNUAL FORBS AGHE 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.4 0.0 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC COPA 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.4 0.0 ' 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 '0.0 NC ERCI 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.1 0.0 79 0.0 0.0 NC 0.0 0.0 NC 0.4 0.0 NC GABO 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.4 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC LEDO 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 T NC 0.0 0.0 NC 1.2 0.0 NC 79 0.0 0.0 NC 1.2 0.0 NC 1.2 0.0 NC MITR 77 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.0 NC 78 0.0 T NC 0.0 0.0 NC 0.0 0.0 NC 79 0.4 0.0 NC 0.0 0.0 NC 0.0 0.0 NC MYMI 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC PLPA 77 0.0 0.6 0.0 0.4 0.2 2.0 0.0 0.6 0.0 78 0.0 2.0 0.0 0.0 2.0 0.0 0.0 1.0 0.0 79 0.0 0.8 0.0 0.0 0.5 0.0 0.0 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.6 0.0 1.0 NC NC NC NC NC 4.0 NC NC NC 0.0 NC NC NC NC 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.6 1.0 NC NC NC NC NC 0.0 NC NC NC NC NC NC NC NC 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.8 0.0 0.4 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.6 1.0 NC NC NC NC NC 4.0 NC NC NC NC NC NC NC NC 0.0 0.0 Appendix 8 (<xntinued) JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI ANNUAL FORBS (continued) PODO 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.5 0.0 0.0 0.5 0.0 0.0 0.5 0.0 0.0 0.5 0.0 79 0.0 0.0 NC 0.0 0.1 0.0 0.0 0.0 NC PCMI 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC SIAL 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 T NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC TAOF 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.1 0.0 0.0 0.1 0.0 0.0 0.1 0.0 0.0 0.1 0.0 79 0.0 0.1 0.0 0.0 0.1 0.0 0.0 0.0 NC TRDU 77 0.0 0.2 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.2 0.0 0.0 0.2 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.1 0.0 0.0 0.0 NC TOTL 77 0.0 0.5 0.0 0.4 0.2 2.0 0.0 0.6 0.0 0.0 0.6 0.0 0.0 0.6 0.0 0.8 0.6 1.3 78 0.0 2.7 0.0 0.0 2.6 0.0 1.6 1.7 0.9 1.2 1.7 0.7 0.4 1.7 0.2 0.4 1.7 0.2 79 0.4 0.9 0.4 1.2 0.8 1.5 1.6 0.3 5.0 DECEMBER JANUARY FEBRUARY MARCH APRIL MAY DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI AGHE 77 0.0 0.0 NC 0.0 0.2 0.0 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC" 0.0 0.0 NC 0.0 0.4 0.0 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.1 0.0 0.0 0.0 NC Appendix 8 (cx^ tmued) DECEMBER JANUARY FEBRUARY MARCH APRIL MAY DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI ANNUAL FORBS (ccntinued) COPA 77 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 1.7 0.0 0.0 8.7 0.0 0.0 10.5 0.0 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.2 0.0 0.0 0.4 0.0 0.0 0.0 NC ERCI 77 0.0 0.0 NC 0.0 0.1 0.0 78 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.1 0.0 0.4 0.1 4.0 0.0 0.2 0.0 79 0.0 0.1 0.0 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC GABO 77 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC LEDO 77 0.0 0.0 NC 0.4 0.1 4.0 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.4 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.4 0.0 NC 0.0 0.0 NC 0.8 T NC MITR 77 0.0 0.0 NC 0.0 0.4 0.0 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.5 0.0 0.4 0.6 0.7 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.5 0.0 0.8 0.5 1.6 MYJVH 77 0.0 0.0 NC 0.4 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.8 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC PLPA 77 0.0 0.6 0.0 0.0 0.2 0.0 78 0.0 1.0 0.0 0.0 0.6 0.0 0.0 0.6 0.0 0.0 T NC 0.0 0.2 0.0 0.0 0.6 0.0 79 0.0 1.0 0.0 0.0 1.0 0.0 0.0 0.2 0.0 0.0 0.0 NC 0.0 0.9 0.0 PCCO 77 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.5 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.5 0.0 0.0 0.5 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC Appendix 8 (cxritinued) DECEMBER JANUARY FEBRUARY MARCH APRIL MAY DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI ANNUAL FORBS (cxx±inued) PCMI 77 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 • 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.0 NC SIAL 77 0.0 0.0 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.8 0.2 4.0 0.0 0.0 NC TAOF 77 0.0 0.0 NC 0.0 T NC 78 0.0 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.2 0.0 79 0.0 0.1 0.0 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.4 0.0 TRDU 77 0.0 0.0 NC 0.0 0.1 0.0 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.1 0.0 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.1 0.0 TOTL 77 0.0 0.6 0.0 0.8 1.1 0.7 78 0.0 1.7 0.0 0.0 0.6 0.0 0.0 0.6 0.0 0.0 1.9 0.0 0.4 9.9 0.0 1.6 12.2 0.1 79 0.0 1.7 0.0 0.0 1.7 0.0 0.4 0.5 0.8 0.8 1.2 0.7 1.6 1.9 0.8 JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI PERENNIAL FORBS AND BRYOPHYTES ACMI 77 0.8 1.0 0.8 0.8 0.6 1.3 0.0 0.3 0.0 0.0 0.3 0.0 3.2 0.3 10.7 4.0 0.3 13.3 78 0.4 1.3 0.3 1.2 1.2 1.0 0.8 1.1 0.7 1.2 1.1 1.1 1.2 1.1 1.1 1.6 1.1 1.5 79 2.0 1.5 1.3 0.4 0.7 0.6 0.0 0.2 0.0 Appendix 8 (continued) JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI PERENNIAL FORBS AND BRYOPHYTES (OTrtinued) ANDI 77 0.0 0.7 0.0 0.0 0.2 0.0 0.0 0.2 0.0 78 0.4 0.7 0.6 1.2 0.3 4.0 0.4. 0.4 1.0 79 0.8 0.4 2.0 2.0 0.4 5.0 1.2 0.4 3.0 ANPA 77 0.0 0.3 0.0 0.0 0.3 0.0 0.0 0.0 NC 78 0.0 0.3 0.0 0.0 0.2 0.0 0.0 0.4 0.0 79 0.0 0.2 0.0 0.0 0.2 0.0 0.0 0.1 0.0 ARBD 77 0.8 0.1 8.0 0.4 0.1 4.0 0.0 0.3 0.0 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.0 NC ARSO 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 1.6 0.2 8.0 0.4 0.1 4.0 0.0 0.0 NC 79 1.6 0.0 NC 0.0 0.0 NC 0.0 0.0 NC ASMI 77 0.0 T NC 0.4 0.0 NC 0.0 0.0 NC 78 2.8 0.2 14.0 2.4 0.1 24.0 0.0 0.0 NC 79 1.2 0.0 NC 0.0 0.0 NC 0.0 0.0 NC ASPU 77 0.4 0.1 4.0 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.4 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC BASA 77 19.2 3.9 4.9 2.4 2.3 1.0 0.4 3.1 0.1 78 16.0 7.0 2.3 21.6 6.4 3.4 4.0 3.4 1.2 79 21.2 5.8 3.7 9.6 2.8 3.4 5.6 1.3 4.3 CAMA 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.2 0.0 0.4 0.0 0.0 0.0 0.4 0.0 0.3 0.4 0.0 0.4 0.0 0.0 0.0 0.0 0.0 0.4 0.0 0.4 0.0 0.0 0.0 0.0 3.1 0.0 3.4 0.0 0.0 0.0 0.0 0.0 0.0 NC 0.0 0.0 NC NC NC NC NC NC NC 0.0 0.0 NC NC 0.0 0.2 0.0 0.4 0.4 0.0 0.0 0.4 0.0 0.3 0.4 0.0 0.0 0.0 0.0 0.0 1.2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 3.1 0.0 3.4 0.0 0.0 0.0 0.0 0.0 0.0 NC 0.0 0.0 NC NC NC NC NC NC NC 0.0 0.0 NC NC 0.0 0.2 1.6 0.4 1.6 0.0 0.0 0.4 0.0 0.3 1.6 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 3.1 0.0 3.4 0.0 0.0 0.0 0.0 0.0 4.0 NC 0.0 0.0 NC NC NC NC NC NC NC 0.0 0.0 NC NC Appendix 8 (contiiiped) JUNE JULY AUGUST SEPTEMBER CCTCBER NOVEMBER DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI PERF2WIAL FORBS AND BRYDPHYTES (cxaitinued) CATH 77 4.0 0.2 20.0 3.6 0.0 NC 0.4 0.0 NC 78 0.4 0.4 1.0 1.2 0.2 6.0 0.8 0.1 8.0 79 0.0 0.5 0.0 0.8 0.0. NC 0.0 0.0 NC CEDI 77 0.4 0.1 4.0 1.6 0.1 16.0 0.0 0.0 NC 78 4.4 T NC 1.6 0.3 5.3 0.0 0.1 0.0 79 0.8 0.1 8.0 1.6 0.1 16.0 1.2 0.1 12.0 CHDO 77 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC COUM 77 0.0 T NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.1 0.0 0.0 0.2 0.0 0.0 0.1 0.0 79 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.0 NC CRAT 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.4 0.0 0.0 0.1 0.0 0.0 0.1 0.0 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC DEBI 77 0.4 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC DOCU 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.4 0.0 NC 0.0 0.0 NC 0.4 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC ERGO 77 0.0 0.2 0.0 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.2 0.0 0.4 0.0 NC 0.0 0.1 0.0 79 0.4 0.2 2.0 0.0 0.0 NC 0.4 0.0 NC 3.2 0.0 NC 0.0 0.1 0.0 1.6 0.0 NC 0.8 0.1 8.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.1 0.0 0.0 0.0 NC 0.8 0.1 8.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 NC NC 0.0 0.0 NC 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.1 0.0 NC NC NC NC 0.4 0.0 NC 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.1 0.0 3.2 0.0 NC 0.0 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.0 0.0 0.4 0.0 NC NC 0.0 0.0 NC 0.0 0.1 0.0 NC 0.0 0.0 0.0 NC 0.0 0.0 NC NC NC 0.0 0.0 NC 0.0 0.1 0.0 Appeaxlix 8 (ccotiiiued) JONE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI PERENNIAL FORBS AND BRYDPHYTES (txr±inued) ERFI 77 0.8 0.1 8.0 0.8 0.0 NC 0.4 0.0 NC 78 0.0 0.1 0.0 0.8 0.2 4.0 1.6 0.0 NC 79 0.8 0.0 NC 0.4 0.1 4.0 1.6 0.1 16.0 ERPU 77 0.0 0.1 0.0 0.0 0.0 NC 0.4 0.1 4.0 78 0.0 0.1 0.0 1.2 0.0 NC 0.4 T NC 79 0.0 0.0 NC 0.4 0.0 NC 0.4 0.0 NC FRPU 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 1.2 0.0 NC 0.0 0.0 NC 79 0.8 0.0 NC 0.0 0.0 NC 0.0 0.0 NC GAAR 77 1.6 0.2 8.0 2.4 0.0 NC 1.6 0.1 16.0 78 0.0 0.4 0.0 6.8 0.2 34.0 0.4 0.1 4.0 79 2.0 0.3 6.7 3.2 0.1 32.0 1.6 0.0 NC GETR 77 0.0 0.0 NC 0.0 0.1 0.0 0.4 0.1 4.0 78 0.0 0.1 0.0 1.2 0.1 12.0 2.4 0.2 12.0 79 1.2 0.1 12.0 0.0 0.1 0.0 1.2 0.1 12.0 HECY 77 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.0 NC 78 0.0 T NC 0.4 0.1 4.0 0.0 0.0 NC 79 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.0 NC LERE 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC LIPA 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 3.6 0.0 NC 0.0 0.1 0.0 0.0 T NC 0.0 0.0 NC 0.0 0.0 NC 1.6 0.1 16.0 2.4 0.1 24.0 1.2 0.1 12.0 0.8 0.2 4.0 0.0 0.0 NC 0.4 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.4 0.0 NC 0.0 0.1 0.0 0.0 T NC 0.0 0.0 NC 0.0 0.0 NC 1.6 0.1 16.0 0.0 0.1 0.0 2.0 0.1 20.0 2.4 0.2 12.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.4 0.0 NC 0.0 0.1 0.0 0.0 T NC 0.0 0.0 NC 0.0 0.0 NC 0.4 0.1 4.0 0.0 0.1 0.0 2.0 0.1 20.0 1.2 0.2 6.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC Appendix 8 (continued) JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI PERENNIAL FORBS AND BRYOPHYTES (ccntdnued) LIRU 77 2.0 0.1 20.0 2.8 0.1 28.0 1.6 0.0 NC 78 0.4 0.1 4.0 1.6 0.1 16.0 0.0 0.1 0.0 79 0.4 0.2 2.0 1.6 0.1 16.0 0.8 T NC LOMA 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 T NC 0.0 0.0 NC 79 0.0 T NC 0.0 0.0 NC 0.0 0.0 NC LOTR 77 0.0 0.0 NC 0.4 0.0 NC 0.0 T NC 78 0.0 0.1 0.0 0.0 T NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC LUSE 77 2.8 0.4 7.0 2.0 0.1 20.0 2.8 0.1 28.0 78 10.0 1.4 7.1 3.2 0.8 4.0 1.2 0.3 4.0 79 5.2 0.2 26.0 8.4 0.0 NC 3.6 0.0 NC MESA 77 > 0.0 * NC 0.0 * NC 0.0 * NC 78 0.0 * NC 0.0 * NC 0.0 * NC 79 0.0 * NC 0.0 * NC 0.0 * NC OPFR 77 0.0 0.0 NC 0.0 T NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.1 0.0 0.0 0.2 0.0 79 0.0 0.1 0.0 0.0 0.2 0.0 0.0 0.1 0.0 PHHA 77 0.0 0.1 0.0 0.0 0.0 NC 0.8 0.0 NC 78 0.0 0.2 0.0 0.4 0.1 4.0 0.8 0.1 8.0 79 0.8 0.1 8.0 0.4 0.1 4.0 0.4 0.0 NC PHLO 77 0.4 0.6 0.7 0.0 0.1 0.0 0.4 0.7 0.6 78 1.6 0.7 2.3 2.0 0.4 5.0 0.8 0.3' 2.7 79 0.8 0.6 1.1 0.4 0.3 1.3 0.8 0.3 2.7 5.6 0.0 NC 0.8 0.1 8.0 0.0 0.0 NC 0.0 0.0 NC 0.0 T NC 0.0 0.0 NC 0.8 0.1 8.0 0.4 0.3 1.3 0.0 * NC 0.0 * NC 0.0 0.0 NC 0.0 0.2 0.0 0.0 0.0 NC 2.0 0.1 20.0 0.8 0.7 1.1 1.2 0.3 4.0 2.8 0.0 NC 0.8 0.1 8.0 0.0 0.0 NC 0.0 0.0 NC 0.0 T NC 0.0 0.0 NC 0.0 0.1 0.0 0.0 0.3 0.0 0.0 0.0 * * NC NC 0.0 0.0 NC 0.0 0.2 0.0 0.4 0.0 NC 1.2 0.1 12.0 0.8 0.7 1.1 0.0 0.3 0.0 0.0 0.0 NC 0.8 0.1 8.0 0.0 0.0 NC 0.0 0.0 NC 0.4 T NC 0.0 0.0 NC 0.0 0.1 0.0 0.0 0.3 0.0 0.0 0.0 NC NC 0.0 0.0 NC 0.0 0.2 0.0 0.0 0.0 NC 0.0 0.1 0.0 0.0 0.7 0.0 1.2 0.3 4.0 Appendix 8 (continued) JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI PERENNIAL FORBS AND BRYOPHYTES (continued) RAGL 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC SAIN 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.8 0.1 8.0 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC SEWA 77 0.0 4.4 0.0 0.0 5.5 0.0 0.0 6.2 0.0 78 0.0 4.3 0.0 0.0 5.9 0.0 0.0 5.8 0.0 79 0.0 5.0 0.0 0.0 4.8 0.0 0.0 8.4 0.0 SUSD 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.1 0.0 0.4 T NC 0.4 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC SMRA 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC ZIVE 77 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.0 NC 78 0.0 T NC 0.0 T NC 0.0 0.0 NC 79 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.0 NC OTHR 77 6.8 0.0 NC 7.2 0.0 NC 4.8 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC MOSS 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.3 0.0 0.0 0.2 0.0 0.4 0.7 0.6 79 0.0 1.5 0.0 0.0 1.2 0.0 0.0 1.4 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 6.2 0.0 0.0 5.8 0.0 0.0 0.0 NC 0.0 0.0 NC 0.4 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.7 0.0 0.0 0.0 NC 1.6 0.0 NC 0.4 0.0 NC 0.0 0.0 NC 0.0 ' 6.2 0.0 0.4 5.8 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.6 0.0 0.4 0.7 NC NC 0.4 0.0 NC 0.0 0.0 NC NC NC 0.0 0.0 NC 0.0 0.0 NC NC 0.6 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.7 NC NC NC NC 2.4 6.2 0.4 0.0 5.8 0.0 NC NC NC NC 0.0 0.0 NC 0.0 0.0 NC NC NC NC 0.0 Appendix 8 (coitinued) JUNE JULY AUGUST SEPTEMBER COCBER NOVEMBER DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI PERENNIAL FORBS AND BRYOPHYTES (<xntinued) TOTL 77 78 79 40.4 13.2 42.0 19.0 40.0 17.2 3.1 2.2 2.4 24.8 9.6 50.4 17.3 29.6 11.2 2.6 2.9 2.6 14.0 14.8 18.8 11.2 13.6 12.5 1.3 1.1 1.5 16.0 14.4 11.2 13.6 1.4 1.1 15.2 8.0 11.2 13.6 1.4 0.6 14.0 8.8 11.2 13.6 1.3 0.7 DECEMBER JANUARY FEBRUARY MARCH APRIL MAY DIET SITE SI DIET SITE SI DIET SITE SI • DIET SITE SI DIET SITE SI DIET SITE SI ACMI 77 78 79 0.0 0.0 0.3 1.1 0.0 0.0 0.4 0.0 0.3 1.1 1.3 0.0 0.0 0.8 0.3 1.1 0.0 0.7 1.2 1.2 0.3 0.3 4.0 4.0 0.8 0.0 1.2 1.2 0.7 0.0 2.0 0.8 0.8 3.0 1.2 2.0 0.7 0.7 0.4 ANDI 77 78 79 0.0 0.8 0.2 0.4 0.0 2.0 0.0 0.4 0.2 0.4 0.0 1.0 0.0 0.4 0.2 0.4 0.0 1.0 0.0 0.0 0.3 1.0 0.0 0.0 0.4 0.0 0.6 1.0 0.7 0.0 0.0 0.4 0.0 0.7 0.6 1.1 0.0 0.7 0.0 ANPA 77 78 79 0.4 0.0 0.0 0.4 NC 0.0 0.0 0.4 0.0 0.4 NC 1.0 0.4 0.4 0.0 0.4 NC 1.0 0.4 0.0 0.1 0.1 4.0 0.0 0.0 0.0 0.1 0.3 0.0 0.0 0.0 0.4 0.0 0.6 0.3 0.4 0.0 1.3 0.0 ARHO 77 78 79 0.4 0.4 0.3 0.0 1.3 NC 0.0 0.0 0.3 0.0 0.0 NC 0.8 0.0 0.3 0.0 2.7 NC 0.4 0.4 0.1 0.0 4.0 NC 0.0 0.8 0.2 0.0 0.0 NC 1.6 0.0 0.0 0.4 0.0 0.1 4.0 NC 0.0 ARSO 77 78 79 0.0 0.0 0.0 0.0 NC NC 0.0 0.0 0.0 0.0 NC NC 0.0 . 0.0 0.0 0.0 NC NC 0.0 0.4 0.0 0.0 NC NC 0.0 0.0 T 0.2 NC 0.0 0.0 0.4 0.8 0.1 0.3 0.2 0.0 1.3 4.0 ASMI 77 78 79 0.4 0.0 0.0 0.0 NC NC 0.0 0.0 0.0 0.0 NC NC 0.0 0.0 0.0 0.0 NC NC 0.0 0.0 0.0 0.0 NC NC 0.0 1.2 0.1 T 0.0 NC 0.0 0.0 0.8 0.2 0.2 .0.3 0.0 0.0 2.7 Appendix 8 (continued) DECEMBER JANUARY FEBRUARY MARCH APRIL MAY DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI PERENNIAL FORBS AND BRYCEHYTES (ccntirued) ASPU 77 78 79 BASA 77 78 79 CAMA 77 78 79 CATH 77 78 79 CEDI 77 78 79 CHDO 77 78 79 COUM 77 78 79 CRAT 77 78 79 0.0 0.0 0.0 0.0 2.0 3.1 4.8 3.4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.8 0.0 0.0 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.0 0.4 0.0 0.1 NC NC 0.6 1.4 NC NC NC 0.0 NC 0.0 NC NC NC 0.0 NC 0.0 0.0 0.0 0.0 0.0 NC NC 0.0 0.0 NC 0.0 0.0 NC 0.0 1.0 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 3.1 0.0 0.0 3.1 0.0 0.0 0.9 0.0 11.2 1.5 7.5 0.8 3.4 0.2 1.2 3.4 0.4 2.0 T NC 2.4 1.5 1.6 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.3 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.3 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 T NC 0.4 0.2 2.0 0.0 0.1 0.0 0.0 0.1 NC 1.2 0.0 NC 0.8 0.3 2.7 0.0 0.0 NC 0.8 0.0 NC 0.8 0.5 1.6 0.0 0.1 0.0 0.4 0.1 4.0 1.6 0.1 16.0 0.8 0.4 2.0 0.8 0.4 2.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.2 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 T NC 0.0 0.1 0.0 0.0 0.1 0.0 0.0 0.0 NC 0.0 T NC 0.0 0.0 0.0 T 0.8 0.0 8.0 5.4 13.2 5.7 8.8 5.6 1.2 0.2 0.8 0.0 0.8 0.3 NC NC NC 1.5 2.3 1.6 0.0 0.1 0.0 0.0 0.2 0.0 0.0 0.0 NC 0.0 0.2 0.0 0.4 0.5 0.8 0.4 0.4 1.0 6.0 NC 2.7 0.0 0.0 NC 0.0 0.1 0.0 0.0 0.0 NC 0.0 T NC 0.4 T NC 0.0 0.1 0.0 0.4 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.1 0.0 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.5 0.0 0.0 0.4 0.0 0.0 0.3 0.0 0.0 0.2 0.0 Appendix 8 (continued) DECEMBER JANUARY FEBRUARY MARCH APRIL MAY DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI PERENNIAL FORBS AND BRYDPHYTES (ccntinued) DEBI 77 78 79 DOCU 77 78 79 ERGO 77 78 79 ERFI 77 78 79 ERPU 77 78 79 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.1 0.0 0.0 0.0 0.0 0.0 0.1 0.4 T NC NC NC NC NC 4.0 NC NC 0.0 NC 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 NC NC NC NC 0.0 0.0 NC 0.0 0.1 0.0 NC NC 0.0 0.1 0.0 0.0 T NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.1 0.0 0.4 0.0 NC 0.0 0.0 NC 0.0 0.1 0.0 0.0 T NC 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 T NC 0.4 0.0 NC 0.0 0.1 0.0 0.0 0.3 0.0 0.4 0.2 2.0 0.0 1.0 0.0 0.4 1.1 0.4 0.0 T NC 0.0 0.3 0.0 0.0 0.3 0.0 0.0 0.3 0.0 0.0 0.4 0.0 0.4 0.2 2.0 0.0 0.0 0.4 T 0.3 T 0.0 0.1 0.0 0.5 0.0 0.3 0.4 T 0.0 0.1 0.4 0.0 NC 0.0 NC 0.0 0.0 NC 0.0 0.6 0.0 0.0 0.4 0.0 0.0 0.0 0.0 0.4 0.0 NC 0.4 0.2 2.0 1.2 0.4 3.0 NC 0.0 NC FRPU 77 78 79 GAAR 77 78 79 GETR 77 78 79 0.0 0.0 0.4 0.0 0.0 0.1 0.4 0.1 0.0 0.1 0.0 0.2 NC NC 0.0 4.0 0.0 0.0 0.0 0.0 0.0 0.0 NC NC 0.4 0.1 4.0 0.0 0.1 0.0 1.6 0.1 16.0 0.8 0.2 4.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.1 0.0 0.0 0.1 0.0 0.0 0.1 0.0 0.4 0.2 2.0 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.1 0.0 0.4 0.0 NC 1.2 0.0 NC 0.0 T NC 0.4 0.1 4.0 0.0 0.0 NC 0.0 0.1 0.0 1.2 T NC 2.4 T NC 0.0 T 0.4 T 0.4 0.0 0.0 0.8 0.0 0.2 0.0 0.6 0.0 0.1 0.4 0.1 0.0 0.2 NC NC NC 0.0 0.0 0.0 0.0 4.0 0.0 <7 Appendix 8 (cmtinusd) DECEMBER JANUARY FEBRUARY MARCH APRIL MAY DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI PERENNIAL FORBS AND BRYOPHYTES (cmtinued) HECY 77 78 79 LERE 77 78 79 LIRA 77 78 79 LIRU 77 78 79 LOMA 77 78 79 LOTR 77 78 79 LUSE 77 78 79 0.4 0.0 0.0 0.0 0.0 0.0 2.4 0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.0 0.0 T 0.0 0.1 0.3 NC NC NC NC NC NC NC 0.0 NC NC NC NC 0.0 1.3 0.0 0.0 0.0 0.0 NC NC 0.0 0.0 NC 0.0 0.1 0.0 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.3 0.0 0.0 0.0 NC 0.0 0.0 NC 0.8 0.6 1.3 0.8 0.0 0.0 1.2 0.0 NC 0.0 0.0 NC 0.4 0.0 0.1 0.0 0.0 0.1 0.0 0.8 0.0 NC 0.4 0.0 T 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 1.4 0.0 0.0 NC 0.0 0.0 NC 0.0 0.2 0.0 1.6 1.0 MESA 77 10.4 * NC 78 0.0 * NC 5.6 * NC 10.0 * NC 79 0.0 * NC 0.0 * NC 1.2 0.1 12.0 0.0 0.1 0.0 0.0 0.1 0.0 0.0 0.0 NC 0.8 0.2 4.0 0.0 0.1 0.0 0.0 0.2 0.0 0.0 0.0 NC 0.0 0.0 NC .0.0 0.0 NC 0.0 1.0 0.0 0.0 2.2 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 T NC 0.0 0.6 0.0 NC NC 0.0 1.6 0.0 T NC 0.0 T NC 0.0 0.0 NC 2.4 0.3 8.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.4 0.3 1.3 1.6 0.1 16.0 0.0 0.1 0.0 0.4 0.0 NC 0.0 0.5 0.0 0.0 0.3 0.0 0.0 0.3 0.0 0.0 0.0 NC 0.8 0.2 4.0 0.0 0.0 0.0 0.7 0.0 0.0 2.8 1.2 2.0 0.0 * NC 0.0 * NC 0.0 * NC 0.0 * NC 3.2 8.4 4.8 0.0 0.0 0.0 T 0.0 0.0 0.0 0.1 0.0 0.3 0.0 0.5 1.1 1.0 0.6 * * * NC 0.0 NC NC NC NC 0.0 0.0 0.0 0.4 0.1 4.0 0.8 T NC 0.0 0.1 0.0 2.9 8.4 8.0 NC NC NC Appendix 8 (continued) DECEMBER JANUARY FEBRUARY MARCH APRIL MAY DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI PERENNIAL FORBS AND BRYQPHYTES (ccntinued) OPFR 77 78 79 PHHA 77 78 79 0.0 0.0 0.0 0.2 1.6 0.0 0.8 0.1 NC 0.0 NC 8.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.2 0.0 0.0 0.2 0.0 0.4 0.0 NC 0.4 0.0 NC 0.0 0.1 0.0 0.4 0.1 4.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.4 0.0 NC 0.0 0.1 0.0 0.4 T NC 0.0 0.2 0.0 0.4 0.1 4.0 0.0 0.1 0.0 0.0 0.0 NC 0.0 0.1 0.0 0.4 0.1 4.0 0.4 0.1 4.0 0.8 0.1 8.0 PHLO 77 78 79 0.4 0.7 1.2 0.3 0.6 4.0 0.4 0.7 0.6 1.2 0.3 4.0 0.8 0.7 1.1 0.8 0.3 2.7 0.4 0.2 2.0 0.8 0.2 4.0 0.4 0.5 0.8 0.0 0.3 0.0 2.0 1.5 1.3 1.2 1.2 1.0 1.2 0.8 1.5 RAGL 77 78 79 0.0 0.0 0.0 0.0 NC NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.4 0.8 0.4 0.4 1.2 0.3 0.8 2.1 0.4 0.0 1.9 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC SAIN 77 78 79 0.4 0.0 0.0 0.0 NC NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.4 0.0 0.0 1.2 0.0 0.0 1.4 0.0 0.0 0.0 NC 0.0 1.1 0.0 0.0 0.5 0.0 SEWA 77 78 79 SINO 77 78 79 SMRA 77 78 79 0.0 6.2 0.4 5.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 NC NC NC NC 0.0 6.2 0.0 0.0 5.8 0.0 0.0 6.2 0.0 0.0 5.8 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.8 6.1 0.1 0.0 6.0 0.0 0.0 0.0 NC 0.0 0.0 NC 0.4 0.0 NC 0.0 0.0 NC 0.0 4.3 0.0 0.4 4.1 0.1 0.0 0.0 NC 1.6 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 5.1 0.0 3.8 0.0 3.3 0.0 0.0 0.0 0.4 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.8 0.0 NC Appendix 8 (continued) DECEMBER JANUARY FEBRUARY MARCH APRIL MAY DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI PERENNIAL FORBS AND BRYOPHYTES (continued) ZIVE 77 0.0 0.0 NC 0.0 0.4 0.0 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.2 0.0 0.0 0.1 0.0 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.1 0.0 0.4 0.4 1.0 0.4 0.4 1.0 OTHR 77 0.0 0.0 NC 11.6 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC MOSS 77 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.7 0.0 0.0 0.0 NC 0.0 0.0 NC 0.0 1.7 0.0 0.0 2.1 0.0 0.8 0.5 1.6 79 0.0 0.7 0.0 0.0 0.7 0.0 0.0 2.2 0.0 0.0 2.1 0.0 0.0 1.0 0.0 TOTL 77 20.0 11.2 1.8 35.6 20.5 1.7 78 10.0 13.6 0.7 11.2 11.2 1.0 14.8 11.2 1.3 6.0 12.6 0.5 18.8 23.4 0.8 30.8 20.5 1.5 79 4.0 13.6 0.3 6.0 13.6 0.4 10.4 12.9 0.8 16.4 20.5 0.8 25.6 20.1 1.3 JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI TREES AND SHRUBS ACGL 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 -0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.4 0.0 NC 1.6 0.0 NC 0.4 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 •NC 0.0 0.0 NC 0.4 0.0 NC AMAL 77 4.0 0.0 NC 2.0 0.0 NC 1.2 0.0 NC 0.4 0.0 NC 3.6 0.0 NC 1.2 0.0 NC 78 2.0 0.0 NC 1.6 0.0 NC 1.6 0.0 NC 0.4 0.0 NC 1.6 0.0 NC 1.2 0.0 NC 79 0.4 0.0 NC 0.4 0.0 NC 0.8 0.0 NC Appendix 8 (cxxitiiiued) JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI TREES AND SHRUBS (cxx±inued) ARFR 77 0.4 0.2 2.0 0.0 0.0 NC 0.0 T NC 78 0.4 0.1 4.0 0.4 0.1 4.0 0.4 0.1 4.0 79 0.0 T NC 0.0 6.0 NC 0.4 0.0 NC ARTR 77 0.8 8.8 0.1 0.0 11.3 0.0 0.0 10.7 0.0 78 0.0 8.4 0.0 0.4 10.8 0.0 0-.0 12.1 0.0 79 0.0 12.8 0.0 0.0 12.7 0.0 1.2 13.5 0.1 BEfiQ 77 0.4 0.0 NC 0.4 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.4 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC CHNA 77 0.0 0.7 0.0 0.0 0.5 0.0 0.4 0.8 0.5 78 0.0 0.7 0.0 0.4 0.7 0.6 2.4 0.9 2.7 79 0.0 1.0 0.0 0.0 0.6 0.0 0.4 1.0 0.4 ERHE 77 2.0 1.2 1.7 0.8 1.1 0.7 0.4 1.3 0.3 78 1.2 0.8 1.5 0.4 0.9 0.4 1.2 0.9 1.3 79 2.4 0.4 6.0 2.4 0.5 4.8 1.2 0.1 12.0 ERNI 77 0.8 1.6 0.5 1.2 2.6 0.5 0.0 2.6 0.0 78 0.0 0.9 0.0 0.0 1.0 0.0 0.4 1.4 0.3 79 0.4 0.6 0.7 2.0 0.6 3.3 1.6 0.7 2.3 PEER 77 0.0 0.0 NC 1.2 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC PHLE 77 0.4 0.0 NC 1.2 0.0 NC 0.0 0.0 NC 78 1.6 0.0 NC 0.4 0.0 NC 0.4 0.0 NC 79 0.8 0.0 NC 0.8 0.0 NC 0.4 0.0 NC 1.6 0.8 T 0.1 0.0 10.7 2.4 12.1 0.0 0.0 0.4 1.6 2.4 2.8 1.2 0.8 0.0 0.0 0.0 0.0 0.0 0.0 0.8 0.9 1.3 0.9 2.6 1.4 0.0 0.0 0.0 0.0 NC 8.0 0.0 0.2 NC NC 0.5 1.8 1.8 3.1 0.5 0.6 NC NC NC NC 0.0 0.4 T 0.1 0.0 10.7 0.0 12.1 0.0 0.0 0.8 1.2 2.8 2.8 3.2 0.0 0.0 0.0 1.2 0.0 0.0 0.0 0.8 0.9 1.3 0.9 2.6 1.4 0.0 0.0 0.0 0.0 NC 4.0 0.0 0.0 NC NC 1.0 1.3 2.2 3.1 1.2 0.0 NC NC NC NC 0.4 T 0.8 0.1 1.2 10.7 0.8 12.1 0.0 0.0 0.0 0.0 0.4 0.8 1.2 0.9 7.6 1.3 3.2 0.9 4.8 2.6 0.4 1.4 0.0 0.0 0.0 0.0 0.8 0.0 1.2 0.0 NC 8.0 0.1 0.1 NC NC 0.5 1.3 5.8 3.6 1.8 0.3 NC NC NC NC Appendix 8 (continued) JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI TREES AND SHRUBS (continued) PIPO 77 1.2 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.4 0.0 NC 1.6 0.0 NC 3.2 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.8 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC PRVI 77 0.8 0.0 NC 1.6 0.0 NC 0.8 0.0 NC 0.4 0.0 NC 1.2 0.0 NC 1.6 0.0 NC 78 0.8 0.0 NC 0.4 0.0 NC 0.0 0.0 NC 0.8 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC .0.0 0.0 NC 0.4 0.0 NC PSME 77 0.0 0.0 NC 0.0 0.0 NC 1.6 0.0 NC 0.0 0.0 NC 2.0 0.0 NC 1.2 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.4 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC RHGL 77 0.8 0.0 NC 0.0 0.0 NC 0.4 T NC 0.8 T NC 0.8 T NC 1.2 T NC 78 0.0 0.0 NC 0.4 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC RICE 77 0.0 0.0 NC 0.8 0.0 NC 0.4 0.0 NC 0.0 0.0 NC 1.6 0.0 NC 0.4 0.0 NC 78 0.4 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.4 0.0 NC RCNU 77 0.4 0.0 NC 0.4 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.4 0.0 NC 0.0 0.0 NC 78 0.8 0.0 NC 0.4 0.0 NC 0.8 0.0 NC 0.8 0.0 NC 0.4 0.0 NC 0.4 0.0 NC 79 0.0 0.0 NC 0.4 0.0 NC 0.0 0.0 NC SACE 77 0.4 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC SYAL 77 0.0 0.4 0.0 0.0 0.4 0.0 0.0 0.5 0.0 0.4 0.5 0.8 0.0 0.5 0.0 0.0 0.5 0.0 78 2.0 0.2 10.0 0.4 0.3 1.3 1.2 0.5 2.4 0.0 0.5 0.0 0.0 0.5 0.0 0.0 0.5 0.0 79 0.0 0.5 0.0 0.0 0.3 0.0 0.8 0.4 2.0 Appendix 8 ((Continued) JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI TREES AND SHRUBS (cxxitinued) OTHR 77 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC TOTL 77 12.8 12.9 1.0 10.8 15.9 0.7 7.2 16.0 0.5 8.0 16.0 0.5 19.2 16.0 1.2 24.0 16.0 1.5 78 9.6 11.1 0.9 5.6 13.8 0.4 10.8 15.9 0.7 10.8 15.9 0.7 6.4 15.9 0.4 10.4 15.9 0.7 79 4.0 15.0 0.3 6.0 14.7 0.4 8.0 15.7 0.5 DECEMBER JANUARY FEBRUARY MARCH APRIL MAY DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI ACGL 77 0.0 0.0 NC 0.4 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.4 0.0 NC 0.4 0.0 NC 0.4 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC AMAL 77 1.6 0.0 NC 3.2 0.0 NC 78 3.2 0.0 NC 0.8 0.0 NC 3.6 0.0 NC 6.0 0.0 NC 4.8 0.0 NC 2.0 0.0 NC 79 4.4 0.0 NC 3.6 0.0 NC 10.4 0.0 NC 5.2 0.0 NC 3.6 0.0 NC ARFR 77 0.4 T NC 0.0 0.4 0.0 78 0.4 0.1 4.0 0.0 T NC 0.8 T NC 0.4 0.1 4.0 0.0 T NC 0.4 0.0 NC 79 0.4 0.1 4.0 0.0 0.1 0.0 0.4 T NC 0.0 0.2 0.0 0.0 0.1 0.0 ARTR 77 2.8 10.7 0.3 1.2 10.1 0.1 78 1.6 12.1 0.1 0.8 10.7 0.1 1.6 10.7 0.2 4.4 15.0 0.3 1.6 10.1 0.2 0.4 9.2 0.0 79 2.4 12.1 0.2 2.4 12.1 0.2 1.6 14.1 0.1 0.4 11.8 0.0 0.0 9.9 0.0 BEAQ 77 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 3.6 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC . 0.4 0.0 NC 0.0 0.0 NC 0.0 0.0 NC Appendix 8 (a^tjUTued) DECEMBER JANUARY FEBRUARY MARCH APRIL MAY DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI TREES AND SHRUBS (cmtunued) CHNA 77 0.0 0.8 0.0 0.0 0.4 0.0 78 2.0 0.9 2.2 0.0 0.8 0.0 2.0 0.8 2.5 0.0 1.0 0.0 0.0 0.7 0.0 0.0 0.7 0.0 79 2.4 0.9 2.7 0.4 1.9 0.4 1.2 0.6 2.0 0.4 0.6 0.7 0.0 0.7 0.0 ERHE 77 7.2 1.3 5.5 3.6 2.0 1.8 78 3.2 0.9 3.6 6.0 1.3 4.6 8.0 1.3 6.2 5.2 1.3 4.0 1.6 1.1 1.5 2.0 1.0 2.0 79 5.2 0.9 5.8 8.8 0.9 9.8 3.6 0.7 5.1 3.2 0.8 4.0 1.6 0.4 4.0 ERNI 77 6.8 2.6 2.6 3.6 2.2 1.6 78 0.8 1.4 0.6 3.2 2.6 1.2 4.8 2.6 1.8 8.8 2.3 3.8 2.4 0.9 2.7 0.4 1.1 0.4 79 3.6 1.4 2.6 4.8 1.4 3.4 4.4 0.7 6.3 2.4 0.5 4.8 2.4 0.7 3.4 PEFR 77 0.0 0.0 NC 0.4 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC . 0.0 0.0 NC 0.0 0.0 NC PHLE 77 0.8 0.0 NC 0.4 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.4 0.0 NC 1.2 0.0 NC 1.6 0.0 NC 1.6 0.0 NC 79 0.0 0.0 NC 0.4 0.0 NC 1.2 0.0 NC 0.4 0.0 NC 0.4 0.0 NC PIPO 77 0.0 0.0 NC 1.2 0.0 NC 78 0.0 0.0 NC 1.2 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC . 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC PRVT 77 2.4 0.0 NC 2.4 0.0 NC 78 0.0 0.0 NC 1.6 0.0 NC 1.6 0.0 NC 2.0 0.0 NC 1.6 0.0 NC 0.8 0.0 NC 79 0.4 0.0 NC 0.0 0.0 NC 1.6 0.0 NC 0.4 0.0 NC 0.0 0.0 NC PSME 77 0.4 0.0 NC 0.0 0.0 NC 78 0.4 0.0 NC 1.2 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.8 0.0 NC 0.8 0.0 NC 79 0.4 0.0 NC 0.4 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.4 0.0 NC Appendix 8 (rantinued) DECEMBER JANUARY FEBRUARY MARCH APRIL MAY DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI DIET SITE SI TREES AND SHRUBS (continued) RHGL 77 0.4 T NC 0.8 0.0 NC 78 0.0 0.0 NC 0.0 T NC 0.4 T NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 - 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC RICE 77 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC RCNU 77 0.0 0.0 NC 0.8 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.8 0.0 NC 0.4 0.0 NC 1.2 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.4 0.0 NC 0.0 0.0 NC SAGE 77 0.0 0.0 NC 0.0 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC SYAL 77 0.4 0.5 0.0 0.8 0.5 1.6 78 0.4 0.5 0.0 0.0 0.5 0.0 0.0 0.5 0.0 0.0 0.8 0.0 0.4 0.5 0.8 0.8 0.3 2.7 79 0.0 0.5 0.0 0.0 0.5 0.0 0.0 0.6 0.0 0.8 0.3 2.7 0.0 0.4 0.0 OTHR 77 0.0 0.0 NC 0.8 0.0 NC 78 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 79 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC 0.0 0.0 NC TOTL 77 23.2 16.0 1.5 19.6 15.7 1.2 78 11.6 15.9 0.7 14.8 16.0 0.9 24.0 16.0 1.5 28.8 20.9 1.4 16.4 13.3 1.2 13.2 12.3 1.1 79 19.2 15.9 1.2 20.8 15.9 1.3 24.8 16.7 1.5 13.6 14.2 1.0 8.4 12.1 0.7 NC = Not calculated, T = Trace (less than 0.05% oocurrenoe). TOTL = TOTAL for plant species group, OTHR = OTHER plant species including unkncwns. * = Non-native plant species not established on the site but introduced as forage for bighorn in hay. MOSS = Cumulative total or a l l bryophytes sampled. PUBLICATIONS (continued): Wikeem,Br ian M.,and R.M.Strang- 1983. P r e s c r i b e d b u r n i n g on B.C. r a n g e l a n d s : t h e s t a t e o f t h e a r t . J . R a n g e Manage. 36 ( 1 ) : 3 - 8 . Wikeem,Brian M^,and M i c h a e l D. P i t t . 1979. I n t e r p r e t i n g d i e t p r e f e r e n c e o f C a l i f o r n i a b i g h o r n s h e e p on n a t i v e r a n g e l a n d i n s o u t h - c e n t r a 1 B r i t i s h C o l u m b i a . R a n g e l a n d s 1 ( 5 ) : 2 0 0 - 2 0 2 . P i t t , M.D., and B.M. Wikeem. 1978. D i e t p r e f e r e n c e o f C a l i f o r n i a b i g h o r n s h e e p on n a t i v e r