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Phytophagous insects on the ashnola bighorn sheep range Maynard, Richard John 1972

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PHYTOPHAGOUS INSECTS ON THE ASHNOLA BIGHORN SHEEP RANGE by RICHARD JOHN MAYNARD B.Sc. ( A g r i c ) , University of B r i t i s h Columbia, 1968 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n the Department of Plant Science We accept t h i s thesis as conforming to the required standard. THE UNIVERSITY OF BRITISH COLUMBIA September 1972 I n p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l l m e n t o f t h e r e q u i r e m e n t s f o r an advanced degree a t t h e U n i v e r s i t y o f B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s t u d y . I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y purposes may be g r a n t e d by t h e Head of my Department or by h i s r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . Department o f The U n i v e r s i t y o f B r i t i s h Columbia Vancouver 8, Canada Date O^tjrfe*- 3J /J?Z. i ABSTRACT There a re c o n f l i c t i n g s t a t e m e n t s i n t h e l i t e r a t u r e c o n c e r n i n g t h e e f f e c t s o f phytophagous i n s e c t s on r a n g e l a n d g r a s s y i e l d s . T h i s p r e l i m i n a r y s t u d y was i n t e n d e d t o ass e s t h e use o f range f o r a g e by i n s e c t s , e s p e c i a l l y g r a s s h o p p e r s . The s t u d y a r e a s were two s o u t h - f a c i n g s l o p e s a t about 5500 f e e t e l e v a t i o n i n the A s h n o l a R e s o u r c e s Management Are a i n South C e n t r a l B r i t i s h Columbia. A p l a n t community a n a l y s i s was made t o dete r m i n e w h i c h g r a s s e s and f o r b s were most numerous and which p r o v i d e d most ground-cover i n s e l e c t e d a r e a s . The commun-i t i e s under s t u d y were c h a r a c t e r i z e d by v a r i o u s c o m b i n a t i o n s o f f o u r prominent g r a s s s p e c i e s : Bluebunch Wheatgrass (Agropyron s p i c a t u m ) , J u n e g r a s s ( K o e l e r i a c r i s t a t a ) , K entucky B l u e g r a s s (Poa p r a t e n s i s ) , and Columbia N e e d l e g r a s s ( S t i p a c o l u m b i a n a ) . I n s e c t g r a z i n g damage t o g r a s s e s was e s t i m a t e d by random s a m p l i n g o f i n d i v i d u a l g r a s s b l a d e s . The " p r e f e r r e d " ( m o s t - u t i l i z e d ) s p e c i e s were K o e l e r i a c r i s t a t a , Poa p r a t e n s i s , Poa secunda, and S t i p a columbiana, i n t h a t o r d e r . Agropyron  s p i c a t u m was not v i s i b l y u t i l i z e d . G r a s s hopper numbers were e s t i m a t e d i n s e v e r a l ways; the most common s p e c i e s were Camnula p e l l u c i d a , C. x a n t h i p p u s , and M e l a n o p l u s s a n g u i n i p e s . G r a s s h o p p e r s were l e a s t numerous on the c l i m a x Agropyron s p i c a t u m community where o n l y 21% i i o f t h e t o t a l g r a s s was o f the f o u r p r e f e r r e d s p e c i e s , and where o n l y 32% o f t h e ground was c o v e r e d by v e g e t a t i o n . H i g h e s t numbers of g r a s s h o p p e r s were found on a " d i s c l i m a x " Poa community, where 90% o f the g r a s s was o f a p r e f e r r e d s p e c i e s , and where the ground was 62% c o v e r e d . E x p e r i m e n t s t o d e t e r m i n e t h e e f f e c t s o f g r a s s h o p p e r s on g r a s s y i e l d s used e x c l o s u r e cages p l a c e d on t h r e e d i f f e r e n t communities ( S t i p a - Agropyron, Poa - S t i p a , and Poa) i n 1969 and 1 9 7 0 . I n a l l a r e a s t h e mean g r a s s y i e l d s were h i g h e r i n s i d e t h e cages, but t h e d i f f e r e n c e s were n o t s t a t i s t i c a l l y s i g n i f i c a n t . T h i s r e s u l t i s s i m i l a r t o t h o s e o f o t h e r workers who have attempted t o demonstrate e f f e c t s o f g r a s s h o p p e r s on r a n g e l a n d g r a s s y i e l d s ; . w h i l e g r a s s h o p p e r s consume a f a i r l y l a r g e amount o f g r a s s , t h e y appear t o have l i t t l e e f f e c t on t h e t o t a l s t a n d i n g y i e l d o f g r a s s , as d e t e r m i n e d by an end-of-season c l i p o f v e g e t a t i o n . G r a s s h o p p e r s may be a t t r a c t e d t o m o i s t a r e a s , f o r example p l a n t communities dominated by s u c c u l e n t g r a s s e s , where t h e y c o n g r e g a t e on s p o t s which have been c l i p p e d , t r a m p l e d , g r a z e d by l i v e s t o c k , o r o t h e r w i s e d i s t u r b e d . I n the absence o f o v e r g r a z i n g by l i v e s t o c k , even h i g h numbers of g r a s s h o p p e r s p r o b a b l y can do l i t t l e permanent damage, s i n c e t h e i r g r a z i n g i s d i s t r i b u t e d over a l a r g e number o f h e a l t h y , i n t a c t p l a n t s . The mature g r a s s l a n d , dominated by Agropyron s p i c a t u m , seems t o be r e l a t i v e l y immune t o d r a m a t i c developments i n i n s e c t p o p u l a t i o n s . i i i TABLE OF CONTENTS PAGE ABSTRACT i TABLE OF CONTENTS i i i LIST OF TABLES v LIST OF FIGURES . . . v i ACKNOWLEDGMENTS v i i 1. INTRODUCTION 1 2 . DESCRIPTION OF STUDY AREA 4 3 . MATERIALS AND METHODS 6 3 . 1 Measurement of climatic and edaphic 6 variables 6 7 3 . 2 Sampling for grasshoppers 7 3 . 2 . 1 Sweep net 3 . 2 . 2 Thrown traps 7 7 3 . 2 . 3 Dropping cage . 3 . 2 . 4 Convergence on a spot by two people 7 3 . 3 Sampling, other insects 7 3 . 4 Sampling, s o i l invertebrates ............ 8 3 . 5 Sampling, vegetation 8r 3 . 5 . 1 Community analysis g. 3 . 5 * 2 Insect, use of plant communities ... g. 3 . 5 . 2 . 1 Grazed, blade 8-3 . 5 . 2 . 2 Wind tunnel g . 3 . 5 . 2 . 3 Exclosure cages g 3 . 5 . 2 . 4 Insect grazing observations... ]_0 iv PAGE 4 . OBSERVATIONS AND RESULTS 11 4.1 Environment , ... 11 4 . 2 Sampling, grasshoppers 13 4 . 3 Sampling, other insects 15 4 . 4 Sampling, s o i l invertebrates 15 4 . 5 Sampling, vegetation 16 4.5.1 Community analysis 16 4 . 5 . 2 Insect use of plant communities ... 16 4 . 5 . 2.1 Grazed blade 16 4 . 5 . 2 . 2 Wind tunnel 18 4 . 5 . 2 . 3 Exclosure cages 18 5 . DISCUSSION 20 5 .1 Background 20 5 . 2 E f f e c t s of temperature and s o i l moisture on insects and grass • 22 5 . 3 Insect sampling 24 5 . 4 Community analysis 26 5 . 5 E f f e c t s of grasshoppers on grass y i e l d ... 27 5 . 6 Grazing mammals 31 5 . 7 Wind tunnel 33 6 . SUMMARY 35 LITERATURE CITED 37 APPENDICES 56 V LIST OF TABLES TABLE NUMBER PAGE 1. E l e v a t i o n , a s p e c t , s l o p e , and s o i l c l a s s e s o f each s t u d y a r e a 41 2A, C l i m a t i c d a t a f o r J u n i p e r S l o p e 1969.,. 42 2B. C l i m a t i c d a t a f o r South S l o p e 1969... 43 3. Grasshopper phenology, J u n i p e r S l o p e , 1970 44 4. Common phytophagous i n s e c t s o f the A s h n o l a . 45 5. V e g e t a t i o n : b a s a l h i t a n a l y s i s 46 6. V e g e t a t i o n : c o v e r h i t a n a l y s i s 47 7. I n s e c t g r a z i n g o f g r a s s e s on J u n i p e r s l o p e , 1970 48 8. G r a s s e s g r a z e d by i n s e c t s : c o n s o l i d a t e d e s t i m a t e s 4 9 9. C a r r y o v e r on the J u n i p e r s l o p e P o a - S t i p a community, 14 May 1970 50 10. E x c l o s u r e cage r e s u l t s : Mean g r a s s y i e l d s from t h r e e communities i n I969 and 1970.. 5 1 v i LIST OF FIGURES PAGE FIGURE 1. S o i l moisture at a depth of 30 cms on two communities on Juniper Slope, 1970 52 FIGURE 2. Grasshopper numbers i n r e l a t i o n to grass phenology on Juniper Slope ridge community 5 3 FIGURE 3« A i r and s o i l temperatures, Juniper Slope 1970 54 FIGURE 4 . (A and B) Changes i n abundance of insects on seven communities, 1 9 7 0 , . . . . , . 5 5 v i i ACKNOWLEDGMENTS I am e x t r e m e l y g r a t e f u l t o Dr. B r i n k f o r g i v i n g me so much h e l p . My w i f e , J e n n i f e r , h e l p e d t h r o u g h o u t t h e p r o j e c t , sep-a r a t i n g samples, p a c k i n g h o r s e s , p r o o f r e a d i n g and t y p i n g , Bruce Begg, my f i e l d a s s i s t a n t , was an e x c e l l e n t companion and worker. Due t o h i s i n g e n i o u s South S l o p e Shower we were a b l e t o l i v e i n c o m f o r t . Bud T i l l o t s o n , p i l o t f o r Okanagan H e l i c o p t e r s , k i n d l y f l e w i n s u p p l i e s d u r i n g h i s t r a i n i n g f l i g h t s . Tuke and Margaret M e n n e l l , as w e l l as Susan, W i l f r i d , and R o b e r t , cannot be thanked enough f o r t h e i r k i n d n e s s t o us d u r i n g our Keremeos s t o p o v e r s . Dr. Scudder and M i s s K a t h l e e n S t e w a r t p r o v i d e d entomol-o g i c a l i n f o r m a t i o n . Dr. R. H. Wrig h t o f B. C. R e s e a r c h k i n d l y a l l o w e d me t o use h i s wind t u n n e l . Dr. V, R. V i c k e r y , of t h e Lyman E n t o m o l o g i c a l Museum, M c G i l l U n i v e r s i t y , i d e n t i f i e d t h e O r t h o p t e r a . -1-1 . INTRODUCTION "The land i s as the Garden of Eden before them, and behind them a desolate wilderness, yea, and nothing s h a l l escape them." ( J o e l 2s2 Reference to grasshopper plagues) Some i n s e c t s have brought f e a r and famine to every continent at one time or another. I n North America, s i n c e man's e a r l i e s t a g r i c u l t u r e i n s e c t s have destroyed crops. On the n a t i v e grasslands a major f a c t o r compounding the problems of i n s e c t damage i s overgrazing by l i v e s t o c k . I n Oklahoma Smith ( 1940) found that the t o t a l p opulation of i n s e c t s on overgrazed mixed grass p r a i r i e s was about four times as lar g e as normal on moderately grazed lands. Taylor ( 1935) found 782 , 0 0 0 i n s e c t s per acre on overgrazed land compared w i t h 186 , 0 0 0 on moderately used range. I n North America l i f e - h i s t o r y and e c o l o g i c a l data are g e n e r a l l y not a v a i l a b l e f o r grassland i n s e c t herbivores wi t h the exception of some species of grasshoppers (Blocker 1 9 6 9 ) . However damage and consumption by grasshoppers has been i n v e s t i g a t e d by some researchers. Using the data of Barnes ( 1 9 W , Pfadt (19^ 9 ) , Anderson and Wright ( 1 9 5 2 ) , Harper ( 1 9 5 2 ) , and Putnam ( 1 9 6 2 ) , B u l l e n (1966) determined t h a t on North American rangelands grasshoppers at d e n s i t i e s of 20 per square yard cause, on the average, a l o s s of 7 pounds of ve g e t a t i o n per acre per day. He f e l t t h a t -2-i n f e s t a t i o n s at t h i s l e v e l for three months during the summer would consume at least 600 pounds per acre, i . e . equivalent to the entire production of t y p i c a l shortgrass p r a i r i e . He says that "densities as low as 3 grasshoppers per square yard on poor grazing land can destroy more than 50% of the vegetation, the maximum permitted i n good range practice, so that any feeding by c a t t l e impoverishes the range". In other parts of the world i t i s the locust rather than the grasshopper which i s feared. In A f r i c a i n I887 locusts (Shistocerca gregaria) were reported to have swarmed over 2000 l i n e a r miles. The migratory locust (Locusta  migratoria) has a wider range than any other A c r i d i d ; i t i s found i n grasslands and savannah of A f r i c a , most of Eurasia south of the Taiga forest, East India, t r o p i c a l A u s t r a l i a , and New Zealand. The extent of range within these countries varies greatly, subject to temperature, burning of grasslands, floods, etc.; with i d e a l conditions there i s overcrowding and production of the gregarious phase (Davey and Johnston 1 9 5 6 ) . The smaller I t a l i a n and Moroccan locusts (Calliptamus  halicus and Dociostaurus maroccanus) do much inj u r y i n the Mediterranean area (Dempster 195^-48). In Canada and U. S. A. i n the 18?0's the Rocky Mountain locust or lesser migratory grasshopper (Melanoplus mexicanus phase spretus) created havoc on the p r a i r i e farms but l a t e r disappeared. I t was probably the gregarious phase of the common and widespread M, mexicanus ( a t l a r i s ) which i s , with the clear-winged grasshopper (Camnula pell u c i d a) , a major -3-crop pest i n North America. Many other species of Acrididae i n d i f f e r e n t regions occasionally increase to plague prop-ortions, hut few of them compare i n economic importance with those named above. In the Ashnola Resources Management area i n South Central B r i t i s h Columbia, c a t t l e , deer, and C a l i f o r n i a bighorn sheep have been accorded attention as major users of the grassland ranges (Blood 1961, Demarchi 19&5* Harper I969, Scheffler 1972). However, v i r t u a l l y nothing i s known about use by other grassland animals such as rodents, lagomorphs, birds, and phytophagous insects. The prime objective of t h i s preliminary study was to obtain a quanti-t a t i v e or semi-quantitative assessment of the use of range forage by in s e c t s . -4-2. DESCRIPTION OF STUDY AREA Detailed description of the study area, some of i t s plant communities, and range history have been given by Scheffler (1972), Blood (1961), Demarchi (1965), and Harper (1969); therefore only an outline w i l l be given here. The whole area i s of great r e l i e f ; the semi-arid Simil-kameen Valley l i e s at 1200 feet above sea level and the nearby mountains rise to 9000 feet above sea level. The transition to an Alpine climate, s o i l , and vegetation i s made at 6800 feet. Bordering the grasslands i s montane forest where Douglas f i r (Pseudosuga menziesii) and lodgepole pine (Pinus contorta). and an undercover species, pine grass (Calamagrostis rubescens) are the dominants. To the south-west the land f a l l s away steeply. A number of small gulleys accept the runoff and carry i t to Juniper and Ewart creeks. Running south to north, the latter creek is relatively inaccessible from the east side in a l l but a few places, due to the roughness of the terrain. A four-mile t r a i l along the west side of the Ewart creek i s used for hiking access and sheep migrations during the spring and f a l l . To the north-east the h i l l s are covered in serai forest, in which lodgepole pine i s dominant. The alplands, about two miles from the intensive study area, are dotted with lakes and lush meadows. On Flatiron mountain there are four open slopes: Flatiron, Starvation, Juniper, and South slope. -5-A f t e r some p r e l i m i n a r y study, South slope and Juniper slope were chosen f o r t h e i r a c c e s s i b i l i t y , convenience, v a r i e t y of reasonably homogenous grass communities, and l a r g e numbers of i n s e c t s . South slope i s a c r i t i c a l area f o r the w i n t e r s u r v i v a l of bighorn sheep (Ovis canadensis c a l i f o r n i a n a DouglasK In w i n t e r , sheep congregate on t h i s s o uth-facing area, where escape t e r r a i n i s nearby and where wind and g r e a t e r exposure to s u n l i g h t reduce the snow cover. Juniper slope d i f f e r s s u b s t a n t i a l l y from South slope I The s o i l of most of the area of Juniper slope i s O r t h i c Black S i l t ; on exposed r i d g e s , as on South slope, i t i s Rego Dark Grey (Table 1) ( S o i l Survey 1968). S e v e r a l moist swales occupy about two acres. The South slope v e g e t a t i o n y i s predominantly Agropyron spicatum, a climax grass between 1000 and 6000 f e e t e l e v a t i o n . Juniper slope i s composed of mixed communities. The aspect on South slope i s south-south-east, while t h a t of Juniper slope i s south-west. The slopes are 28% and 5% r e s p e c t i v e l y . A narrow band of t r e e s , and a creek, separate South and Juniper slopes. This appears t o . a c t to some degree as a b a r r i e r , preventing walking i n s e c t s from moving between the two open slopes. The climate and v e g e t a t i o n of the Ashnola are s u i t a b l e f o r a wide array of i n s e c t s , e s p e c i a l l y Camnula p e l l u c i d a of the order Orthoptera. The warm summers and green succulent Poa stands are i d e a l f o r s e v e r a l orders. -6-3 . MATERIALS AND METHODS A l l equipment had to be back-packed or horse-packed from road end at 2000 feet elevation to the study s i t e s . 3 . 1 MEASUREMENT OF CLIMATIC AND EDAPHIC VARIABLES Two climatic stations recording basic measurements were maintained during May, June, July, and August of 1969 and 1 9 7 0 . The stations were e s s e n t i a l l y those established by Harper (1969) two years p r i o r to the i n i t i a t i o n of t h i s study. One was situated on Juniper slope i n the Poa  pratensis community (5225 feet a. s. 1 . ) and the other i n the Agropyron community on upper South slope (5750 feet a . s . l . ) . Weather data of d i r e c t use have been abstracted, the balance are i n Table 2 . Measurements include wind speed, temperature, evapor-ation, p r e c i p i t a t i o n , s o i l moisture, and r e l a t i v e humidity. A Stevenson screen housed a hygrothermograph and a maximum-minimum thermometer. Preceding and throughout the grass-hopper l i f e - c y c l e the s o i l temperature at the 5 em depth was recorded. S o i l study was undertaken by Scheffler (1972) and by the C. D. A. and B.C. D. A. s o i l surveys Scheffler also includes geological and physiographical descriptions. -7-3 . 2 SAMPLING FOR GRASSHOPPERS Grasshopper counts were made throughout the summer by: 3 . 2 . 1 Sweep Net Four standard sweeps of a net 12 inches i n diameter, every ten days on a Poa or Stipa community gave a f a i r l y r e l i a b l e census over one square meter. 3 . 2 . 2 Thrown Traps A square meter frame was thrown about 15 feet onto unsuspecting grasshoppers. The top of the permascreen cage had a sleeve i n i t so the grasshoppers could be extracted and counted. 3 . 2 . 3 Dropping Cage A square meter frame was suspended between poles and l e f t for 30 minutes for the grasshoppers below to resume normal a c t i v i t y . The frame was then dropped by a t r i p wire onto the unsuspecting insects. Care was taken not to use t h i s method at mid-day when the shadow of the frame f e l l d i r e c t l y below i t . 3 . 2 . 4 Convergence on a Spot by Two People (Dempster 1954) Premarked square meter areas were slowly converged upon by two people from d i f f e r e n t d i r e c t i o n s , A count was made as the grasshoppers hopped, walked, or flew out of the square. 3 . 3 SAMPLING, OTHER INSECTS A q u a l i t a t i v e sample of the grassland insects was obtained by placing paired traps i n each of s i x plant communities. They were coll e c t e d weekly. The traps were jars f i l l e d with water and ethylene g l y c o l , and buried with -8-the rim f l u s h with ground l e v e l . Unsuspecting insects f a l l i n g or a l i g h t i n g i n the solution were trapped, drowned, and preserved. 3 . 4 SAMPLING, SOIL INVERTEBRATES S o i l invertebrates were sampled monthly by digging to a three inch depth and then using a Berlese funnel (Kuhnelt 1961) to screen out the animals. 3 . 5 SAMPLING, VEGETATION 3 . 5 . 1 Community Analysis A point frame was used to determine the plant cover frequency and basal frequency. Four hundred to 800 random points i n each plant community gave two measures of the f l o r a l composition. As the pin descended through the veget-ation the cover species was recorded. The plant species touched by the end of the pin was noted as a basal h i t . Basal h i t s are a measure of composition, while cover h i t s give an estimate of the "biomass"of each species. 3 . 5 » 2 Insect Use of Plant Communities 3 . 5 , 2 . 1 Grazed Blade. To estimate insect grazing damage the plant material which was touched by the basal h i t was pulled up and examined. The numbers of intact and injured blades were recorded, and the amount removed from each injured blade was estimated. To determine the amount removed by insects the blade was divided on the midrib and then divided transversely i n h a l f . To calculate an o v e r a l l percentage of grass removed the percentage of injured blades was multiplied -9-by the average percent removed from them. The term "injured" r e f e r s to the fact that a grass blade has been grazed by in s e c t s . In many cases the extent of grazing could only be a rough estimate, since insects often ate across a blade, and the size of the uneaten terminal portion was unknown. 3 . 5 . 2 . 2 Wind Tunnel. In an e f f o r t to determine whether grasshoppers select p a r t i c u l a r plants, four groups of 30 grasshoppers (collected on Juniper slope and carried to the laboratory), a l l the same age and starved f o r 48 hours, were placed i n a wind tunnel. Five d i f f e r e n t species of grass (Poa pratensis; Agropyron spicatum, Koeleria c r i s t a t a , S tipa columbiana, Calamagrostis rubescens) were inserted i n a p i l e , one at a time, upwind, and the response recorded. 3 . 5 . 2 . 3 Exclosure Cages. Sites f o r experimental determination of e f f e c t s of grasshoppers on grass y i e l d were chosen f o r homogeneity of vegetation and for high insect populations, as well as for use by deer and sheep at some time of the year. Both the l a t t e r had emigrated for the summer at the time of the experiment, so that v i r t u a l l y a l l grazing during the exper-iment was by insects; the cages were located well away from rodent burrows and runways. In 1969 the cages were placed on two communities: South slope f l a t s dominated by Stipa columbiana and Agropyron spicatum, and on a Juniper slope community domin-ated by Stipa columbiana and Poa spp. (denoted Juniper slope -10-Poa-Stipa). In 1970 the cages were moved from the f l a t s t o a Poa community on Juniper slope where the grasshopper po p u l a t i o n was the highest of e i t h e r slope. The exclosure cages were made of permascreen on an i r o n frame. They were c y l i n d r i c a l w i t h a diameter of 1.41 meter so that they only touched the square meter experimental p l o t s at the four corners; t h i s e l i m i n a t e d an "edge-effect" of the cages. Any "greenhouse" e f f e c t could be determined by using three treatments. On each community three treatments were used w i t h 8 r e p l i c a t e s each (South slope F l a t s and Juniper slope Poa ended up w i t h only 7 r e p l i c a t e s due to l o s s of a cage duri n g a s p r i n g storm). I n order to measure the e f f e c t on grass growth of the a l t e r e d micro-environment w i t h i n the cage, one c o n t r o l cage was r a i s e d 12 to 20 cm to al l o w i n v e r t e b r a t e s to move i n and out. The experimental cage was lowered to exclude i n v e r t e b r a t e s . Nearby there was another c o n t r o l p l o t without a cage. The f i r s t s i t e of each r e p l i c a t e was placed randomly, and s i m i l a r spots with s i m i l a r d e n s i t y and type of v e g e t a t i o n picked f o r the other two s i t e s . The assignment of treatments t o the three p l o t s was a l s o random. The cages were placed on the range i n the l a s t week of May before the grasshopper eggs hatched, and removed f o r c l i p p i n g on 20 September 1969 and 4 October 1970. A l l p l a n t s were c l i p p e d to ground l e v e l and oven-dried before weighing; grasses, f o r b s , and shrubs were weighed s e p a r a t e l y . 3.5.2.4 Insect Grazing Observations. Observations of gr a z i n g by i n s e c t s other than Orthoptera were not made. -11-4. OBSERVATIONS AND RESULTS 4 . 1 ENVIRONMENT Climatic data f o r the Ashnola are shown i n Table 2 . The climate i s Dfc (Krajina 1959, after Koppen) with the summers receiving about 4 - 8 inches of r a i n , while the winters have about 36 inches of snow. Harper ( 1969) records 9 . 0 1 and 1 2 . 3 7 inches of p r e c i p i t a t i o n for 1967 and I 9 6 8 , r e s p e c t i v e l y . The summer of 1970 (May 1 to September 30) had only 1 .25 inches. The summer temperatures are quite high, often going above 100 degrees i n the shade. (The Stevenson screen, however, gave low readings compared to a thermometer on the shady side of the cabin.) In I 9 6 9 the temperature i n the screen r a r e l y reached 70 degrees F, while i n 1970 "the mercury" frequently climbed above that. The r e l a t i v e humidity i n summer, as would be expected i n a sub-humid climate i n a mountain lee, was very low, usually below 15% at mid-day. A l i g h t breeze blows a good deal of the summer and f a l l (averages 4 . 2 miles per hour). The yearly evaporation was highest from 22 July to 21 August (1100 mis). S o i l moisture d i r e c t l y a f f e c t s plant growth as well as l o c a l grasshopper movements and l i f e cycle. Hatching of eggs (Fig. 1) occurred on a l l plant communities when s o i l moisture was 85 to 90% and s o i l temperature 60 degrees. Shotwell (1941) has shown i n the laboratory that eggs w i l l not hatch -12-i f allowed to get too dry. In the f i e l d , i n the middle of the summer, i t was observed that a r a i n shower brought on a fresh hatching, a clear sign that eggs stop hatching as moisture diminishes. On the ridge the hopper populations b u i l t up to about 50 per square meter by 11 June, then started to decrease as the s o i l moisture decreased. On k June on the ridge the s o i l moisture was 90%; by 10 June i t was down to 50%, while on the Poa s i t e i t was s t i l l at 90%. The grasshoppers then moved into the l o c a l i z e d Poa swales where they were uncount-able due to the density of the cover; they were probably i n excess of 80 per square meter. On the large Poa areas, about 1000 feet from the ridge, the grasshoppers did not s t a r t hatching u n t i l 20 June (moisture 85 to 90%, temperature 60 degrees). By 17 July the ridge grasshoppers s t a b i l i z e d at about 7 per square meter. The grasshoppers i n the Poa stand of two acres averaged about 50 per square meter on 1 August. Copulation was i n i t i a t e d about 3 August. Ovipositing was f i r s t seen on 7 August; a noticeable decrease i n numbers was then evident. Hatching started on 2 to 6 June, both years, on the ridges (Fig. 2 ) . Since the range has a southern exposure, a r e l a t i v e l y large part of the solar r a d i a t i o n i s absorbed and held by the earth. The daytime temperatures of the ridge averaged 9 degrees F warmer than on the swales. With a mid-day temperature of 60 degrees F the temperature of the bare dry ridge s o i l at a depth of 3 cms would go as high as -13-78 degrees F; a t t h e same time under m o i s t s o i l o f Poa spp. the t e m p e r a t u r e was 63 degrees F. O b s e r v a t i o n s o f f i r s t appearance o f nymphs i n abundance i n a l l a r e a s and a s t u d y of t h e weather r e c o r d s show t h a t g e n e r a l h a t c h i n g o f Melano-p l u s spp. and Camnula spp. eggs t a k e s p l a c e d u r i n g t h e f i r s t warm p e r i o d o f from 3 t o 5 days, h a v i n g a maximum a i r temp-e r a t u r e above 65 degrees and a s o i l t e m p e r a t u r e above 60 d e g r e e s . A i r and s o i l t e m p e r a t u r e s on J u n i p e r s l o p e a r e shown i n F i g u r e 3 . W i t h i n t h e f i r s t two weeks o f J u l y the v e g e t a t i o n t h r o u g h o u t F l a t i r o n mountain, e x c e p t i n t h e m o i s t s s w a l e s , goes i n t o dormancy. T h i s i s i m p o r t a n t from a n u t r i t i v e p o i n t o f view, f o r t h e p r o t e i n c o n t e n t o f g r a s s can d r o p f o u r t o f i v e t i m e s . For example, Agropyron inerme i n t h e s p r i n g has a p r o t e i n c o n t e n t o f about 15%; when the p l a n t s e r e s p r o t e i n d rops t o 3 t o k% (Maclean and T i s d a l e i 9 6 0 ) . The A l p i n e v e g e t a t i o n s t a y s g r e e n t h r o u g h o u t t h e s h o r t summer, but t h e t e m p e r a t u r e i s t o o low f o r a l l b u t a few g r a s s h o p p e r s p e c i e s and i n d i v i d u a l g r a s s h o p p e r s . The temp-e r a t u r e f r e q u e n t l y f a l l s below 50 degrees F, w h i c h i s l e t h a l i f i t happens d u r i n g h a t c h i n g . k.2 SAMPLING, • GRASSHOPPERS By t h e use o f a d r o p p i n g frame and "convergence on a s p o t " , e s t i m a t e s were made o f the number of g r a s s h o p p e r s per square meter. The f i g u r e s are c o n s e r v a t i v e . The h i g h e s t p o p u l a t i o n was 102 per square meter on a Poa community on 1 August 1 9 7 0 . The summer average on t h i s a r e a was 50 per -14-square meter. The lowest numbers were on Agropyron spicatum where only one grasshopper per 20 square meters was found. A few adult Cratypedus neglectus were seen i n a l l locations during the v/inter. On warm days they could be found on grassy patches between snow d r i f t s . Grasshopper phenology i s shown i n Table 3 • Weighing of 60 adult dried grasshoppers, of mixed species, gave an average weight of 72 mg per grasshopper. Thus a maximum estimate of mass of grasshoppers on a Poa community was about 7 . 5 gms per square meter. On the grasslands the common Orthoptera of the Acridae family were Camnula pellucida, Melanoplus sanguinipes, and Bruneria brunnea; of the Tettigoniidae family, Gyphoderris  spp. Camnula p e l l u c i d a was at le a s t 20 times more p l e n t i f u l than any other species. The sweep net was unsuccessful i n very sparse or very thick vegetation. I f too sparse, such as on ridges established to Artemesia f r i g i d a , i t was impossible to c o l l e c t from the s o i l surface. I f too dense the net was prevented from passing close to the ground. I t was a s a t i s f a c t o r y method for comparison of populations on one area on successive dates. The dropping frame was the best sampling method used, and was s a t i s f a c t o r y i n a l l areas for both nymphs and adults. Convergence on a spot by two people was used successfully for immature grasshoppers up to a density of about 4-0 per square meter. Above t h i s number they were too d i f f i c u l t to count. -15-4 . 3 SAMPLING, OTHER INSECTS The herbivorous orders that recured i n the samples were Orthoptera, Coleoptera, Hemiptera, Homoptera, and Lepidoptera. Many Diptera and Hymenoptera were also caught but plant-eating families were uncommon (Table 4 ) . Only Orthoptera, Hemiptera, and Homoptera occurred i n large numbers. Scarabidae (Coleo-ptera) and Aphidae (Homoptera) numbers were found to f l u c t -uate throughout the summer, varying from negligable to very numerous. The e f f e c t on t h e i r food species during t h e i r few periods of high numbers may have been just as great as that of species present i n moderate numbers throughout the summer. The largest number of insects was found i n the P. prat- ens i s grassland. The permanent w i l t i n g point i n the Poa communities i s not reached u n t i l much l a t e r i n the summer than i n most other communities (Table 2). I t i s i n t e r e s t i n g to note that i n the two climax communities, Pseudosllga-Calamagrostis and Agropyron spicatum, the insect numbers remained r e l a t i v e l y low and the species composition remained quite uniform throughout the summer (Fig. 4 ) , 4 . 4 SAMPLING, SOIL INVERTEBRATES Few s o i l invertebrates were found on South slope, other than Coleoptera and Arachnida sheltering under rocks. A t y p i c a l catch from Juniper slope was Heteroptera 47%, Homoptera 28%, Coleoptera 3%, Diptera 2%, and Arachnida 20%. 4.5 SAMPLING, VEGETATION 4 . 5 . 1 Community Analysis The r e s u l t s are shown i n Tables 5 and 6. 4 . 5 . 2 Insect Use of Plant Commionities (Fig. 4) 4 . 5 . 2 . 1 Grazed Blade (Table 7 ) . Poa pratensis, P. secunda, and Koeleria c r i s t a t a were the plants most often eaten by grasshoppers (Tables 7 and 8 ) . Damage was to the grass blades, r a r e l y to the stem.' Bernays and Chapman (1970) also made t h i s observation, that "only the grass blades were of general importance to the grasshopper as food". When a l l grass had cured grasshoppers were observed eating Wooly Mullein (Verbascum thapsis) and Arternesia t r i d e n t a t a. There was very l i t t l e grazing on Agropyron spicatum. Although there were many other plants i present i n each area, only those l i s t e d i n Table 7 showed more than a trace of damage. On the Juniper slope A. f r i g i d a community, P. secunda was the only important grasshopper food species. Of 69 P. secunda blades examined, 45% showed signs of injury; further examination showed that about 42% material was removed from the injured blades. Thus the o v e r a l l removal from the t o t a l blades (both injured and uninjured) was about 19%. On the Juniper slope Poa community, P. pratensis comprised 74% or the vegetation (Table 5 h of 700 grass blades of a l l species examined 523 were P. pratensis. Of the Poa blades 77% were injured, with an average of 43% f o l i a g e removed. The o v e r a l l percent removed for P. pratensis was about 33%. -17-On the Juniper slope Poa-Stipa community, the two main grasses were P. p r a t e n s i s (51%) and S. columbiana (18%). Of 263 P. p r a t e n s i s blades examined 32% were i n j u r e d , the average amount removed from the i n j u r e d blades was 55%» g i v i n g a t o t a l removal of about 18%. The second most abund-ant grass, S. columbiana, had 17% of 138 blades i n j u r e d , 24% removal from the i n j u r e d blades; removal t o t a l was about 4%. Using weighted means f o r the t o t a l s , on the Juniper slope A* f r i g i d a community of 75 blades of a l l grass species examined 44% were i n j u r e d , w i t h an average of 43% f o l i a g e removed from each blade. One might say, then, t h a t about 19% of the a v a i l a b l e grass on the A. f r i g i d a community was removed by-grasshoppers and other g r a z i n g i n s e c t s . On the Juniper slope Poa community 700 blades of a l l species were examined. Of these 80% were i n j u r e d , and 35% of the a v a i l a b l e grass was consumed by i n s e c t s . On the Poa-S t i p a community 135 blades out of a t o t a l of 472 of a l l species were i n j u r e d , and 14% of the t o t a l grass was removed. Of the grasses i n the Ashnola, K. c r i s t a t a and P. p r a t e n s i s were consumed f i r s t , and P. secunda and S. columbiana were t h i r d and f o u r t h choices (Table 8 ) . K. c r i s t a t a , a f t e r being averaged over a l l the areas, showed 46% of 99 leaves to be removed by i n s e c t s ; P. p r a t e n s i s had 28% of 786 leaves removed; and S. columbiana had 13% of 203 leaves removed by g r a z i n g i n s e c t s . -18-4.5.2.2 Wind Tunnel. The wind tunnel experiments were carefully designed and conducted. However there was no significant difference in response by the grasshoppers to any of the five grasses; in fact their use of any of the five species was minimal. 4.5.2.3 Exclosure Cages. On 14 May 1970 the standing dead phytomass on the Juniper slope Poa-Stipa community averaged 9.1 gms per square meter, while that of fallen phytomass plus that standing averaged 52.2 gms per square meter (Table 9). By f a l l the previous year's carryover had almost disappeared and what remained was not separated from the exclosure cage clippings. The vegetation from the cages was not collected unt i l late September when copulation, egg-laying, and feeding of grass-hoppers was completed. The exclosure cages worked very well when the grass-hoppers were fewer than 28 per square meter, but when their numbers were very high on hot days they crawled on top of the cages and ate large holes in the screening, through which they entered the cage. This happened on the Poa community during August 1970; accordingly during this time the cages ,were sprayed with insecticide to k i l l the few grasshoppers which had gained entry. The results from the exclosure cages are shown in Table 10. Although in a l l four areas the mean grass yields were higher in the exclosure (lowered) cage, and lower and approximately equal in the two control plots (no cage and -19-r a i s e d c a g e ) , none of the d i f f e r e n c e s 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 . The t - t e s t g i v e n i n the t a b l e used n o n - p a i r e d sample means; a t e s t was a l s o done u s i n g d i f f e r e n c e s between means o f p a i r e d samples, and t h i s a l s o gave a i n o n - s i g n i f i c a n t r e s u l t . The uncaged c o n t r o l p l o t and t h e r a i s e d cage p l o t means were v e r y c l o s e , i n d i c a t i n g t h a t the cages t h e m s e l v e s had l i t t l e e f f e c t on g r a s s y i e l d . -20-5. DISCUSSION 5.1 BACKGROUND In the Ashnola the predominant plant on the open range was Agropyron spicatum. Since the l a t e 1800's l i v e s t o c k , horses, c a t t l e , and sheep, have grazed the plateaux, basins, and moderate slopes of the area. Where the grasses are a c c e s s i b l e to cows c e r t a i n species have diminished or d i s -appeared. Less d e s i r a b l e " i n c r e a s e r s " have become more abundant, e.g. S t i p a columbiana, S. r i c h a r d s o n i , Bromus  tectorum, Antennaria rosea, Taraxacum o f f i c i n a l e , Lupinus spp., Astragalus sp., Poa p r a t e n s i s , P. secunda. Of these the two most common are S. columbiana and P. p r a t e n s i s . I t i s i n t e r e s t i n g to note that the l a t t e r i s p o s s i b l y an i n t r o -duced pl a n t from Europe, but so completely has i t replaced the indigenous A. spicatum that i t w i l l probably be a long time before A. spicatum r e t u r n s . On Juniper slope P. p r a t e n s i s i s i n d i s c l i m a x , and appears to have reached a s t a t e of e q u i l i b r i u m with the cl i m a t e , s o i l , and b i o t a . Oosting (1948) d e f i n e s d i s c l i m a x : "When disturbance i s such t h a t true climax becomes modified or l a r g e l y replaced by new species, the r e s u l t i s an apparent climax, c a l l e d d i s c l i m a x . " There are few st u d i e s anywhere of i n s e c t s on climax grasslands of the nature found i n the Ashnola at between 4000 and 6000 f e e t . The Ashnola o f f e r s a unique opportunity f o r a comparative study f o r there i s both d i s t u r b e d and undisturbed biome. I n s e c t s , u n l i k e cows and horses, do not -21-appear t o cause d r a s t i c immediate changes on t h e f l o r a l c o m p o s i t i o n . Presumably t h e c l i m a x South s l o p e has e v o l v e d t o t h i s s t a t e and remained s t a b l e ever s i n c e , even t h r o u g h t h e bad g r a s s h o p p e r o u t b r e a k s o f 1 9 2 1 - 2 3 , a c c o r d i n g t o r e p o r t s t h e wo r s t i n B. C.'s h i s t o r y ( B r i n k , p e r s . comm.). From my o b s e r v a t i o n s , and o t h e r s , i t appears t h a t i f t h e g r a s s l a n d s a r e i n good c o n d i t i o n t h e y can w i t h s t a n d i n s e c t a c t i v i t y . Treherne and B u c k e l l (1924) say "...where t h e numbers o f s t o c k t o t h e a r e a a v a i l a b l e f o r r a n g i n g i s i n j u d i c i o u s p r o p o r t i o n o r where r o t a t i o n s o f g r a z i n g grounds a r e p r a c t i s e d , g r a s s h o p p e r s do n o t , o r even cannot, perman-e n t l y i n j u r e t h e r a n g e - g r a s s e s . " I n t h e N i c o l a V a l l e y , about 80 m i l e s t o t h e n o r t h o f th e s t u d y a r e a i n B r i t i s h Columbia, most o f t h e c l i m a x bunchgrass " b e l l y h i g h t o a cow" has d i s a p p e a r e d . There i s no r e c o r d o f g r a s s h o p p e r numbers b e f o r e t h e i n t r o d u c t i o n o f c a t t l e , but f o r t h e p a s t 50 y e a r s s p r a y i n g ( b a i t i n g f i r s t ) has a p p a r e n t l y been n e c e s s a r y t o p r e v e n t o u t b r e a k s . Without c o n t r o l many ranges were s t r i p p e d o f t h e i r v a l u a b l e f o r a g e . I n t h e A s h n o l a , on t h e o t h e r hand, t h e g r a s s l a n d s have always been i n r e l a t i v e l y good c o n d i t i o n . There has ne v e r been any g r a s s h o p p e r c o n t r o l . -22-5 . 2 EFFECTS OF TEMPERATURE AND SOIL MOISTURE ON INSECTS AND GRASS P a r k e r ( 1930) i n Montana found t h a t about 75 degrees F. s o i l t e m p e r a t u r e f o r t h r e e days was n e c e s s a r y b e f o r e h a t c h i n g would o c c u r . I n t h e A s h n o l a 60 degrees F. s o i l t e m p e r a t u r e was n e c e s s a r y b e f o r e h a t c h i n g o c c u r r e d . T h i s d i f f e r e n c e between our f i n d i n g s c o u l d be r e a l o r a p p a r e n t . An apparent d i f f e r e n c e c o u l d be caused by a d i f f e r e n c e i n exposure o f the egg pod s i t e s ; u n f o r t u n a t e l y he doesn't s t a t e a l t i t u d e , a s p e c t , o r s l o p e o f h i s s t u d y a r e a , a l l o f which c o u l d i n f l u e n c e t h e s o i l t e m p e r a t u r e , which appears t o be more i m p o r t a n t t h a n a i r t e m p e r a t u r e . On the o t h e r hand, t h e d i f f e r e n c e c o u l d be r e a l , due t o s e l e c t i o n f o r nymphs which h a t c h a t c o o l e r t e m p e r a t u r e s , s i n c e t e m p e r a t u r e s as h i g h as P a r k e r ' s o b l i g a t e t e m p e r a t u r e s a re i n f r e q u e n t a t h i g h e l e v a t i o n s . I n 1969 and 1970 t h e t h r e e warm days p r e c e d i n g h a t c h were the f i r s t warm days s i n c e the w i n t e r . Such warm p e r i o d s g e n e r a l l y do n o t o c c u r i n t h e A s h n o l a u n t i l t h e l a s t two weeks o f May or t h e f i r s t week o f June. H a t c h i n g s t a r t e d 2 June 19&9 and 6 June 1970 on t h e x e r i c J u n i p e r r i d g e s (the A r t e m e s i a f r i g i d a community) (Table 3). The r i d g e has a southwest exposure, i s wind-swept, and has s p a r s e v e g e t a t i o n compared w i t h t h e s w a l e s ; t h u s i t q u i c k l y r e a c h e s t h e " r e q u i r e d " s o i l t e m p e r a t u r e o f 60 degrees f o r h a t c h i n g . W i t h i n two weeks many o f t h e f i r s t and second i n s t a r s walked as f a r as 300 f e e t t o t h e h y d r i c Poa s w a l e s . I n t h e swales t h e p o p u l a t i o n p r o b a b l y s t a y e d above 8 0 per square meter. - 2 3 -H a t c h i n g was n e x t observed 22 June 1970 on t h e mesic P o a - S t i p a community. Immature hoppers soon c r a w l e d t o nearby patches o f Poa spp. where th e p o p u l a t i o n was g r e a t e r t h a n 20 per square meter, w h i l e t h e nearby S t i p a c o n t a i n e d about 8 per square meter. H a t c h i n g o c c u r r e d n e x t on a mesic Poa community about 20 June. About two a c r e s o f P. p r a t e n s i s p r o v i d e d f o o d and c o v e r f o r up t o 100 g r a s s h o p p e r s per square meter. On one s i d e o f t h i s s t a n d was f o r e s t , and on t h e o t h e r , S t i p a  c o l u m b i a n a ; t h e numbers dropped s h a r p l y t o about 7 per square meter 100 f e e t on e i t h e r s i d e o f t h e Poa. S o i l m o i s t u r e i s r e l a t e d t o p l a n t s u c c u l e n c e and j u i c y p l a n t s are chosen by nymphs and a d u l t s . T h i s f a c t p a r t i a l l y a c c o u n t s f o r t h e numbers o f g r a s s h o p p e r s a t d i f f e r e n t e l e v a t i o n s . On t h e l o w e r g r a s s l a n d s ( e l e v a t i o n s c a . 1500 f e e t ) t h e r e a r e few g r a s s h o p p e r s . The p l a n t s d r y e a r l i e r and l o s e t h e i r s u c c u l e n c e . The g r a s s h o p p e r s , when t h e y o c c u r , home i n on g r e e n p l a n t s (Poa spp.) and are abundant where m o i s t u r e i s a v a i l a b l e . Perhaps t h i s i s why t h e y are so p l e n t i f u l a t 4000 t o 6000 f e e t . Above t h i s e l e v a t i o n t h e season i s p r o b a b l y t o o s h o r t f o r many g r a s s -hoppers (and o t h e r g e n e r a l l y - a d a p t e d i n s e c t s ) t o s u c c e s s f u l l y complete t h e i r l i f e c y c l e . A h i g h m o r t a l i t y has been ob-s e r v e d i f newly-hatched nymphs o f C. p e l l u c i d a are s u b j e c t e d t o t e m p e r a t u r e s below 50 degrees F. At 7000 f e e t t h e weather i s o f t e n c o l d f o r l o n g p e r i o d s even i n summer, which may account f o r t h e r e d u c t i o n o f numbers w i t h a l t i t u d e . Only -24-G. p e l l u c i d a was found i n t h e A l p i n e r e g i o n s . S h o t w e l l (19^1) b e l i e v e s t h i s s p e c i e s t o be adapted t o a s h o r t g r o w i n g season. At a l l e l e v a t i o n s C. p e l l u c i d a was t h e f i r s t s p e c i e s t o r e a c h m a t u r i t y . 5.3 INSECT SAMPLING On J u n i p e r s l o p e t h e r e was an abundance of i n s e c t s , but o n l y a few o r d e r s c o n t a i n e d phytophagous i n s e c t s ; C o l e o p t e r a , L e p i d o p t e r a , O r t h o p t e r a , Hemiptera, and Homoptera. Only t h e l a t t e r t h r e e o r d e r s were r e p r e s e n t e d by i n s e c t s i n l a r g e numbers. P o p u l a t i o n counts were made, but t h e amount o f damage t o v e g e t a t i o n by i n s e c t s cannot be r e l a t e d s o l e l y t o i n s e c t numbers: c l i m a t i c c o n d i t i o n s and t h e c o m p o s i t i o n and c o n d i t i o n o f t h e v e g e t a t i o n must a l s o be t a k e n i n t o a c c o u n t . A l l p i t t r a p s were l a i d out and c o l l e c t e d a t t h e same t i m e ; t h u s t h e samples are comparable as t o c a t c h . The tendency was p r o b a b l y t o c o l l e c t a h i g h e r p r o p o r t i o n o f t h o s e i n s e c t s a t t r a c t e d t o t h e s w e e t - s m e l l i n g a n t i - f r e e z e , and c r a w l i n g i n s e c t s . Those t h a t f l e w from p l a c e t o p l a c e were p r o b a b l y n o t sampled i n t h e same p r o p o r t i o n . By f a r t h e most abundant i n s e c t i n t h e samples, except f o r a n t s , was C. p e l l u c i d a . I t s presence was p r o b a b l y r e l a t e d t o t h a t o f Poa spp. (Putnam 1962). A c c o r d i n g t o Treherne and B u c k e l l (1924) i t i s by f a r t h e most common s p e c i e s o f g r a s s h o p p e r found on c a t t l e ranges of B. C. and i s n e a r l y u b i q u i t o u s on open g r a s s y a r e a s a t a l l a l t i t u d e s and l a t i t u d e s i n s o u t h -25-c e n t r a l B. C. Throughout t h e Agropyron s p i c a t u m s i t e o n l y a few s p e c i e s o f i n s e c t s and o t h e r i n v e r t e b r a t e s were n o t i c e d . The most common were dung b e e t l e s , f l i e s , and b u t t e r f l i e s ; s p i d e r s a l s o were common. O c c a s i o n a l l y a c r i c k e t ( f a m i l y T e t l i g o n -i d a e ) was found c l o s e t o t h e f o r e s t b o r d e r . I n s e c t s m a i n l y c r a w l e d about t h e base o f g r a s s t u s s o c k s . Sweeps d i d n o t r e v e a l many i n v e r t e b r a t e s on t h e g r a s s b l a d e s o r stems. I n s e c t numbers and f a m i l y c o m p o s i t i o n remained r e l a t i v e l y low and c o n s t a n t t h r o u g h o u t t h e summer, a f i n d i n g t h a t i s c o n s i s t e n t w i t h t h e e c o l o g i c a l p r i n c i p l e o f s t a b i l i t y i n c l i m a x communities. Anderson (1964) c l a i m s t h a t C. p e l l u c i d a , the most abundant g r a s s h o p p e r , " i s i n v a r i a b l y a s s o c i a t e d w i t h " P. p r a t e n s i s ( a l t h o u g h , i n t h e A s h n o l a and e l s e w h e r e , i t has been found i n t h e A l p i n e where t h e r e i s no Poa) . B e s i d e s o f f e r i n g many n u t r i e n t s , t h e p l a n t s a re s u c c u l e n t and j u i c y , w h i l e A. s p i c a t u m i s " d r y " and c o n t a i n s t h i c k e n e d c e l l w a l l s . Because i t i s t a l l and has t o bear more weight the c e l l w a l l becomes t h i c k e n e d ( B e l l 1971). P. p r a t e n s i s has l i t t l e w eight t o s u p p o r t and has t h i n c e l l w a l l s , making i t i d e a l f o r young nymphs which seem t o r e l y on the t e n d e r b l a d e s . Nymphs o f most s p e c i e s may s i m p l y be unable t o get enough t o eat i n an A. s p i c a t u m community, Anderson (1964) i n Montana observed A u l o c a r a e l l i o t t i i n p a t c h e s o f Agropyron s m i t h i i and A. c r i s t a t u m . 5 . 4 COMMUNITY ANALYSIS Vegetation appears t o play an important r o l e i n deter-mining grasshopper d i s t r i b u t i o n and numbers beyond that of p r o v i d i n g s p e c i f i c h o s t - p l a n t s . For example, Russian entomologists (Bei-Bienko 1930, Netedor 1931 , Rubtzor 1932, 1934) not only found d i r e c t c o r r e l a t i o n s between the abundance of c e r t a i n grasshopper species and the taxonomic c o n s t i t u t i o n of grasslands, but a l s o w i t h the amount of plant cover. I n England, C l a r k (1948) found that the d e n s i t y and the height of the vegetation are important features f o r grass-hoppers . An attempt i s made here to c o r r e l a t e grasshopper numbers wi t h predominant grass species and/or cover d e n s i t y . Table 8 shows the four m o s t - u t i l i z e d grasses to be K o e l e r i a  c r i s t a t a , Poa p r a t e n s i s , P. secunda, and S t i p a columbiana. The lowest grasshopper population was found on upper South slope. The plan t species composition here (Table 5) was 57% Agropyron spicatum, 24% Artemesia f r i g i d a , both unpalat-able t o grasshoppers, and only 17% K, c r i s t a t a and 4% Poa spp. In a d d i t i o n the cover was very sparse; only 32% of the area was covered w i t h vegetation (Table 6 ) . The Artemesia f r i g i d a r i d g e s are a l s o very s p a r s e l y covered (24%), but the grass species composition (25% Poa  spp., 6% K o e l e r i a and S t i p a ) appeared to be favorable f o r feeding by young nymphs, and indeed the nymph population was very high f o r a short time a f t e r hatching occurred on the -27-r i d g e . However, the newl y - h a t c h e d nymphs q u i c k l y moved t o the more s u c c u l e n t and d e n s e l y - c o v e r e d nearby Poa s w a l e s . The two a r e a s most d e n s e l y p o p u l a t e d by g r a s s h o p p e r s were J u n i p e r Poa and P o a - S t i p a communities. T h e i r c o v e r was r e l a t i v e l y dense, b e i n g 62 and 48%, r e s p e c t i v e l y . On t h e Poa community, 76% o f t h e v e g e t a t i o n c o n s i s t e d o f Poa spp. and a ' f u r t h e r 14% o f t h e o t h e r two m o s t - u t i l i z e d s p e c i e s , K o e l e r i a and S t i p a ( T able 5 ) . On t h e P o a - S t i p a community, t h e p l a n t c o m p o s i t i o n was 57% Poa spp., and a f u r t h e r 21% K o e l e r i a and S t i p a . I t would seem, t h e n , t h a t g r a s s h o p p e r p o p u l a t i o n s are h i g h e r on a r e a s w i t h a h i g h f r e q u e n c y o f Poa spp., and o t h e r p a l a t a b l e g r a s s e s , and w i t h a r e l a t i v e l y l a r g e amount of c o v e r . However, a s i m p l e c o r r e l a t i o n does n o t n e c e s s a r i l y i m p l y a cause and e f f e c t r e l a t i o n s h i p , and i t would seem p r o b a b l e t h a t t h e ap p a r e n t importance o f co v e r i s due t o i t s r e l a t i o n s h i p t o s p e c i e s - c o m p o s i t i o n . 5 . 5 EFFECTS OF GRASSHOPPERS ON GRASS YIELD The e x c l o s u r e cage r e s u l t s ( T a b l e 10) were unex p e c t e d . I n v i e w o f t h e f a c t t h a t t h e g r a z e d - b l a d e a n a l y s i s i n d i c a t e d a l a r g e (19 t o 35%) consumption o f g r a s s by g r a s s h o p p e r s , i t was expected t h a t t h e g r a s s y i e l d i n g r a z e d ( c o n t r o l ) t r e a t m e n t s would be much l o w e r 'than i n the ungrazed (ex-c l o s u r e ) t r e a t m e n t . A l t h o u g h t h e mean g r a s s y i e l d s on a l l a r e a s d i f f e r e d i n t h e expected d i r e c t i o n s , the d i f f e r e n c e s 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 . ( T h i s d i s c u s s i o n assumes -28-t h a t t h i s c o n f i r m a t i o n o f t h e n u l l h y p o t h e s i s i s r e a l , and n o t due t o some u n i f o r m b i a s o r t o chance.) Combining t h e s e two r e s u l t s , one c o n c l u s i o n t h a t can be reached i s t h a t a l -though g r a s s h o p p e r s eat a l o t o f g r a s s , f o r some r e a s o n t h e y do n o t s i g n i f i c a n t l y a f f e c t i t s a n n u a l y i e l d . A l t e r n a t i v e l y , b e t w e e n - r e p l i c a t e v a r i a b i l i t y was so g r e a t as t o make s t a t -i s t i c s u n r e l i a b l e w i t h such a s m a l l sample. Anderson (1961) a l s o made an attempt t o d e t e r m i n e g r a s s h o p p e r damage by s p r a y i n g a l a r g e a r e a o f Montana r a n g e l a n d w i t h i n s e c t i c i d e , and t h e n s u b s e q u e n t l y comparing g r a s s y i e l d s on t h e s p r a y e d and' unsprayed a r e a s . He, t o o , was s u r p r i s e d a t h i s r e s u l t s w h i c h showed an apparent i n c r e a s e i n g r a s s y i e l d on unsprayed a r e a s . He found t h a t " i n s p i t e o f t h e presence o f t h e s e s p e c i e s o f g r a s s h o p p e r s b o t h t h e s p r a y e d and unsprayed a r e a s o f K. c r i s t a t a had i n c r e a s e d i n y i e l d d u r i n g t h e season. The d i f f e r e n c e between t h e two p o r t i o n s o f t h e a r e a , however, was n o t s i g n i f i c a n t . . . A number o f u n e x p l a i n a b l e d i s c r e p a n c i e s appear i n t h e d a t a , e.g., w e s t e r n wheatgrass (Agropyron s m i t h i i ) . . . , Sandberg b l u e g r a s s (Poa s e c u n d a ) , . . . and n e e d l e and t h r e a d ( S t i p a comata),..decreased i n weight between t h e f i r s t and second c l i p p i n g s i n t h e s p r a y e d a r e a s and i n c r e a s e d i n weight i n t h e unsprayed a r e a s where g r a s s h o p p e r s were f e e d i n g . From t h i s r e s u l t one might c o n c l u d e t h a t t h e presence o f g r a s s -hoppers was r e s p o n s i b l e f o r an i n c r e a s e i n p r o d u c t i o n of t h e s e g r a s s e s . " He a t t r i b u t e s t h i s r e s u l t t o a l a c k o f homogeneity o f the v e g e t a t i o n i n t h e a r e a t h a t he s t u d i e d , and c o n c l u d e d -29-t h a t "random s a m p l e s . . . d i d not g i v e a r e l i a b l e measure o f t h e l o s s e s caused by g r a s s h o p p e r s . " I n the p r e s e n t s t u d y , however, an attempt was made when s e l e c t i n g t h e t r e a t m e n t p l o t s t o o b t a i n t h r e e a r e a s as homogeneous as p o s s i b l e , so t h a t h i s e x p l a n a t i o n may n o t a p p l y t o my r e s u l t s . Anderson d i s c u s s e s a n o t h e r u n u s u a l f i n d i n g : " V i c i a  s p a r s i f o l i a i s one o f the p r e f e r r e d f o o d p l a n t s o f M e l a n o p l u s  p a c k a r d i i , M. b i l i t u r a t u s , M. b i ' v i t t a t u s . . .and M. c o n f u s u s . . . a l l o f w h i c h were p r e s e n t on t h e unsprayed p o r t i o n o f t h e s t u d y a r e a . However, the l o s s i n weight o f V. s p a r s i f o l i a was not s i g n i f i c a n t on t h i s p o r t i o n but was s i g n i f i c a n t where t h e r e was no g r a s s h o p p e r f e e d i n g . The d i f f e r e n c e i n amounts p r e s e n t on t h e two a r e a s a t the' end o f t h e season was a l s o s i g n i f i c a n t . N o r m a l l y , even w i t h no g r a s s h o p p e r s p r e s e n t , one might expect l o s s e s o f V i c i a d u r i n g a season because o f t h e d r y i n g - u p o f t h e p l a n t s and consequent breakage and l o s s o f p l a n t p a r t s . The d i f f e r e n c e r e c o r d e d between t h e two a r e a s i s n o t e a s i l y e x p l a i n e d . I t i s a p o s s i b i l i t y t h a t t h e f e e d i n g by g r a s s h o p p e r s on t h e unsprayed a r e a s t i m u l a t e d growth of V. s p a r s i f o l i a by r e m o v a l o f v e g e t a t i o n w h i c h on t h e s p r a y e d a r e a competed f o r l i g h t . Thus, th e f e e d i n g on V i c i a i n t h e unsprayed a r e a may have been masked t o some e x t e n t by i n c r e a s e d growth of t h i s s p e c i e s . " Anderson summarizes h i s work by s a y i n g , " L i t t l e c o r r e l -a t i o n was found between numbers of g r a s s h o p p e r s per u n i t a r e a and t h e l o s s o f v e g e t a t i o n . T h i s may be accounted f o r by t h e d i f f e r e n c e i n f e e d i n g h a b i t s o f t h e v a r i o u s s p e c i e s -30-c o m p r i s i n g any p a r t i c u l a r g r a s s h o p p e r p o p u l a t i o n . " T h i s c o u l d a l s o be accounted f o r by t h e f a c t t h a t g r a s s h o p p e r f e e d i n g i s d i r e c t l y a f f e c t e d by t e m p e r a t u r e ; Anderson r e p o r t s t h a t an a d u l t g r a s s h o p p e r e a t s n e a r l y 2|- t i m e s as much f o o d a t 100 degrees as a t 80 d e g r e e s F. Another p o s s i b i l i t y i s t h a t t h e v e g e t a t i o n compensates f o r l o s s e s due t o i n s e c t s and i s a c t u a l l y s t i m u l a t e d by a c e r t a i n amount o f i n s e c t g r a z i n g . I f t h e g r a s s stems a r e b r o k e n by l i v e s t o c k t r a m p l i n g , g r a s s h o p p e r s congregate on t h e s e a r e a s . S i n c e g r a s s h o p p e r s congregate on t h e s e t r a m p l e d a r e a s , t h e s l i g h t e s t damage by l i v e s t o c k i s g r e a t l y m a g n i f i e d by t h e g r a s s h o p p e r p o p u l a t i o n . I n t h e absence of l i v e s t o c k , t h e g r a s s h o p p e r g r a z i n g i s d i s t r i b u t e d over a l a r g e number o f h e a l t h y , i n t a c t p l a n t s , and u n l e s s t h e p o p u l a t i o n r e a c h e s an e x t r a o r d i n a r i l y h i g h l e v e l no damage i s done t o t h e r a n g e . T h i s l e v e l , however, cannot be p r e d i c t e d a t t h e p r e s e n t t i m e s i n c e i n g e s t i o n r a t e s depend upon so many d i f f e r e n t f a c t o r s . I t i s a l s o p o s s i b l e t h a t an e r r o r i n t e c h n i q u e a f f e c t e d t h e r e s u l t s . C l i p p i n g t h e cured p l a n t s i s an e x t r e m e l y d e l i c a t e j o b , e s p e c i a l l y i f a wind i s b l o w i n g . When t h e c l i p p e r s t o u c h t h e stem t h e d r y b l a d e s f a l l t o t h e ground, and one t h e n o b t a i n s more stem t h a n b l a d e . T h i s might account f o r t h e - u n e x b e c t e d l y s m a l l d i f f e r e n c e between c o n t r o l and e x p e r i m e n t a l p l o t y i e l d s , s i n c e g r a s s h o p p e r s m o s t l y e a t t h e b l a d e s . -31-5 . 6 GRAZING MAMMALS As has been mentioned cows and h o r s e s have g r a z e d t h e range s i n c e t h e 1 8 0 0 's. I n I969 and 1970 t h e g r a z i n g l e a s e s were c a n c e l l e d t o l e t t h e range r e c u p e r a t e . I n th o s e two y e a r s a re m a r k a b l e d i f f e r e n c e was seen. F o r t h e f i r s t t i me i n y e a r s many o f t h e g r a s s e s were a b l e t o s e t seed. I n s t e a d o f t h e u s u a l 4 i n c h h i g h g r a s s , i n some ar e a s i t grew 2\ f e e t h i g h . I n t h e summer o f 1970 seven cows escaped onto J u n i p e r s l o p e f o r s i x days, d u r i n g which time t h e y d i d a l o t o f damage. They a t e and t r a m p l e d a l a r g e p o r t i o n o f t h e g r a s s i n t h e Poa s w a l e s . T h e i r f e c e s seemed t o co v e r much t h a t wasn't t r a m p l e d . They d e s t r o y e d t h e s h a l l o w d r i n k i n g p o o l , and eroded t h e s t e e p s i d e s o f t h e c r e e k . The damage t o my stud y a p p a r a t u s was c o n s i d e r a b l e ? t h e y a t e t h e l e a d s coming from t h e ground f o r t h e s o i l m o i s t u r e , knocked over 7 o f 16 e x c l o s u r e cages, and d e s t r o y e d most o f the i n s e c t c o l l e c t i n g j a r s . Anderson (1961) r e p o r t s t h a t "changes i n g r a s s h o p p e r d i s t r i b u t i o n and a c t i v i t i e s r e s u l t from d i s t u r b a n c e s t o an a r e a , p a r t i c u l a r l y t h a t o f t r a m p l i n g v e g e t a t i o n i n l o c a l i z e d s p o t s . " On J u n i p e r s l o p e g r a s s h o p p e r s d i d seem t o congregate on a r e a s t h a t had been s p r i n g - c l i p p e d , t r a m p l e d , o r g r a z e d by c a t t l e or h o r s e s . I n a d d i t i o n , p o p u l a t i o n d e n s i t y appeared t o be i n v e r s e l y r e l a t e d t o Poa h e i g h t , an o b s e r v a t i o n a l s o r e p o r t e d by Anderson (1964). -32-W h i l e g r a s s h o p p e r s ' g r a s s s e l e c t i o n appears t o he r e l a t e d t o s u c c u l e n c e , the sheep p r e f e r t h e c o a r s e - s t r u c t u r e d A. s p i c a t u m t o t h e p r o t e i n - r i c h l e a f o f Poa, B l o o d ' s (1967) s p r i n g grazed-stem count r e v e a l e d t h a t A. s p i c a t u m made up 4-7% o f t h e sheep's d i e t ; t h e n e x t h i g h e s t was K o e l e r i a w i t h 18%, t h e n Poa spp. w i t h 15%. I t i s almost c e r t a i n t h a t sheep choose t h e h a b i t a t r a t h e r t h a n t h e g r a s s community. W i n t e r snows c o l l e c t f i r s t i n t h e swales and p r o t e c t e d a r e a s ; t h e r i d g e s and s t e e p s l o p e s are r e a s o n a b l y f r e e o f snow, and here the sheep f o r a g e . As soon as t h e snow r e c e d e s , most of t h e sheep m i g r a t e t o h i g h e r e l e v a t i o n s . Soon a f t e r l a m b i n g about h a l f t h e ewes and lambs l e a v e t h e w i n t e r r a n g e . I t i s t h e r e m a i n i n g sheep which have an o p p o r t u n i t y t o u t i l i z e t h e Poa communities, but t h e y make l i t t l e use o f them. Sugden (I96I) says o f t h e A s h n o l a range, "the l a r g e expanse of p r i m i t i v e bunchgrass s l o p e , i n t e r s p e r s e d w i t h b r o k e n b l u f f s . . . p r o v i d e s an e x c e l l e n t c o m b i n a t i o n o f b i g h o r n r e q u i r e m e n t s . " I t seems t h a t t h e s e broken b l u f f s and s t e e p s l o p e s a r e e s s e n t i a l . My o b s e r v a t i o n s i n d i c a t e t h a t ewes and lambs r e q u i r e e i t h e r a wide open s l o p e , or a l o o k - o u t s i t e w i t h nearby s t e e p escape t e r r a i n . Near th e bottom o f J u n i p e r s l o p e t h e r e are s m a l l p a t c h e s o f P. p r a t e n s i s w h i c h sheep g r a z e e x t e n s i v e l y , and w i t h i n a few hundred f e e t t h e r e i s a s t e e p c l i f f . F r i g h t e n e d sheep always dashed f o r t h e s e escarpments. Even i n l a t e summer when the l o w e r Poa s e r e d t h e y r a r e l y v e n t u r e d f a r from t h e c l i f f s , and t h u s seldom -33-sampled t h e g r e e n Poa f u r t h e r up t h e s l o p e . S i n c e i n s e c t s do n o t need t h i s k i n d o f escape t e r r a i n t h e y have c e r t a i n l u s h a r e a s p r e t t y much t o the m s e l v e s t h r o u g h o u t t h e summer. Thus t h e r e seems t o be l i t t l e c o m p e t i t i o n between sheep and g r a s s h o p p e r s d u r i n g t h e summer, and s i n c e g r a s s h o p p e r s seem t o have l i t t l e e f f e c t on g r a s s y i e l d i t would appear t h a t t h e y a re n o t a f f e c t i n g f o r a g e f o r t h e w i l d h e r b i v o r e s of t h e A s h n o l a . 5.7 WIND TUNNEL There a re p r o b a b l y s e v e r a l r e a s o n s a c c o u n t i n g f o r t h e f a i l u r e o f t h e wind t u n n e l e x p e r i m e n t . Perhaps the trauma of t h e j o u r n e y from f i e l d t o l a b o r a t o r y , and t h e two-day i n t e r v a l between c a p t u r e and t e s t i n g was t h e r e a s o n the g r a s s h o p p e r s f a i l e d t o r e s p o n d . S h o t w e l l (19^1) had observed nymphs and a d u l t s m i g r a t i n g a g a i n s t t h e wind toward f i e l d s o f gr e e n g r a i n or c o r n . He b e l i e v e s " . . . t h a t t h e y f o l l o w up t h e stream o f m o i s t a i r coming from t h e s e g r e e n f i e l d s . " He says t h e same r e a c t i o n may be caused by a pan o f wet b a i t o r a pe r s o n wet w i t h p e r s p i r a t i o n . Female mosquitoes a re a t t r a c t e d t o t h e i r b l o o d s o u r c e by a c o m b i n a t i o n o f warmth and m o i s t u r e e m i t t i n g from t h e body o f t h e h o s t . G r a s s h o p p e r s might l o c a t e food by a s i m i l a r method, a h y p o t h e s i s s u p p o r t e d by t h e o b s e r v a t i o n t h a t t h e y congregate on t h e m o i s t Poa s w a l e s . I n t h i s e xperiment w a t e r was s p r i n k l e d on t h e g r a s s b l a d e s t o keep them from d r y i n g out, w i t h t h e r e s u l t t h a t when t e s t i n g a l l -34-t h e g r a s s e s had about the same m o i s t u r e c o n t e n t . A l t h o u g h t h i s experiment showed no d i f f e r e n c e s i n r e s p o n s e t o g r a s s e s , s e l e c t i o n o f h a b i t a t by p r e f e r e n c e f o r c e r t a i n g r a s s s p e c i e s cannot be r u l e d o u t . Other p o s s i b l e elements o f i m p o r t a n c e i n c l u d e ground c o v e r ( b o t h h e i g h t and d e n s i t y ) , s o i l t y p e , s o i l m o i s t u r e , and degree o f d i s t u r b a n c e t o t h e s o i l and v e g e t a t i o n . Of t h e s e b o t h c o v e r and d i s t u r b -ance have been suggested by t h i s s t u d y t o be o f major i m p o r t a n c e . The p a r t i c u l a r c h a r a c t e r i s t i c s o f an a r e a which are i m p o r t a n t i n h a b i t a t s e l e c t i o n would be an i n t e r e s t i n g s u b j e c t f o r f u r t h e r e x p e r i m e n t . I t i s p o s s i b l e t h a t t h e a l t e r a t i o n o f one c r i t i c a l c h a r a c t e r i s t i c o f an a r e a would be s u f f i c i e n t t o p r e v e n t c o n g r e g a t i o n s o f g r a s s h o p p e r s . 6. SUMMARY 1. Grasshopper numbers ranged from l e s s t h a n one per square meter on t h e c l i m a x Agropyron s p i c a t u m community, t o more t h a n 100 per square meter on t h e d i s c l i m a x Poa communities. The most common s p e c i e s were Camnula p e l l u c i d a , C. x a n t h i p p u s , and M e l a n o p l u s s a n g u i n i p e s . 2 . The l a r g e s t numbers o f i n s e c t s t h r o u g h o u t t h e summer were found i n t h e d i s c l i m a x Poa communities, perhaps because i n t h e s e communities t h e permanent w i l t i n g p o i n t was n o t re a c h e d u n t i l much l a t e r i n t h e summer t h a n i n o t h e r communities. On t h e c l i m a x (Agropyron s p i c a t u m ) communities t h e i n s e c t numbers remained r e l a t i v e l y low and t h e s p e c i e s c o m p o s i t i o n q u i t e u n i f o r m t h r o u g h o u t t h e summer. 3 . A p l a n t community a n a l y s i s showed t h a t t h e a r e a s under s t u d y were c h a r a c t e r i z e d by v a r i o u s c o m b i n a t i o n s o f f o u r prominent g r a s s s p e c i e s : Agropyron s p i c a t u m , K o e l e r i a c r i s t a t a , Poa p r a t e n s i s , and S t i p a c o l u m b i a n a . 4. A g r a z e d b l a d e a n a l y s i s o f t h r e e communities ( A r t e m e s i a  f r i g i d a , Poa - S t i p a . and Poa) showed t h a t 19%, 14%, and 35%, r e s p e c t i v e l y , o f g r a s s b l a d e s was removed by g r a z i n g i n s e c t s . 5 . The g r a s s s p e c i e s most u t i l i z e d by g r a s s h o p p e r s were K o e l e r i a c r i s t a t a (46% damage), Poa p r a t e n s i s ( 2 8 % ) , P. secunda (21%), and S t i p a c o l u m b i a n a (13%). There was v i r t u a l l y no g r a z i n g on Agropyron s p i c a t u m . -36-6 . G r a s s h o p p e r s were l e a s t numerous on the c l i m a x Agropyron  s p i c a t u m community where o n l y 21% o f the t o t a l g r a s s was o f t h e f o u r p r e f e r r e d s p e c i e s , and where o n l y 32% o f t h e ground was cove r e d by v e g e t a t i o n . H i g h e s t numbers o f g r a s s h o p p e r s were found on a d i s c l i m a x Poa community, where 90% o f t h e g r a s s was o f a p r e f e r r e d s p e c i e s , and where t h e ground was 62% c o v e r e d . W i t h i n t h e s e communities, t h e y tended t o con-g r e g a t e on a r e a s t h a t had been g r a z e d o r t r a m p l e d by l i v e s t o c k . 7. The e x c l o s u r e cage experiment showed t h a t w h i l e g r a s s -hoppers consume a f a i r l y l a r g e amount o f g r a s s , t h e y appar-e n t l y have l i t t l e o r no e f f e c t on the t o t a l s t a n d i n g y i e l d o f g r a s s as det e r m i n e d by an end-of-season c l i p o f v e g e t a t i o n . - 3 7 -LITERATURE CITED Anderson, N. L. and J . C. Wright 1 9 5 2 . Grasshopper i n v e s t i g a t i o n s on Montana range l a n d s . Montana Agr. E x p t . S t a . Tech. B u l l . 486. 46 pp. Anderson, L. I 9 6 I . S e a s o n a l l o s s e s i n r a n g e l a n d v e g e t a t i o n due t o g r a s s h o p p e r s . J . Econ. Entomol. 5 4 : 3 6 9 - 3 7 8 . Anderson, L. 1 9 6 4 . Some r e l a t i o n s h i p s between g r a s s -hoppers and v e g e t a t i o n . Ann. Entomol. Soc. Amer. 5 7 : 736-742. Barnes, 0 . L. 1 9 4 8 . P r o g r e s s r e p o r t on some range and g r a s s r e s e a r c h a t A r c h e r F i e l d S t a t i o n . Agr. Exp. S t a . 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R e p o r t o f t h e N i n t h m e e t i n g o f t h e N a t i o n a l S o i l S urvey committee of Canada. Can. Exp. Farm, Can. Dept. Agr. ( Ottawa). -39-Nefedov, N. I . 1931. On the degree o f i n f e s t a t i o n o f s o i l s o f T r o i t z k Steppe F o r e s t Reserve w i t h egg-pods o f A r c y p t e r a m i c r o p t e r a F.W. ( I n R u s s i a n w i t h E n g l i s h summary.) B u l l . I n s t . Rech., B i o l . Perm 8: 1-17. P a r k e r , J . R. 1930. Some e f f e c t s o f t e m p e r a t u r e and m o i s t u r e upon Melanoplus mexicanus s a u s s u r e and Camnula p e l l u c i d a Scudder ( O r t h o p t e r a ) . U n i v . o f Montana A g r i c . E x p e r . S t a . , Bozeman, Montana B u l l . No. 223. 132 pp. P f a d t , R. E. 194-9. Range g r a s s h o p p e r s as an economic f a c t o r i n the p r o d u c t i o n o f l i v e s t o c k . A g r i c . Exp. S t a . U n i v . Wyoming, Laramie. Putnam, L..G. 1962. The damage p o t e n t i a l o f some g r a s s -hoppers ( O r t h o p t e r a ; A c r i d i d a e ) o f t h e n a t i v e g r a s s -l a n d s o f B r i t i s h C o lumbia. Can. J . P l a n t S c i . 42: 496-601. Rubtzov, I . A. 1932. On th e amount of food consumed by l o c u s t s . ( I n R u s s i a n w i t h E n g l i s h summary) P l a n t P r o t . , L e n i n g r a d . 1932 (2): 31-40. Rubtzov, I . A. 1934. F e r t i l i t y and c l i m a t i c a d a p t a t i o n s i n S i b e r i a n g r a s s h o p p e r s . B u l l . E n t omol. Res. 25: 339-348. S c h e f f l e r , E. G. 19?2. An a p p r a i s a l o f u n g u l a t e h a b i t a t s i n t h e A s h n o l a Resource Management U n i t . M.Sc, T h e s i s , U n i v e r s i t y o f B. C. S h o t w e l l , R. L. 1941. L i f e h i s t o r i e s and h a b i t s o f some g r a s s h o p p e r s o f economic importance on the g r e a t p l a i n s . U. S. Dep. Agr. Tech. B u l l . 774. 47 pp. Smit h , C. C. 1940. The e f f e c t o f o v e r g r a z i n g and e r o s i o n yupon the b i o t a o f t h e mixed-grass p r a i r i e o f Oklahoma. E c o l o g y 21: 381-397. Spencer, G. J . 1956. The n a t u r a l c o n t r o l complex a f f e c t i n g g r a s s h o p p e r s i n t h e d r y b e l t o f B r i t i s h Columbia. P r o c . Tenth I n t . Congress o f E n t . 4: 497-502. Sugden, L. G. I96I. The 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 olumbia w i t h p a r t i c u l a r r e f e r e n c e t o t h e Churn Creek h e r d . B. C. Dept. o f Rec. and Con. Pub. ( V i c t o r i a ) . -40-T a y l o r , W. P., C. T. V o r h i e s , and P. B. L i s t e r . 1 9 3 5 . The r e l a t i o n o f j a c k r a b b i t s t o g r a z i n g i n s o u t h e r n A r i z o n a . J . F o r e s t r y 3 3 : 4-90-498. T r e h e r n e , R. C. and E. R. B u c k e l l . 1 9 2 4 . G r a s s h o p p e r s of B r i t i s h C olumbia. Dept. o f A g r i c . B u l l . No. 3 9 . -41-TABLE 1. E l e v a t i o n , a s p e c t , s l o p e , and s o i l c l a s s e s o f each s t u d y a r e a . I n f o r m a t i o n i s from t h e N a t i o n a l S o i l Survey Committee o f Canada ( 1 9 6 8 ) , Harper ( 1 9 6 9 ) , and from t h e p r e s e n t s t u d y . SITE ELEVATION ASPECT SLOPE SOIL CLASS SOUTH SLOPE: Mesi c Ridge (A. s p i c a t u m ) 5 7 5 0 ' SSE 28 Rego Dark Grey JUNIPER SLOPE: Me s i c Met S t a t i o n (P. p r a t e n s i s ) 5 5 2 5 ' SW 5 O r t h i c B l a c k S i l t H y d r i c Swale (P. p r a t e n s i s ) 5 6 0 0 ' SE 2 O r t h i c B l a c k S i l t M e s i c " P o a - S t i p a " (P. p r a t e n s i s , S. columbiana) 5400' SW 12 O r t h i c B l a c k S i l t M e sic Ridge ( A r t e m e s i a f r i g i d a ) 5 6 O O ' SW 23 Rego Dark Grey TABLE 2 A. C l i m a t i c d a t a f o r J u n i p e r S l o p e 1 9 6 9 . DATE ANEMOMETER EVAPORATION PRECIPITATION SOIL MOISTURE TEMPERATURE ( M i l e s ) (mis) ( i n c h e s ) ( p e r c e n t ) (F.) 1 0 * 20 30 50 Max. Min. May 19 424 , 3 1 8 - - - 6 9 . 5 2 2 . 0 June 18 6 , 9 3 8 (1) 275 (1) n i l (1) 43 61 78 95 _ _ (2) 275 (2) n i l (2) 28 36 70 80 (3) 41 60 72 85 (4) 44 70 80 86 J u l y 22 8 9 5 , 0 4 3 (1) •750 (1) 0 . 2 0 (1) 28 21 55 75 48 (2) 715 (2) 0 . 2 1 (2) pw** pw pw 31 (3) pw pw pw 20 (4) 18 pw 21 70 August 24 152,715 (1) 1100 (1) pw a t a l l depths 80 _ (2) 1100 (2) pw at a l l depths (3) pw a t a l l depths (4) pw a t a l l depths S e p t . 28 3 9 9 , 3 5 0 (1) 750 _ (1) pw a t a l l depths 52 36 (2) 775 (2) pw a t a l l depths (3) pw a t a l l depths (4) pw at a l l depths * Depth i n cms below s o i l s u r f a c e . ** Below permanent w i l t i n g p o i n t . TABLE 2 B. C l i m a t i c Data f o r South S l o p e 1 9 6 9 . DATE ANEMOMETER ( m i l e s ) EVAPORATION (mis) PRECIPITATION ( i n c h e s ) SOIL MOISTURE ( p e r c e n t ) 10* 20, 3 0 , 5 0 TEMPERATURE (F.) Max. M i n . May 20 June 19 J u l y 22 S e p t . 28 729 333,084 August 24 622,873 958,670 (1) 306 (2) -(1) 750 (2) -(1) 1026 (2) 947 (1) 446 (2) 475 (1) n i l (2) n i l (1) 0 . 2 5 (2) 0 . 2 5 (1) 0 . 3 3 (2) 0 . 3 9 (1) 0 . 7 0 (2) 0 . 6 9 pw a t a l l s t a t -i o n s and a l l d e p t h s . (1) (2) (3) (4) pw pw 44 pw 38 pw pw a t a l l d e p t h s pw a t a l l d e p t h s 76 74 80 70 30 35 36 30 * Depth i n cms below s o i l s u r f a c e . ** Below permanent w i l t i n g p o i n t . -44-TABLE 3 . G r a s s h o p p e r phenology, J u n i p e r s l o p e , 1 9 7 0 . STAGE RIDGE POA SWALE (A. f r i g i d a ) MET STATION POA-STIPA (Poa) COMMUNITY HATCH June 6 June 20 June 22 FIRST INSTAR June 11 June 22 June 2k t o June 23 J u l y 1? IMMATURE J u l y 1 J u l y 10 June 2 6 J u l y 10 IMMATURE PLUS ADULTS J u l y 10 J u l y 16 J u l y 10 J u l y 19 ADULTS J u l y 17 J u l y 28 August 1 August 1 COPULATION August 3 OVIPOSITION August 5 August 7 August 7 August 8 DECREASE IN NUMBERS J u l y 20 August 20 August 15 August 15 -45-TABLE 4. Common phytophagous insects of the Ashnola. ORDER Orthoptera FAMILY. GENUS. AND SPECIES Acrididae: Camnula p e l l u c i d a  Camnula xanthippus  Melanoplus sangumipes Tettigoniidae: Cyphoderris sp. Coleoptera Chrysomelidae, Blateridae, Carabidae, Scarabidae, Tenebrionidae, Curculionidae. Diptera Cecidomyiidae, Tipulidae, Bibionidae. Hemiptera and Homoptera Cicadellidae, Miridae, Cercopidae. Hymenoptera Lepidoptera Formicidae, Megachididae. Nymphalidae, Hesperiidae, Pieridae -46-TABLE 5 . V e g e t a t i o n : b a s a l h i t a n a l y s i s . T o t a l number o f h i t s made i n each community i s i n p a r e n t h e s e s b e s i d e community name. The f i g u r e s i n p a r e n t h e s e s b e s i d e t h e number o f v e g e t a t i o n h i t s i n d i c a t e the p e r c e n t a g e o f t o t a l v e g e t a t i o n h i t s ; t h e f i g u r e s i n p a r e n -t h e s e s b e s i d e the n o n - l i v i n g m a t e r i a l i n d i c a t e the p e r c e n t a g e o f t o t a l h i t s o f b o t h l i v i n g and n o n - l i v i n g m a t e r i a l . Dominant s p e c i e s are s t a r r e d . SPECIES SOUTH Upper (400) SLOPE P l a t s (400) JUNIPER SLOPE Poa P o a - S t i p a (HOO) (800) Ridge (370) K o e l e r i a c r i s t a t a 5 (17) 11 (9) 14 (8) 5 (3) 2 (3) Poa secunda 1 (4) 12 (9) 4 (2) 9 (6) 19 (25)* P. p r a t e n s i s 0 1 (1) 130 (74) * 78 ( 5 D * 0 S t i p a c o l u m b i a n a 0 33 (26)* 11 (6) 27 (18)* 0 Agropyron s p i c a t u m 17 (57) * 18 (14)* 2 (1) 4 (3) 1 (1) A r t e m e s i a f r i g i d a 7 (24) 0 0 8 (5) 7 (9) E r i o g o n i u m h e r a c l e o i d e s 0 2 (2) 0 0 0 A c h i l l e a ' , m i l l e f o l i u m 0 2 (2) 2 (1) 4 (3) 0 A n t e n n a r i a spp . 2 (7) 0 2 (1) 10 (7) 0 P o t e n t i l l a spp . 0 0 9 (5) 1 (1) 0 Lupinus spp. 0 2 (2) 0 0 0 Taraxacum o f f i c i n a l e 0 0 0 2 ( l ) 0 A s t e r spp. 0 0 0 1 ( l ) 0 Verbascum t h a p s u s 0 0 0 1 ( l ) 0 T r i f o l i u m spp. 0 0 0 3 (2) 0 A r a b i s spp. 1 (4) 0 0 0 0 L e w i s i a r e d i v i v a 0 0 0 0 1 (1) O x y t r o p i s 0 0 1 (1) 0 0 B r y o p h y t e s 0 47 (37)* 0 0 46 (6o)* TOTAL VEGETATION 30 (8) 128 (32) 173 (22) 152 (19) 77 (21) NON-LIVING MATTER 36? (92) (68) (78) (81) (79) -47-TABLE 6 , V e g e t a t i o n s c o v e r h i t a n a l y s i s . T o t a l number of h i t s made i n each community i s i n p a r e n t h e s e s b e s i d e community name. The f i g u r e s i n p a r e n t h e s e s r e p r e s e n t t h e pe r c e n t a g e o f t o t a l h i t s w h i c h touched v e g e t a t i o n . Comparison o f t h i s t a b l e w i t h T a b l e 5 shows t h a t g e n e r a l i m p r e s s i o n s o f wh i c h s p e c i e s a r e abundant are u n r e l i a b l e e s t i m a t e s o f a c t u a l p l a n t numbers, s i n c e a s i n g l e p l a n t o f a bushy s p e c i e s may p r o v i d e more c o v e r t h a n s e v e r a l p l a n t s o f a s p a r s e l y f o l i a g e d s p e c i e s . SPECIES SOUTH SLOPE Upper F l a t s (400) (400) JUNIPER SLOPE Poa P o a - S t i p a (800) (800) Ridge (370) K o e l e r i a c r i s t a t a 13 do) 19 (10). 27 (5) 9 (2) 9 (10) Poa secunda 1 (1) 15 (8) 11 (2) 18 (5) 22 ( 2 5 ) * P. p r a t e n s i s 0 1 (1) 278 (56) * 122 ( 3 2 ) * 0 S t i p a c o l u m b i a n a 0 74 ( 3 8 ) * 27 (5) 78 ( 2 0 ) * 6 (7) Agropyron s p i c a t u m 87 ( 7 0 ) * 48 ( 2 5 ) * 22 (4) 11 (3) 4 (5) A r t e m e s i a f r i g i d a 20 (16) 6 (3) 2 (1) 26 (7) 46 ( 5 2 ) * E r i o g o n i u m h e r a c l e o i d e s 2 (2) 14 (7) 0 24 (6) 0 A c h i l l e a m i l l e f o l i u m 2 (2) 14 (7) 0 39 (10) 2 (2) A n t e n n a r i a spp, . 0 0 4 (1) 2 (1) 0 P o t e n t i i l a spp 0 0 105 (21) * 21 (6) 0 L u p i n u s spp 0 4 (2) 0 0 0 Taraxicum o f f i c i n a l e 0 0 3 (1) 11 (3) 0 A s t e r spp 0 0 0 7 (2) 0 Verbascum t h a p s u s 0 0 1 (1) 3 (1) 0 T r i f o l i u m spp 0 0 0 0 0 A r a b i s spp 0 L e w i s i a r e d i v i v a 0 0 0 0 0 1 (1) 0 1 (1) 0 O x y t r o p i s 0 0 10 (2) 3 (1) 0 A l l i u m cernuum 0 0 0 4 (1) 1 (1) U n i d e n t i f i e d 2 (1) 0 8 (2) 4 (1) 0 No c o v e r h i t : 270 (68) 202 (51) 301 (38) 418 (52) 281 (76) Cover h i t s : 125 (32) 195 (49) 499 (62) 382 (48) 89 (24) -48-TABLE 7 , Insect grazing of grasses on Juniper slope, 1 9 7 0 . The t o t a l number of blades and the number of these that are i n -jured are straight counts. The "percentage removed" from injured blades i s an estimate. The " t o t a l percentage removed" i s c a l -culated from the number of injured blades and the estimated "percentage removed". The t o t a l percent damage (to a l l species) i n each area i s a weighted mean of the " t o t a l percentage re-moved" from each species, and i s underlined. ARTEMESIA FRIGIDA RIDGE COMMUNITY Grass species No. blades No. injured % Removed from Total % injured blades removed Koeleria c r i s t a t a -Poa secunda 69 31 (45%) 42% 19% Poa pratensis - - - -Stipa columbiana - - - -Agropyron spicatum 6 2 (33%) 50% 17% A l l species (weighted t o t a l ) 75 33 (44%) 43% 19% POA COMMUNITY Koeleria c r i s t a t a 75 71 (95%) 54% 51% Poa secunda 28 23 (82%) 48% 39% Poa pratensis 523 405 (77%) 43% 33% Stipa columbiana 65 51 (78%) 40% 31% Agropyron spicatum 9 7 (78%) 85% 66% A l l species 700 557 (80%) 45% 3 ^ POA - STIPA COMMUNITY Koeleria c r i s t a t a 24 13 (54%) 53% 29% Poa secunda 35 8 (23%) 48% 11% Poa pratensis 263 83 (32%) 55% 18% Stipa columbiana: 138 24 (17%) 24% 4% Agropyron spicatum 12 7 (58%) 53% 31% A l l species 472 135 (29%) 49% 14% -49-TABLE 8 . G r a s s e s g r a z e d by i n s e c t s : C o n s o l i d a t e d E s t i m a t e s . The weig h t e d d a t a from t h e t h r e e communities shown i n Table 7 i s summed t o g i v e an e s t i m a t e o f g r a s s e s p r e f e r r e d by g r a s s h o p p e r s . GRASS SPECIES MEAN % INJURED TOTAL % REMOVED (weighted) K o e l e r i a c r i s t a t a 85% 46% (N~^~99l Poa p r a t e n s i s 62% 28% (N = ? 8 6 ) Poa secunda 47% 21% (N = 132) S t i p a c o l u m b i a n a 37% 13% (N = 203) -50-TABLE 9. C a r r y o v e r on t h e J u n i p e r s l o p e P o a - S t i p a community, 14 May 1970. MEAN WEIGHT OF CARRYOVER (Gms/square meter) S t a n d i n g (8 r e p l i c a t e s ) 9.15 + 1.7 * F a l l e n p l u s s t a n d i n g (8 r e p l i c a t e s ) 52.2 + 18.7 * S t a n d a r d e r r o r -51-TABLE 10. E x c l o s u r e cage r e s u l t s : Mean g r a s s y i e l d s from t h r e e communities i n 1969 and 1970. None o f t h e d i f f e r -ences are s i g n i f i c a n t . S t a t i s t i c s a r e shown i n Appendix 2. COMMUNITY CONTROL RAISED CAGE LOWERED CAGE grams per square meter SOUTH SLOPE: S t i p a - Agropyron 6l + 7 . 6 * 78 + 7.6 95 + 7.6 TT?69) JUNIPER SLOPE: Poa - S t i p a 57 + 14.9 59 + 14.9 81 + 14.9 (1969) Poa - S t i p a 46+12.6 54+12.6 76+12.6 TT970) Poa 140 + 21.5 144 + 21.5 171 + 21.5 TT970) * S t a n d a r d e r r o r -52-FIGURE 1. . Soil moisture at depth of 30 cms on "two communities on Juniper slope, 1970. 0 MESIC POA: MET STATION -53-FIGURE 2. Grasshopper numbers in relation to grass phenology on Juniper slope ridge community. Cover composition: 52% Artemesia frigida, 25% Poa'secunda, 10% Koeleria cristata. JUNE KOELERIA BLOOMING COVER COMPOSITION. A. FRIGIDA 5 2 % POA SECUNDA 25 % KOELERIA SPP 10% 15 POA BLOOMING 22 29 6 JULY 13 SEEDS KOELERIA DISSEMINATING CURED 20 f POA\ CURED I -54-FIGURE 3. •Air and soil temperatures, Juniper slope 1970. SOIL T E M P E R A T U R E S AT 3 CMS O ARTEMESIA FRIGIDA RIDGE • M E T STATION -55-FIGURE.LL. Changes in abudnance of insects on seven communities, 1970. South slope Agropyron spicatum and Juniper slope Calamagrostis are climax ccsmunities. Juniper slope Poa communities are dominated by Poa pratensis and P_^  secunda, and the Ridge community by Artemesia frigida and P. secunda. POA COMMUNITY JUNIPER NET. STATION CALAMAMOSTI8 JUMPER SLOPE 4 5 6 7 8 9 10 • oracnnt O HOMOmM A ouam** 6 • POA (WALE SOUTH JUMPER SLOPE A R T E M E S I A F R I G I D A R I D G E J U N I P E R S L O P E AOMPYMM SPICATUM SOUTH SLOPE -J i T POA SWALE NORTH JUNIPER SLOPE TIME IN WEEKS BEGINNING'JUNE 1 -56-APPENDIX I S c i e n t i f i c and common names, and date of flowering for plants mentioned. P r i n c i p a l references: Hitchcock ( 1 9 5 0 ) , Hitchcock et a l ( 1955 , 1959, 1961, 1964, 1 9 6 9 ) . Where nomenclatural c o n f l i c t s arose the l a t t e r was taken as the authority. SCIENTIFIC NAME COMMON NAME FIRST DATE OF FLOWERING 1970.at 5000' GRASSES: Agropyron spicatum Pursh Scnbn & Smith Bromus tectorum L. Calamagrostis rubescens Buckl. Festuca idahoensis Elmer Koeleria c r i s t a t a (L) Pers. Poa ampla Merr, Poa pratensis (L) Poa secunda (Presl.) Stipa columbiana Macoon Stipa richardsoni Link. Bluebunch wheatgrass Downy Chess Pine grass Bluebunch fescue June grass Big bluegrass Kentucky bluegrass Sandberg bluegrass Columbia needlegrass Richardson needlegrass June 25 June 29 June 29 June 11 June 3 June 9 June 4 July 10 June 25 SEDGES: Carex spp. FORBS : A c h i l l e a millefolium L. var, lanulosa Nutt. Agoseris glauca (Pursh) Raf. Allium cernuum Anemone spp Antennaria spp. L. Aquilegia formosa Arabis h o l h i e l l i i Arenaria formosa Fisch. Aster campestris L. Sedge Yarrow False dandelion Nodding onion Anemone Pussytoes Columbine Rockcress Sandwort Aster June 4 June 26 June 9 July 15 June 22 June 9 May 24 June 4 -57-APPENDIX I Co n t i n u e d A s t r a g a l u s m i s e r C a l o c h o r t u s macrocarpus D o u g l . C a s t i l l e j a m i n i a t a C i r s i u m spp. L C o l l i n s i a p a r v i f l o r a D o u g l . D e l p h i n i u m spp. Dodecatheon sp Draba sp. E p i l o b i u m a n g u s t i f o l i u m  E r i g e r o n spp. Eriogonum h e r a c l e o i d e s N u t t . F r a g a r i a g l a u c a F r i t i l l a r i a p u d i c a Geranium v i s c o s i s s i m u m F i s c h . & Mey G i l i a sp L a p p u l a f l o r i b u n d a  L e w i s i a r e d i v i v a  L u p i n u s s e r i c e u s Pursh O x y t r o p i s c a m p e s t r i s (L) D.C Pentstemon p r o c e r u s D o u g l . P h a c e l i a l i n e a r i s  Polemonium spp L. P o t e n t i l l a g r a c i l i s D a r y l Ranunculus g l a b e r r i m a s  S a x i f r a g a s p. Sedum spp. Taraxacum o f f i c i n a l e Weber T e l l i m a p a r v i f l o r a  Verbascum t h a p s u s  V i o l a sp Zigadenus venenosus M i l k v e t c h June 22 M a r i p o s a l i l y I n d i a n p a i n t b r u s h Canada t h i s t l e B l ue-eyed Mary June 25 D e l p h i n i u m June 7 Peacock May 23 W h i l l o w " g r a s s " June 7 Fireweed Fleabane June 9 Eriogonum W i l d s t r a w b e r r y June 11 Y e l l o w b e l l May 24 S t i c k y geranium June 22 G i l i a June 3 F a l s e forget-me-not June 7 B i t t e r r o o t P e r e n n i a l l u p i n e .Loco-weed June 26 S l e n d e r b l u e b e a r d -tongue June 22 P h a c e l i a June 29 B l u e Jacob's l a d d e r June 11 C i n q u e f o i l June 26 B u t t e r c u p May 24 S a x i f r a g e June 21 S t o n e c r o p D a n d e l i o n May 23 F r i n g e cup May 23 Common m u l l e i n V i o l e t . May 23 Death camas June 11 -58-APPENDIX I Co n t i n u e d SHRUBS AND TREES: A r c t o s t a p h y l u s u v a - u r s i (L) Spreng A r t e m e s i a f r i g i d a W i l l d . J u n i p e r u s commonis P i c e a engelmanni P a r r y P i n u s c o n t o r t a Loudon v a r . l a t i f o l i a Engelm. Populus t r e m u l o i d e s Michx. Pseudotsuga m e n z i e s i i ( M i r b . Franco v a r . g l a u c a R i b e s spp. L. Rosa w o o d s i i L i n d l . S h e p h e r d i a c a n a d e n s i s (L) N u t t . B e a r b e r r y June 9 P a s t u r e sage Ground j u n i p e r Engelmann spruce Lodgepole p i n e T r e m b l i n g aspen ) Douglas f i r C u r r a n t W i l d r o s e Canada b u f f a l o b e r r y APPENDIX I I Ana l y s i s of variance of exclosure cage r e s u l t s . SOUTH SLOPE: S t i p a - Agropyron (1969) Source df Mean Square t (18 d f ) T o t a l 20 563 Treatment 2 2006 R e s i d u a l 18 403 1.7 JUNIPER SLOPE: Poa - S t i p a (1969) Source df T o t a l Treatment R e s i d u a l 23 2 21 Poa - S t i p a (1970) Source T o t a l Treatment R e s i d u a l Poa (1970) Source T o t a l Treatment R e s i d u a l df 23 2 21 df 20 2 18 Mean Square 1760 1410 1793 Mean Square 1449 3284 1279 Mean Square 3092 1564 3261 t (21 d f ) 1.1 t (21 d f ) 1.4 t (18 d f ) 0 . 9 

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