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Physiological response of deer on ranges of varying quality. Klein, David R. 1963

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PHYSIOLOGICAL RESPONSE OP DEER ON RANGES OF VARYING QUALITY by DAVID ROBERT KLEIN A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY i n the Department of Zoology We accept t h i s t h e s i s as conforming to the requ i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA March, 1 9 6 3 In presenting 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 m e n t of the requirements f o r an advanced degree at the Un i v e r s i t y of B r i t i s h Columbia, I agree that 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 reference and study. I fu r t h e r agree that permission f o r extensive copying of 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 granted by the Head of my Department or by h i s representatives. It 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 f o r f i n a n c i a l gain s h a l l not be allowed without my written permission. Department of Zoology  The U n i v e r s i t y of B r i t i s h Columbia, Vancouver 8, Canada. Date March 12, 1963 PUBLICATIONS 1957 - The b l a c k - t a i l e d deer i n Alaska. U.S.F.W.S., Alaska W i l d l . Mgmt. Series No. 1, 13 p. 1958 - The status of the Brown Bear in Alaska. 9th Alaska Science Conference, U n i v e r s i t y of Alaska. 1959 - Saint Matthews Island reindeer-range study. U.S.F.W.S. Spec. S c i . Report No. 43, 48 p. 1959 - Track d i f f e r e n t i a t i o n for censusing bear populations. J . W i l d l . Mgmt. 23: 361-363. 1960 - Natural m o r t a l i t y patterns of deer i n South-east Alaska. J . Wildl. Mgmt. 24: 80-88. 1962 - Rumen contents analysis as an index to range q u a l i t y . Trans.N.A. W i l d l . Conf. 27: 150-164. The U n i v e r s i t y of B r i t i s h Columbia FACULTY OF GRADUATE STUDIES PROGRAMME OF THE FINAL ORAL EXAMINATION FOR THE DEGREE OF DOCTOR.OF PHILOSOPHY of DAVID ROBERT KLEIN B . S.j U n i v e r s i t y of Connecticut, 1951 M.S., U n i v e r s i t y of Alaska, 1953 TUESDAY, MARCH 12, 1963 AT' 11:00 A.M. IN ROOM 3332, BIOLOGICAL SCIENCES BUILDING : COMMITTEE IN CHARGE Chairman: F.H. Soward J.F. Bendell I. McT. Cowan V.J. K r a j i n a M.F. McGregor H.C. Nordan T.M.C. Taylor M.D.F. Udvardy A.J. Wood External Examiner: A. Starker-Leopold U n i v e r s i t y of C a l i f o r n i a Berkeley, C a l i f o r n i a PHYSIOLOGICAL RESPONSE OF DEER ON RANGES OF VARYING QUALITY ABSTRACT Limited work has been done in the f i e l d of ecology to r e l a t e growth and development of wild ungulates to the q u a l i t y of t h e i r natural forage. This study was conducted i n Southeast Alaska during the summers of 1959, 1960 and 1961 to i d e n t i f y the factors of the environment which a l t e r the plane of n u t r i t i o n of deer (Odocoileus hemionus s i t k e n s i s ) and result i n v a r i a -tions in body s i z e . Woronkofski and Coronation Islands, suspected to produce deer of wide contrast i n body s i z e , were chosen as study areas and q u a l i t a t i v e and q u a n t i t a t i v e measurements were made of both the deer and the range on the two islands. Results of q u a n t i t a t i v e analyses of vegetation on the two islands i n d i c a t e that Woronkofski Island g r e a t l y outranks Coronation Island i n : 1) plant den-s i t y and species abundance i n the forest and muskeg types, 2) t o t a l area of subalpine and alpine types and t o t a l area of f o r e s t type on an equal density basis and 3) t o t a l vegetated area on an equal density basi s . Q u a l i t a t i v e evaluation of forage species through the use of chemical analyses did not show s i g n i f i c a n t d i f f e r e n c e s between islands i n comparisons of s i m i l a r species under comparable s i t e conditions. The physio-l o g i c a l stage of plant growth appeared to be the most important f a c t o r i n determining n u t r i t i v e q u a l i t y of vegetation. Analyses of rumen samples enabled a clear separa-t i o n between Woronkofski and Coronation Islands on the basis of range q u a l i t y . Nitrogem content of both the gross and washed rumen samples was c o n s i s t e n t l y higher i n the Woronkofski group than i n those from Coronation Island. An inverse r e l a t i o n s h i p existed with respect to the f i b e r content. Other techniques of rumen con-tents analyses supported the comparative evidence from the chemical analyses. Regression analyses of weights and skeletal, measure-ments of the specimen deer showed growth differences between the two islands which are a t t r i b u t a b l e to d i f -f e r i n g l e v e l s i n the annual n u t r i t i o n a l regimens of the xieer. The use of the femur/hind foot r a t i o supports the thesis that the larger s i z e of deer on Woronkof-s k i than on Coronation Island i s the product of nu-t r i t i o n a l rather than genetic causes. No s i g n i f i c a n t d i f f e r e n c e s , that could be r e l a t e d to n u t r i t i o n a l f a c t o r s , were found i n the levels of "parasitism among the deer of the two i s l a n d s . The sex and age composition of the deer popula-tions on the two islands r e f l e c t s the q u a l i t y and quantity of forage present on the ranges. Conclusions of the study are that the larger s i z e and more rapid rate of growth of deer on Woronkofski Island i n comparison to those on Coronation Island are the r e s u l t of the p h y s i o l o g i c a l response of the deer on both islands to pronounced differences i n the n u t r i t i v e q u a l i t y and quantity of t h e i r respective ranges. These n u t r i t i v e f a c t ors are p r i m a r i l y opera-t i v e during the summer period of growth of both the vegetation and the deer. GRADUATE STUDIES F i e l d of study:. Zoology Invertebrate Zoology Quantitative Methods i n Zoology Seminar i n Ecology Comparative Physiology P.A. Dehnel P.A. Larkin S t a f f W.S. Hoar Other Studies: Fundamentals of N u t r i t i o n Fundamentals of Animal Growth and Energetics Advanced Animal. N u t r i t i o n Forest Synecology Introduction to Synoptic Oceanography J. B i e l y A.J. Wood A.J. Wood V.J. K r a j i n a G.L. Pickard i i ABSTRACT PHYSIOLOGICAL RESPONSE OP DEER ON RANGES OF VARYING QUALITY. Limited work has been done i n the f i e l d of ecology to relate growth and development of wild ungulates to the quality of t h e i r natural forage. This study was conducted i n Southeast Alaska during the summers of 1959, I960 and 1961 to i d e n t i f y the factors of the environment which a l t e r the plane of n u t r i t i o n of deer (Odocoileus hemionus sitkensis) and res u l t i n variations in body s i z e . Woronkofski and Coronation Islands, suspected to produce deer of wide contrast i n body s i z e , were chosen as study areas and q u a l i t a t i v e and quantitative measure-ments were made of both the deer and the range on the two islands. A t o t a l of 63 deer specimens were co l l e c t e d , from which sex, age, weights and measurements were recorded and samples of rumen contents were coll e c t e d and analysed. Specimens were examined to determine lev e l s of parasitism. Sex and age status of deer that died from natural causes were u t i l i z e d for additional data. The range was evaluated through the use of l i n e intercept transects correlated with chemical analyses of major forage species. Results of quantitative analyses of vegetation on the two islands indicate that Woronkofski Island greatly outranks Coronation Island i n : 1) plant density and species abundance in the forest (110 to 5^ interceptions) and muskeg (297 to 242 interceptions) types, 2) t o t a l area of subalpine (4.72 to 1.82 i i i sq.mi.) and a l p i n e (5.00 to 0.24 sq.mi) types and t o t a l area of f o r e s t type on an equal density b a s i s (13.05 to 11.64 sq.mi.), and 3) t o t a l vegetated area on an equal density b a s i s (24.31 to 16.51 sq.mi.). Q u a l i t a t i v e e v a l u a t i o n of forage species through the use of chemical analyses d i d not show s i g n i f i c a n t d i f f e r e n c e s between i s l a n d s i n comparisons of s i m i l a r species under comparable s i t e c o n d i t i o n s . There were i n d i c a t i o n s that a l p i n e and muskeg ve g e t a t i o n was of higher q u a l i t y than f o r e s t v e g etation and a l p i n e p l a n t s appeared of s l i g h t l y higher q u a l i t y than s i m i l a r species growing on low e l e v a t i o n muskegs. The p h y s i o l o g i c a l stage of plant growth appeared to be the most important f a c t o r i n determining n u t r i t i v e q u a l i t y of v e g e t a t i o n . Analyses of rumen samples enabled a c l e a r s e p a r a t i o n between Woronkofski and Coronation Islands on the basis of range q u a l i t y . Nitrogen content of both the gross and washed rumen samples was c o n s i s t e n t l y higher i n the Woronkofski group than i n those from Coronation I s l a n d . An inverse r e l a t i o n s h i p e x i s t e d w i t h respect to the f i b e r content. Other techniques of rumen contents analyses i n v o l v i n g c e n t r i f u g e f r a c t i o n a t i o n of microorganisms, l i g h t transmittancy determinations of rumen l i q u o r and microscope counts of protozoa supported the comparative evidence from the chemical analyses. Regression analyses of weights and s k e l e t a l measurements of the specimen deer showed growth d i f f e r e n c e s between the two i s l a n d s which are apparently a t t r i b u t a b l e to d i f f e r i n g l e v e l s \ i v i n the annual n u t r i t i o n a l regimens of the deer. Skeletal r a t i o s were found to be more r e l i a b l e than body weight as measures of growth differences because s k e l e t a l parts are less subject to short term fluctuations i n the environment and they, therefore, more accurately r e f l e c t p hysiological age. The use of the femur/hind foot r a t i o supports the thesis that the larger size of deer on Woronkofski than on Coronation Island i s the product of n u t r i t i o n a l rather than genetic causes. No s i g n i f i c a n t differences, that could be related to n u t r i t i o n a l factors, were found i n the levels of parasitism among the deer of the two i s l a n d s . The sex and age composition of the deer populations on the two islands r e f l e c t s the quality and quantity of forage present on the ranges. Conclusions of the study are that the larger size and more rapid rate of growth of deer on Woronkofski Island i n comparison to those on Coronation Island are the r e s u l t of the p s y s i o l o g i c a l response of the deer on both islands to pronounced differences in the n u t r i t i v e quality and quantity of t h e i r respective ranges. These n u t r i t i v e factors are primarily operative during the summer period of growth of both the vegetation and the deer. The factors of the environment responsible for the differences i n quality and quantity of forage present on the two islands are primarily differences i n the degree of a l t i t u d i n a l and topographic V a r i a t i o n and i n the r e l a t i v e proportions of alpine and subalpine areas and secondarily i n the regional c l i m a t i c differences and the presence or absence of predation. V TABLE OF CONTENTS Page INTRODUCTION 1 METHODS 6 THE STUDY AREAS 9 Woronkofski Island 9 Coronation Island 15 THE VEGETATION 21 Methods of Evaluation 2 1 Quantitative Evaluation of the Vegetation 23 Forest Type 23 Muskeg Type 32 Subalpine Type 34 Alpine Type 37 Other Vegetation Types *H Quantitative Comparison of Woronkofski and Coronation Island Ranges 43 Pressure of Deer on the Range 6^ Qualitative Evaluation of the Vegetation ^8 Discussion of Factors Governing Range Quality 59 Physiological Stage of Plant Growth 59 Photos'ynthetic Variation 6l Topographic Variation 64 S o i l F e r t i l i t y 72 THE DEER 75 Function and Adaptability of the Rumen 75 v i Page Rumen Contents Analysis 76 Methods of Analysis 78 Results and Discussion 80-Conclusions 92 Weights and Skeletal Measurements 93 Methods 95 Results and Discussion 97 Annual Cycle of Nutritio n 119 Levels of Parasitism 123 The Deer Populations 128 CONCLUSIONS 1^3 APPENDIX 151 LITERATURE CITED 160 v i i TABLES Table 1. Areas of Coronation and Woronkofski Islands 12 2 . Analyses of s o i l s 14 3 . Weather data 16 4 . Areas of vegetation types 24 5 . Comparison of plant density i n vegetation types 28 6.. Comparison of plant species abundance 29 7. Areas and plant densities on the study islands 45 8. Analyses of forage from Woronkofski Island 50 9 . Analyses of forage from Coronation Island 51 1 0 . Analyses of forage from Mitkof Island and the mainland 52 11 . Average composition of domestic green forages 55 12 . Chemical analyses of rumen samples 83 1 3 . Comparison of treatment methods for rumen samples 89 14. Weights and measurements of male deer from the study islands 98 15 . Weights and measurements of the female deer from the study islands 101 16 . Weights of male deer from the study islands and adjacent areas 115 17 . Weights of female deer from the study islands and adjacent areas 116 1 8 . Hind foot lengths of male deer from the study islands and adjacent areas 117 19. Hind foot lengths of female deer from the study islands and adjacent areas 118 2 0 . Degree of parasite i n f e s t a t i o n 126 2 1 . Deer observations 138 v i i i Table Page 2 2 . Relative Proportions of young and old deer 139 2 3 . Causes of death and sex rat i o s among the natural mortality 141 Tables i n Appendix 24. Age, weight and s k e l e t a l ratios of Woronkofski males . 152 2 5 . Age, weight and ske l e t a l r a t i o s of Coronation males 153 2 6 . Age, weight and s k e l e t a l r a t i o s of Woronkofski females 155 2 7 . Age, weight and s k e l e t a l r a t i o s of Coronation females 156 2 8 . Age, sex, femur length and condition of Woronkofski natural mortality 157 2 9 . Age, sex, femur length and condition of Coronation natural mortality 158 ix FIGURES Figure Page 1. Map showing location of study areas 5 2. Map of Woronkofski Island 10 3. D i s t r i b u t i o n of t o t a l land areas by a l t i t u d e 13 4. Average monthly temperatures 17 5. Map of Coronation Island 18 6. Comparisons of vegetation types on the study islan d s - 25 7. Forest f l o o r vegetation on Woronkofski Island 27 8. Forest type on Coronation Island 27 9. Vegetation out of reach of deer on Coronation Island- 31 10. Hedging of spruce by deer on Coronation Island 31 11. Muskeg type on Coronation Island 35 12. Subalpine vegetation on Woronkofski Island 35 13. Subalpine vegetation on Coronation Island 38 14. Residual snow i n mid-summer on Woronkofski Island 38 15. Vegetation on limestone on Coronation Island 40 16 . Seasonal change i n mineral composition of forage 57 17. Topographic effects on solar intensity 67 18. Relationship between f i b e r and nitrogen i n rumen samples 85 19. Nitrogen content of rumen samples under varying treatments • 90 20. Weight comparisons of male deer 100 21. Comparisons of weights and measurement of female deer 102 22. Ef f e c t of plane of n u t r i t i o n on growth 104 2 3 . Skeletal relationships among the bones of the hind leg 109 X Figure Page 24. Relationship of length of bones of the hind leg to age 111 25. Skeletal relationships of male deer from the study islands 113 26. Annual rela t i o n s h i p of n u t r i t i o n a l requirements to forage 119 x i PREFACE The f i e l d work upon which t h i s report i s based was financed by Federal A i d to W i l d l i f e R e s t o r a t i o n funds under p r o j e c t W-3-R-13 and W-6-R-1, W-6-R-2 and W-6-R-3. During the p e r i o d of the study I was employed by the U.S. F i s h and W i l d l i f e Service through June 3 0 , 1959 and a f t e r that date by the Alaska Department of F i s h and Game. The a n a l y s i s of forage samples was a c o n t r i b u t i o n of General M i l l s I nc., Sperry Operations Laboratory at Stockton, C a l i f o r n i a . S c i e n t i f i c names f o r pl a n t s f o l l o w the usage of Hulten (19^1-1950) while common names are taken from Anderson ( 1 9 5 9 ) . Several people generously c o n t r i b u t e d t h e i r time and thought to the study. Many ideas incorporated i n t o the planning of the p r o j e c t developed from d i s c u s s i o n s w i t h Dr. Ian McT. Cowan of the Department of Zoology and Dr. A. J . Wood of the D i v i s i o n of Animal Science, U n i v e r s i t y of B r i t i s h Columbia. Mr. Harry Merriam and Mr. Paul Garceau, both b i o l o g i s t s with the Alaska Department of F i s h and Game were of immeasurable help to the study as w e l l as being welcomed companions i n the f i e l d . Thanks are due to Dr. A l b e r t W. Johnson of the Department of B i o l o g y , U n i v e r s i t y of Alaska and Dr. L e s l i e A. V i e r e c k , B i o l o g i s t , Alaska Department of F i s h and Game f o r t h e i r a s s i s t a n c e i n p r o v i d i n g the plant i d e n t i f i c a t i o n s ; to Mr. Kenneth A. x i i Neiland, B i o l o g i s t , Alaska Department of Pish and Game for his assistance i n the f i e l d and for i d e n t i f i c a t i o n of parasite material; and to Mr. Joseph Johnson and Mr. Charles Graham of the U.S. Pish and W i l d l i f e Service and Mr. Thomas O'Parrell of the Alaska Department of Pish and Game for t h e i r help during certain phases of the f i e l d research. I am indebted to Dr. Bonita Neiland and Dr. Clyde P. Herreid of the Department of Biology, University of Alaska and Dr. L e s l i e A. Viereck and Dr. Robert B. Weeden of the Alaska Department of Pish and Game and Mr. Valerius Geist of the Department of Zoology, University of B r i t i s h Columbia for t h e i r valuable c r i t i c i s m of various sections of the manuscript; Dr. Cowan and Dr. Wood and Dr. Miklos M.D.F. Udvardy of the Department of Zoology, University of B r i t i s h Columbia for t h e i r c r i t i c i s m of the f i n a l manuscripts and to Mrs. Helen V. Anderson who typed t h i s f i n a l draft of the the s i s . To my wife, Arlayne who endured with patience my long absences during the f i e l d seasons and the sometimes hectic moments of thesis preparation I extend my he a r t f e l t thanks. INTRODUCTION Growth responses of deer (Odocoileus spp.) to variations in range qu a l i t y have not been intensively studied. However publications by Hosley and Ziebarth (1935) , Clepper (1936) , Julander (1937) and most other early reports stressed the importance of winter range i n deer n u t r i t i o n . As a resu l t of these and l a t e r studies, workers have emphasized the co r r e l a t i o n often found to exist between size of deer and the protein content of the winter range forage upon which they subsist. Winter forage quality, as r e f l e c t e d i n protein content, and quantity as measured by units of available browse have been generally accepted as bases for the evaluation of range pot e n t i a l for the production of deer and maintenance of t h e i r physiological welfare. More recently, detailed studies by Cowan and Wood (1955) , Riney (1955) , French, et_ a l . (1955) , Taber and Dasmann (1958) , Wood, et a l . (1962) and other workers have led to a better under-standing of some of the seasonal n u t r i t i v e requirements of wild ruminants. However,in spite of these studies major emphasis has been focused on aspects of the winter range requirements of deer without proper consideration of the significance of the spring, summer and f a l l components of the range i n the annual n u t r i t i o n a l regimen of deer. In the f i e l d of w i l d l i f e management there has been a general lack of recognition of the complex physiological basis of growth and i t s course i n wild ungulates. L i t t l e use has been made of the wide scope of l i t e r a t u r e on the subject of n u t r i t i o n 2 available i n the f i e l d of animal husbandry. Much of the theory and many of the techniques developed through experiments with domestic stock are d i r e c t l y applicable to work with wild ungulates. In Alaska, b l a c k - t a i l e d deer (Odocoileus hemionus sitkensis) show pronounced variations i n body size from islan d to i s l a n d within the Alexander Archipelago and on the adjacent mainland. In most cases the islands are s u f f i c i e n t l y i s o l a t e d to guarantee the discreteness of populations although over a period of years enough movement of deer between islands apparently exists to preclude the p o s s i b i l i t y of genetic i s o l a t i o n accounting for size variations i n the deer. Environmental factors are therefore assumed to be primarily responsible for differences i n growth and development as r e f l e c t e d i n body s i z e . This unique s i t u a t i o n of ins u l a r deer populations, showing measurable differences i n body size and growth, offers the opportunity to conduct studies on discrete populations of deer. In addition, because of the li m i t e d opportunity for movement of the deer, they are subject to the long range effects of the. environmental conditions e x i s t i n g on the i s l a n d on which they l i v e . This s i t u a t i o n was taken advantage of to study the factors of the environment which a l t e r the plane of n u t r i t i o n of deer and result i n variations i n body s i z e . Two islands were chosen as study areas which were suspected to produce deer of wide contrast i n body s i z e . Islands of approximately 25 square miles i n area were chosen; f i r s t , to 3 insure adequate area to include wide a l t i t u d i n a l , topographic and vegetative v a r i a t i o n s ; second, to be of small enough size to guarantee homogeneous deer populations and to insure that each islan d would f a l l within a single climatic zone; and t h i r d , to be of a size conducive to the analyses of the vegetation components present. The islands chosen are within the natural range of the Sitka b l a c k - t a i l e d deer i n Southeast Alaska, (Figure 1 ) . The two islands, Woronkofski and Coronation, are forested with a western hemlock-Sitka spruce forest type and with varying amounts of muskeg and alpine areas. Woronkofski Island i s located adjacent to the coastal mountains and has r e l a t i v e l y warm summers and cold winters with heavy snowfall. Coronation Island, i n contrast, l i e s on the western edge of the archipelago adjacent to the P a c i f i c Ocean and has cool summers and mild winters of l i g h t snowfall. Over long periods of time these climatic d i s p a r i t i e s have had markedly d i f f e r e n t effects upon the deer populations of the two islands. On Woronkofski Island, deer numbers have fluctuated widely in association with a series of r e l a t i v e l y mild winters interrupted by severe ones. Heavy winter losses have been frequent and severe enought to prevent excessive overuse of the range. Even during the r e l a t i v e l y mild winters, a v a i l a b i l i t y of forage i s greatly r e s t r i c t e d and protected from overuse at elevations above a few hundred feet by the accumulation of deep snows. On Coronation Island, deer populations have not been r e s t r i c t e d by winter snow accumulation 4 and i t i s l i k e l y that a continuing heavy population pressure on the range has resulted i n the elimination of important winter and summer forage species. 5 F i g . 1. L o c a t i o n of study areas and other l o c a t i o n s mentioned i n the t e x t . The n a t u r a l range of deer i n A l a s k a i n c l u d e s the i s l a n d s and mainland southeast of Icy S t r a i t . 6 METHODS This study was conducted during the summers of 1959, I960 and 1961 although during a t r i p to Coronation Island i n March, 1958 seven deer were collected which are included i n these data. Petersburg was the base of operations and t r a v e l to and from the islands was by boat, airplane and helicopter. The f i e l d i t i n e r a r y was as follows: Date 1958 March 12-13 1959 June 9-12 July 7-9 August 4-10 August 11-12 I960 May 19-22 May 24-26 Island Coronation Coronation Woronkofski Coronation Woronkofski Coronation Woronkofski F i e l d Investigations Co l l e c t i o n of deer specimens. Col l e c t i o n of forage samples, deer sex and age observations, natural mortality data. Es t a b l i s h vegetation transects, c o l l e c t s o i l samples, forage samples, deer sex and age composition. Es t a b l i s h vegetation transects, deer specimen c o l l e c t i o n , natural mortality data, sex and age composition. Estab l i s h vegetation transects, deer sex and age composition, forage samples. Collect forage samples, deer specimens, natural mortality data, establish vegetation transects, deer sex and age composition. Collect forage samples, deer specimens, natural mortality data, est a b l i s h vegetation transects,-deer sex and age composition. 7 June 17-22 Coronation June 28-30 July 11-15 July 27-August 18 August 27 ' 1961 July 11-20 Woronkofski Woronkofski Coronation Woronkofski Woronkofski Collect forage samples, deer specimens, natural mortality data, es t a b l i s h vegetation transects, deer sex and age composition. Collect forage samples, deer specimens, natural mortality data, es t a b l i s h vegetation transects, deer sex and age composition. Collect forage samples, deer specimens, natural mortality data, es t a b l i s h vegetation transects, deer sex and age composition. Collect forage samples, deer specimens, natural mortality data, e s t a b l i s h vegetation transects, deer sex and age composition. Establish vegetation transects, deer sex and age composition. Collect deer specimens, natural mortality data/ sex and age composition. Qualitative and quantitative measurements were made of both the deer and the range on the two islands. Twenty-six deer specimens were coll e c t e d from Woronkofski and 37 from Coronation Island. Sex, age, weights and length measurements were recorded and samples of rumen contents were collected from a l l specimens. In addition specimens were examined to determine the degree of parasite i n f e s t a t i o n . Sight records were kept of the deer observed to rel a t e sex and age composition of the populations. Remains of deer that died from natural 8 causes were examined and age, sex, femur length and cause of death were ascertained whenever possible. The range was evaluated through the use of l i n e intercept transects located i n the major cover types and correlated with chemical analyses of major forage species. Weather summaries from adjacent stations were analyzed and s o i l s of the two islands were tested. 9 THE STUDY AREAS The Southeast or "Panhandle" region of Alaska i s character-ized by abrupt, mountainous topography f i n e l y dissected by numerous water channels, deep fjords and bays. Mountains r i s e d i r e c t l y from the sea to elevations usually not exceeding 3,500 feet on the islands but frequently over 7,000 feet on the mainland. The dense, coniferous r a i n forests of the region strongly r e f l e c t the influence of the r e l a t i v e l y mild and moist maritime climate. Western hemlock (Tsuga heterophylla) and Sitka spruce (Picea sitchensis) are the dominant forest trees with varying amounts of yellow (Chamaecyparis no'otkatenis) and red cedar (Thuya p l i c a t a ) . Lodgepole pine (Pinus contorta) i s r e s t r i c t e d to poorly drained bog s i t e s and mountain hemlock (Tsuga mertensiana) i s common at higher elevations. Forest f l o o r vegetation i s usually dense but varies with the degree of closure of the forest canopy and other edaphic conditions. Bog vegetation occurs on the open muskegs and the alpine areas are characterized by a lush growth of forbs and sedges. Woronkofski Island Woronkofski Island i s located adjacent to the coastal mountains i n the central portion of the Alexander Archipelago (Figures 1 and 2). It i s approximately six miles long by four wide and comprises 24.4 square miles. No deep bays penetrate the shoreline and the land r i s e s f a i r l y abruptly from the sea on a l l sides to elevations of 2,500 feet or more. Mount Woronkofski r i s e s to 3,240 feet, the highest point on the i s l a n d . F i g . 2. Woronkofski Island. U.S. Geological Survey, Petersburg (B-2) Quadrangle, 1957; scale of one inch to the mile (1:63, 360). 11 The mountainous nature of the island r e s u l t s i n over h a l f of the land area l y i n g at elevations above 1 , 0 0 0 feet (Table 1 and Figure 3 ) . Woronkofski Island i s geologically a segment of the Coast Range batholith that forms the mountains of the adjacent mainland. The parent rock i s gr a n i t i c i n nature; predominantly quartz d i o r i t e , quartzites, quartz p h y l l i t e and hornblendite, which are intrusives of Upper Jurassic or Lower Cretaceous o r i g i n (Buddington and Chapin, 1 9 2 9 ) . Radio carbon dates (Heusser, i 9 6 0 ) indicate that recession of the late Pleistocene ice sheet in the Alexander Archipelago and adjacent mainland took place about 1 0 , 0 0 0 years ago. Soils r e f l e c t the recent g l a c i a l scouring and on Woronkofski Island, v i r t u a l l y the entire s o i l complex i s derived from the g r a n i t i c bedrock with e s s e n t i a l l y no morainal deposits. Lithosols are common on a l l of the steeper slopes p a r t i c u l a r l y at elevations above 1 , 0 0 0 feet while highly acid podzol s o i l s (pH 4) predominate at lower elevations. Above 2 , 5 0 0 feet alpine meadow s o i l s occur wherever slopes are gradual enough to allow s o i l s t a b i l i z a t i o n . At low elevations on the northwest and northeast portions of the isl a n d a few areas of bog s o i l s have developed where benches and slopes of less than 15 percent occur. Table 2 l i s t s the analyses of s o i l samples from alpine and forest areas of Woronkofski Island. C l i m a t i c a l l y , Woronkofski Island comes under the influence of the maritime climate c h a r a c t e r i s t i c of the entire Alexander Archipelago. However, wide variations i n temperature and p r e c i p i t a t i o n occur throughout the region. Annual p r e c i p i t a t i o n TABLE 1. Areas of Coronation and Woronkofski Islands (Planimetric and slope corrected values i n square miles) Coronation Island" Woronkofski Island" P l a n i - Corrected Percent P l a n i - Corrected Percent metric Area of Total metric Area of Total Total Area 28.69 30.02 22.74 24.37 Total Land Area 28.65 29.98 100.0 22.55 24.18 100.0 Land Areas: 0 - 500 f t . 12.24 12.84 42.83 5.88 6.17 25.52 Above 500 f t . 16.41 17.14 57.17 16.67 18.01 74.48 500 - 1000 f t . 11.46 11.95 39.86 4.26 4.56 18.86 Above 1000 f t . 4.95 5.19 17.31 12.41 13.45 55.62 1000 - 1500 f t . 4.11 4.31 14.38 4.17 4.54 I 8 . 7 8 Above 1500 f t . 0.84 0.88 2.94 8.24 8.91 36.85 1500 - 2000 f t . 0.84 0.88 2.94 3.39 3.69 15.26 Above 2000 f t . 0.0 4.77 5.22 21.59 2000 - 2500 f t . 0.0 3.34 3.64 15.05 Above 2500 f t . 0.0 1.43 1.58 6.53 2500 - 3000 f t . 0.0 __— 1.34 1.48 6.12 Above 3000 f t . 0.0 0.09 0.10 0.41 Total Water Area (lakes) 0.04 0.04 0.13 0.19 0.19 0.78 Perimeters (shoreline) 51.0 mi. 22.0 mi. Increase i n Land Area Due to slope 1.33 4.67 I . 63 7.23 h-1 < 500 1000 1500 2000 2500 3000 3000 A L T I T U D E (ft.) F i g . 3. Dis t r i b u t i o n of t o t a l land areas by a l t i t u d e on Woronkofski and Coronation Islands, showing the significance of al t i t u d e range and r e l a t i v e d i s t r i b u t i o n of land areas by a l t i t u d e . TABLE 2 . Analyses of s o i l s from Woronkofski and Cornation Islands^ WORONKOFSKI CORONATION f ! n n s h l f . i i i n f t n t . R \ Forest Alpine Forest Muskeg pH (Acidity) 4 . 0 4. 6 6.4 3 . 8 Organic Matter (50 1 7 . 6 8 . 8 33.4 7 5 . 2 Nitrogen 0 . 5 3 0 . 33 1 . 0 1 1 . 44 Phosphate (Lbs. Per Acre)2 15 10 20 40 Potash II 105 38 100 200 Calcium it 2 , 3 0 0 1 , 8 0 0 1 0 , 0 0 0 6 2 0 4,400 Magnesium it 320 160 1,240 Sulphur n 2 0 0 50 1 , 0 0 0 1 , 0 0 0 Iron II 2 0 0 2 2 5 5 "10 Manganese II 25 25 5 5 Copper II 1 1 3 3 Boron ti 3 i 10 - 8 Zinc II 0 0 0 Sodium II 110 60 7 2 0 620 • Approximate conversion factors: P X 2.3 = P 2 0 5 K X 1.2 = K 20 Ca X 1.4 = CaO Mg X 1.7 = MgO 1-All values are approximate, with the exception of pH, organic matter and nitrogen, and are based upon colorimetric and spectrographic analyses of extracted available constituents. Tested by Laucks Testing Laboratories, Seattle, Washington. 2 p o u n d s per acre on basis of two m i l l i o n pounds of s o i l per acre. 15 may- vary from less than 50 inches to i n excess of 200 inches while d a i l y temperatures may d i f f e r by as much as 30 or more degrees from area to area i n both summer and winter. The close proximity of Woronkofski Island to the Coast Mountains and the Stikine River valley brings i t under the influence of the continental climate to a greater extent than islands to the west (Table 3 ) . Its summers are noticeably warmer and winters colder than the average. Annual p r e c i p i t a t i o n averages 83 inches with winter snow accumulation normally greater than i n areas to the west. Figure 4 shows graphical comparisons of temperatures at weather stations adjacent to Woronkofski and Coronation Islands. Coronation Island Cornation Island l i e s on the southwestern side of the Alexander Archipelago adjacent to the P a c i f i c Ocean (Figures 1 and 5 ) . It i s i r r e g u l a r l y shaped, being incised by several bays and i n l e t s ; the is l a n d i s approximately ten miles long by three and one ha l f miles wide and comprises 30 square miles. The t e r r a i n of the is l a n d i s generally i r r e g u l a r , Karst topography i s common and c l i f f s r i s e sharply from the sea on the south and west; but altitudes are not as great as on Woronkofski Island. The highest land on Coronation Island i s 1,960 feet at Needle Peak, but over 80 percent of the land area l i e s below 1,000 feet (Table 1 and Figure 3 ) . Coronation Island i s composed predominantly of Paleozoic limestone (Buddington and Chapin, 1929) ; f o s s i l i z e d corals 16 TABLE 3. Weather Data recorded at stations adjacent to Woronkofski and Coronation Islands (U.S. Weather Bureau, 1959) Location of stations: Wrangell 37 f t . elevation, 56° 28' x 132° 23', 3 mi. N.E. of Woronkofski Island. Cape Decision - 39 f t . elevation, 56° 00' x 134° 08 4 mi. N.E. of Coronation Island. Avg. P r e c i p i t a t i o n (in.) Avg. Temperature (°F)  Wrangell Cape Decision Wrangell Cape Decision 1931-55 1941-52 1931-55 1941-52 Jan. 7.83 6.99 30.0 33.9 Feb. 6.02 4.99 31.5 35.6 Mar. 5.48 5.56 36.2 36.6 Apr. 5.22 5.14 42.6 40.5 May 4.13 3.76 49.7 45.1 June 4.17 2.83 55.0 50.1 July 5.30 4.12 57.3 52.7 Aug. 6.20 4.01 56.6 53.3 Sept. 8.55 7.92 51.9 51.3 Oct. 12.36 13.15 45.1 46.7 Nov. 9.76 9.74 37.3 40.6 Dec. 7.88 8.21 31.5 37.8 Total 82.90 76.42 Mo. Avg. 43.7 43.7 Wrangell Cape Decision Average length of growing season (days) 169 219 Average monthly snowfall (Nov.-March, in.) 12.90 3.13 (Period of record: 1950-51 and 1955-59) F i g . 5. Coronation Island. U.S. geological Survey, Craig (D-7 and D-8), Quadrangle, 1958; scale of one inch to the mile (1:63, 360). 19 c o l l e c t e d d u r i n g t h e s t u d y a t Windy Bay have been d a t e d f r o m t h e Upper D e v o n i a n p e r i o d by V . J . O k u l i t c h o f 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 G e o l o g y D e p a r t m e n t . I g n e o u s i n t r u s i v e s , a p p a r e n t l y a s s o c i a t e d w i t h t h e S i l u r i a n c o n g l o m e r a t e s and v o l c a n i c s o f K u i u I s l a n d a r e f o u n d on t h e e a s t e r n p o r t i o n o f t h e i s l a n d e a s t o f G i s h B a y . The c a l c a r e o u s bed r o c k on C o r o n a t i o n I s l a n d r e s u l t s i n e x c e l l e n t d r a i n a g e and a l t h o u g h t h e p a r e n t m a t e r i a l i s s t r o n g l y b a s i c t h e s o i l s a r e o n l y s l i g h t l y l e s s a c i d t h a n t h o s e d e v e l o p e d on n o n - c a l c a r e o u s r o c k . F o r e s t s o i l s a r e o f t h e brown p o d z o l i c t y p e . Bog s o i l s a r e n o t e x t e n s i v e on t h e l i m e s t o n e a r e a s b u t a r e common on t h e i g n e o u s b e d r o c k on t h e e a s t e r n p o r t i o n o f t h e i s l a n d . A l p i n e s o i l s a r e r e s t r i c t e d t o a v e r y l i m i t e d a r e a on N e e d l e P e a k . , S o i l sample a n a l y s e s a r e i n c l u d e d i n T a b l e 2. The c l i m a t e o f C o r o n a t i o n I s l a n d i s s t r o n g l y i n f l u e n c e d by i t s g e o g r a p h i c l o c a t i o n , j u t t i n g out i n t o t h e P a c i f i c Ocean ( T a b l e 3). B e c a u s e o f i t s r e l a t i v e l y low t e r r a i n , much o f t h e m o i s t u r e i n t h e o n - s h o r e f l o w o f a i r i s n o t i n t e r c e p t e d and i t p a s s e s o v e r h e a d t o t h e h i g h e r i s l a n d s and m a i n l a n d . A n n u a l p r e c i p i t a t i o n a t C o r o n a t i o n I s l a n d i s a p p r o x i m a t e l y 76 i n c h e s w h i c h i s a p p r e c i a b l y l e s s t h a n s u r r o u n d i n g a r e a s . O n l y 35 m i l e s t o t h e n o r t h w e s t , L i t t l e P o r t W a l t e r on B a r a n o f I s l a n d r e c o r d s an a n n u a l p r e c i p i t a t i o n o f 250 i n c h e s . The m o d e r a t i n g m a r i t i m e i n f l u e n c e r e s u l t s i n c o o l e r summers and m i l d e r w i n t e r s t h a n on 20 Woronkofski Island and other islands closer to the mainland (Figure 4). The warm winters res u l t i n a minimum of snow accumulation as average January temperatures are above freezing. 21 THE VEGETATION Methods of Evaluation In order to evaluate the vegetation complex of Woronkofski and Coronation Islands, so that comparisons would be possible, standard techniques of vegetation analysis were employed. The islands were mapped according to major vegetation types u t i l i z i n g U. S. Navy v e r t i c a l a e r i a l photographs with a scale of 1 : 2 1 , 1 2 0 . Vegetation types were then plotted on U. S. Geological Survey topographic maps with a scale of 1 : 6 3 , 3 6 0 . Areas occupied by the various vegetation types on each island were determined with a planimeter and the average slope within each of the smallest units of vegetation types was u t i l i z e d to make area corrections r e s u l t i n g from slope. Thirty, point-intercept, vegetation transects, modified a f t e r Canfield's (19^1) method, were located on each i s l a n d . The transects were allocated within vegetation types according to the r e l a t i v e proportion of each vegetation type to the t o t a l vegetated area of the i s l a n d . Transect locations were randomly chosen within vegetation types and were marked on the a e r i a l photos which were taken into the f i e l d to a s s i s t i n t h e i r location on the ground. The transects were one hundred feet long with one hundred points located at one foot i n t e r v a l s along a t i g h t l y stretched s t e e l tape. A l l interceptions of vegetation within reach of deer or ground surface material were recorded within a c i r c l e of one inch diameter at each foot i n t e r v a l . Species abundance and vegetative density, which i s comparable to plant cover, were then calculated from the transect data for each vegetation type. It should be understood that the density values include only vegetation within reach, or available to, deer (generally less than f i v e feet i n height). Also these values relate only to the frequency of transect interceptions and therefore may not be comparable where wide species v a r i a t i o n e x i s t s , for example between di f f e r e n t vegetation types. However, for the purposes of thi s study, where comparisons are made between sim i l a r vegetation types, i t was f e l t that t h i s method was adequate to enable comparisons of the vegetation on the two study islands. Samples of the common forage species used by deer were collected on the two islands. In addition, forage samples were collected from other areas for comparative purposes and to determine the variations i n n u t r i t i v e quality of the forage associated with the physiological stages of plant growth, al t i t u d e variations and other edaphic factors. After c o l l e c t i o n , samples were weighed, a i r dried and re-weighed before being shipped for chemical analysis. A l l of the forage samples were analyzed by General M i l l s , Inc., Sperry Operations Laboratory at Stockton, C a l i f o r n i a using Association of O f f i c i a l A g r i c u l t u r a l Chemists methods ( 1 9 5 5 ) . Analyses were made for nitrogen, crude f a t , crude f i b e r , t o t a l ash, calcium, phosphorus and moisture. Replicate tests of randomly selected forage samples were made at the Sperry Operations Laboratory as a check on the accuracy of the analyses. Testing error did not exceed three percent. 23 Quantitative Evaluation of the Vegetation There i s considerable difference i n the vegetation of Woronkofski and Coronation Islands on the basis of gross comparisons as well as comparisons of similar vegetation types. The difference i n the proportions of area occupied by the various vegetation types on each i s l a n d i s primarily the product of the topography of the two islands. Woronkofski Island, with extensive areas above timber l i n e , has a correspondingly greater proportion of subalpine and alpine vegetation than Coronation Island, while the forest type occupies approximately 80 percent of the t o t a l area on Coronation Island. Table 4 shows the areas occupied by the various major vegetation types on each i s l a n d while Figure 6 (a) shows comparisons of the proportions of the t o t a l i s l a n d areas occupied by each vegetation type. Forest t y p e . — C h a r a c t e r i s t i c a l l y , the forests of both Woronkofski and Coronation Islands are climax western hemlock-Sitka spruce stands, with proportions of these trees varying from about 60 percent hemlock—40 percent spruce to 80 percent hemlock—20 percent spruce. Yellow cedar i s often present as a subordinant tree i n the over mature stands but i n blowdown areas and muskeg edges on Coronation Island and i n an old burn on Woronkofski Island i t i s frequently a dominant species or codominant with hemlock and spruce. In the overmature forest the overstory canopy i s broken by frequent openings r e s u l t i n g from recent wind f a l l of overage trees. TABLE 4. Vegetation Types on Coronation and Woronkofski Islands (Planimetric and slope corrected value i n square miles) . .CORONATION ISLAND WORONKOFSKI ISLAND P l a n i - C o r r e c t e d % of V e g . N o . P l a n i - C o r r e c t e d % 'Of V e g . N o . metric Area Area Transects metric Area Area Transects Porest 22. 78 23 .76 80 .00 10 12 .20 13 .05 53. .97 10 Subalpine 1. 74 1 .82 6 .13 4 4 .33 4 .72 19. .52 6 Alpine 0. 23 0 .24 0 .81 3 4 .52 5 .00 20, .68 7 Muskeg 10% 0. 43 0 .43 1 .45 1 20% 0. 38 0 .38 1 .28 1 ko% 0 .30 0 .30 1, .24 1 50% 0. 67 0 .67 2 .26 1 10% o: 47 0 .47 1 .58 1 100% 1. 41 1 .41 4 .75 3 0 .80 0 .80 3. .31 2 Total 3. 36 3 .36 11 .31 7 1 .10 1 .10 4, .96 3 Alder Slide 0. 30 0 .31 1 .04 1 0 .40 0 .44 1, .82 2 Water 0. 04 0 .04 0 .131 0 .19 0 .19 0, . 7 8 1 Rock 0. 24 0 .24 0 . 8 0 1 none none — — Total - -j -1 Veg. Area 28. 41 29 .70 98 . 9 3 1 30 22 .55 24 .18 99. . 2 2 1 30 Percent of t o t a l area. 2 5 ( b ) - 51 0% F O R E S T M U S K E G S U B A L P I N E A L P I N E A L D E R S L I D E F i g . 6. Comparisons of vegetation types on Coronation Island with those on Woronkofski Island by t o t a l area (a) and when areas have been adjusted to correspond to equal forage densities (b). Some open scrub forests are present on poorly drained s i t e s on the eastern portion of Coronation Island and adjacent to muskegs on both islands. On such si t e s lodgepole pine i s usually the dominant tree form although i t i s frequently replaced by yellow cedar on Coronation Island. Trees are dwarfed, commonly not exceeding 20—30 feet i n height, and widely spaced. Porest understory vegetation varies greatly between islands although the shrubs, Vaccinium ovalifolium, V. parvifolium, Menziesia ferruginea and Oplopanax horridus and the forbs, Cornus  canadensis, Rubus pedatus, Moneses u n i f l o r a and Coptis a s p l e n i f o l i a are generally common throughout the forests of t h i s region. Generally a dense growth of shrubs and forest f l o o r forbs i s present throughout the forests on Woronkofski Island while on Coronation Island there i s an obvious paucity of shrubs and forbs within the forests (Figures 7 and 8). This difference i s r e f l e c t e d i n the transect analysis data i n Table 5. This i s also apparent i n the reduced number of plant species encounter-ed on the forest transects on Coronation Island (Table 6). One explanation for t h i s d i s p a r i t y i s the contrasting effects of the deer on the vegetation of the two island ranges. On Woronkofski Island heavy winter losses of deer have been frequent and severe enough to prevent excessive overuse of the range. Even during mild winters, a v a i l a b i l i t y of forage i s greatly r e s t r i c t e d and protected from overuse at elevations above a few hundred feet by the accumulation of deep snows. On Coronation Island, deer populations have not been r e s t r i c t e d by F i g . 8 . Forest type on Coronation I s l a n d showing the r e l a t i v e absence of f o r e s t f l o o r vegetation (June 7 , 1 9 6 2 ) . TABLE 5. Comparison of plant density in various vegetation types on Woronkofski and Coronation Islands Vegetation No. Mean No. Standard Level of Type Island Transects Interceptions Error t Significance W 10 109.6 19.48 -Porest 2.36 0.05 c 10 53.7 1 3 . 4 9 w 3 296.7 18.41 Muskeg 2.44 0.05 c 6 241.8 12.88 w 6 2 0 0 . 8 2 2 . 1 6 p Subalpine 0.07 n. s. c 4 2 0 3 . 8 33.78 w 7 294.5 9.47 Alpine 0.48 n.s. c 3 27-4.7 40.18 W = Woronkofski Island and C = Coronation Island. Not s i g n i f i c a n t at the 0.05 l e v e l . ro co TABLE 6. Comparison of abundance of plant species i n various vegetation types on Woronkofski and Coronation Islands Vegetation "I No. Total Species Mean No. Species Standard Level of Type Island Transects ( A l l Transects) Per Transect Error t Significance W 10 133 13.3 1.10 Forest 22.29 0.001 c 10 82 8.2 0.92 w 3 66 22.0 0.58 Muskeg 3.50 0.01 c 6 114 19.0 0.63 w 6 103 17.2 1.56 Subalpine 0.13 n. s.cL c 4 67 16.8 2.69 w 7 145 20.7 2.03 Alpine 0.54 n. s. c 3 69 23.0 3.79 W = Woronkofski Island 'and C = Coronation Island. Not s i g n i f i c a n t at the^O;'^ l e v e l . / ro 30 winter snow accumulation and a continuing heavy population pressure on the range has resulted i n the elimination of important winter and summer forage species. This was dramatically apparent on masses of s o i l adhering to the roots of wind-thrown trees and other such s i t e s unavailable to deer (Figure 9 ) . Under these conditions many species such as Vaccinium ovalifolium, V. parvifolium, Sambucus racemosa and hemlock reproduction attained luxuriant growth out of the reach of deer. Decaying, but elevated, trunks of f a l l e n trees support dense hemlock reproduction, while on lower decaying logs within reach of deer and on the forest f l o o r , hemlock reproduction i s v i r t u a l l y absent. The obvious heavy spring use of Polystichum muniturn and Oplopanax horridus, species of apparent low p a l a t a b i l i t y elsewhere, attests to the pressure of the deer upon the Coronation Island range. Occasional plants of Vaccinium ovalifolium and V. parvifolium that have grown above the reach of deer on Coronation Island crown out into vigorous growing shrubs, although shoot growth from the roots i s pe r s i s t e n t l y brox^sed back. In some areas new-growth spruce has been hedged by deer. This i s most apparent adjacent to the beaches at the heads of bays (Figure 1 0 ) although i t also occurs where dwarfed spruce i s available to deer at timberline. Spruce i s rarely eaten by deer i n Southeast Alaska and hedging of new-growth spruce has only been observed on small islands that have continued to support r e l a t i v e l y high deer densities for many years. 31 F i g . 9. Vaccinium o v a l i f o l i u m growing on a decaying stump on Coronation I s l a n d out of reach of deer (June 7, 1962). F i g . 10. Hedging of young spruce by deer adjacent to the beach on Coronation I s l a n d (June 9, 1959). 32 A comparison of the transect analyses on the forest types indicates s i g n i f i c a n t differences between islands i n both plant density and species abundance (Tables 5 and 6 ) . The mean plant density i n the forest types was over twice as great on Woronkofski as on Coronation Island. Species abundance varied from a mean of 1 3 . 3 per transect on Woronkofski to 8 . 2 on Coronation Island. The forest type occupies 1 3 . 0 5 square miles or 54 percent of the t o t a l vegetated area of Woronkofski Island i n contrast to 2 3 . 7 6 square miles or 80 percent on Coronation Island (Table 4 and Figure 6(a)). Muskeg type. — The muskeg type i s the product of excessive r a i n f a l l , cool summer temperatures which i n h i b i t decay, rapid vegetative growth and impeded drainage (Figure 1 1 ) . On the study islands, muskegs are not as extensive as on other islands of Southeast Alaska. On Woronkofski Island, only on a few s i t e s are slopes gradual enough to allow muskeg formation, while on Coronation Island the excellent drainage of the limestone substratum offers l i t t l e opportunity for the establishment of muskegs. The only extensive muskegs on Coronation Island l i e on the eastern portion where igneous intrusive rock makes up the substratum. Muskegs occupy 1 .10 square miles or 2 percent of the vegetated area on Woronkofski while on Coronation Island they make up 3 . 3 6 square miles or 11 percent of the vegetated area (Table 4 and Figure 6(a)). The muskeg i s e s s e n t i a l l y a sphagnum bog with sedges and 33 ericaceous decumbent shrubs present. Grasses, rushes, t y p i c a l bog forbs and lodgepole pine, yellow cedar and western and mountain hemlock are present but vary greatly i n numbers as s i t e conditions change. The transect analyses of the muskeg types indicate a s i g n i f i c a n t difference between islands i n plant density and species abundance (Tables 5 and 6). The mean density of plants was 297 per transect on Woronkofski i n contrast to 242 per transect on Coronation Island. This difference was s i g n i f i c a n t at the 0.5 confidence l e v e l . Plant densities varied from a transect mean of 22 on Woronkofski to 19 on Coronation at the 0.1 confidence l e v e l . These differences i n plant density and species abundance, as i n the case of the forest types, are apparently partly the resu l t of d i f f e r e n t i a l pressure of the deer on the two respective ranges. It i s apparent that on Coronation Island the forage species of the muskeg that are most eagerly sought by deer have been v i r t u a l l y eliminated. On muskegs on Woronkofski Island such succulent forbs as Fauria c r i s t a - g a l l i , Caltha b i f l o r a and Lysichitum americanum often form dense stands which dominate the gross aspect of lo c a l i z e d areas. The absence of these species on Coronation Island i s not just a product of d i f f e r e n t i a l edaphic factors as such species as Fauria c r i s t a - g a l l i and Lysichitum americanum are s t i l l present where they are p a r t i a l l y submerged i n the small pot hole ponds or where protected from the deer by thickets of dwarf, shrubby yellow cedar and lodgepole pine. 34 Generally, however, the effects of the deer on the vegetation of the muskeg are not as readily apparent as i n the forest type on Coronation Island. Subalpine type. — The subalpine vegetation i s e s s e n t i a l l y an intergradation of the forest and alpine types and i s made up of vegetation components of each of them. The a l t i t u d i n a l range of the subalpine vegetation extends from approximately 1,500 to 2,800 feet on Woronkofski Island and 1,000 to 1,800 feet on Coronation Island although the width of t h i s band of vegetation varies considerably with exposure and other s i t e conditions. The subalpine type occupies 4.72 square miles or 20 percent of the vegetated area on Woronkofski Island i n contrast to 1.82 square miles or 6 percent on Coronation Island. The subalpine forests are open, tree growth i s limited i n both height and diameter and trees have rapidly tapering trunks. (Figures 12 and 13). On Woronkofski Island spruce i s much less common than at lower elevations, being replaced by mountain hemlock and to a lesser extent yellow cedar. On Coronation Island spruce becomes more abundant than western hemlock i n subalpine areas and mountain hemlock and yellow cedar are only ra r e l y encountered. Understory vegetation varies from dense shrub growth of Vaccinium ovalifolium, V. parvifolium, V. membranaceum, Menziesia  ferruginea and Cladothamnus p y r o l i f l o r u s to open wet meadows of sedges and forbs c h a r a c t e r i s t i c of the alpine type. 35 F i g . 11 . Muskeg type on Coronation Island. Note the pools of standing water, the dwarfed lodgepole pine and Pin Peak i n the background (June 9 , 1 9 5 9 ) . F i g . 1 2 . Subalpine vegetation on Woronkofski Island. Note the almost pure stand of the glossy-leaved Fauria c r i s t a - g a l l i (July 8 , 1 9 5 9 ) . 36 No s i g n i f i c a n t differences between islands were found i n the transect analyses of the subalpine types. Differences i n the subalpine vegetation as a result of the deer would not be as apparent as at lower elevations. Winter snows tend to protect the summer forage species and to a lesser extent the winter browse species from d e b i l i t a t i n g u t i l i z a t i o n by deer on Coronation as well as on Woronkofski Island. Also the subalpine vegetation supports a much shorter period of use by deer than segments of the range at lower elevations. In spite of these factors there were' some apparent differences i n the subalpine vegetation on the two Islands that resulted from the inten s i t y of deer use but did not show up i n the transect analyses. For example, such highly preferred summer forage species as Fauria c r i s t a - g a l l i and Caltha b i f l o r a , which were abundant i n the subalpine areas of Woronkofski Island, were present only i n areas protected from deer use on Coronation Island. This i s perhaps not an e n t i r e l y v a l i d comparison as subalpine and alpine areas on Coronation Island were r e l a t i v e l y dry i n comparison to Woronkofski Island and therefore not as favorable for the above species. However, t h e i r absence from wet s i t e s on Coronation Island, unless protected by shrub growth does r e f l e c t the intense pressure of the deer on the subalpine range. Also Vaccinium ovalifolium and V. parvifolium which were extremely vigorous and dense i n the subalpine type on Woronkofski Island and showed no apparent winter use by deer, were not abundant on Coronation Island and where they did occur, 37 pronounced hedging, through continued heavy use by deer, was evident. In such areas on Coronation Island dead branches and entire plants were common and apparently resulted from the heavy winter use by deer. Apparently winter snow accumulation i n the subalpine areas of Coronation Island i s generally not great enough to prevent deer from u t i l i z i n g such areas. Alpine type. — Vegetation of the alpine areas i s a composite of a r c t i c - a l p i n e and boreal zone species. Dwarfed mountain hemlock, yellow cedar and lodgepole pine assume shrub form from timber-l i n e (approximately 2,500 feet on Woronkofski Island and 1,800 feet on Coronation Island) to 3S500 feet on protected s i t e s . On Coronation Island, Sitka spruce assumes shrub form i n the alpine areas and i s e s s e n t i a l l y the only conifer there although lodgepole pine occurs on very dry subalpine si t e s on Pin Peak. On Woronkofski Island the alpine type occupies f i v e percent of the t o t a l vegetated area while on Coronation Island i t occupies less than one percent of the vegetated area. The alpine vegetation generally r e f l e c t s the "snow f l u s h " conditions and the heavy p r e c i p i t a t i o n of the region (Figure 14). Alpine meadows support lush growths of sedges, grasses and forbs. On Woronkofski Island succulent forbs, such as Fauria c r i s t a - g a l l i and Caltha b i f l o r a form dense stands i n the alpine meadows (Figure 12). The limestone substratum on Coronation Island plus the reduced snow accumulation result i n more rapid water loss i n alpine areas during spring and summer and the vegetation 38 m i 1 3 . Subalpine vegetation on Coronation I s l a n d . Note the stand of Vaccinium o v a l i f o l i u m . i n which the person i s standing, which has been browsed down to the snow l e v e l by deer (June 1 8 , i 9 6 0 ) . 14. Residual snow i n mid-summer at an e l e v a t i o n of approximately 2,500 feet on Woronkofski I s l a n d ( J u l y 21, i 9 6 0 ) . 39 i s of a more xeric nature than on Woronkofski Island. (Figure 1 5 ) . Grasses and sedges dominate the vegetation of the alpine meadow while forbs are less abundant and include several drought tolerant species such as Artemisia a r c t i c a , Lupinus nootkatensis and several saxifrages. On Woronkofski Island on ridges and rocky areas of limited s o i l development and on north-facing slopes on both islands alpine heath f l o r a i s well developed. Such ericaceous forms as Phyllodoce g l a n d u l i f l o r a , Cassiope mertensiana, C. s t e l l e r i a n a and Vaccinium uliginosum are the dominant vegetation on such s i t e s . Results of the transects established i n the alpine areas show no s i g n i f i c a n t difference between islands on the basis of species abundance or plant density. The alpine type i s perhaps the most varied botanically as well as supporting an extremely dense growth of low growing vegetation available to deer. The long range e f f e c t s of deer on the vegetation are perhaps less apparent i n the alpine type than i n any other vegetation type. This i s because alpine vegetation i s available for but a b r i e f period during the summer after the snow melts. In addition alpine vegetation undoubtedly can tolerate heavier summer use than vegetation i n the forest or muskeg where poorer plant growth conditions e x i s t . Evaluation of d i f f e r e n t i a l e f f e c ts of the deer on the alpine vegetation of the two islands was d i f f i c u l t because of the widely contrasting edaphic conditions which i n turn resulted i n d i f f e r e n t vegetative complexes. While no apparent reduction i n the highly palatable summer forage 40 F i g . 1 5 . Vegetation on well-drained limestone substrate at an elevation of 1 ,800 feet on Coronation Island. Residual snow i s r e s t r i c t e d to the "sink hole" depressions of the Karst topography(June 1 8 , I 9 6 0 ) . 4 l species occurred on Woronkofski Island, the absence of at least some of the same species on Coronation Island may have been a product of the substratum differences rather than deer pressure. The only evidence of heavy deer pressure encountered i n the alpine type was hedging and dieback i n Vaccinium  uliginosum on Coronation Island. This apparently resulted from heavy browsing during late f a l l and early winter when snow accumulation was not great enough to cover these shrubs, which are usually less than a foot i n height. Other vegetation types. — Two additional d i s t i n c t vegetation types were present on both Woronkofski and Coronation Island. The "alder s l i d e " community i s common on steep slopes where land slides or avalanches have occurred. It occupies about two percent and one percent respectively of the t o t a l vegetated areas of Woronkofski and Coronation Islands. This type originates when alder (Alnus oregona and A. crispa sinuata) establishes as the pioneer woody species on exposed mineral s o i l a f t e r a land s l i d e . Alder f u l f i l l s an important ecological role i n rebuilding the s o i l necessary for the successful establishment of conifers c h a r a c t e r i s t i c of the climax f o r e s t . Alder roots are hosts to nitrogen-fixing organisms and nitrogen i s added to the s o i l through the accumulation and decomposition of alder leaf l i t t e r (Lawrence, 1958). No recent land s l i d e s were present on either Woronkofski or Coronation Island and most alder stands i n s l i d e areas were 42 i n the 10- to 30-year age category. In some of the alpine and subalpine areas of Woronkofski Island alder i s maintained by the regular winter avalanching of snow on steep slopes. The growth form of alder allows i t to survive under such conditions where the t a l l e r and more b r i t t l e conifers f a i l . Understory vegetation i n the alder s l i d e s varies with the age of the stand but common forms include the annuals Circaea alpina, Epilobium spp., Galium t r i f l o r u m , the perennials T i a r e l l a  t r i f o l i a t a j V i o l a e p i p s i l a ssp. repens, Aruncus S y l v e s t e r and the ferns Athyrium f i l l i x - f e m i n a , Dryopteris phegopteris and D. linnaeana. The beach edge i s another unique vegetation type present to a l i m i t e d extent on both islands. The land forms of these islands with t h e i r abrupt r i s e s from the sea are not favorable for the development of extensive i n t e r t i d a l f l a t s at the heads of bays. Consequently vegetated beach areas were limited to a very few acres on each i s l a n d . The beach vegetation was predominantly Carex lyngbyei ssp. cryptocarpa and t y p i c a l halophytes such as Atr i p l e x gmelini, Honckenya peploides and T r i g l o c h i n maritimum i n areas below extreme high t i d e , while Elymus arenarius ssp. mollis,the umbellifers Heracleum lanatum, Osmorhiza purpurea, Conioselinum  benthami were the common forms of vegetation above the t i d a l e f f e c t s . A much wider d i v e r s i t y of species was present on the Woronkofski beaches than at Coronation which probably results from the former's close proximity to the wide vegetative complex of the Stikine River delta area. i 43 These beach areas, although limited i n area, receive heavy use by deer during the early spring when new growth vegetation f i r s t makes i t s appearance on such s i t e s . The Carex i s then a highly preferred species and i s closely cropped on both islands by deer during the f i r s t two weeks of i t s growth. However, on Woronkofski Island the deer s h i f t to other forages to the point that v i r t u a l l y no use i s made of t h i s species .after the f i r s t month of i t s growth, while on Coronation Island heavy use of th i s sedge by deer continues for at least two months. Quantitative comparison of Woronkofski and Coronation  Island ranges. — The obvious effects of deer on the vegetation of Coronation Island, discussed e a r l i e r , are d i f f i c u l t to measure qu a n t i t a t i v e l y . In addition, variations between islands i n edaphic conditions within cover types are d i f f i c u l t to assess i n r e l a t i o n to the effects of deer on the range. Quantitative comparisons of the vegetation of the two islands, however, are possible through the analyses of the transect data. Obviously quantitative d e f i c i e n c i e s w i l l affect the deer during periods of i n t r a s p e c i f i c competition and i f such de f i c i e n c i e s are more pronounced on one i s l a n d , under comparable deer densities, the responses of the deer w i l l also vary. Table 6 shows a breakdown of the r e l a t i v e abundance of plant species i n the major cover types of the two isla n d s . S i g n i f i c a n t differences (0.001 and 0.01, respective le v e l s of confidence) were found only i n the forest and muskeg types, but i n both cases the number of species encountered, was greater on Woronkofski than on Coronation Island. Table 5 compares r e l a t i v e plant density i n the major vegetation types of the two islands. Here again plant density was found to be s i g n i f i c a n t l y greater (0.05 l e v e l of confidence) i n both the forest and musket types on Woronkofski than on Coronation Island. In addition a basis exists for a rough comparison of the t o t a l quantity of vegetation available to deer on the two islands. If the mean plant density values for in d i v i d u a l vegetation types are taken into consideration the t o t a l areas occupied by vegetation types on each island are not comparable one to another. To enable such a comparison, the areas should be considered on an equal density basis. This has been done i n Table 7 by assuming equal plant densities i n similar vegetation types on the two islands and correcting the area values on the basis of the mean densities obtained from the transect data. The results of thi s comparison bring about a 44 percent reduction of the Coronation Island vegetated area, most of which occurs i n the forest type. It i s i n t e r e s t i n g that on th i s basis the t o t a l vegetated area of Coronation Island, for comparative purposes, to t a l s 16.5 square miles i n contrast to 24.3 square miles for Woronkofski Island. Putting i t another way, i t takes 1.8 units of range on Coronation Island to equal one unit on Woronkofski Island. The histograms i n Figure 6(b) show the r e l a t i v e .effect on vegetation types of t h i s correction to equate plant density. This method of treatment of the data i s e f f e c t i v e for comparative purposes but from the standpoint TABLE 7 . Areas of vegetation types on Woronkofski and Coronation Islands and t h e i r comparisons when the areas are adjusted so that plant densities are equal within comparable vegetation types on both isla n d s . Woronkofski Coronation Coronation Woronkofski Coronation Vegetative Mean No. "Mean No. Revalued Type Interceptions Interceptions Area Area Area % Change Forest 1 0 9 . 6 5 3 . 7 2 3 . 7 6 1 3 . 0 5 11.64 - 5 1 . 0 1 Muskeg 2 9 6 . 7 241.8 3 . 3 6 1 .10 2.74 - 1 8 . 4 5 Subalpine 2 0 0 . 8 2 0 3 . 8 1 .82 4 . 7 2 I . 8 5 + 1 .65 Alpine 2 9 4 . 6 2 7 4 . 7 0.24 5 . 0 0 0 . 2 2 - 8 . 3 3 Alder 1 7 8 . 0 3 6 . 0 0 . 3 1 0 . 4 4 0 . 0 6 - 8 0 . 6 5 TOTALS 2 9 . 4 9 24 .31 1 6 .51 1 44.01% reduction i n t o t a l area of Coronation Island on basis of equal plant density. 46 of deer-use of the range, f a c t o r s of e f f i c i e n c y of grazing of the deer i n r e l a t i o n to the area r e q u i r e d to obtain the necessary d a i l y forage requirements (time-energy budget) must als o be considered. I t i s apparent that q u a n t i t a t i v e l y Woronkofski I s l a n d g r e a t l y outranks Coronation I s l a n d i n : 1) plant density and species abundance i n the f o r e s t and muskeg types, 2) t o t a l area of subalpine and a l p i n e types and t o t a l area of f o r e s t type on an equal density b a s i s , and 3) t o t a l vegetated area on an equal de n s i t y b a s i s . Pressure of deer on the range. — Deer have had a pronounced e f f e c t i n b r i n g i n g about a d i f f e r e n c e i n the q u a n t i t y of forage a v a i l a b l e on Woronkofski and Coronation I s l a n d s . On Woronkofski I s l a n d , although deer d e n s i t i e s are r e l a t i v e l y h i g h , they have b u i l t up from a low i n 1950 a f t e r large losses during s e v e r a l severe w i n t e r s . This has been the h i s t o r y of the i s l a n d ; wide popu l a t i o n f l u c t u a t i o n s with the range protected from overuse by frequent winter "die o f f s " . In a d d i t i o n the l a r g e p o r t i o n of the i s l a n d l y i n g at moderately high e l e v a t i o n s plus the i s l a n d ' s p r o x i m i t y to the coast r e s u l t s i n the " p r o t e c t i o n " of much of the range from use by deer because of annual deep snows. Wolves have .also been a f a c t o r i n c o n t r o l l i n g the deer on the i s l a n d . Consequently, the deer have had very l i t t l e e f f e c t on the v e g e t a t i o n of Woronkofski I s l a n d . On Coronation I s l a n d winters are m i l d and l i t t l e snow accumulates even at the higher e l e v a t i o n s . The deer po p u l a t i o n 47 there has been able to maintain a more constant pressure on r the range as a re s u l t of the mild winters and absence of predators. The result has been the almost complete elimination of the more palatable and most important forage and browse species within the forest type. This i s r e f l e c t e d i n the vegetative analysis of forest types on the two islands (Tables 5 and 6 ) . A decrease i n both density and species abundance of forage plants i s apparent in the Coronation Island forest type. This observation i s substantiated by the presence of dead stems of Vaccinium ovalifolium and V. parvifolium with the closely browsed root suckers s t i l l remaining. Also, on si t e s that have been protected from use by deer, such as the decaying trunks and upturned roots of wind-thrown trees, steep stream banks and ledges, luxuriant growth of browse and forage species occurs (Figure 1 1 ) . The pressure of the deer on the Coronation Island range has not only eliminated many of the important food species and reduced the plant density, but establishment of hemlock and spruce reproduction has been r e s t r i c t e d . As a result of the reduced abundance of forage species within the forest type of Coronation Island, i n spring and early summer when new growth vegetation i s only available at low elevations deer are forced to u t i l i z e plants, such as Polysticum munitum, which are of low p a l a t a b i l i t y and poor n u t r i t i v e q u a l i t y . On the muskeg and i n the subalpine and alpine areas of Coronation Island the effects of the deer are not as apparent 48 as i n t h e f o r e s t t y p e ; h o w e v e r , t h e r a n g e has been a l t e r e d by t h e i r p r e s e n c e . Many o f t h e most p a l a t a b l e f o r a g e s p e c i e s , w h i c h o c c u r i n r e l a t i v e abundance on s i m i l a r s i t e s on W o r o n k o f s k i I s l a n d a r e a b s e n t on C o r o n a t i o n I s l a n d . Such h i g h l y p r e f e r r e d and h i g h q u a l i t y s p e c i e s as F a u r i a c r i s t a - g a l l i and L y s i c h i t u m  a m e r i c a n u m a r e f o u n d o n l y where t h e y a r e u n a v a i l a b l e t o d e e r u n d e r t h e ' p r o t e c t i o n o f dense growths o f d w a r f s p r u c e o r c e d a r o r i n t h e s m a l l p o t h o l e s and ponds o f t h e m u s k e g s . On C o r o n a t i o n I s l a n d t h e d e e r t h e m s e l v e s have l o w e r e d t h e q u a n t i t y and q u a l i t y o f f o r a g e a v a i l a b l e t o them t h r o u g h t h e i r c o n s t a n t p r e s s u r e on t h e r a n g e o v e r a l o n g p e r i o d o f t i m e . The r e s u l t has been t h e e s t a b l i s h m e n t o f an i s l a n d d e e r r a n g e c o n s i d e r a b l y b e l o w t h e norm f o r t h e r e g i o n i n b o t h q u a l i t y and q u a n t i t y o f a v a i l a b l e f o r a g e . Q u a l i t a t i v e E v a l u a t i o n o f t h e V e g e t a t i o n D i f f e r e n c e s i n t h e q u a l i t y o f t h e v e g e t a t i o n on W o r o n k o f s k i and C o r o n a t i o n I s l a n d s , w h i l e o b v i o u s l y p r e s e n t , a r e d i f f i c u l t t o a s s e s s d i r e c t l y . L o c a l v a r i a t i o n s i n s i t e c o n d i t i o n s s u c h as s o i l t y p e , d r a i n a g e , s l o p e , e x p o s u r e , e l e v a t i o n and v e g e t a t i v e complex c a n g r e a t l y i n f l u e n c e t h e n u t r i t i v e q u a l i t y o f f o r a g e p l a n t s . C o n s e q u e n t l y , b r o a d c o m p a r i s o n s o f n u t r i t i v e a n a l y s e s o f f o r a g e s a m p l e s f r o m t h e two i s l a n d s a r e g o v e r n e d by t h e s e e d a p h i c v a r i a b l e s and a r e , t h e r e f o r e , o f a somewhat t e n u o u s n a t u r e . Some u s e f u l i n f o r m a t i o n c a n be o b t a i n e d , h o w e v e r , f r o m t h e c h e m i c a l a n a l y s e s o f f o r a g e s a m p l e s . Knowledge o f t h e 49 magnitude of the effects of s p e c i f i c edaphic factors on forage quality can be obtained by s e l e c t i v e l y c o l l e c t i n g forage samples under conditions where quality differences are primarily the r e s u l t of only one environmental factor. The evaluation of the effects of i n d i v i d u a l s i t e factors on forage quality enables a comparison of the two islands on the basis of the magnitude of the effects of i n d i v i d u a l s i t e factors and t h e i r r e l a t i v e importance on each i s l a n d . Samples of the summer forage species preferred or commonly used by deer were collected from both Woronkofski and Coronation Islands. The results of the analyses of these samples are presented i n Tables 8 and 9. Table 10 includes the results of analyses of vegetation samples from areas i n Southeast Alaska adjacent to the study areas. In comparisons of forage analyses nitrogen has been used as the primary c r i t e r i o n of quality of forage plants. Because of i t s direct relationship to protein, nitrogen content r e f l e c t s the potential value of a forage plant i n meeting the high physiological demands of deer for growth and development during the spring and summer. Although quality of the nitrogen source may vary between plant species, seasonally or from s i t e to s i t e , protein q u a l i t y , while important, i s not as es s e n t i a l to the well-being of ruminants as i t i s among many other animals. The unique biochemistry of the rumen, r e s u l t i n g from the presence of symbiotic microorganisms, enables the u t i l i z a t i o n of nitrogen i n the diet i n forms t o t a l l y unavailable to the non-ruminant. TABLE 8 . Analyses of forage from Woronkofski Island 1 9 5 9 - 1 9 6 0 (Dry weight basis) Species Date A l t . (ft) % N i t -rogen % Prnt: , 2_ % % % A=h % TvTFF. % rial . % Phnn , Caltha b i f l o r a 5-24 2 0 0 0 3 . 8 9 24 .3 2 . 0 14 .8 1 0 . 6 48 .3 0 . 6 1 0.41 II it 6 - 2 8 400 2 . 2 1 1 3 . 8 1 . 7 1 8 . 3 1 3 . 4 5 2 . 8 1 . 8 9 0 . 1 3 it it 7 - 8 2500 2 . 9 6 1 8 . 5 3 . 4 14 .5 1 1 . 3 5 2 . 3 0 . 8 0 0 . 2 0 tt tt 8 - 1 1 3 0 0 0 3 . 4 9 2 1 . 8 2 . 8 14 .6 1 2 . 9 4 7 . 9 0 . 8 1 0 . 6 2 Pauria c r i s t a - g a l l i 6 - 2 8 250 2 . 0 5 1 2 . 8 1 . 1 1 1 . 4 1 0 . 1 64 .6 0 . 9 1 0 . 1 3 tt tt 6 - 2 9 1 8 0 0 3 . 6 0 2 2 . 5 1 . 1 1 1 . 8 8 . 6 5 6 . 0 0 . 4 7 0 . 3 4 it tt 7 - 8 2 5 0 0 3 . 0 7 1 9 . 2 2 . 1 9 . 6 9 . 4 5 9 . 7 0 . 6 1 0 . 2 2 tt it 7 - 2 3 2 2 0 0 3.84 24 .0 1 . 2 1 1 . 7 8 . 9 5 4 . 2 0 . 4 3 0.41 it tt 8 - 1 1 , 3 0 0 0 3 . 2 2 2 0 . 1 1 . 8 1 0 . 4 1 0 . 7 5 7 . 0 0 . 6 1 0.-38 Carex lyngbyei ssp. cryptocarpa 5 - 2 5 10 2 . 9 8 1 8 . 6 3 . 6 2 1 . 7 7 . 4 48 .7 0 . 2 2 0 . 2 7 ti it II 7-14 10 2 . 0 3 1 2 . 7 2 . 6 2 1 . 1 6 . 4 5 7 . 2 0 . 2 2 0 . 1 9 Carex macrochaeta 7 - 1 3 1750 2 . 6 9 1 6 . 8 1 . 8 24 .3 6 . 1 5 1 . 0 0 . 1 8 0 . 2 3 Plantago maritima 7 - 9 0 1 . 6 6 1 0 . 4 2 . 8 14 .0 24 .2 48 .6 0 . 3 8 0 . 2 1 Lysichitum americanum 5-24 2 0 0 0 6 . 0 0 3 7 . 5 3 . 1 1 1 . 3 1 3 . 2 3 4 . 9 1 . 0 0 0 . 6 5 V i c i a gigantea 6 - 3 0 10 6 . 2 9 3 9 . 3 2 . 0 1 8 . 3 8 . 5 3 1 . 9 0 . 2 2 0 . 7 0 Vaccinium ovalifolium 7 - 2 3 2200 3 . 3 0 2 0 . 6 4 . 0 14 .8 3 . 7 5 6 . 9 0 . 4 7 0 . 2 9 T r i g l o c h i n maritimum 6 - 3 0 10 4.24 2 6 . 5 2 . 5 1 5 . 5 1 8 . 6 3 6 . 9 0 . 5 8 0 . 3 2 Protein = nitrogen x 6 . 2 5 . o TABLE 9. Analyses of forage from Coronation Island 1959-1960 (Dry weight basis) ATT. % N i t - % ~~J> I W % fo f Species Date ( f t ) rogen Prot.-'-Fat Fiber Ash' NFE Cal. Phos. Fauria c r i s t a - g a l l i 8-2 100 2 .54 15 .9 1 .7 13 .6 11 .6 57 .2 1 .13 0.20 it it 8-14 1250 2 .90 18 .1 1 .4 11 .6 9 .6 59 .3 1 .74 0.34 Carex lyngbyei ssp. cryptocarpa5-22 10 3 .02 18 .9 2 .7 24 .9 6 .8 46 .7 0 .28 0.40 ti II II 6-11 0 3 .02 18 .9 4 .3 23 .8 6 .0 47 .0 0 .41 0.33 II II n 8-8 0 2 .38 14 .9 3 .3 24 .3 6 .6 50 .9 0 .54 0.22 Carex macrochaeta 6-18 1750 3 .84 24 .0 2 .8 24 .8 5 .9 42 .5 0 .41 0.33 it II 7-29 1500 2 .75 17 .2 1 .4 26 .1 4 .7 50 .6 0 • 71 0.22 it it 8-9 1900 3 .01 18 .8 2 .9 26 .0 5 .8 46 .5 0 .46 0.26 Heracleum lanatum 5-22 30 5 .78 36 .1 3 .2 15 .2 13 .6 31 .9 0 .70 0.95 II u 8-9 1700 3 .30 20 .6 3 .8 14 .1 10 .5 51 .0 2 .23 0.41 Polystichum munitum 6-10 100 2 .82 17 .6 2 .7 23 .7 6 .7 49 .3 0 .23 0.31 it it 8-6 100 1 .23 7 .7 0 .9 37 .7 3 .8 49 .9 0 .34 0.20 Artemesia a r c t i c a 6-10 1900 3 .74 23 .4 3 .3 18 .8 9 .2 45 .3 0 .87 0.59 it it 8-9 1900 2 .83 17 .7 2 .7 14 .8 8 .8 56 .0 0 .98 0.34 Elymus arenarius ssp. mollis 5-22 10 4 .77 29 .8 3 .4 26 .8 7 .9 32 .1 0 .20 0.38 Calamagrostis nutkaensis 5-22 50 3 .36 21 .0 2 .3 31 .2 8 .6 36 .9 0 .15 0.32 Protein = nitrogen x 6.25. V J l TABLE 10. Analyses of forage from Mitkof Island and the Mainland 1959-1960 (Dry v;eight basis) AltT % N i t - % 7~% % % % % % Species Date ( f t . ) rogen Prot. Fat ' Fiber Ash NFE Cal. Phos. MITKOF ISLAND Fauria c r i s t a - g a l l i 5-30 300 3.01 18.8 0.8 9.8 8.1 62.5 0 .63 0.26 TT I I 7-2 300 2.54 15.9 1.0 8.7 9.2 65.2 0.86 0.15 I I I I 7-26 300 2 . 0 3 12.7 0.7 8.3 9.4 68.9 1.02 0.11 IT I I 8-29 300 1 .76 11.0 1.3 8.8 9.6 69.3 1.17 0.15 I I it 6-16 1500 3.68 23.0 0.9 10.6 7.7 57.8 0.43 0.39 it I I 6-3 50 3.94 24.6 2.2 9.2 7.7 56.3 0 .63 0 .36 IT I I 7-5 50 2.51 15.7 2.7 8.3 9.1 64.2 0.75 0.17 MAINLAND Fauria c r i s t a - g a l l i 6-6 150 2.99 18.7 2.0 9.8 8.8' 60.7 0.59 0.17 I I I I 7-16 150 2.05 12.8 1.1 10.2 9.3 66.6 0.97 0 .18 IT IT 7-18 1400 2.10 13.1 1.4 10.3 8.6 66.6 0.75 0.24 Carex lyngbyei ssp. cryptocarpa 6-6 0 2.66 16.6 4.6 20.5 4.7 53.6 0.22 0 .18 I I I I IT 7-16 0 3.06 19.1 2.5 24.5 5.1 48.7 0.18 0.21 Elymus arenarius ssp. mollis 6-6 0 3.95 24.7 4.3 28.8 7.5 34.7 0.24 0.47 Protein = nitrogen x 6 . 2 5 . ro 53 Consequently, comparisons of t o t a l nitrogen content of forage samples enables a considerably more r e a l i s t i c comparison of forage quality for ruminants than for non-ruminants. Protein content of the forage samples was obtained by multiplying the nitrogen content by the constant 6 . 2 5 . There are obvious, p i t f a l l s i n t h i s technique as pointed out by Wood, e_t a l . ( i 9 6 0 ) . Obviously, a l l of the nitrogen present i n the samples i s not derived from plant proteins i n the r a t i o of 6 . 2 5 to 1. There may be considerable v a r i a t i o n from t h i s r a t i o among plant proteins (Block and B o i l i n g , 1 9 4 5 ) . In addition such nitrogenous plant constituents as nucleic acids, amino acids, etc., while non-protein i n nature, contribute s i g n i f i c a n t l y to the t o t a l plant nitrogen. However, workers i n the a g r i c u l t u r a l sciences have consistently used 6 . 2 5 as a nitrogen to protein conversion factor i n analyses of forage crops and i f comparisons are to be made with such previous analyses a s i m i l a r basis for comparison must e x i s t . Considerable v a r i a t i o n i n n u t r i t i v e components between species was found although generally the most important summer forage species, Fauria c r i s t a - g a l l i , Caltha b i f l o r a , Carex lyngbyei ssp. cryptocarpa and C. macrochaeta varied between 15 and 25 percent protein content on a dry weight basis. Although the average protein content of forage samples was higher on Woronkofski than Coronation Island t h i s was apparently the product of l o c a l l y more favorable edaphic conditions on Woronkofski Island rather than the broad effects 54 of climatic or s o i l d i f f e r e n t i a l s . Protein content of the forage species analyzed varied from 7 . 7 percent for sword fern (Polystichum munitum), collected during late summer, to a high of 3 9 . 3 percent for the legume, V i c i a gigantea. However, most species varied between 10 and 25 percent protein content, which compares favorably with domestic forage crops, (Table 1 1 ) . Surprisingly high protein contents, i n excess of 35 percent, were found for samples of skunk cabbage (Lysichitum americanum) and Heracleum lanatum. With the exception of skunk cabbage, which i s eagerly sought by deer during i t s early stages of growth and i s r e l a t i v e l y common on Woronkofski Island, the other species exceeding 30 percent protein are either not normally a t t r a c t i v e to deer or are very r e s t r i c t e d i n occurance. Generally, protein content wras found to be adequate to very high i n comparison to standards established for domestic forages. In addition to variations i n n u t r i t i v e quality (nitrogen content) between species, considerable v a r i a t i o n was found to exist within species when co l l e c t i o n s were made at d i f f e r e n t s i t e s or times. Such variations i n quality within a species appeared to be associated with the physiological stage of development of the plants more than any unrelated s p e c i f i c factor of the environment such as s o i l type or drainage. The physiological stage of development of forage plants i s the product of several i n t e r a c t i n g factors of the environment. The seasonal climatic progression i n terms of temperature, p r e c i p i t a t i o n and sunlight, of course, i s the primary c o n t r o l l i n g feature of TABLE 11. Average composition of domestic green forages (Morrison, 1948) (Dry weight basis) oi 07 a a a a a a lo lo lo lo lo lo lo lo Species Nitrogen Protein Fat ' Fiber Ash NFE Cal. Phos. A l f a l f a (young) 4.26 26.7 4.62 17 .9 12.3 38 .5 - -A l f a l f a (before bloom) 3.33 20.7 3.54 23 .2 10.6 41 .9 2.42 0.35 A l f a l f a (after bloom) 1.54 9.7 2.01 43 .0 7.4 37 .9 - -Bluegrass (young) 2.91 18.2 3.97 25 .2 8.3 44 .4 0.53 0.43 Bluegrass (nearly mature)1.56 9.7 2.61 34 .8 7.3 45 .5 0.19 0.31 Bluestem pasture (young) 1.34 8.5 2.33 31 .5 9.0 48 .7 0.44 0.15 Peas and oats 2.27 14.2 4.00 28 .0 8.4 45 .3 0.76 0.31 Turnip tops 3.00 18.7 2.67 10 .0 20.0 48 .7 3.27 0.40 56 the environment. In addition, l o c a l s i t e factors such as exposure, slope, elevation and relationship to other vegetation present res u l t i n l o c a l variations i n the seasonal progression of plant growth. Consequently, variations i n forage quality of the same species growing on a muskeg a few feet above sea l e v e l and i n an alpine meadow at 3 S 0 0 0 feet may be more d i r e c t l y the result of d i f f e r i n g stages of growth than d i f f e r i n g s o i l conditions or other edaphic factors. Undoubtedly s i t e f actors, such as the a v a i l a b i l i t y i n the s o i l of e s s e n t i a l elements for plant growth and competition with plant associates for these elements and for l i g h t and space, play an important part i n plant growth and, consequently, affect n u t r i t i v e quality of the forage. However, these s i t e factors probably have a greater eff e c t on the duration of the peak of forage quality i n plants rather than the height of the peak i t s e l f . The effect of the physiological stage of growth on the nitrogen content of forage plants i s shown i n Figures 1 6(a), 1 6(b), and 1 6(c). In instances where samples of the same species were collected from the same s i t e s but at l a t e r dates nitrogen content had decreased markedly. There was no noticeable trend i n fat content while f i b e r content increased as expected with maturity of the plants and therefore was inversely related to nitrogen content. Calcium content was found to increase gradually with summer growth while phosphorus content was highest i n the new growth vegetation and decreased as the plants matured (Figures 1 6(a), 1 6(b), and 1 6(c)) The possible significance of distorted calcium: phosphorus r a t i o s i n the F i g . 1 6 . Seasonal change i n mineral composition of forage plants. Diagram (a) shows the change i n mineral composition of Fauria c r i s t a - g a l l i from muskeg sit e s on Mitkof Island and the adjacent mainland. Diagram (b) shows the same type of change i n Carex lyngbyei spp. cryptocarpa, while diagram (c) shows changes i n mineral composition for several species (data from Tables 8 , 9 and 1 0 ) . 58 summer forage w i l l be discussed i n a following section under Rumen Analyses. Vegetation -collected i n alpine and muskeg areas appeared to be of higher quality than forest vegetation, independent of the e f f e c t of i t s physiological stage of development. This c h a r a c t e r i s t i c was apparently the product of greater l i g h t and temperature i n t e n s i t i e s i n alpine and muskeg areas and consequently, higher rates of growth. Plants growing on the forest f l o o r receive greatly reduced l i g h t i n t e n s i t i e s because of the shading of the dense coniferous overstory. In addition, the forest microclimate never i s subjected to the r e l a t i v e l y high temperatures encountered i n muskegs and alpine meadows on clear sunny days. Records kept on Prince of Wales Island by the U. S. Forest Service show temperature d i f f e r e n t i a l s between forest and cutover areas of up to 12 degrees i n the a i r at three feet, and up to 17 degrees i n the s o i l at three inches below the surface (Gregory, 1956). Mean differences were approximately two degrees i n the a i r and six degrees i n the s o i l . Temperatures at the s o i l surface and up to a few inches above the surface may show even wider differences between the forest and cutover openings. There were also indications that alpine forage plants were of higher quality than similar muskeg plants. The most apparent reason for th i s difference i s the limited a v a i l a b i l i t y of esse n t i a l elements for plant growth i n the muskeg areas. The extremely acid conditions encountered on the muskegs undoubted-ly r e s u l t i n greatly r e s t r i c t i n g the a v a i l a b i l i t y of calcium 59 and other e s s e n t i a l elements for plant growth. However, var i a t i o n i n the duration and i n t e n s i t y of l i g h t at high and low a l t i t u d e s may also be an influencing factor. Discussion of Factors Governing Range Quality The following discussion i s an attempt to postulate the mechanism most l i k e l y responsible for the variations i n forage q u a l i t y , and hence range quali t y , which were found to exist i n Southeast Alaska. Further, i t should be understood that components of the environment which may be of primary import-ance for plant growth need not necessarily be factors " l i m i t i n g " forage q u a l i t y , or at least accounting for the variations i n quality found to e x i s t . Physiological stage of plant growth. — Perhaps the most important single factor d i r e c t l y governing the quality of summer forage on deer ranges i n Alaska i s the physiological stage of growth or maturity of the forage plants. It has been well domonstrated i n basic studies i n plant physiology as well as i n the f i e l d of agronomy that the above-ground parts of plants f i r s t i n i t i a t i n g growth are of higher n u t r i t i v e quality than such parts a f t e r the plants approach maturity. While t h i s i s most pronounced i n perennials i t i s true of annuals as well. This quality v a r i a t i o n of forage i s understandable i n view of the p h y s i o l o g i c a l processes taking place within the plant that are associated with i t s growth, flowering and dormancy. In a rapidly photosynthesizing l e a f , nitrogen levels (and protein) are high, primarily because nitrogen i s an 60 e s s e n t i a l chemical component of protoplasm and i s therefore necessary for growth. C h a r a c t e r i s t i c a l l y , a high nitrogen/ carbohydrate r a t i o i s associated with rapid shoot growth and a low one with root growth (Loomis, 1953). Young leaves accumulate protein but i n older ones hydrolysis predominates. However, i n herbaceous plants the nitrogen used by the l a t e r formed leaves i s supplied i n part by transfer from those e a r l i e r formed ones that have become senescent. While flowering i s determined by the maintenance of sugars i n the plant above a certa i n c r i t i c a l l e v e l during the dark period i t also involves the mobilization of le a f protein and associated decrease i n protein synthesis i n the leaves. The nitrogen l e v e l of forage, therefore, appears to be associated most d i r e c t l y with the rate of plant growth and i s most often highest i n rapidly growing vegetation just i n i t i a t i n g growth. Fiber content also increases with maturity, and the presence of the f i b e r plus the l i g n i f i c a t i o n of c e l l walls reduces the quality of the forage by rendering c e l l contents unavailable and reducing the o v e r a l l d i g e s t i b i l i t y of the forage. The a b i l i t y of native forage plants to accomplish t h e i r mineral and carbohydrate-demanding spring growth flush i s ex-plained by several factors. F i r s t , p r i o r to winter dormancy there i s an accumulation of carbohydrates i n the root system, which are drawn upon as soon as growth starts i n the spring, which lessens the demand for the production of carbohydrates (Mooney and B i l l i n g s , i960). Mineral reserves may also accumulate i n the s o i l adjacent to the roots during growth dormancy and w i l l be available when growth i s r e i n i t i a t e d i n the spring. In addition, the short growing season fosters the evolution of rapid maturing plants with b r i e f vegetative stages ( B l i s s , 1962). The effect of growth physiology i n plants on t h e i r quality as forage can be equated to t h e i r three major phases of growth: 1) the i n i t i a l n u t r i t i v e stage, when the intake of inorganic nutrients and protein synthesis are rapid and quality of forage i s high, 2) the stage of accelerated accumulation of carbohydrates, diminishing protein synthesis, and increasing f i b e r content; decreased forage quality through lowered nitrogen content and decreased d i g e s t i b i l i t y and 3) the flowering stage i n which catabolism results in the use and r e d i s t r i b u t i o n of nutrients within the plants and f i b e r content and l i g n i f i c a t i o n of c e l l walls markedly increases; forage quality i s greatly reduced unless concentrations of nutrients i n f r u i t s and seeds become avai l a b l e . Photosynthetic v a r i a t i o n . — Environmental factors which control rates of photosynthesis may d i r e c t l y affect the quality of plant parts used as forage. High photosynthetic rates are e s s e n t i a l for the rapid growth of new vegetation and are therefore e s s e n t i a l l y synonymous with high forage qu a l i t y . Climate, through the mediums of l i g h t , temperature and moisture,' i s perhaps the primary control of photosynthetic 62 rate under natural conditions, although s o i l quality and species v a r i a t i o n are of obvious importance. On the study areas, although moisture i s probably not a major factor l i m i t i n g photosynthesis or plant growth, i t may under certain conditions influence vegetative growth. Annual p r e c i p i t a t i o n i s not greatly d i f f e r e n t on the two islands (Table 3) although during the months of most active vegetative growth, May, June, July and August, p r e c i p i t a t i o n on a monthly basis i s 10 to 35 percent greater on Woronkofski than on Coronation Island. This d i s p a r i t y , coupled with the excellent drainage i n the limestone substrate of Coronation Island could conceivably result i n b r i e f periods of semi-drought i n the alpine and subalpine areas there. Such a condition would l i k e l y r e f l e c t i t s e l f i n reduced forage q u a l i t y . Huffman and Duncan (1944) have shown that there i s a tendency for the protein content of forage to be lower i n areas of limited r a i n f a l l than where the r a i n f a l l i s greater. Light, while important for photosynthesis, i s quite l i k e l y not greatly d i f f e r e n t i n terms of intensity and length of photoperiod under s i m i l a r s i t e conditions at the two islands. Both islands l i e at approximately the same l a t i t u d e . Temperature, which i s i d e n t i c a l on the two islands on an annual basis, i s markedly d i f f e r e n t during the summer months and quite l i k e l y has an important ef f e c t on photosynthetic rate. In the r e l a t i v e l y low temperature ranges that p r e v a i l during the summer months i n coastal regions of Alaska the difference of approximately f i v e degrees i n the monthly averages that exists between Woronkofski and Coronation Islands may-resul t i n s i g n i f i c a n t differences'in photosynthetic rates. Popp (1926), Hicks (1934) and others have shown that growth rates of plants, and hence photosynthetic rates, decrease greatly i n most temperate region plants with any decrease i n temperature when a i r temperatures are below 70° P. Although plants native to the study region are adapted to cool growing seasons, temperatures are undoubtedly frequently below optimun for photosynthesis under the cool summer conditions that p r e v a i l ( B l i s s , 1 9 6 2 ) . Consequently, summer temperature d i f f e r e n t i a l s on the two islands during the period of d a i l y solar r a d i a t i o n could conceivably re s u l t i n s i g n i f i c a n t differences i n growth rates of plants and therefore the quality of the forage they produce. Indirect factors of the environment which modify external climatic features can have a very pronounced effect on forage q u a l i t y . Shading i s perhaps the most important factor within the forest type governing growth rate of forest vegetation. The forest canopy not only reduces l i g h t penetrating to the forest f l o o r but i t tends to moderate the temperature and consequently does not benefit plant growth under the already cool summer conditions. Light i n t e n s i t i e s , which may be marginal for photosynthesis under a closed forest canopy during clear days may not be adequate for photosynthesis on overcast days. Of course, i t should be borne i n mind that optimum l i g h t i n t e n s i t i e s for photosynthesis vary considerably 64 between species. Withrow (1951) points out that i n most temperate region plants, photosynthesis requires r e l a t i v e l y high l i g h t i n t e n s i t i e s to proceed at an optimum rate. Other photochemical reactions, such as chlorophyll synthesis, phototropism and photoperiodism are saturated at r e l a t i v e l y low l i g h t i n t e n s i t i e s of 20 foot-candles or l e s s . Popp (1926) has shown that shading not only reduces l i g h t i n t e n s i t y but also eliminates the shorter wave length portion of the spectrum reducing growth rate i n plants. Other workers have shown that in many plants the relationship between rate of photosynthesis and l i g h t i n t e n s i t y i s nearly a l i n e a r one up to about 1 , 0 0 0 foot-candles at normal atmospheric carbon dioxide concentrations of 0 . 0 3 volume percent (Hoover, et a l . , 1 9 3 3 ) . Above 1 , 0 0 0 -2 , 0 0 0 foot-candles, increases are less rapid than at lower values. Optimum l i g h t i n t e n s i t i e s for photosynthesis are generally i n the 1 , 0 0 0 - 2 , 0 0 0 foot-candle range. Light i n t e n s i t i e s within the forest type with a closed canopy undoubtedly are frequently less than 100 foot-candles even on clear days i n contrast to i n t e n s i t i e s i n excess of 5 S 0 0 0 foot-candles on open muskegs or i n alpine areas (Oosting, 1 9 5 3 ) . Obviously overcast skies can greatly influence photosynthetic rate within the forest type where l i g h t i n t e n s i t i e s are marginal at best. Plants common to the forest f l o o r , such as Cornus canadensis, Rubus pedatus, Maianthemum dilatum and Polystichum muniturn have a high tolerance for shade and cool summer temperatures, 65 however, this tolerance i s apparently gained through s a c r i f i c e d growth rate and associated low n u t r i t i v e q u a l i t y . Data are not available to enable a direct comparison of summer l i g h t conditions on Woronkofski and Coronation Islands. While Woronkofski has more summer p r e c i p i t a t i o n and associated overcast skies, Coronation Island i s frequently shrouded by coastal fog which would tend to offset any advantage from i t s location i n an area of lower summer r a i n f a l l . Prom the foregoing discussion i t can be expected that vegetation growing i n the shade on the study islands w i l l be of lower quality than that growing i n the open. Of course, species v a r i a t i o n and edaphic factors may l o g i c a l l y a l t e r t h i s relationship to some extent. It follows then, that since the highest quality vegetation w i l l be found outside of the forest type, where shading i s not an important factor, the r e l a t i v e proportion of forest type (or conversely unshaded areas) on each i s l a n d determines to a large extent the r e l a t i v e abundance and a v a i l a b i l i t y of high quality deer forage. Topographic v a r i a t i o n . — Any variations i n exposure, al t i t u d e and slope from a f l a t p l a i n at sea l e v e l w i l l a l t e r the phenological progression. The i n i t i a t i o n of vegetative growth i n the spring i s progressively delayed as alti t u d e increases, other factors being equal. S i m i l a r l y , exposure governs seasonal progression. South-facing slopes are frequently tvio to three weeks ahead of l e v e l areas i n growth of vegetation and an even wider gap may exist with north-facing 66 slopes. The degree of slope i s important when the angle of the sun i s low. Steep south slopes receive more d a i l y sunlight, which i s of a greater i n t e n s i t y , than nearly l e v e l areas which may be shaded by adjacent mountains when the sun i s low. The angle that the sun makes with the land surface governs to a large extent the int e n s i t y and the available energy of the l i g h t received from i t . Figure 17 shows thi s r e l a t i o n s h i p in terms of l i g h t i n t e n s i t y on surfaces perpendicular and horizontal to the rays of the sun. Extremely steep slopes shed snow and south slopes receive the f u l l force of the r e l a t i v e l y warm southeast storms of late winter and spring which re s u l t s i n premature snow melt even at higher elevations. In addition, dark colored rock ledges and outcrops absorb solar energy and reradiate i t to the immediately surrounding areas, which results i n i n i t i a t i o n of growth of plants i n rock crevices and adjacent to outcrops even before the snow has l e f t nearby areas. The slope ef f e c t can be an extremely important factor leading to variations of up to several weeks i n the i n i t i a t i o n and progression of spring and summer growth. Elevation, exposure and slope a l l affect the period of i n i t i a t i o n of new vegetative growth following the period of winter dormancy. Since plants i n early physiological stages of growth are most n u t r i t i o u s , the greater the topographic v a r i a t i o n , i n the form of a l t i t u d e , slope and exposure, the longer w i l l be the period during the growing season when high 67 80-1 55 00 c o o a> o O O — 40 O >-00 20-(a) X O to a <t (u a 5° 10° 20° 30° 40° A L T I T U D E 50° 0 F 60° 70° S U N 80° 90< Pig. 17. Topographic effects on solar i n t e n s i t y . The diagram shows the s o l a r intensity on a f l a t surface perpendicular to the rays of the sun. Data from Trewartha ( 1 9 5 4 ) . 68 q u a l i t y forage w i l l be a v a i l a b l e f o r herbivores capable of ranging over the topographic extremes. Alpine and subalpine areas, i n a d d i t i o n to being s t r o n g l y a f f e c t e d by f a c t o r s of e l e v a t i o n , exposure and slop e , are subject t o other environmental c o n d i t i o n s which lead t o high q u a l i t y forage. Although a l p i n e areas u s u a l l y r e c e i v e heavier p r e c i p i t a t i o n than adjacent f o r e s t and muskeg types, drainage-^ i s f r e q u e n t l y good because of the steep slopes and the r e l a t i v e l y low organic content of the s o i l . A l s o , evaporation, which i s high under the intense s o l a r r a d i a t i o n , the r a p i d a i r movements and the absence of a f o r e s t cover, removes much of the excess moisture i n a l p i n e areas. Temperatures and l i g h t c o n d i t i o n s of a l p i n e areas are unique and are p a r t l y r e s p o n s i b l e f o r the c h a r a c t e r i s t i c plant complexes found there. Temperatures are ge n e r a l l y c o o l e r i n the al p i n e areas than at lower e l e v a t i o n s . Winter snows are l a t e i n m e l t i n g , d e l a y i n g the i n i t i a t i o n of plant growth. Cool summer temperatures are common i n a l p i n e areas, although daytime temperatures on s t i l l , c l e a r days may g r e a t l y exceed those i n the f o r e s t or at sea l e v e l . Temperature extremes are c h a r a c t e r i s t i c of a l p i n e areas even during the summer growing p e r i o d . A r c t i c - a l p i n e plant forms are w e l l adapted to these temperature extremes, o f t e n being able to survi v e f r e e z i n g during t h e i r a c t i v e growth p e r i o d ( P o r s i l d , 1951). Temperature extremes may al s o be b e n e f i c i a l f o r plant growth. Low temperatures i n h i b i t v egetative growth and lower the r e s p i r a t i o n r a t e which r e s u l t s i n increased osmotic conce n t r a t i o n • ' • ' , . 69 and allows for sugar accumulation. Repletion of mineral levels i n the root system can also take place during the vegetative dormancy of the cool nights of alpine areas. Even during periods of r e l a t i v e l y cool daytime a i r temperatures alpine plants may be capable of an active photosynthetic rate. Withrow (1951) has shown that sunlight absorption by plant parts frequently results i n shoot and root temperatures s i g n i f i c a n t l y higher than the ambient a i r temperature to the point of accelerating thermal reactions. .He points out that horizontal leaf surfaces at midday during clear weather i n the Temperate Zone are exposed to sunlight i n t e n s i t i e s ranging from 1.2 to 1.5 gram calor i e s per square centimeter per minute. Of t h i s incident energy, 20 to 30 percent i s r e f l e c t e d by t h i n leaves, some i s transmitted and the remainder i s absorbed. Most of the absorbed energy i s degraded to heat and manifests i t s e l f as a temperature r i s e i n the exposed portions while less than five percent-is used i n photosynthesis. Likewise Curtis (1936) has shown that the temperature of c i t r u s leaves i n intense sunlight may be 10-15° C above a i r temperature. Tikhomirov, et_ a l . (I960) found that a r c t i c plant parts i n northeast S i b e r i a were 2-5° C above a i r temperatures on sunny days. . The duration and quality of l i g h t plays an important part i n the physiology of alpine plants. During the summer growth period the average da i l y period of solar ra d i a t i o n i n alpine areas exceeds that at sea l e v e l i n adjacent areas because of the lower angle that the horizon presents to alpine areas. 70 This phenomenon i s probably not greatly s i g n i f i c a n t i n t r o p i c a l or temperate regions where the sun approximates a perpendicular with the horizon when r i s i n g and s e t t i n g ; however, in a r c t i c , subarctic and north temperate regions the summer sun approaches the horizon at a r e l a t i v e l y low angle and t o t a l d a i l y solar r a d i a t i o n and day length are substantially increased i n alpine areas over surrounding areas of low elevation. This increased day length i n alpine areas allows for a longer photosynthetic period which i s l i k e l y r e f l e c t e d i n increased rate of growth. It seems l i k e l y that t h i s would also hold true for some plants i n polar regions although i n experiments with domestic plant species Pohjakallio (1951) suggests that increased day length i n a r c t i c regions i s apparently offset by the decrease i n i n t e n s i t y and therefore does not re s u l t i n increased growth rate. Warren Wilson (i960) concluded that low temperatures are primarily responsible for depression of net assimilation i n a r c t i c plants rather than levels of l i g h t i n t e n s i t y . Obviously much additional work remains to be done on photosynthetic rates of a r c t i c plants. Increased day length i n both alpine regions and the A r c t i c means decreased darkness and therefore shorter nighttime periods, when catabolic energy losses in plants through r e s p i r a t i o n are not offset by the anabolism of photosynthesis, than at lower elevations and l a t i t u d e s . Generally, the long daylight hours i n a r c t i c and alpine regions re s u l t i n continual, although perhaps slow, da i l y growth and accumulation of plant nutrients and the b r i e f cool nights result i n minimum 71 nutrient losses to r e s p i r a t i o n (Kislyakova, i960). In contrast high temperatures of the tropics result i n rapid daytime growth and rapid nighttime r e s p i r a t i o n during the r e l a t i v e l y long warm nights, with associated u t i l i z a t i o n of nutrients by the plants. Since i n summer, alpine nights are cool and b r i e f , nitrogen and carbohydrate levels remain high for a longer portion of the day and decreases are not of as large a magnitude as at lower elevations where nighttime temperatures are usually warmer. Animals, such as ruminants, that must graze at frequent i n t e r v a l s including the night and early morning, are able to secure summer forage of r e l a t i v e l y constant nitrogen and carbohydrate levels when i n alpine areas, while t h i s i s probably not the case i n non-alpine areas where nitrogen and carbohydrate lev e l s may drop s i g n i f i c a n t l y during the longer and warmer nights. Summer vegetation i n a r c t i c regions, under 24 hours daylight conditions, undoubtedly benefits from the absence of catabolic nighttime metabolism. The high q u a l i t y of a r c t i c forage which i s r e f l e c t e d i n the unparalled growth rates of caribou and other a r c t i c herbivores during the b r i e f a r c t i c summers ( K i t t s , et a l . , 1956 and Krebs, 1959), quite l i k e l y r e s u l t s , at least i n part, from t h i s phenomenon. The quality of l i g h t i n alpine regions i s somewhat higher than that reaching lower elevations. The earth's atmosphere f i l t e r s out about 40 percent of the incident solar energy. Since the-earth's atmosphere i s most dense at sea l e v e l and decreases i n density rapidly with increases i n a l t i t u d e any appreciable increase i n elevation results i n an increased portion of the sun's energy reaching i t . The magnitude of the e f f e c t of a l t i t u d e on l i g h t quality i s obviously not great i n Alaska, where alpine vegetation i s only a few thousand feet above sea l e v e l , i n contrast to high alpine plant communities i n more temperate regions. However, any difference that may exist would tend to contribute to the higher quality of alpine vegetation. Some difference i n the spectra of l i g h t at sea l e v e l and at high altitudes exists but i s apparently not great enough to affect plant processes. U l t r a v i o l e t r a d i a t i o n which can be destructive to protoplasm i n large^ doses i s v i r t u a l l y eliminated by the f i l t e r i n g e f f e c t of ozone concentrated i n the upper atmosphere. S o i l f e r t i l i t y . — S o i l condition and quality undoubtedly play important roles i n determining forage quality; however, s o i l s on the study areas and throughout Southeast Alaska i n general are probably not nearly as Important i n bringing about d i f f e r e n t i a l range quality within the region as the factors of a l t i t u d e , exposure, and cover type, as discussed above. S o i l s are perhaps more Important i n determining the extent and location of vegetation types and therefore more d i r e c t l y affect quantity than quality of forage. However, s o i l i s an i n t e g r a l part of an ecosystem and cannot be i s o l a t e d from other factors of the environment, being a product of both climate and parent material. 73 Under natural conditions, even where r e l a t i v e l y poor s o i l s are involved, production per acre i n volume may be only a f r a c t i o n of domestic crop production per acre, however, what i s produced may be of equal or higher q u a l i t y . Mineral d e f i c i e n c i e s that are common to a g r i c u l t u r a l crops are probably rarely encountered under natural conditions i n the absence of intensive cropping. Under natural conditions shortages of e s s e n t i a l minerals usually r e s u l t i n the absence of plant species unable to derive t h e i r mineral needs from the s o i l ; however, these are frequently replaced by forms which are more tolerant of the mineral d e f i c i e n t conditions. Such plants are frequently recognized by the plant ecologist as " i n d i c a t o r s . " Drainage greatly affects the vegetation i n Southeast Alaska and t h i s i s graphically apparent i n the contrast between forest, muskeg and alpine s o i l s . On the muskeg, minerals may be present but t h e i r a v a i l a b i l i t y i s often limited by an extremely low pH. In such s i t e s s o i l s are waterlogged and nitrogen and other minerals are t i e d up i n the high content of organic material. The r e s u l t i s a unique complex of vegetation developed to survive under these r e l a t i v e l y adverse conditions. In spite of these apparent poor conditions for plant growth, the quality of surface vegetation i n muskegs may exceed that within the forest due to the more favorable l i g h t and temperature conditions during the summer growing period. However, the period during which the vegetation i s of high quality may be very b r i e f due to growth li m i t a t i o n s imposed by the poor a v a i l a b i l i t y of minerals or other factors. Both forest and alpine s o i l s are greatly affected by the mountainous t e r r a i n 74 of the region. Seepage i s an important factor i n s o i l f e r t i l i t y i n mountainous regions of high p r e c i p i t a t i o n . Ions leached from rocks and s o i l at higher elevations are constantly brought down by percolating seepage water and replenish losses below. Exposure i s also important to s o i l f e r t i l i t y . S o i l s on south-facing slopes receiving more solar i n s o l a t i o n , both da i l y and seasonally, than cool north slopes provide more favorable conditions for the growth of s o i l b uilding bacteria and fungi. Consequently, decay processes are speeded up and there i s a rapid release of nutrients to the s o i l . There i s some evidence from the s o i l analysis data i n Table 2 that s a l t spray, blowing onto the land, may influence s o i l conditions on Coronation Island. The r e l a t i v e l y high lev e l s of s u l f u r , sodium and boron found i n the s o i l samples from Coronation Island apparently are derived from t h i s source. The s a l t spray effect may prevent many s a l t intolerant species of plants from occurring on Coronation Island and therefore s a l t spray i s quite l i k e l y a factor i n bringing about the reduced abundance of plant species on t h i s i s l a n d . In Southeast Alaska the nature of the parent material from which s o i l s are derived apparently does not greatly influence the forage quality of the vegetation growing on them. This i s undoubtedly partly a result of the extremely high r a i n f a l l of the region which results i n strong leaching of a l l mineral s o i l s . 75 THE DEER Function and Adaptability of the Rumen The function of the rumen as a fermentation vat enables deer and other ruminants to u t i l i z e vegetation not normally available to mammals as a food source. The highly complex microorganism environment within the rumen enables a wide va r i a t i o n i n the diet by providing for synthesis of es s e n t i a l vitamins, amino acids and other nutrients from dietary elements normally unavailable to nonruminants. In addition, b a c t e r i a l and protozoal action within the rumen can result i n the breakdown and conversion of c e l l u l o s e and other plant components to rea d i l y metabolizable products. The excess heat of fermentation, which requires work to accomplish i t s d i s i p a t i o n i n warm climates, i s an advantage i n cold climates and may p a r t i a l l y account for the success of ruminants i n a r c t i c and subarctic regions. The ruminant, because of the c a p a b i l i t y of the rumen microorganisms to synthesize e s s e n t i a l dietary components, i s better equipped than most mammals to adapt to variations i n range q u a l i t y . However, there are l i m i t a t i o n s as with any organism. In northern regions s u r v i v a l of the species i s p a rtly dependent upon the a b i l i t y of the young to a t t a i n s u f f i c i e n t growth during the b r i e f summers to enable them to survive the long winters when forage i s l i m i t e d i n both quality and quantity. Quality l i m i t a t i o n s i n the summer di e t , which 76 might be compensated for by the adaptability of the rumen i n more temperate regions, are r e f l e c t e d i n growth responses i n northern regions where growth i s more rapid and the animals more nearly approach t h e i r physiological l i m i t a t i o n s . Deer, and quite l i k e l y a l l other ruminants i n cold climates, experience well-defined periods of rapid summer groxvth as contrasted to a state of r e l a t i v e physiological dormancy during the winter. During these two periods the animals are essentually two completely d i f f e r e n t physiological e n t i t i e s . Dietary requirements are vastly d i f f e r e n t during the summer than i n the winter. The summer growth period requires a high proportion of proteinaceous or amino ac i d - y i e l d i n g substances i n the diet to enable the extensive tissue p r o l i f e r a t i o n associated with rapid summer growth. In contrast, during winter when growth has v i r t u a l l y ceased, energy requirements for metabolism are paramount and the nitrogenous component of the diet' need only be large enough to supply the requirements of the rumen microorganism^, which i n turn w i l l usually be adequate for maintenance needs of the deer. Rumen Contents Analysis In the f i e l d of w i l d l i f e management, the chemical determination of nutrient contents of winter browse species has been employed as a standard technique for the evaluation of the ranges of wild ungulates (Einarsen, 1946; Hundley, 1956; Lay, 1957 and others). There has been considerable speculation as to the v a l i d i t y of t h i s approach i n the absence of an understanding 77 of the seasonal n u t r i t i v e requirements of the animals studied. This attention to winter browse species has tended to divert interest from other seasonal range components which can be of greater importance i n the annual n u t r i t i v e regimen of ungulates. Researchers i n the a g r i c u l t u r a l sciences have developed techniques for the evaluation of forage quality through the use of the a r t i f i c i a l rumen and i n vivo studies i n f i s t u l a t e d animals (Burrough, e_t a l . , 1 9 5 0 ; Pigden and B e l l , 1 9 5 5 ; Kamstra, et a l . , 1958; Blackburn and Hobson, I 9 6 0 ; and others). These techniques have not been applicable to wild or range ruminants and alternative attempts have been made by Norris (19^3) and B i s s e l l (1959) to use rumen contents analysis to r e f l e c t range q u a l i t y . Norris and B i s s e l l , however, both indicate that variations i n n u t r i t i v e constituents of the rumen contents cannot be d i r e c t l y associated with forage quality and therefore they question the use of such analyses i n range evaluation. B i s s e l l , i n finding higher protein values i n the rumen contents of deer than i n the forage collected from the range, assumed that i t was l i k e l y the deer were sel e c t i n g plant parts that had a higher protein content than those selected for analysis by the b i o l o g i s t s . That range animals are capable of a c t i v e l y selecting high quality forage has been pointed out by Swift (1948) and Dietz, e_t a l . ( 1 9 5 8 ) . Nevertheless, Wood, et a l . ( I 9 6 0 ) pointed out that the phenomenon of higher ruminal protein levels i s partly 78 explained by the presence of large numbers of bacteria and protozoa i n the rumen as well as the presence of mucin and the p o s s i b i l i t y of urea nitrogen derived from the s a l i v a . Even i f operative, a selective factor should not affect r e l a t i v e comparisons of rumen contents with standards or between areas and times. It was decided therefore to explore thi s means of comparing the two islands. Methods of analysis. — Rumen samples were collected from deer specimens during the. standard autopsy procedure. Samples were removed from the opened rumen, placed i n p l a s t i c bags and the a i r expelled from the bags before sealing. Fecal samples were coll e c t e d from the lower portion of the rectum. Twelve to twenty-four hours l a t e r the samples were broken into subsamples and prepared i n the following manner: Subsample Preparation A Gross f r a c t i o n ; no further treatment. B Gross sample was thoroughly washed with water on a 10 mesh/inch s o i l sieve (size of openings 1 .981 millimeters) and the remaining vegetative material saved (ca l l e d the washed vegetative f r a c t i o n ) . C-, Gross sample was strained through two layers of cheesecloth; the l i q u i d obtained was strained through a 60 mesh/inch s o i l sieve (size of openings 0.246 millimeters) and the collected l i q u i d saved (called the whole l i q u i d f r a c t i o n ) . C 2 The C,, or whole l i q u i d f r a c t i o n was centrifuged at 1500 g for 20 minutes and the supernatant l i q u i d saved (called the clear l i q u i d f r a c t i o n ) . 79 D The deposit from the above centrifuging of the C-j_ component was saved ( c a l l e d the microorganism f r a c t i o n ) . Fecal material. A l l subsamples were preserved with 0.5 m i l l i l i t e r of 10 percent formaldehyde per 100 m i l l i l i t e r s of sample. F i n a l treatment of the rumen subsamples was as follows: Subsample A Gross f r a c t i o n B Washed vegetative f r a c t i o n Whole l i q u i d f r a c t i o n D Microorganism f r a c t i o n Chemical analyses for nitrogen, crude f a t , crude f i b e r , t o t a l ash, calcium, phosphorus and moisture. Chemical analyses for nitrogen, crude f a t , crude f i b e r , t o t a l ash, calcium, phosphorus and moisture. Microscope counts of a l l protozoa and separate counts of the large o l i g o t r i c h , Metadinium sp., by the hemocytometer. Centrifuging of 15 m i l l i l i t e r portions at 1500g for 20 minutes to determine r e l a t i v e volumes of C2 and D f r a c t i o n s . Chemical analyses for nitrogen, crude f a t , t o t a l ash, calcium, phosphorus and moisture. Percent transmittancy of 1:20 d i l u t i o n at a wave length of 5^5 in the Beckman spectrophotometer. Chemical analyses for nitrogen, crude f a t , t o t a l ash, calcium, phosphorus and moisture. E Fecal material Chemical analyses for nitrogen, crude f a t , crude f i b e r , t o t a l ash, calcium, phosphorus and moisture. A l l chemical analyses were of a quantitative nature and were made by Curtis and Tompkins, Ltd., commercial a n a l y t i c a l chemists at San Francisco, using Association of O f f i c i a l A g r i c u l t u r a l Chemists methods (1955). 80 Results and discussion. — Digestion and growth studies with domestic ruminants show a positive c o r r e l a t i o n between nitrogen content (protein) of forage plants and t h e i r n u t r i t i v e q u a l i t y , while f i b e r content i s negatively correlated with forage q u a l i t y . It was therefore assumed that similar cor-relations should exist between nitrogen and f i b e r i n the forage eaten by wild ruminants and that i n the contents of the rumen (which consist of the forage eaten plus symbiotic microorganisms and t h e i r products and s a l i v a ) . The negative correlations found to exist between nitrogen and f i b e r content of both the gross rumen samples and the washed vegetative portion of the rumen contents are shown i n Figures 18(a) and 1 8(b). The higher c o r r e l a t i o n i n the gross rumen contents i s surprising but may r e f l e c t the retention by rumen microorganisms of readily convertible nitrogen. In the washed samples the microorganisms have been removed. Moir and Williams (1950) estimated that about 50 percent of the protein ingested by sheep i s broken down and converted to microbial protein. The large da i l y variations found to exist i n n u t r i t i v e components i n the rumen contents of sheep by Blackburn and Hobson ( I 9 6 0 ) and Ch r i s t i a n and Williams (1957) were associated with the length of time after feeding at which the samples were co l l e c t e d . For example Blackburn and Hobson found that sheep which were fed diets containing protein of varying d i g e s t i b i l i t y a l l showed highest t o t a l nitrogen values i n t h e i r rumens shortly a f t e r feeding with values rapidly decreasing 81 to the prefeeding l e v e l s during the following eight hours. They also found that levels of protozoal and b a c t e r i a l nitrogen remained f a i r l y constant and interpreted t h i s as a near- balance between growth of microorganisms and t h e i r loss to the abomasum. The s a l i v a of ruminants i s e s s e n t i a l l y a buffering agent for the rumen environment and contains large amounts of bicarbonate and phosphate ions as well as nitrogen i n the form of urea and mucin nitrogen. Bailey (1959) found that the s a l i v a flow added 98 to 190 l i t e r s to the rumens of experimental cows d a i l y , and t h i s flow, was lowest immediately aft e r eating and steadily increased to maximum values immediately before the next meal; he related t h i s to i t s function of maintaining a constant state within the rumen. These reported variations i n nitrogen content, microorganism l e v e l and s a l i v a flow were a l l associated with time of feeding, and were not considered important i n t h i s study because wild ruminants are known to feed at frequent in t e r v a l s during the daylight hours on early summer range, thus maintaining a r e l a t i v e l y constant state within the rumen (Bubenik, i 9 6 0 ) . Increased feed intake and f u l l rumens during spring and early summer are associated with peak physiological demands for growth, l a c t a t i o n and recovery of fat reserves lost during the winter. In support of t h i s assumption of a r e l a t i v e l y constant rumen environment as the normal condition 82 i n ruminants are the i n vivo studies of Moir and Somers (1956) with domestic sheep. They showed that when the same r a t i o n was fed i n four portions per day instead of one, the protozoan population increased to approximately three times i t s previous l e v e l . Rakes, et a l . (I960) found that lambs made more rapid gains when the same amount of feed was consumed i n eight meals per day rather than one. Also observations on i n v i t r o cultures indicate that rumen protozoa appear devoid of reserve polysaccharide 24 hours aft e r the addition of substrate and therefore cannot multiply or even maintain t h e i r numbers (Hungate, i960). It was also f e l t that the phenomena of d i f f e r e n t i a l growth of rumen microorganisms on diets of di f f e r e n t q u a l i t y and varying length of retention i n the rumen of plant nitrogens of unlike quality would tend to be compensatory and would have a minimal effect on the rumen samples. Results of the chemical analyses of the variously treated rumen subsamples are shown i n Table 12. It i s apparent from the data that the gross and washed rumen samples both show highly s i g n i f i c a n t differences between islands for nitrogen and f i b e r although the " t " values are s l i g h t l y higher for the gross samples. Figures 18(c) and 18(d) show the clear separation obtained between islands i n the nitrogen and f i b e r content of both the gross and washed rumen samples. Other components of the rumen analyses do not show d i s t i n c t differences between islands with the exception of ash and TABLE 12. Comparison of chemical analyses of summer rumen samples from Woronkofski and Coronation Island deer Components-Sample treatment Island 2 Sample size Mean Standard error t Level of significance Gross sample (A) W c 22 24 6 . 4 2 '4.47 0 .096 0 .097 14 .35 0 .001 Washed sample (B) w c 21 15 3 . 9 5 ' 2 .63 0..129 0 .110 7 . 7 8 0 .001 Nitrogen Clear l i q u i d f r a c t i o n (Cp) w c 15 14 5.62 ' 5 .07 0 .375 0 .300 1 .15 n.s . 3 Microorganisms (D) w c 4 4 8 . 6 6 •8.18 O.Otfb 0 .177 2 .43 0.1 Fecal material (E) w c 3 5 4.44 3 . 6 7 0 .49b 0 .202 1.44 n.s. Gross sample (A) w c 22 24 ' 14 .17 2 1 . 2 7 0 .512 0 .589 9 .10 0 . 0 0 1 Fiber Washed sample (B) w c 21 ' 15 2 9 . 0 3 34.55 1 .085 1.040 3 . 6 8 0 . 0 0 1 Fecal material (E) w c 3 5 18 .87 24 .75 2 .087 1 .979 2.041 0.1 Gross sample (A) w c 22 •24 8.67 8 . 2 1 0 .357 0 .255 1 .05 n.s. Washed sample (B) w c 21 15 7 .87 6 . 5 9 ' 0 .254 0 .266 1 .10 n.s. Fat Clear l i q u i d f r a c t i o n (C 2) w c 15 14 7 .12 4 .93 1.098 0 .323 1 .91 0.1 Microorganisms (D) w c 4 4 1 0 . 0 9 9 .28 0.425 0 .393 1.40 n.s. Fecal material (E) w c 3 ' 5 ' 11 .94 9.00 1 .177 1 .305 1 .73 n.s. Gross sample (A) w c 22 24 1 3 . 3 9 14.24 0 .218 0 .329 2 .16 0 .05 Total ash Washed sample (B) w c 21 15 b .05 6 . 2 3 0.2bb 0 .319 0 .43 n.s. o Clear l i q u i d f r a c t i o n (Cp) w c 15 14 3 3 . 5 6 38.72 1.728 1 .744 2 .10. . 0 .05 TABLE 12. continued Component Sample treatment 2 Island Sample size Mean Standard error t Level of significance Microorganisms (D) W c 4 4 16 .61 16.21 1.124 1.764 0 .17 n. s. Total ash Fecal material (E) ' w c 3 5 10.00 12.28 1.834 0 .629 1 .18 n.s. Gross sample (A) w c 6 10 0.854 1.534 0 .092 0.114 4 .65 0.001 Washed sample (B) w C ' 6 3 0.658 1 . 103 0.042 0.089 4 .53 0 .005 Calcium Clear l i q u i d f r a c t i o n (C?) w c 4 3 0 .«32 0.666 • 0.184 0.111 0 .77 n.s. Microorganisms (D) w c 2 2 0 .637 2 .070 0 .037 0 .500 2 .86 n.s. Fecal material (E) w c 2 2 1.514 4.090 0.620 0.740 2 . 6 7 n.s. Gross sample (A) w c 6 10 2 . 2 0 3 2.266 0.136 0 . 0 9 3 0 . 3 8 n.s. Washed sample (B) w c 6 3 0 .792 0.886 0.058 0 .032 1 .43 n.s. Phosphorus Clear l i q u i d f r a c t i o n (Cp) w c 5 3 5 . 720 5.364 0.294 0.199 1 . 0 0 . n.s. Microorganisms (D) w c 2 2 3.342 3.-410 0.141 0.255 0 .80 n.s. Fecal material (E) w - c 2 2 0.894 0 .620 ,0.471 0.348 0 .47 n. s. Moisture Gross sample (A) w c 22 22 88.86 88.99 ,0.191 0 .203 0 .47 n.s. A l l values on a dry weight basis except moisture. W = Woronkofski Island and C = Coronation Island ' Mot s i g n i f i c a n t at the 0.1 l e v e l . 85 40- , jf SO-K U 2 0 CD (c) B B v 1 c 1 G R O S S V 'c' WASHED UJ o o oe (d) 'w' 'c' OROS 3 B v v WASHED F i g . 18 . Correlation diagrams, (a) and (b), show the relationship e x i s t i n g between f i b e r and nitrogen contents of both gross and washed rumen samples. Diagrams (c) and (d) show comparisons of mean f i b e r and nitrogen contents of gross and washed rumen samples from Woronkofski (w) and Coronation (c) Islands. The heights of the rectangles indicate the range of 1 two standard errors. 86 calcium which are s i g n i f i c a n t l y higher i n some of the Coronation Island samples. This i s readily explained on the basis of the high calcium content of the limestone-derived s o i l s of Coronation Island i n contrast to the g r a n i t i c s o i l s of Woronkofski Island. Although high calcium: phosphorus r a t i o s , i n excess of 2 to 1, are frequently encountered i n the forage of Coronation Island, i t i s not l i k e l y that such distorted r a t i o s could result i n inadequate absorption of phosphorus i n wild ruminants where: (1) plant nutrients are not removed from the land and phosphorus levels i n the forage appear adequate, (2) vitamin D i s probably never i n short supply and (3) large amounts of phosphorus are recycled to the rumen v i a the s a l i v a . Calcium levels i n the vegetation appear to be adequate i n both areas and therefore the differences occurring i n the rumen contents are not pertinent here. Suggestions by sportsmen that the largest trophies (horns and antlers) come from limestone areas because of the abundance of calcium for antler growth are not consistent with the available evidence. It i s possible that large trophies can come from limestone regions; however, other factors of the range than the surplus calcium i n the s o i l are undoubtedly responsible. Fail u r e of the clear l i q u i d fractions and the concentrated microorganisms to show s i g n i f i c a n t differences (p = 0 . 0 5 ) between islands i s understandable i n l i g h t of the method of t h e i r derivation. The clear l i q u i d f r a c t i o n or rumen liquor includes primarily fermentation products and s a l i v a i n a 87 water solution and i s constantly subject to s t a b i l i z a t i o n through absorption v i a the rumen wall and the addition of s a l i v a . Large amounts of water, v o l a t i l e fatty acids and ammonia are absorbed v i a the rumen epithelium (Annison and Lewis, 1959) and recent studies have demonstrated the absorption of amino acids as well (Smith, 1 9 5 9 ) . Salivary contributions to the rumen include as much as 10 percent of the nitrogen requirements in sheep (Somers, 1957) while phosphate and sodium may exceed dietary sources (Bailey, 1 9 5 9 ) . A r e l a t i v e l y constant state of the rumen liquor i s e s s e n t i a l for the maintenance of a suitable medium for proper rumen function and therefore one would expect only s l i g h t variations with d i e t . The D samples represent microorganisms of the rumen concentrated through centrifugation and therefore chemical analyses of these samples are not representative of r e l a t i v e numbers of bacteria and protozoa. The high nitrogen content and phosphorus: calcium r a t i o s obtained from the D samples are comparable to the chemical analyses of microorganisms (Porter, 1 9 4 6 ) . The f e c a l sample analyses suggest a possible difference between islands i n f i b e r content. Sample sizes were small and additional work i s required to further explore the p o s s i b i l i t y of using f e c a l samples as v a l i d indicators of forage q u a l i t y . Results of the evaluation of other methods of treatment of the rumen samples are presented i n Figures 1 9(a), 1 9(b), 19(c) and 1 9(d). Results of a l l methods, with the exception of the 88 microscope counts of Metadinium sp., showed l i n e a r correlations with the nitrogen content of the gross rumen samples. Positive correlations were found to exist between the nitrogen content of the gross rumen samples and both the volume of microorganisms present and the numbers of protozoa present. A negative c o r r e l a t i o n existed between the nitrogen content and the l i g h t transmittancy of the clear l i q u i d f r a c t i o n ; probably r e f l e c t i n g the greater proportion of disolved plant pigments associated with the higher quality forage. Table 13 shows the evaluation of these treatments applied to the in d i v i d u a l i s l a n d data i n which highly s i g n i f i c a n t differences between islands were obtained with a l l but the Met'adinium counts, i n d i c a t i n g higher quality of range on Woronkofski Island. The degree of separation of mean values obtained, indicated i n Figures 1 9(e), 1 9 ( f ) , 19(g) and 1 9(h), was greatest for the l i g h t transmittancy method, followed by the protozoa counts and the volumetric f r a c t i o n a t i o n of microorganisms. Greater l i g h t transmittancy of the clear l i q u i d f r a c t i o n from low quality rumen samples or, conversely, greater o p t i c a l density of the clear l i q u i d f r a c t i o n from high quality rumen samples are apparently due to the r e l a t i v e amounts of dissolved plant pigments present i n the rumen li q u o r . It seems l o g i c a l that a l i n e a r c o r r e l a t i o n may exist between the r e l a t i v e proportion of plant pigments present and the n u t r i t i v e quality of certain species of plants. This i s quite l i k e l y associated with the stage of growth of plants, i n which plants i n i t i a t i n g TABLE 13. Comparison of summer rumen samples from Woronkofski and Coronation deer subjected to various treatments Treatment Island Sample size Mean Standard error t Level of significance Percent volume of microorganisms in whole l i q u i d f r a c t i o n (C-^ ) Woronkofski Coronation 20 19 60.0 43.5 3.054 2.535 4 .16 0.001 Light transmittancy {%) of clear l i q u i d f r a c t i o n (Cg) Woronkofski Coronation 19 10 10 .85 38.02 0.855 5.464 4.90 0.001 Numbers of protozoa X 10^ per m i l l i l i t e r i n whole l i q u i d f r a c t i o n (C-^ ) Woronkofski Coronation 18 16 1.47 0.75 0 .138 0.047 4.94 0.001 Numbers of o l i g o t r i c h Metadinium sp. X 10^ per m i l l i l i t e r i n the whole l i q u i d f r a c t i o n (C-^ ) Woronkofski Coronation 18 16 4.13 3 .36 0.540 0.493 1.04 n.s. CO VO 90 u »o-a 3 z O o <r (e) B >- 80' u (f) E « o < o i (4) e E O 4 O. » <n a Z o w s (h) 1 w c Pig. 1 9 . The scatter diagrams show the correlations e x i s t i n g between nitrogen contents of the gross rumen samples and values obtained from the following treatments of rumen samples: (a) volumetric determination of micro-organisms, (b) l i g h t transmittancy of rumen liquor and (c) and (d) microscope counts of portozoa. Comparisons of mean values from varying treatments of rumen samples from Woronkofski (W) and Coronation (C) Islands are made i n (e), ( f ) , (g) and (h). The heights of the rectangles show the range of t two standard errors. 91 growth have a r e l a t i v e l y large proportion of highly pigmented and phtosynthetically active tissue i n contrast to maturing and less n u t r i t i o u s plants with a larger proportion of c e l l u l o s e , l i g n i n and other nonpigmented components. Reid, et a l . (1952) and Kennedy and Lancaster (1957) have shown that as forage d i g e s t i b i l i t y increases the concentration of pigments i n the feces of dairy cows also increases. The correlations found to exist between n u t r i t i v e quality of the rumen contents and determinations of amounts of microorganisms both volumetrically and by actual counts are understandable i n the l i g h t of other studies. Mowry and Becker (1930) have shown that protozoa numbers may vary i n sheep rumen contents from 200,000 per m i l l i l i t e r on hay alone to 700,000 when starch i s added and 2,000,000 when protein i s added, while Van der Wath (1942) found seasonal fluctuations of rumen protozoa i n grazing sheep from 98,000-per m i l l i l i t e r i n mid-winter to 455,000 i n summer. Bryant and Burkey (1953) found s i m i l a r fluctuations i n numbers and species of bacteria with di f f e r e n t quality diets but found that the l e v e l of feeding of a given r a t i o n had l i t t l e e f fect on the numbers or d i v e r s i t y of the b a c t e r i a l f l o r a present. Protozoa, while fewer i n numbers than the bacteria and usually numbering less than 1,000,000 per m i l l i l i t e r of rumen contents, may be equivalent i n bulk to the bacteria. Christian and Williams (1957) found higher rumen microbial counts for sheep which were fed fresh grass than for those receiving dried grass while Hamlin and Hungate (1956) found rumen b a c t e r i a l concentrations i n sheep g r e a t e r on a h i g h p r o t e i n g r a i n d i e t t h a n on a hay d i e t . W h i l e c e r t a i n t y p e s o f rumen m i c r o o r g a n i s m s show c o n s i d e r a b l e v a r i a t i o n w i t h t h e t y p e o f d i e t , t h e r e does a p p e a r t o be a g e n e r a l c o r r e l a t i o n between t o t a l numbers o f b a c t e r i a and p r o t o z o a and t h e n u t r i t i v e q u a l i t y o f t h e r a t i o n . C o n c l u s i o n s . — The c h e m i c a l d e t e r m i n a t i o n o f n i t r o g e n c o n t e n t o f g r o s s rumen samples o f f e r s a v e r y r e l i a b l e t e c h n i q u e f o r t h e e v a l u a t i o n o f summer f o r a g e q u a l i t y . A n a l y s e s o f n i t r o g e n c o n t e n t o f t h e washed v e g e t a t i v e rumen components and f i b e r c o n t e n t o f b o t h t h e g r o s s and washed samples a l s o were r e l i a b l e i n d i c a t o r s o f f o r a g e q u a l i t y and c a n be u s e d s e p a r a t e l y o r i n s u p p o r t o f o t h e r a n a l y s e s . U t i l i z a t i o n o f t h e s e s t a n d a r d s e n a b l e d a c l e a r s e p a r a t i o n between W o r o n k o f s k i and C o r o n a t i o n I s l a n d s on t h e b a s i s o f r a n g e q u a l i t y . S i m p l e r t e c h n i q u e s o f rumen a n a l y s e s i n v o l v i n g ( 1 ) c e n t r i f u g e f r a c t i o n a t i o n o f m i c r o o r g a n i s m s , ( 2 ) l i g h t t r a n s m i t t a n c y d e t e r m i n a t i o n s o f rumen l i q u o r and ( 3 ) m i c r o s c o p e c o u n t s o f p r o t o z o a were a l l e f f e c t i v e as t e c h n i q u e s f o r e v a l u a t i o n o f f o r a g e q u a l i t y . A d d i t i o n a l work i s r e q u i r e d t o f u r t h e r i n v e s t i g a t e t h e p o s s i b i l i t y o f t h e use o f f i b e r c o n t e n t o f f e c a l p e l l e t s as an i n d i c a t o r o f f o r a g e q u a l i t y . The s i m p l i c i t y o f c o l l e c t i o n o f f e c a l m a t e r i a l o v e r rumen samples w o u l d make t h i s a v e r y p r a c t i c a l f i e l d t e c h n i q u e s h o u l d i t p r o v e e f f e c t i v e . I t i s c o n c l u d e d t h a t rumen c o n t e n t s a n a l y s e s c a n s e r v e as a u s e f u l t e c h n i q u e f o r e v a l u a t i o n o f f o r a g e and r a n g e q u a l i t y o f w i l d r u m i n a n t s ; h o w e v e r , some b a s i s f o r c o m p a r i s o n o f v a l u e s must e x i s t . This requirement can be met through the adoption of standard values derived from ranges of known quality or comparisons between ranges, seasons or years. Weights and Skeletal Measurements Various methods have been developed for the evaluation of the n u t r i t i o n a l status of animals, several of which are applicable i n the f i e l d of animal ecology. Cheatum (1949) developed the bone marrow index for assessment of malnutrition i n deer; while more recently Riney ( 1 9 5 5 ) , Taber and Dasmann (1958) and others have u t i l i z e d r a t i o s of depot fat or organ and body weights to estimate the physiological status of ungulates. Other studies have related productivity (Cheatum and Severinghaus, 1 9 5 0 ) , population growth (Gunvalson, et a l . , 1952) and mortality (Klein and Olson, i 9 6 0 ) to range qua l i t y . Studies with captive deer by Cowan and Wood (1955) and French, et a l . (1955) have quantified many of the relationships previously acknowledged to exist between the growth of deer and the quality o f , t h e i r d i e t . As a result of this work, Bandy, et a l . (1956) reported on a technique for the assessment of the n u t r i t i o n a l status of deer by comparison of rat i o s of body weight estimated from heart g i r t h , to body weight estimated from hind foot length. This technique, developed on growing, captive deer, has been found r e l i a b l e on young, prepubertal deer i n Alaska but does not compensate for long-range growth effects or the physiological drain of the r u t . Body weight and measurements have long been the standard 94 c r i t e r i a for evaluation of growth i n animals i n the laboratory, among domestic stock, and with wild species as well. Brody ( 1 9 4 5 ) , Von Bertalanffy (1938) and others have developed growth equations, which u t i l i z e such measurements of body " s i z e " , based on the assumption that animals grow toward an "ultimate" or " f i n a l " body s i z e . Modifications of this concept of growth have been made by Parker and Larkin (1959) to more nearly relate i n d i v i d u a l growth stanzas i n fishes to physiological age, rather than chronological age. Wood, et a l . (1962) have shown that i n deer a seasonally c y c l i c growth i s imposed on four d i s t i n c t growth stanzas that occur throughout t h e i r development. One of the major problems i n the use of body measurements to quantify growth has been the possible unknown ef f e c t s of genetic v a r i a t i o n on i n d i v i d u a l animals or between populations. This i s of p a r t i c u l a r importance i n studies with large mammals where i t i s frequently not possible to secure large samples. With domestic animals i n controlled studies t h i s problem can be overcome through the use of monozygotic twins; however, t h i s i s not feasible with animals i n the wild. Wood, e_t a l . (1962) found i n d i v i d u a l v a r i a t i o n i n growth of captive deer to be so great as to obscure i n f l e c t i o n s i n the growth curve when mean values are obtained from several animals. They have met t h i s problem by p l o t t i n g the course of growth for i n d i v i d u a l animals. Knowledge of d i f f e r e n t i a l p r i o r i t i e s for growth of body tissues and the differences inherent between physiological 95 and chronological aging i n animals has enabled the more accurate int e r p r e t a t i o n of the relationship between body weights and measurements to the n u t r i t i o n a l history of the animals (Hammond, 1932, and McMeekan, 1940). -1 Several workers i n the f i e l d of animal ecology have employed body weights and measurements to r e f l e c t size differences i n animals r e s u l t i n g from variations i n the n u t r i t i v e quality of t h e i r diet (Park and Day, 1942; Severinghaus and Gottlieb, 1959; Taber and Dasmann, 1958 and others). However, i n most of such cases large numbers of animals were available for study from the populations under consideration. Individual v a r i a t i o n was not an important factor because of the large sample s i z e s . In the present study large samples were not obtainable and techniques had to be developed to u t i l i z e most expeditiously the weights and measurements of the sample specimens. Methods. — Total weight and field-dressed weight (viscera removed) were taken from the deer collected using spring scales of 50 pound capacity. When necessary, specimens were cut into segments to f a c i l i t a t e weighing. Body measurements were taken i n millimeters using a f l e x i b l e s t e e l tape. Total body length was taken from the t i p of the nose to the t i p of the last t a i l vertebra along the contour of the back, neck and head. Height at shoulder was taken from the t i p of the fore hoof i n a straight l i n e to the top of the scapula with the leg 96 approximating the standing p o s i t i o n . Chest g i r t h was taken immediately behind the shoulders. The length of the hind foot was taken from the t i p of the hoof to the proximal end of the calcaneous. The length of the ear was taken from the t i p of the ear to the notch, while t a i l length was from the t i p of the l a s t vertebra to the base of t a i l (held at a right angle to the back). The t o t a l length of the femur was determined and the metatarsal was measured from the d i s t a l end to the base of the deepest facet on the proximal a r t i c u l a t i o n . Weights and measurements of the deer specimens collected i n r e l a t i o n to age, sex and the date they were k i l l e d are included i n the Appendix. When possible, age, sex and femur length were obtained from deer that died of natural causes and these data have been included with other specimen data i n the s t a t i s t i c a l analyses. Of the weights and measurements taken from the deer co l l e c t e d , t o t a l body weight, femur length and hind foot length showed less v a r i a t i o n due to measurement techniques and were considered most r e l i a b l e for the purposes of the study. These measurements were therefore used almost exclusively i n the data analyses. In the comparison of growth rates between islands, weights, femur lengths and femur/hind foot r a t i o s were plotted against age. Age was determined from the degree of tooth development and erosion and was adjusted to correspond to the seasonal growth of deer. This method of aging deer, while with obvious limi t a t i o n s i n the older age categories, was considered accurate 97 through the four-year category where comparisons could be made with large numbers of specimens from hunter-killed deer. On the basis of observations of wild Alaska deer and those raised i n c a p t i v i t y (Cowan, i n corresp. 1 9 6 2 ) , a five month period of active growth of the skeleton and t o t a l body mass was assumed to approximate Alaskan conditions. This period of most active growth takes place during May 15 through October 1 5 . During the remainder of the year a state of physiological dormancy exists i n which growth i s greatly r e s t r i c t e d ; but for the purposes of data comparisons the amount of growth from October 15 to May 15 was considered to be equal to the average growth during one month of the summer growth period. In the s t a t i s t i c a l comparisons of sample means of weights, measurements and r a t i o s from the two islands, variances are pooled i n the c a l c u l a t i o n of standard errors of the means as described by Steel and Torrie ( i 9 6 0 ) . Results and discussion. — Weight, the standard c r i t e r i o n for measuring growth, was tested as a basis for comparison of the two populations of deer being studied. Standard s t a t i s t i c a l techniques were employed to compare means of body weights for the various age groups. Table 14 and Figure 20(a) show these comparisons made on male deer. It i s apparent that s i g n i f i c a n t differences exist between the means for a l l age groups with the exception of the one-year-old animals. This would be expected i n animals of genetically s i m i l a r populations which are subjected to d i f f e r i n g nutrient regimens throughout TABLE 14. Comparison of weights and measurements from Woronkofski and Coronation Island male deer Age Sample Standard Level of Measurement (Yrs.) Island Size ' Mean Error t Significance W 5 62.4 1 1 C 4 53.5 3.H2 1.33 n.s. W 4 98.5 2 c • 5 79.6 ' 3.855 2.52 0.05 Weight w 3 115.7 (lbs.) 3 C 3 88.3 ' 2.431 3.52 0.05 w 5 143.4 4+ C 6 104.7 5.253 3.75 ' 0.005 w 5 20.68 1 c 2 18.90 0.2884 '2.60 0.05 w 4 24.05 2 C ' 5 22.14 ' 0.2101 4.85' - 0.005 Femur w 4 25.58 (cm.) 3 c 5 - 23.02 0.2953 4.67 0.005 w 7 25.13 4+ C ' 21 23.34 0.1057 6.78 ' 0.001 w 5 39.12 1 C 4 37.80 0.4197 1.47 n.s. w 4 43.00 2 c 5 41.10 0.3700 2.55 ' 0.05 Hind Foot w 3 44.00 (cm.) 3 c - 3 42.83 0.3261 ' 1.84 n.s. w 5 43.72 4 + c 6 41.60 0.2349 ' 4.52 0.005 w 5 0.528b 1 c 2 0.5165 0.01126 1.8'2 n.s.' w 4 0.5595 2 c 5 0.5364 O.OO830 3.20 0.05 Ratio of w 3 0.5820 femur/hind 3 c 3 0.5487 0.00897 5.15 0.01 foot w 5 0.5778 4+ c 4 0.5713 0.00752 0.97 n.s. Not s i g n i f i c a n t at the 0.05 l e v e l . t h e i r l i v e s . Growth differences become more pronounced as the animals age. Figure 20(b) portrays the d i f f e r e n t i a l growth rates apparently e x i s t i n g within male deer of the two islands which are r e f l e c t e d i n body weight. The diverging slopes of the growth regressions suggest that animals from both islands are of equal body weight at or s l i g h t l y before p a r t u r i t i o n . It i s quite apparent from these data that male deer on both islands continue to grow i n body weight through t h e i r fourth year. Female deer, presumably because of slower growth and less t o t a l grottfth i n mass than male deer, f a i l e d to show as clear a separation between islands within age classes as the male deer. Only by grouping female deer three years old and older was i t possible to show a s i g n i f i c a n t difference between the weights from the two islands (Table 15 and Figure 21(a)). Studies with captive deer (Cowan and Wood, viva voce, I960) have demonstrated that male deer may continue to grow i n weight for four years or longer, whereas female deer a t t a i n e s s e n t i a l l y a l l of t h e i r mature body weight during t h e i r f i r s t two years of l i f e . In addition, growth rates of male deer must be more rapid than those of females to account for the differences i n size of sexes i n the one and two year age categories (Klein, 1959). Growth studies made by McMeekan (1940), Wallace (1948), Palsson and Verges (1952 and others), u t i l i z i n g diets producing low and high planes of n u t r i t i o n and re p l e t i o n techniques, have (0) 140 120 100 eo 6 0 40 I • Woronkofski o Co rona t ion 4 + (yrs ) 160 140 120 100 X CP 8 0 60 UJ 5 40 20 (b) r : 0.9638 Y= 32.10 + 25 99X S b = I 867 r- 0.8686 Y* 29.93 + 18.32 X S b = 2.638 • Woronkofsk i O Co rona t i on (yrs ) 4 + F i g . 20. Weight comparisons of male deer from Woronkofski and Coronation Islands. Diagram (a) shows the mean weight of deer plotted against age with a range of - t.05 X S. Diagram (b) shows growth rates reflected i n the slopes of the l i n e a r regressions of weight against age. TABLE 15 . Comparison of weights and measurements from Woronkofski and Coronation Island female deer Age Sample Standard Level of Measurement (yrs) Island Size ' Mean Error t Significance Weight W 5 9 8 . 4 (lbs.) 3+ ' c 12 ' 7 8 . 2 •2.6618 2 .34 0 . 0 5 Femur w 8 2 2 . 8 9 (cm.) 2 + c 12 21 .75 ' 0 . 1 3 8 1 3 . 6 9 0 . 0 0 5 Hind Foot w 9 4 1 . 0 3 (cm.) 2 + c 12 3 9 . 3 0 0 . 2 0 6 6 4 . 0 2 0 . 0 0 1 Ratio of femur/hind w 7 0 .5573 1 foot 2 + c 9 0 . 5 4 9 3 0 . 0 0 2 7 5 1 .40 n.s. Not s i g n i f i c a n t at the 0 . 0 5 l e v e l W E I G H T ( l b s . ) P 3 CL O CD XJ C P H J OJ O O O 3 P cf-H-O 3 OJ 3" O =S M 3 OJ Oq O H->S 09 O • 3 P ct ro o • 3 M O OJ o M 3 P n 3 p a ^ 0) H-OJ O 3 OJ o Mi p <r+ 3 3" CL CD 0q 3" cf OJ P 3 4 P 3 OQ CD O >-*> 3 CD l + P OJ rr C •-i CD 3 CD 3 cl-C/0 OJ O o 3 ct 3" CD X O *-!> >"t> CD 3 P (—1 CD CL CD P CD X ^ CD OJ s: o CD c P M o OJ 3 s: o OJ O o 3 o p 3 OJ CL O 00 O CO o o o + -< CD a CO F E M U R L E N G T H (cm.) ro ro ro ro ro + -< CD a ~% CO HIND F O O T L E N G T H (cm.) 00 o Ol CC T -o ro ro + -< CD a CO F E M U R / H I N D F O O T o C71 o -T-0) ro + -< CD Q CO SOT 103 c l e a r l y demonstrated the significance of physiological and chronological time i n animal growth rates. These studies have shown that while a low plane of n u t r i t i o n slows the growth rate and delays aging of the t i s s u e s , i t may allow for the greater development of the digestive t r a c t and other organ systems. Consequently, a poorly fed animal may actually have a greater potential for growth than an animal raised on a high plane of n u t r i t i o n but of the same chronological age (Figure 22). The importance of this growth phenomenon i n wild ungulates and i t s effect on t h e i r ultimate body size i s d i f f i c u l t to determine. It has been suggested that t h i s would be a compensating factor allowing animals on poor quality range to continue to grow for a longer period, although at a slower rate, than comparable animals on higher quality ranges. Two fa c t o r s , however, tend to prevent t h i s "equalization" of growth from being r e a l i z e d . F i r s t , growth hormones, primarily those associated with sexual maturation, control growth and can subvert the growth processes to assure reproductive success. Both somatotropic and thyrotropic hormones l i m i t s k e l e t a l growth with the approach of sexual maturity, thus possibly counter-acting genetic growth p o t e n t i a l . This i s of greater consequence i n females than i n males. Secondly, a continual, low quality diet may exist i n the wild i n which elements e s s e n t i a l for more than minimal growth may be lacking. Deer on such a d i e t , while capable of surviving and possibly reproducing, cannot 104 4 0 - | — 30-1 X UJ 2 0 -UJ > 10 o o V o > V O Q> RE ALIMENTATION O K ^ O V-—I BIRTH 8 16 2 4 32 4 0 (w k s .) F i g . 22. The e f f e c t of plane of n u t r i t i o n on the growth curves of the female East A f r i c a n dwarf goat. Note the delayed p h y s i o l o g i c a l age of the low plane animal which became apparent when the animal was r e a l i m e n t e d to a high plane d i e t (data from Wilson, 1958). 105 f u l f i l l t h e i r genotypic growth p o t e n t i a l . Skeletal measurements appear to be more r e l i a b l e indicators of growth i n wild ungulates than body weight. The extreme fluctuations i n body weight associated with accumulation of fat reserves i n summer and f a l l and the catabolism of these reserves during winter, and the weight loss i n males associated with r u t t i n g a c t i v i t i e s , tend to mask the sequence of growth. Cowan (viva voce, I960) has found that male b l a c k - t a i l e d deer i n c a p t i v i t y stop eating and can loose up to 40 percent of t h e i r body weight during the r u t t i n g period. Correspondingly, wild female deer may loose 35 percent of t h e i r body weight during severe winters i n Alaska. These d i f f i c u l t i e s encountered i n assessing growth can be p a r t i a l l y avoided by u t i l i z i n g f a t - f r e e body weight, or by measuring the degree of hydration of muscle tissue or by determining the protein to water r a t i o of body tis s u e s . Bailey, et a l . (I960) have developed the protein to water r a t i o as a method for assessment of physiological age i n laboratory mice. This technique takes advantage of the phenomenon of dehydration of tissues which i s associated with growth and aging. Unfortunately these refinements for assessing growth are not suitable for use with large ungulates under f i e l d conditions. The skeleton does not undergo negative growth during the periods of physiological stress as i s the case for fat and muscle tissues and consequently serves as a more r e l i a b l e indicator of growth i n deer and other wild ungulates. In 106 addition, more accurate measurements of bones of the skeleton of f i e l d - c o l l e c t e d specimens can be taken than i s the case for body weight, which i s subject to variations due to the degree of " f i l l " of the digestive t r a c t and blood lo s s . True, the skeleton has been shown to have a higher p r i o r i t y for growth than muscle or fat tissue and i s therefore less affected by n u t r i t i o n a l deficiences i n the diet than t o t a l body mass (Hammond, 1944). However, under wild conditions a more complex relationship apparently exists between seasonal variations i n the quality of the diet and p r i o r i t i e s for growth of the various body t i s s u e s . The winter condition of growth cessation i n deer i n northern regions (Wood, e_t a l . , 1962) probably extends to s k e l e t a l tissue as well. Therefore, in the spring when growth of body tissues i s r e i n i t i a t e d , apparently through photostimulation (French, et a l . , i 9 6 0 ) , and high quality forage i s often i n short supply, s k e l e t a l growth may be i n h i b i t e d along with the growth of muscle and fat tissues. In addition, growth of the long bones may be limited by closure of the epiphysial cartilages before the genetic p o t e n t i a l of the animal has been r e a l i z e d . Not only are the effects of growth i n h i b i t i o n on the skeleton r e f l e c t e d i n reduced growth of the entire skeleton, but the growth of i n d i v i d u a l bones i s affected d i f f e r e n t l y . A sequence of growth p r i o r i t y i s exhibited i n the growth of the s k e l e t a l components just as variations i n growth p r i o r i t i e s exist between the various body t i s s u e s . This has been 107 demonstrated i n feeding experiments with domestic stock by McMeekan (1940) and others. Furthermore, at b i r t h there i s considerable v a r i a t i o n i n the r e l a t i v e proportion of growth remaining to be made by the bones of the skeleton. A positive c o r r e l a t i o n appears to exist between the r e l a t i v e proportion of growth made by a bone p r i o r to b i r t h and i t s p r i o r i t y for growth. For example the s k u l l which has completed approximately 40 percent of i t s growth at b i r t h has an extremely high p r i o r i t y for growth immediately af t e r b i r t h , but the growth accomplished a f t e r b i r t h i s , of course, correspondingly less than that obtained by the pelvis or the late maturing long bones. From Palsson and Verges' (1952) work with growth i n lambs i t i s possible to l i s t the approximate sequence of p r i o r i t y of growth of the major bones of the skeleton af t e r b i r t h as follows: s k u l l , fore feet, hind feet, metacarpals, metatarsals, c e r v i c a l and thoracic vertebrae, radius-ulna, humerus, t i b i a - f i b u l a , caudal vertebrae, scapula, lumbar vertebrae, sacral vertebrae, femur, pelvis and r i b s . It i s apparent from t h i s l i s t i n g that a sequence of growth takes place from the extremities (the head, feet and t a i l ) , toward the central portion of the body i n the pelvis region. The vertebrae, proximal portions of the limbs, scapula and pelvis are late developing i n contrast to the s k u l l , lower legs and t a i l , The forelegs develop before the hind legs. In view of thi s knowledge the femur i s perhaps the most suitable bone of the skeleton to use as a measure of r e l a t i v e growth accomplished 108 a f t e r b i r t h . In contrast, the hind cannon bones (metatarsals), which have accomplished a much larger proportion of t h e i r growth at b i r t h , o f f e r a suitable basis for comparison. This d i f f e r e n t i a l growth of the femur and cannon bones i s demonstrated in Figure. 23(a). Therefore, a r a t i o of the femur length to hind cannon length w i l l r e f l e c t - the magnitude of growth accomplished and w i l l serve as a basis for r e l a t i n g physiological to chronological age. Hind foot length, i n place of cannon length, has been found to be simpler to obtain i n the f i e l d and shows less sample v a r i a t i o n (Figure 23(b)). Figure 23(c) shows the c u r v i l i n e a r relationship e x i s t i n g between femur and hind foot length i n the sample deer. Genetic v a r i a t i o n , which could r e s u l t i n a difference i n ultimate body s i z e , w i l l not a l t e r the usefulness of t h i s r a t i o for making comparisons between animals from d i f f e r e n t populations. Skeletal measurements appear to be useful c r i t e r i a for comparisons between populations of deer or other animals. Variations i n size of animals i n d i f f e r e n t populations may be of genetic o r i g i n or a product of t h e i r n u t r i t i o n . The deer populations on Woronkofski and Coronation Islands are assumed to be genetically s i m i l a r . I f such i s the, case, differences i n lengths of the long bones between islands among deer of comparable age are attributable to n u t r i t i o n a l factors. The scatter diagrams- i n Figures 24(a) and 24(b) show the relationships of femur lengths of both male and female deer from Woronkofski and Coronation Islands. A f a i r l y clear sep-aration of populations i s indicated i n these diagrams. Table Pig. 23. Skeletal relationships among the bones of the hind leg. Diagram (a) demonstrates the rela t i o n s h i p of the growth of the femur to that of the metatarsal bone i n Woronkofski Island male deer (curves f i t t e d by eye). Diagram (b) shows the better f i t obtained i n the analysis of regression of femur/hind foot than for femur/metatarsal. Diagram (c) shows the c u r v i l i n e a r r e l a t i o n s h i p When growth of the femur i s plotted against the growth of the hindfoot (curve f i t t e d by eye). 110 14 and Figure 24(c) show the complete separation of the Woronkofski and Coronation Island male deer i n a l l age classes on the basis of femur length. This i s i n contrast to Figure 24(d) where hind foot length did not r e f l e c t as great a difference between the i s l a n d deer, which i s understandable i n view of the above discussions of d i f f e r e n t i a l s k e l e t a l growth. As i n the case of the, weight comparisons, the female sample, which was small, had to.be grouped to include a l l age classes of two years or older to y i e l d s i g n i f i c a n t differences between islands on the basis of femur and hind foot lengths (Table 15 and Figures 21(b) and 21(c)). Figure 25(a) shows the d i f f e r e n t i a l growth i n femur length of male deer from Woronkofski and Coronation Islands. In the Woronkofski deer the femur ceased to show measurable growth i n length a f t e r the t h i r d year, thus, a l l of the femur lengths from deer over three years of age have been included with the three-year-old deer to obtain a straight l i n e r e l a t i o n s h i p . In the case of the Coronation deer the femur ceased to grow in length a f t e r the fourth year, and a s i m i l i a r procedure was followed to enable comparisons of the growth regressions for the two islands. The femur to hind foot r a t i o s , while not showing as high levels of significance i n the differences between means (Tables 14 and 15), are less affected by genetic factors which may govern body s i z e , and are therefore more r e l i a b l e I l l (a) F E W A L E S E 2 . • Woronkof.kl ° Coronation 2 3 4 5 6 7 8 9 A G E (yrs ) e » 2 2 (b) M A L E S • Woronkof.ki o Coronation 2 3 4 5 6 7 8 9 10 A G E ( y r s ) (c) • Woronkof.kl O Coronation A G E ( y r s I I Id) • Woronkofsk i O C o r o n a t i o n 2 3 A G E ( y r s ) P i g . 24. R e l a t i o n s h i p of the length of the bones of the hind l e g to age. S c a t t e r diagrams (a) and (b) show the femur lengths of female and male deer p l o t t e d ' against age. Diagrams (c) and (d) show the comparisons of lengths of femur and hind foot between deer from Woronkofski and Coronation Islands showing the range o f ~ t.05 x sx« 112 for r e f l e c t i n g n u t r i t i o n a l e f f e c t s . Correspondingly, s k e l e t a l r a t i o s used i n conjunction with body or l i n e a r measurements should be e f f e c t i v e i n i s o l a t i n g genetic e f f e c t s . Figure 25(b) c l e a r l y r e f l e c t s the d i f f e r e n t i a l e f f e c t s of the environment on the male deer of the two islan d s . In the one-year age class the effects of the sim i l a r prenatal environments are s t i l l apparent; however, after two and three years the d i s s i m i l a r external environmental effects are dramatically apparent i n the femur to hind foot r a t i o s between islands. In the four-year class a closing of the gap has taken place because s k e l e t a l growth v i r t u a l l y ceased at three years i n Worokofski males while Coronation males continued to grow s k e l e t a l l y for another year. In Figure 25 (c) rates of completion of s k e l e t a l growth among male deer from the two islands are compared. Again, a much more rapid growth of the skeleton i s evident among the Woronkofski deer. Among female deer the femur to hind foot r a t i o did not show a clear difference between islands, perhaps because of small sample size as well as the reduced rate and magnitude of growth of females (Figure 2 1(d)). A basis exists for the comparison of Woronkofski and Coronation Island deer with those from other areas throughout Southeast Alaska. Many hunter-killed deer have been examined annually by Federal and State game b i o l o g i s t s and dressed weights and measurements have been obtained (Klein, 1 9 5 7 , 1958 3 O 53 z (b) • W o r o n k o f s k i O C o r o n a t i o n O O u. 0 96 c 0 52 2 UJ u. 0 50 (c) W o r o n k o f s k i Is r = 0 9 3 2 2 Y = 0 4 9 8 4 + 0 0 2 4 8 X S h = 0 0 0 2 4 8 Cor onation It r= 0 9189 Y= 0 4974 +0 0163 X S h = 0 00187 A G E (yrs ) 6 E ( y r s ) Pig. 25. Skeletal relationships of Woronkofski and Coronation Island male deer. Diagram (a) shows the d i f f e r e n t i a l growth rates of male deer from the two study islands r e f l e c t e d i n the slopes of the l i n e a r regressions of femur length against the logarithm of age. Diagram (b) i s a comparison of femur/hind foot r a t i o s of deer from the two study islands (the range of - t^Qf- X S^ i s shown). Diagram (c) i s a comparison of d i f f e r e n t i a l growth rates r e f l e c t e d i n the slopes of the l i n e a r regressions of the length of femur/hind foot length. 114 and 1959 and Merriam, i 9 6 0 and 1 9 6 1 ) . While these measure-ments have been obtained from deer k i l l e d during the f a l l , and therefore r e f l e c t the f u l l summer growth period, they do enable a comparison with deer from the study islands i f t h i s difference i s borne i n mind. Tables 16 and 17 show the mean dressed weights (eviscerated; but head, hide and feet attached) of Woronkofski and Coronation Island deer i n comparison to dressed weights of hunter-killed deer from adjacent areas and throughout a l l of Southeast Alaska. It i s apparent, i n view of the two - to four-month growth d i f f e r e n t i a l between the summer-killed specimen deer and the f a l l - k i l l e d hunter-harvest deer, that the Woronkofski deer undoubtedly exceed the Southeast Alaska mean while the Coronation islan d deer f a l l f a r short of this mean. This i s also apparent i n the lengths of the hind foot which are compared i n Tables 18 and 1 9 . Annual Cycle of Nut r i t i o n Since the n u t r i t i o n a l requirements of deer, as well as the quality and quantity of the range forage, show considerable va r i a t i o n throughout the course of the year, t h e i r r e l a t i o n s h i p , one to another, i s of utmost importance i n the annual cycle of n u t r i t i o n of deer. Figure 26 shows thi s assumed relationship for a young growing deer during i t s f i r s t and second year. The n u t r i t i o n a l requirements of deer during winter are usually s l i g h t l y i n excess of available forage quantity and quali t y . This i s apparent i n the gradual loss of body weight TABLE 16 . Comparison of summer dressed weights of male deer from Woronkofski and Coronation Islands to mean dressed weights of f a l l - k i l l e d male deer from adjacent areas and from a l l of Southeast Alaska (Klein, 1957 and 1958 and Merriam, 1959 and i 9 6 0 ) (Weights i n pounds) Age (yrs.) Woronkofski Coronation Adjacent Area A l l S. E. Alaska 1 to 1 1/2 44 39 69 71 2 to 2 1/2 75 58 93 93 3 to 3 1/2 86 57 105 108 4 to 4 1/2 111 80 124 127 5+ 124 80 127 130 Sample Size 17 14 250 564 TABLE 17. Comparison of summer dressed weights of female deer from Woronkofski and Coronation Islands to mean dressed weights of f a l l - k i l l e d female deer from a l l of Southeast Alaska (Klein, 1958 and 1959 and Merriam-, 1959 and I960) Weights i n pounds) Age (yrs.) Woronkofski Coronation A l l S. E. Alaska 1 - 1 1 / 2 — 38 62 2 - 2 1/2 54 — 77 3 - 3 1/2 69 47 72 4 - 4 1/2 74 50 77 5+ 80 51 79 Sample Size 9 14 104 r—1 t—' CT\ TABLE 1 8 . Comparison of summer hind foot lengths of male deer from Woronkofski and Coronation Islands to mean hind foot lengths of f a l l - k i l l e d male deer from adjacent areas and a l l of Southeast Alaska (Klein, 1957 and 1958 and Merriam, 1959 and i 9 6 0 ) (Measurements i n centimeters) Age (yrs.) Woronkofski Coronation Adjacent Areas A l l S. E. Alaska 1 - 1 1 / 2 39.12 37.80 41.97 42.04 2 - 2 1/2 43.00 41.10 43.62 43.37 3 - 3 1/2 44.00 42.83 43.62 43.62 4 + 43.72 41 .60 44.20 44.07 Sample Size 17 18 357 514 TABLE 19. Comparison of summer hind foot lengths of female deer from Woronkofski and Coronation Islands to mean hind foot lengths of f a l l - k i l l e d female deer from a l l of Southeast Alaska. (Klein, 1957 and 1958 and Merriam, 1959 and I960) (Measurements i n centimeters) Age (yrs.) Woronkofski Coronation A l l S. E. Alaska 2 + 41.03 39.30 41.57 Sample Size 9 12 71 F i g . 26. Assumed yearly relationship of quality and quantity of forage u t i l i z e d by deer, at a low elevation s i t e , to the n u t r i t i o n a l requirements of deer (both energy and £ esse n t i a l nutrients). vo 120 of deer throughout the winter. Wood, et_ a l . (1962) have shown that winter reduction i n feed consumption, with growth retardation i n young deer and loss of weight i n adults, i s ch a r a c t e r i s t i c of captive deer raised under optimum conditions. This physiological c h a r a c t e r i s t i c i s obviously a s u r v i v a l factor selected for during the course of t h e i r evolution. The physiological demands of deer during t h e i r winter growth dormancy are therefore r e l a t i v e l y low and can usually be met through the limited available forage plus fat reserves. In the spring and summer the reverse s i t u a t i o n exists when growth i s rapid i n young deer, does are l a c t a t i n g and bucks are recovering from the rigors of winter and building fat reserves i n preparation for the rut . N u t r i t i o n a l requirements at t h i s time^are high and whereas forage i s also r e l a t i v e l y abundant and of good quality any def i c i e n c i e s i n quality or quantity w i l l be greatly f e l t by the deer during t h e i r spring and summer period of high metabolism. The greatest po t e n t i a l for dietary inadequacy occurs during the early spring when n u t r i t i o n a l requirements are rapidly increasing, the quality of the new growth forage i s high but the quantity of such forage i s very l i m i t e d . I n t r a s p e c i f i c competition for t h i s l i m i t e d supply of high quality forage may take place at thi s time. Also, at thi s time deer have to rapidly adapt to the diet of new growth vegetation, which undoubtedly requires a considerable physiological adaptation of the rumen microorganism complex. Consequently, once they have modified t h e i r diet to coincide with the new growth forage of limited a v a i l a b i l i t y they are i n effect committed 121 to t h i s forage and i f i t i s i n short supply through slow i n i t i a t i o n of the spring, i n t r a s p e c i f i c competition or other factors, the deer are unable to successfully revert to t h e i r winter diet and they may suffer a growth setback or more severe consequences. As forage quantity increases throughout the summer, quality decreases through the gradual maturing of the vegetation. I f deer are unable to move to areas where new growth vegetation i s available throughout the summer they are forced to consume abundant, but lower quality maturing vegetation. Competition for forage i s no longer a factor, but the general low quality of the forage (in comparison to vegetation i n i t i a t i n g growth) means that deer cannot consume enough to meet t h e i r optimum growth require-ments. Spring and summer are the c r i t i c a l periods for deer growth and i t i s during these periods that environmental factors may r e s t r i c t the quality and quantity of forage available for deer with the result that l i m i t a t i o n s are placed upon the growth of deer. Winter i s the period of growth dormancy i n deer and although dietary d e f i c i e n c i e s in both quantity and quality of forage may occur, t h e i r r e s u l t w i l l be loss of condition and possibly death of the deer, a however, the e f f e c t upon growth i n surviving individuals w i l l be n e g l i g i b l e . Considerable difference exists i n the annual n u t r i t i o n a l regimen of deer between sexes. Adult bucks undergo t h e i r 122 period of greatest physiological drain during the rut when food intake i s d r a s t i c a l l y c u r t a i l e d , but rate of metabolism i s obviously increased. Cowan (viva voce) found that r u t t i n g b l a c k - t a i l bucks i n c a p t i v i t y took no food for as much as 60 days and i n some cases actually starved themselves to death. Such animals may lose i n excess of 40 percent of th e i r body weight. Wild deer may not reach these extremes; however, f i e l d dressed weights of hunter-killed male deer i n Southeast Alaska show mean weight losses within adult age classes of approximately 20 percent during the month and a half period that encompasses the rut (Klein, 1959). Following the rut, male deer a c t i v e l y feed and may regain some of t h e i r lost depot f a t ; however, at thi s late period forage quality and quantity are both r e l a t i v e l y low and adverse snow conditions frequently e x i s t . Deer may only be able to recover a small percent of t h e i r lost weight before winter conditions further l i m i t available forage (Magruder, et a l . , 1957). In the spring metabolic demands of the buck increase. Although there are requirements for physiological r e h a b i l i t a t i o n from the stresses of winter and for pelage and antler growth, these are usually r e a d i l y met and a large proportion of the c a l o r i c production i s converted to adipose t i s s u e . Restricted summer dietary intake i n terms of either quality or quantity usually only results i n reduced fat deposition i n bucks; although a b r i e f c r i t i c a l period does exist i n early spring, 123 when physiological demands are high but the quantity of high quality forage available may be lim i t e d . Of course, young bucks are a c t i v e l y growing and, therefore, quite subject to any dietary l i m i t a t i o n s i n either quality or quantity. Female deer are i n t h e i r optimum physical condition, with maximum fat reserves present, when winter begins. The physi o l o g i c a l drain of the developing embryo i n pregnant does i s almost neg l i g i b l e u n t i l t h e i r f i n a l stages of gestation, and i s minimal i n comparison to the stresses on the doe during l a c t a t i o n . The doe, during l a c t a t i o n , experiences her poorest physical condition and greatest metabolic needs at the time when forage i s abundant and of high q u a l i t y , whereas the opposite i s true of bucks. In addition the doe possesses a further s u r v i v a l factor; i n the event that she i s reduced to c r i t i c a l physical condition a f t e r p a r t u r i t i o n , l a c t a t i o n i s reduced or ceases and the fawn, not the doe, suffers reduced growth or mortality. However, partly because of the heavy reproductive burden on the doe, which occurs within the spring and summer growth period, growth of the doe v i r t u a l l y ceases aft e r the b i r t h of her f i r s t fawn. Undoubtedly the onset of puberty with i t s associated hormonal response, also plays an important part i n growth l i m i t a t i o n i n the female. Levels of Parasitism Parasite-host relationships are i n t r i c a t e l y controlled by factors of the environments i n which the parasites gain 124 t h e i r nourishment, reproduce and complete t h e i r l i f e cycles. Parasites are highly specialized organisms which are dependent upon t h e i r hosts for sur v i v a l although t h e i r very presence may frequently res u l t i n the d e b i l i t a t i o n of the host species. In Alaska, external parasites of deer are v i r t u a l l y absent. Only one occurrence has been recorded and thi s was a t i c k (Dermacentor sp.) found as a single specimen on the nose of a deer col l e c t e d on Coronation Island during the course of t h i s study. Several species of in t e r n a l parasites have been recorded from Alaska deer (Klein, 1959); however, numbers of species are fewer and levels of i n f e s t a t i o n l i g h t e r than have been recorded among the bl a c k - t a i l e d deer i n B r i t i s h Columbia (Cowan, 1951) and further south (Herman, 1945; Longhurst, 1956 and Brown, 1961). It has been shown that among host species, resistance to parasite i n f e s t a t i o n i s frequently associated with physiological well-being. For example, i n B r i t i s h Columbia when moose are i n good physical condition they harbor few ti c k s while the reverse appears to. be true when moose are poor (Hatter, 1950). Longhurst (1956) found a sim i l a r c o r r e l a t i o n to exist i n domestic sheep and b l a c k - t a i l e d deer i n C a l i f o r n i a and high levels of parasitism have been associated with deer range deterioration and associated malnutrition by Whitlock (1939), Cheatum (1951) and others. While the mechanisms involved i n a l l of these relationships are not c l e a r l y understood i t i s known that those parasites 125 that make intimate contact with the host's c i r c u l a t o r y system can e l i c i t an antibody response i n the host which may result i n a long l a s t i n g immunity i f the i n i t i a l i n f e c t i o n i s thrown o f f . Also i t i s understandable that a healthy animal with abundant body reserves i s better able to withstand a parasite attack than an animal i n a malnourished or weakened condition. On the basis of these observations i t was f e l t that the l e v e l of parasitism encountered i n the Woronkofski and Coronation Island deer might r e f l e c t the difference i n t h e i r physical condition, and i n d i r e c t l y , differences i n range quality that were believed to be present. Of course, factors not necessarily related to range q u a l i t y , such as presence of intermediate hosts, sources of i n f e c t i o n , effect of climatic conditions on the f r e e - l i v i n g stages of the parasites and density and age of the host species, also govern parasite l e v e l s . Results of examinations for parasites among the deer collected during the study on Woronkofski and Coronation Islands are summarized i n Table 20. In view of the small numbers of deer examined and the r e l a t i v e l y low l e v e l of infestations encountered among the deer on both islands one must be cautious i n drawing correlations between parasite burden and range q u a l i t y , deer population welfare or phys i o l o g i c a l condition of the deer. The only parasite encountered i n appreciable numbers on the study islands that i s known to be implicated i n deer losses i n Alaska i s the lung worm (Dictyocaulus v i v i p a r u s ) . TABLE 2 0 . Degree of parasite i n f e s t a t i o n among deer on Coronation and Woronkofski Islands Coronation Island No. Deer No. Deer Percent Examined Infected Infected Woronkofski Island No. Deer No. Deer Percent Examined Infected Infected Dictyocaulus viviparus 31 Caecal nematodes: Oesophagostomum venulosum 24 Larval tapeworms: Taenia hydatigena 31 T. krabbei 24 Nasal bots: Cephenemyia j e l l i s o n i 31 Ticks: 31 Skin worts: 31 5 7 1 0 1 1 0 16 29 25 15 24 15 25 25 25 9 2 1 0 2 24 38 8 127 I t was present i n s i m i l a r p o r t i o n s of the samples of deer from both i s l a n d s and no acute i n f e c t i o n s were encountered. I t i s known, however, that young deer ( l e s s than 2 years of age) are more s u s c e p t i b l e to i n f e c t i o n s of the lungworm and most other p a r a s i t e s , than are adu l t s that are b e t t e r equipped to su r v i v e the d e b i l i t a t i n g e f f e c t s of the low q u a l i t y winter d i e t and may have developed an immunity from an e a r l i e r a t t a c k . With t h i s i n mind, then, the numbers of i n f e c t e d animals encountered on each i s l a n d may be more meaningful because a l a r g e r p r o p o r t i o n of young animals were present i n the Worokofski sample than i n the sample from Coronation I s l a n d (Table 22 ) . Consequently, one might expect a higher p r o p o r t i o n of i n f e c t e d animals on Woronkofski, other con d i t i o n s being equal, i n view of t h e i r suspected lower immunity ( l a r g e r p r o p o r t i o n of young animals). The caecal nematode, Oesophagostomum venulosum, was more fr e q u e n t l y encountered i n the Coronation deer, although only l i g h t i n f e s t a t i o n s occurred. Although the samples were not large enough to be s i g n i f i c a n t , the d i f f e r e n t l e v e l s of t h i s p a r a s i t e may r e f l e c t the d i f f e r e n t p h y s i o l o g i c a l c o n d i t i o n s of the deer from the two i s l a n d s . This worm has been as s o c i a t e d w i t h m o r t a l i t y i n deer on Vancouver I s l a n d (Cowan, 1951) and i s known to be most abundant where ranges are poor or overstocked. Again, the age s t r u c t u r e s of the deer, sampled i s p e r t i n e n t . The presence of l a r v a l forms of both species of Taenia r e q u i r e s a canine intermediate host, which accounts f o r the 128 difference i n the numbers of these parasites between islands. Wolves were common on Woronkofski and not present on Coronation Island. The one T. hydatigena larva found i n a five-year-old doe k i l l e d on Coronation Island probably indicates that t h i s animal swam from adjacent, wolf-occupied Kuiu Island sometime i n i t s e a r l i e r l i f e . The l a r v a l stages of Taenia encountered in the deer probably have l i t t l e detrimental e f f e c t . The T. hydatigena cysts were approximately 10 millimeters i n diameter and most frequently were located on the mesenteries although they were occasionally present on or within the l i v e r . They seldom numbered more than 15 i n an infected animal. The T. krabbei cysts were approximately 3 millimeters i n diameter, were found i n the muscles of the upper leg region and were not numerous. Nasal bots (Cephenemyia j e l l i s o n i ) were not encountered i n the summer-collected animals as t h i s was the period when the organism i s free l i v i n g and not present i n deer. Nasal bots were found i n animals from both islands collected during early spring before the larvae had l e f t the pharyngeal pouches. The nasal bot has been associated with winter deer mortality i n Alaska but could not be u t i l i z e d to r e f l e c t range quality i n t h i s study. The Deer Populations Many studies of natural controls of animal populations have been made on a variety of species under varied conditions and throughout the world. Results have enabled the establishment of mathematical bases for describing population growth as well 129 as enumerating the many factors which either d i r e c t l y or i n d i r e c t l y a f f e c t control of animal numbers. Thus far there i s common agreement; however, when one proceeds to the next l e v e l he finds considerable disagreement as to what are the important c o n t r o l l i n g factors of animal populations. The disagreement seems to stem from the fact that researchers tend to extrapolate from t h e i r own data or that of others and make sweeping generalizations to include a l l l i f e forms. Conversely, students of population dynamics tend to associate theories of population control with the men doing the work, frequently ignoring the s p e c i f i c animals involved or the conditions under which the work was done. Elton (1949, p. 19) has supported the assumption that competition i s basic to the control of animal populations and stated: "It i s becoming increasingly understood by population ecologists that the control of populations, i . e . the ultimate upper and lower l i m i t s set to increase, i s brought about by density-dependent factors, either within the species or between species. The chief density-dependent factors are i n t r a - s p e c i f i c competition for resources, space or prestige; and i n t e r - s p e c i f i c competition, predators or parasites." Nicholson (1954, p. 15) has modified this^slightly and states: "Population density governance of a species i s almost always i n t r a - s p e c i f i c competition either for 'transient r e q u i s i t e s ' such as l i g h t , or 'accumulative r e q u i s i t e s ' such as chemical nutrients, or 'reproductive r e q u i s i t e s ' such as a food providing organism." Both Elton and Nicholson have limited bases for making such broad generalizations. While competition ( i . e . j o i n t demand 130 for a common, limi t e d resource) i s frequently a l i m i t i n g factor there are also situations where t h i s does not appear to be the case. Andrewartha and Birch (1954) and Birch (1957) have shown climate to be the major c o n t r o l l i n g factor among certain species of insects i n A u s t r a l i a but they have also been tempted to extrapolate beyond the l i m i t s of t h e i r data and to relegate a predominant role to climate i n the direct control of a l l animal numbers. Errington (1946 and 1957) working primarily with muskrats has been able to show that populations of these animals were controlled neither by competition for food nor the effects of climate. Predation was considered to be the primary factor responsible for the control of his muskrat populations; however, the l e v e l of predation was a product of crowding and therefore competition for space. In a l l instances of his studies Errington maintains that food was not l i m i t i n g and does not seriously consider the p o s s i b i l i t y that i n t r a s p e c i f i c intolerance and associated "crowding" may have been accentuated by a shortage of food. In Lack's The Natural Regulation of Animal Numbers ( 1 9 5 4 ) , he stresses the importance of food as the primary c o n t r o l l i n g factor i n the b i r d environment. Chitty (1955 and 1 9 5 7 ) , on the other hand, appears to have taken the opposite stand and considers food to be rarely a c o n t r o l l i n g factor i n natural animal populations. This i s r e f l e c t e d i n his statement (in Scheffer, 1 9 5 5 , p. 5 0 7 ) , "It i s my b e l i e f that few species, under natural conditions, get anywhere near exhausting t h e i r food supplies." His work with lemmings has led to his conclusion 131 that these animals are controlled through va r i a t i o n i n v i a b i l i t y and i r r i t a b i l i t y associated with changes i n population density. This being a result of o s c i l l a t i o n s i n selec t i v e s u r v i v a l of d i f f e r i n g genotypes i n the populations. Thompson ( i n Milne, 1 9 5 7 , p. 260) refuses to accept any one "control" as dominant f e e l i n g that populations are controlled by the t o t a l environment and he states: "As a general rule the complex of factors which actually effects control i n the case of any species d i f f e r s i n composition from point to point and from year to year i n the area of d i s t r i b u t i o n . It follows that there i s not i n general any (particular) regu-l a t i n g factor (or factors) responsible for the natural control of a species." It i s cert a i n l y true that the population i s the product of the t o t a l environment; however, i t cannot be denied that i n some instances one or a few components of the environment are fundamentally responsible for the ultimate control of animal populations. A review of the l i t e r a t u r e on factors of population control inevitably leads to the conclusion that there are as many theories of what constitutes primary factors of control as there are controls. It i s obvious that these are based on equally varied studies of widely di f f e r e n t animals under highly variable conditions. While food may be l i m i t i n g for the great t i t i n B r i t a i n i t i s not necessarily a control factor i n the ecology of the grasshopper, Antroicetes cruciata i n Au s t r a l i a . Sweeping generalizations about primary c o n t r o l l i n g factors of animal populations obviously should be avoided. Animal populations are controlled by factors of the environment which are frequently s i m i l a r , but as the environment shows extreme 132 variations so also are the factors a f f e c t i n g control, highly-variable . When deer populations have not been controlled by human harvest and predators have been reduced or eliminated, almost invariably the food supply has been implicated, either d i r e c t l y or i n d i r e c t l y , i n the f i n a l control of t h e i r numbers (Boone, 1938; Leopold, e_t a l . , 1947 and others). This also appears to be true i n Alaska, although winter snow accumulation frequently l i m i t s a v a i l a b i l i t y of food and therefore regulates the food supply (Klein and Olson, i 9 6 0 ) . The effects of wolf predation on Alaska deer populations are d i f f i c u l t to evaluate because of the limited recorded evidence and conclusions are of an empirical nature. Some obvious variations exist between those ranges where wolves occur and the wolf-free islands northwest of Frederick Sound. The ch a r a c t e r i s t i c s which as a general rule are unique to deer populations and ranges i n those areas where wolves are absent are (1) stable or slowly increasing populations i n excess of the winter range capacity and with a predominance of overage animals, (2) heavy winter mortality and (3) severely deteriorated winter ranges. In contrast the t y p i c a l c h a r a c t e r i s t i c s of ranges to the southeast supporting both deer and wolves are (1) l i g h t winter mortality from starvation, (2) winter ranges in f a i r to good condition and (3) highly productive deer populations of predominantly young animals. The wolf-populated ranges, as a general r u l e , support a greater annual hunter harvest of deer per unit of area under comparable hunting pressure. 133 Both Woronkofski and Coronation Islands l i e south of Frederick Sound and within the area of normal occurrence of the wolf. However, wolves have not been present on Coronation Island during recent years even though i t i s separated by narrow water channels, not more than a mile and a h a l f wide, from adjacent wolf-occupied Kuiu Island. On Woronkofski Island, wolves have been controlled intermittently through government poison operations u n t i l 1958 when such control was discontinued. These e f f o r t s have, on several occasions, apparently resulted i n the elimination of a l l wolves on the i s l a n d ; however, they have quickly reoccupied the i s l a n d from adjacent E t o l i n Island, which necessitates t h e i r swimming about a mile across Chichagof Pass. Local residents have observed wolves swimming to Woronkofski Island. Hunting pressure i s l i g h t throughout a l l of Southeast Alaska because of the low numbers of hunters i n proportion to the t o t a l deer av a i l a b l e . There are approximately 8,000 deer hunters and an estimated 250,000 deer on 25,000 square miles of range. Woronkofski Island l i e s adjacent to the town of Wrangell, which has a population of approximately 1,200 and the i s l a n d receives limited hunting pressure. Approximately 25 deer are k i l l e d annually on Woronkofski Island by hunters. Coronation Island i s r e l a t i v e l y i s o l a t e d and i s v i s i t e d by only an occasional hunter from a passing f i s h i n g boat. Probably less than f i v e deer are k i l l e d annually by hunters on Coronation Island. 134 There are several ways that range quality can af f e c t the age and sex structures of deer populations and these are enumerated below for consideration i n the discussion that follows. (1) Production i s high on good range through the mechanism of good fawn s u r v i v a l . In addition, conception and p a r t u r i t i o n rate may also be increased (Cheatum and Severinghaus, 1950). On poor range the poor condition of does may result i n a lowered rate of conception, increased i n utero mortality of embryos, high post parturient fawn mortality and high winter fawn mortality due to t h e i r slow summer growth rate. Heavy fawn mortality on poor range results i n reduced proportions of young deer and the dominance of older deer i n the population. The reverse i s true on good range (Klein and Olson, I960). (2) Delayed physiological aging on poor range presumably could result i n a longer l i f e span for those deer surviving into adulthood than such deer on good range although no data i s known to be available to support t h i s contention. The re s u l t would be to contribute to the distorted age r a t i o e x i s t i n g on poor range. (3) On poor range the age of sexual maturity i s delayed which reduces productivity and also contributes to the d i s t o r t i o n of age ra t i o s to a predominance of old individuals (Cheatum and Severinghaus, 1950). 135 Poor physiological condition of deer on poor range re s u l t s i n heavier parasite burdens because of lowered resistance and increased natural mortality from parasitism and other causes. However, such mortality i s greatest i n the younger age classes which have lower resistance to parasites and disease (Longhurst, 1 9 5 6 ) . The result i s again to accentuate the predominance of older deer i n the population. Male deer have a higher mortality rate throughout t h e i r l i v e s than female deer because of t h e i r greater growth requirements when young, t h e i r greater a c t i v i t y , and therefore propensity for accidents, and t h e i r tendency to u t i l i z e t h e i r fat reserves during the rut and enter the winter i n poor condition (Taber and Dasmann, 1954). On poor range, the corresponding poor condition of the deer results i n a greater d i f f e r e n t i a l sex mortality than on good range, and the res u l t i s that sex rat i o s are greatly distorted to females on poor range i n contrast to more nearly equal sex r a t i o s on good range (Klein and Olson, I960). Delayed sexual maturity on poor range means that does usually do not give b i r t h to t h e i r f i r s t fawn u n t i l three years of age while on good range the majority of does quite l i k e l y bear young at two years of age. McDowell (I960) has shown that a s i g n i f i c a n t c o r r e l a t i o n exists between f e t a l sex rat i o s and the age of the dam of 136 white-tailed deer. Males predominate i n the fawns born to young deer while the sex rat i o s of fawns born to older does are more nearly equal with a tendency toward more female births i n the very old deer. While no data are available to support th i s relationship i n b l a c k - t a i l e d deer i t appears as another factor that might contribute to the distorted sex rat i o s on poor ranges i n Alaska. The deer populations on Woronkofski and Coronation Islands show wide differences i n sex and age structures. On Woronkofski Island the deer have been increasing rapidly from a low i n 1 9 5 0 a f t e r f i v e successive severe winters which greatly reduced deer numbers through winter starvation losses. Since 1 9 5 0 winter losses have been minimal and hunter-harvest and predation have also been l i g h t . Deer densities on Woronkofski during the study probably were simi l a r to those of more heavily hunted areas on Mitkof and Kupreanof Islands which approached 25 deer per square mile. Assuming a conservative 20 deer per square mile on Woronkofski Island, a t o t a l population of about 500 animals i s indicated. On Coronation Island the milder winter conditions have allowed a more stable deer population l e v e l to exist over a long period of time. Annual production has apparently been offset by nearly equal winter losses through starvation. Deer densities are presently substantially less than on Woronkofski Island and may be less than 10 deer per square mile, which would place the t o t a l population at s l i g h t l y less than 3 0 0 deer. 137 In support of the above suppositions are sex and age r a t i o data from f i e l d o b s ervations, specimens c o l l e c t e d and from deer dying of n a t u r a l causes. In a d d i t i o n frequency s i g h t i n g s of deer and evidence from n a t u r a l m o r t a l i t y suggest d i f f e r e n c e s i n d e n s i t i e s and welfare of the two p o p u l a t i o n s . A l l deer observed on Woronkofski and Coronation Islands during the course of the study-are l i s t e d i n Table 21 according t o t h e i r sex and age " c l a s s i f i c a t i o n . Some bias may e x i s t i n these data due to the v a r i a t i o n i n time spent by the observers i n the various v e g e t a t i o n types on the two i s l a n d s . The more productive p o p u l a t i o n on Woronkofski I s l a n d i s r e f l e c t e d i n the higher fawn to adult female r a t i o s and the greater frequency of deer s i g h t i n g s on Woronkofski I s l a n d are i n agreement w i t h the greater deer d e n s i t i e s t h e re. Table 22 i n d i c a t e s the sex and age r a t i o s of the deer specimens c o l l e c t e d on both i s l a n d s during the course of the study. Although most deer c o l l e c t e d were the f i r s t animals encountered, and t h e r e f o r e randomly s e l e c t e d , some bias i s present i n the sample due to the areas i n which most of the c o l l e c t i o n s were made. For example on Woronkofski I s l a n d c o l l e c t i n g was done predominantly i n the a l p i n e areas where sex r a t i o s are heavy to males, while on Coronation I s l a n d c o l l e c t i o n s were more evenly d i s t r i b u t e d between vegetation types and a l t i t u d e ranges. Such a b i a s , i f present, would r e f l e c t i t s e l f i n a l a r g e r p r o p o r t i o n of older animals i n the Woronkofski data and t h i s does not appear t o be the case. I t i s apparent 138 TABLE 21. Deer observed on Woronkofski and Coronation Islands during the summers of 1959, I960, and 1961 1959-60 1961 C l a s s i f i c a t i o n Woronkofski Coronation Woronkofski Adult Males 64 47 36 Adult Females 27 30 4 MalesrFemale 7 0 : 3 0 61:39 90:10 Yearlings No. 18 12 0 Percent 15 13 0 Fawns Single 6 5 3 Twins 8 0 1 Fawns/100 Females 52 17 75 Unidentified 73 6 65 Total Deer 196 100 109 Deer Seen/Man Day 14.0 2 .8 10.9 139 TABLE 2 2 . Comparison of proportions of young deer to old deer i n the samples of deer specimens collected from Woronkofski and Coronation Islands during the summers of 1 9 5 9 , I960 and 1961 RATIO OP YOUNG DEER TO OLD DEER (3 yrs. and l e s s : 4 yrs. and older) 1 Sample Sample Adult Sample Island Males Size Females Size Females Size Woronkofski 7 0 : 3 0 17 6 7 : 3 3 6 7 : 3 3 Coronation 6 7 : 3 3 18 3 8 : 6 2 16 23:77 13 Exclusive of fawns which were shot i n c i d e n t a l to the c o l l e c t i o n of does and therefore were not a product of random encounters. Includes deer two years and older which are i d e n t i f i a b l e only as adults i n the f i e l d and therefore, randomly selected. 140 from these data that the younger age classes are more abundant i n the Woronkofski sample than i n those from Coronation Island, which also i s consistant with the indicated differences i n productivity or rates of increase of the two populations. Table 23 l i s t s sex ra t i o s and causes of death of deer l o s t through natural mortality on Woronkofski and Coronation Islands. In a l l of these data sample sizes are small and conclusions are therefore speculative; however, there i s a consistency i n the data which supports the indicated differences i n the two populations. In Table 23 i t i s apparent that the causes of death during recent years have been primarily accidental on Woronkofski and losses have been l i g h t , while on Coronation Island heavier losses are almost exclusively the product of starvation. Again, sex rati o s i n the mortality have been nearly equal on Woronkofski while males dominate i n the Coronation Island losses. There i s evidence that d i f f e r e n t i a l sex mortality, heavier on males, exists among deer and that t h i s i s most pronounced on poor quality ranges. Klein and Olson (I960) found indications of thi s d i f f e r e n t i a l mortality among Alaskan deer and similar evidence has been found i n C a l i f o r n i a by Taber and Dasmann (1954) and Longhurst and Douglas ( 1 9 5 3 ) . In Minnesota, Guvalson, et a l . ( 1 9 5 2 , p. 130) concluded: "In areas which have been protected from hunting for a long time and where the deer populations have increased beyond the sustained carrying capacity and r e s u l t i n g i n known starvation losses, adult does are greatly i n excess of adult males " 141 TABLE 23. Causes of death and sex rat i o s of deer that died from natural mortality on Woronkofski and Coronation Islands (Remains found during 1959 > I960 and 1961) Cause of Death 1 Sample Island Males:Females Starvation(%) Accident($) Size Woronkofski 50:50 40 60 10 Coronation 71:29 89 11 28 A l l remains i n which .the long bones contained watery-bone marrow or none at a l l were considered deaths from starvation while fa t t y bone marrow was considered i n d i c a t i v e of accidental deaths. The greater proportion of males i n the Coronation Island mortality i s consistant with the thesis of higher mortality among males on poor ranges. The sex r a t i o s i n observed deer (Table 21) and c o l l e c t e d specimens (Table 22), although subject to bias, are l o g i c a l i n view of the indicated d i f f e r e n t i a l mortality rates on the two islands. The age d i s t r i b u t i o n of deer i n the natural mortality r e f l e c t s the apparent differences i n age structures of the populations on the two islands. The high proportion of young deer i n the Woronkofski mortality (67 percent of a sample of 9) and the predominance of deer four years and older i n the Coronation Island losses (59 percent of a sample of 22) are i n agreement with the apparent age structures of the deer populations of the two islands. 143 CONCLUSIONS This has been a study of cause and e f f e c t . Emphasis has been placed equally on the factors of the range governing quality and the responses of the deer to quality v a r i a t i o n s . S i g n i f i c a n t l y , both the range and the deer occupying i t are components of an ecosystem and both are the products of a l l of the factors of t h e i r environment acting .upon t h e i r genotypic bases of o r i g i n . Results of thi s study bear out the contention that differences occurring i n the sizes of deer on the two study islands are primarily the result of differences i n the quality of the two is l a n d ranges. This has been demonstrated both through the analysis of the range and measurements of the responses of the deer. Growth responses of deer to range quality are r e f l e c t e d both i n sk e l e t a l dimensions and t o t a l body mass. On Woronkofski Island (good range) s k e l e t a l growth i n male deer v i r t u a l l y ceased at three years while on Coronation Island (poor range) sk e l e t a l growth continued for another year. However, even with the additional period of growth on poor ranges and corresponding delayed physiological aging, deer on such ranges do not a t t a i n the same sk e l e t a l size as those on the better ranges. This i s apparently the result of several factors including the growth-depressing ef f e c t of gonadotropic hormones following puberty. In addition, growth of the long bones i s lim i t e d by closure of the epiphysis, which i s associated with 144 r hormonal influence, as well as o s s i f i c a t i o n of the long bones, which i s again a product of rate of growth. In female deer, growth responses to range quality are not as pronounced as i n males because of such factors as smaller body s i z e , slower growth rate, e a r l i e r reproductive maturity and the fact that the greatest reproductive burden coincides with the peak of range qua l i t y . The l a t t e r f actor, which necessitates the doe bearing and nursing the young during spring and early summer means a l i g h t e r physiological burden for the doe during f a l l and winter and her better chances of winter s u r v i v a l , whereas the reverse i s true of the male. Growth of body tissues of deer i s subject to t h e i r respective p r i o r i t i e s for growth, and while s k e l e t a l tissue has a higher p r i o r i t y than muscle or fat i t s i r r e v e r s i b i l i t y , in contrast to these, renders i t a better c r i t e r i o n for measurement of growth. Also, the skeleton i t s e l f exhibits variations i n sequence of growth which result i n the delay of completion of growth of the proximal long bones (femur and humerus) u n t i l r e l a t i v e l y late i n the l i f e of deer. Growth of the skeleton follows a ce n t r i p e t a l course with the d i s t a l portions, including the s k u l l , limb extremities and t a i l , maturing f i r s t and the pectoral and pelvic regions and adjacent long bones completing t h e i r growth l a t e r . Body mass r e f l e c t s n u t r i t i o n a l l i m i t a t i o n s ; however, i t i s subject to seasonal and yearly variations i n range condition 145 and includes fat reserves which have a tendency to mask variations i n growth. Through the use of regression analyses of weights and s k e l e t a l measurements from samples of deer from both Woronkofski and Coronation Islands growth- differences were found to exist between the two isla n d deer populations. Skeletal r a t i o s were found to be more r e l i a b l e than body weight as measures of growth differences because s k e l e t a l parts are less subject to short term fluctuations i n the environment and they, therefore, more accurately r e f l e c t physiological age. The use of the femur/hind foot r a t i o takes advantage of the d i f f e r e n t i a l p r i o r i t y and rate of growth of s k e l e t a l parts to d i s t i n g u i s h between n u t r i t i o n a l and genetic differences in growth and body s i z e . Results of the investigations of the deer e x i s t i n g on the islands indicate that deer on Woronkofski Island,are s i g n i f i c a n t l y larger than those on Coronation Island both i n t o t a l body mass and on the basis of t h e i r s k e l e t a l s i z e . Through the use of s k e l e t a l r a t i o s these differences were shown to be primarily the result of n u t r i t i o n a l rather than genetic causes. Other facets of the study were designed to substantiate the evidence pointing toward a quality difference i n the two is l a n d ranges and to i d e n t i f y the factors responsible for these differences. 146 Considerable difference exists i n the amount of forage available for deer on the two study isl a n d s . The t o t a l quantity of forage on Woronkofski Island on a unit area basis i s f ar i n excess of that on Coronation Island. Results of quantitative analyses of vegetation on the two islands indicates that Woronkofski Island greatly outranks Coronation Island i n the following manner. (1) Plant density and species abundance i n the forest (110 to 54 interceptions) and muskeg (297 to 242 interceptions) types. (2) Total area of subalpine (4.72 to 1.82 sq.mi.) and alpine (5.00 to 0.24 sq.mi.). (3) Total vegetated area on an equal density basis (24.31 to 16.51 sq.mi.). Differences i n the areas of each cover type on the two islands account for a large difference i n the t o t a l quantity of forage present on the islands. On both islands plant density within the forest type i s very low i n comparison to the muskeg, subalpine and alpine types. Consequently, the proportion of forest to muskeg, subalpine and alpine areas i s important i n determing the t o t a l quantity of forage available. On Coronation- Island the forest type represents 80 percent of the t o t a l vegetated area i n contrast to 54 percent on Woronkofski Island, while muskeg, subalpine and alpine types occupy the major portion of the remaining vegetated areas on the two islands. The high proportion of 147 forest type on Coronation Island with i t s r e l a t i v e l y low plant density i n contrast to the larger areas of alpine and subalpine vegetation on Woronkofski Island account for a large difference i n the t o t a l forage available for deer. The r a t i o of forest to muskeg, subalpine and alpine vegetation i s undoubtedly d i r e c t l y related to the quality and productive p o t e n t i a l of deer ranges i n Alaska. This s i t u a t i o n probably also applies to the P a c i f i c Northwest coastal region i n general although i n B r i t i s h Columbia, Washington, Oregon and northern C a l i f o r n i a cut-over areas are extensive and are comparable to the muskeg, subalpine and alpine areas i n plant density. Qualitative evaluation of forage species through the use of chemical analyses did not show s i g n i f i c a n t differences between islands i n comparisons of s i m i l a r species under comparable s i t e conditions. There were indications that alpine plants appeared of s l i g h t l y higher quality than sim i l a r species growing on low elevation muskegs. The seasonal v a r i a t i o n i n chemical contents of plants indicated that the physiological stage of plant growth was one of the most important factors determining the n u t r i t i v e quality of vegetation. Variations i n the ecological conditions of temperature, p r e c i p i t a t i o n , exposure, slope, a l t i t u d e and topography were considered to have very pronounced effects upon the plant physiology associated with the n u t r i t i v e quality of the vegetation. 148 The long range d i f f e r e n t i a l affect of the deer on the ranges of the two islands was apparent. On Woronkofski Island, where deer have been controlled through occasional severe winters, wolf predation and l i g h t hunting pressure, the range vegetation has not been materially affected by the deer. On Coronation Island, on the other hand, mild winters, the ab-sence of predators and v i r t u a l l y no hunting have meant that starvation through food shortage has been the major population control. This pressure of the deer upon the range has resulted i n a very pronounced reduction of t o t a l vegetation available to deer on Coronation Island. Techniques were developed, u t i l i z i n g samples of rumen contents, which enabled the d i f f e r e n t i a t i o n of the quality of forage being consumed by deer. Analyses of the rumen contents enabled a clear separation between Woronkofski and Coronation Islands on the basis of range q u a l i t y . Chemical analyses showed that the nitrogen content of both the gross and washed rumen samples was consistently higher among the Woronkofski group than i n those deer from Coronation Island. An inverse rel a t i o n s h i p existed between f i b e r content and quality of the vegetation i n the rumen. Other techniques of rumen contents analyses involving centrifuge f r a c t i o n a t i o n of microorganisms, l i g h t transmittancy determinations of rumen liqu o r and microscope counts of protozoa, supported the comparative evidence from the chemical analyses pointing toward higher quality range on Woronkofski than on Coronation Island. 149 Attempts to u t i l i z e parasite incidence among the deer as an i n d i c a t i o n of the physical condition of the deer did not y i e l d s i g n i f i c a n t differences between the two islands. The dynamics of the deer populations on the two islands were analysed i n an attempt to i d e n t i f y c h a r a c t e r i s t i c s of the populations which r e f l e c t the welfare of the animals and i n d i r e c t l y the quality of the ranges. Knowledge of the structure of the deer populations on Woronkofski and Coronation Islands i s sketchy because of the limited opportunity during the study to c o l l e c t t h i s information. However, the data that are available consistently point toward an increasing, healthy population on Woronkofski Island with a predominance of young animals and not a greatly distorted sex r a t i o . Indicated sex and age r a t i o s for Coronation Island suggest a more stable population heavy to older age animals and with a sex r a t i o greatly distorted toward females. These observations of the two deer populations are consistent with the measured differences i n range q u a l i t y . As a r e s u l t of these investigations i t Is apparent that deer show c h a r a c t e r i s t i c physiological responses to variations i n range q u a l i t y . These responses or variations from the optimum are brought about through l i m i t a t i o n s i n the quality and quantity of forage consumed belov; that required for optimum growth and development. The nature of the annual physiological status of ruminants i n northern regions, t h e i r rapid summer growth rates and the annual variations i n forage 150 q u a l i t y a l l lead to the apparent conclusion that the s p r i n g and summer growth pe r i o d i s the most c r i t i c a l time of the year from the standpoint of growth and development and the attainment of u l t i m a t e body s i z e . The f a c t o r s of the environment re s p o n s i b l e f o r the d i f f e r -ences i n q u a l i t y and qua n t i t y of forage present on Woronkofski and Coronation Islands are p r i m a r i l y d i f f e r e n c e s i n the degree of a l t i t u d i n a l and topographic v a r i a t i o n and i n the a s s o c i a t e d r e l a t i v e proportions of a l p i n e and subalpine areas. Secondarily the r e g i o n a l c l i m a t i c d i f f e r e n c e s and the presence or absence of predation have been important. These f a c t o r s have been measurable because of the c o n t r a s t i n g ecology of the two i s l a n d s . However, a l l of these physiographic and b i o l o g i c a l features governing range q u a l i t y are i n s t r u m e n t a l to a greater or l e s s e r extent, i n governing the q u a l i t y of a l l of the deer ranges i n Alaska. In a d d i t i o n many of these q u a l i t y c o n t r o l l i n g f a c t o r s undoubtedly i n f l u e n c e the ranges of herbivores throughout the world. A P P E N D I X TABLE 24. Age, weight and skeletal ratios of male deer from Woronkofski Island Specimen No. Age Yr. (Mo. Wt. ) (lbs.) Hind Foot (cm.) Femur (cm.) Metatarsal (cm.) Femur/ Hind Foot' Femur/ Wt. Femur/ Metatarsal 60W4 1 (0) 53 3 8 . 4 19 .6 0.510 0.370 60W8 1 (1) 64 40 .5 21.2 0 . 5 2 3 0 . 3 3 1 6 1 W 2 1 (1) 62 38.5 20.4 1 8 . 6 0 . 5 3 0 0 . 3 2 9 1.097 61W11 1 (1) 61 3 8 . 5 20 .7 1 8 . 8 0 . 5 3 8 0 . 3 3 9 1.101 60W13 1 (2) 72 3 9 . 7 21 .5 0.542 0.299 60W9 2 (1) 95 44.4 24.1 0.543 0.254 61W4 2 (1) 97 42 .3 2 3 . 7 21.0 0 . 5 6 0 0.244 1.129 61W14 2 (1) 109 43.4 24 .6 21 .8 0 . 5 6 7 0.226 1.128 61W15 2 (1) 93 41 .9 2 3 . 8 21.2 0 . 5 6 8 0.256 1 . 1 2 3 61W10 3 (1) 115 43 .7 25.2 21 .7 0 . 5 7 7 0.219 1.161 61W12 3 (1) 119 43 .8 25 .3 21 .4 0 . 5 7 8 0 . 2 1 3 1.182 60W12 3 (2) 113 44 .5 2 6 . 3 0.591 0 . 2 3 3 60W10 4 (1) 119 43 .5 24.7 0 . 5 6 8 0 . 2 0 8 61W3 4 (1) 152 43 .7 25.0 21 .8 0 . 5 7 2 0.164 1.147 61W6 ,4 (1) 144 43.2 25 .3 21 .5 0 . 5 8 6 0.176 1.177 61W9 4 (1) 143 45.0 26 .3 22 .3 0 . 5 8 4 0.184 1.179 61W13 5 (1) 159 43.2 25.0 21.4 0 . 5 7 9 0.157 1 . 1 6 8 TABLE 25. Age, weight and skel e t a l ratios of male deer from Coronation Island Specimen No. Yr. Age (mo.) Wt. , (lbs.) Hind Foot (cm. ) Femur (cm. ) Metatarsal (cm.)' Femur/ Hind Foot ' Femur/ ' • Wt. ' Femur/ Metatarsal 60C20 9wks. 16 27.5 13.5 0.491 0.844 60C19 9wks. 29 31.8 16.0 0.503 0.552 60C3 1 (0) 37 35.7 18.3 0.513 0.495 60C15 1 (2) 54 37.5 19.5 0.520 0.361 60C31 1 (2) 65 39.3 58c4 1 (9) 58 38.7 59C1 2 (2) 65 40.0 21.2 0.530 0.326 59C6 2 (2) 86 41.3 22.5 0.545 .0.262 59C7 2 (2) 92 41.2 22.5 0.546 0.245 60C25 2 (2) 91 42.8 .23.0 0.537 0.253 60C1 3 (0) 89 42.0 23.4 0.557 0.263 60C2 3 (0) 64 40.3 21.1 0.524 0.330 61C16 3 (0) 80 42.5 23.3 21.0 0.548 0.291 1.120 60C22 3 (2) 96 44.0 23.8 0.541 0.248 60C6 4 (1) 96 42.1 23,7 0.563 0.247 TABLE 25 (continued) Specimen Age 'Wt. Hind Foot Femur Metatarsal Femur/ Femur/ Femur/ No. Yr. (Mo.) (lbs .) (cm.) (cm. ) "(cm.) ' Hind Foot Wt. Metatarsal 60C23 4 (2) 130 40.6 23.8 0.586 0.183 58C3 4 (9) 80 40.6 • 59C4 5 (2) 125 41.9 23.3 0.574 0.186 58C1 5+ 97 41.9 60C14 9+ 100 42.5 23.9 0.562 0.239 TABLE 2 6 . Age, weight and sk e l e t a l ratios of female deer from Woronkofski Island Specimen Age No. Yr. (Mo.) Wt. (lbs.) Hind Foot (cm.) Femur (cm.) Metatarsal (cm.) Femur/ Hind Foot' Femur/ Wt. ' Femur/ Metatarsal 60W5 2 (0) 76 41.5 2 2 . 8 0 . 5 4 9 0 . 3 0 0 60W7 2 (1) 72 40.0 2 2 . 4 0 . 5 6 0 0 . 3 1 1 61W1 2 (1) 77 40.1 2 2 . 3 2 0 . 0 0 .556 0 . 2 9 0 1.115 61W5 2 (1) 75 40 .1 21 .7 19 .8 0.541 0 . 2 8 9 1 .096 60W38 2 (6) 100 40.7 61W7 3 (1) 80 41 .9 2 3 . 1 2 0 . 7 0 . 5 5 1 0 . 2 8 9 1 . 116 60W11 4 (1) 100 41.2 2 3 . 9 O.58O 0 . 2 3 9 60W37 4 (6) 128 4 3 . 2 61W8 5 (1) 84 ' 40.6 2 2 . 9 2 0 . 9 0.564 0 . 2 7 3 1 .096 V J l \J1 TABLE 27. Age, weight and s k e l e t a l r a t i o s of female deer from Coronation I s l a n d Specimen Age " Wt. Hind Foot Femur Met a t a r s a l Femur/ Femur/ Femur/ No. Yr. (Mo.) ' ( l b s . ) (cm.) (cm.)' (cm.) Hind Foot Wt. 60C28 lOwks. 29 31.6 16.2 0.513 0.559 60C21 1 (2) 47 36.6 19.0 0.519 0.404 60C24 1 (2) 61 36.7 20.3 0.553 0.333 60C33 1 (2) 58 35.5 19.8 0.558 0.341 58C2 1 (9) 56 38.1 60C16 3 (2) 72 22.4 0.311 60C17 3 (2) 72 40.3 21.7 0.538 0.301 59C2 4 (2) 71 38.1 21.2 0 .556 0.299 59C3 4 (2) 78 39 .3 21.2 0.539 0.272 60C27 4 (2) 81 40.0 21.8 0.545 0.269 60C29 4 (2) 84 39 .5 21 . 5 0.544 0.256 60C26 5-6 79 39.0 21.5 0.551 0.272 59C5 6-7 90 40.0 22.7 0 . 568 0.252 60C30 6-7 71 38.5 21.4 0.556 0 . 3 0 1 60C32 6-7 78 38.7 60C18 7-8 82 40 .8 22.3 0 .547 0.272 157 TABLE 28. Age at death, sex, femur length and condition of the bone marrow of deer that died from natural causes on Woronkofski Island Age Yr. (mo.) Femur Length (cm.) Condition of Bone Marrow1 Remarks M A L E S 1 (9) 22.1 Fatty 1 (9) 22.3 Fatty 3 (9) 25.5 Fatty Antlered 7-8 . 24.3 Absent Jaw necrosis Adult 25.3 Fatty Antlered F E M A L E S (less than 6) 14 .8 Absent (less than-9) 16.4 Fatty (less than 9) 1 8 . 1 Absent (less than 9) 17.4 Absent 6 (9) 24.0 Fatty Animals with bone marrow absent or with only a narrow dry ribbon present were considered to have died from starvation while fatty bone marrow was associated with accidental death. 158 TABLE 29. Age at death, sex, femur length and condition of the bone marrow of deer that died from natural causes on Coronation Island Age Yr. (mo.) Femur Length (cm.) Condition of Bone Marrow Remarks 1 (9) M A 21.0 L E S Absent 1 (9) 21.5 Absent 3 (9) 23.5 Absent 4 (9) 22.7 Fat ribbon Antlers shed 4 (9) 23.3 Absent Antlers shed 4 (9) 23.6 Sol i d fatty Antlered 5 (9) 22.8 Absent 6+ 23.2 Dry ribbon 6+ 21.8 Absent 6+ 24.1 Absent Antlers shed 6+ 22.7 Fatty Antlers shed 8+ 23.6 Absent 8+ 23.3 Absent Antlers shed 9+ 23.8 Absent Antlers shed Adult 22.8 Absent Adult 23.4 Absent Adult 23.6 Absent Adult 23.7 Absent Adult 23.2 Absent Adult 23.8 Absent 159 TABLE 2 9 . continued Age Femur Condition o£ Yr. (mo.) Length (cm.) Bone Marrow Remarks F E M A L E S (9) 1 7 . 5 Dry ribbon (9) 1 7 . 1 Absent (9) 17 .7 Absent (9) 1 7 . 1 Absent 1 (9) 1 7 . 5 Absent 1 (9) 1 8 . 4 Absent 6+ 2 1 . 8 Absent 7+ 2 1 . 5 Dry ribbon Animals with bone marrow absent or with only a narrow dry ribbon present were considered to have died from starvation while fa t t y bone marrow was associated with accidental death. r 160 LITERATURE CITED Anderson, J.P. 1959 . 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