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UBC Theses and Dissertations

Ecological investigation of Dall sheep (Ovis dalli dalli, Nelson) and their habitat on Sheep Mountain,… Hoefs, Manfred 1976

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ECOLOGICAL INVESTIGATION OF DALL SHEEP (QVIS DALLI DALLI, NELSON) AND THEIR HABITAT "ON -SHEEP MOUNTAIN, KLUANE NATIONAL PARK, YUKON TERRITORY, CANADA by MANFRED HOEFS B.Sc. Hons., U n i v e r s i t y o f M a n i t o b a , 1966 M . S c , U n i v e r s i t y o f M a n i t o b a , 1968 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY i n t h e Department o f Zoology We a c c e p t t h i s t h e s i s as c o n f o r m i n g t o t h e r e q u i r e d s t a n d a r d THE UNIVERSITY OF BRITISH COLUMBIA /T\ Manfred Hoefs, 1976 In present ing t h i s thes is in p a r t i a l fu l f i lment o f the requirements fo r an advanced degree at the Un ivers i ty of B r i t i s h Columbia, I agree that the L ibrary s h a l l make i t f r e e l y ava i l ab le for reference and study. I fur ther agree that permission for extensive copying of th is thesis for s c h o l a r l y purposes may be granted by the Head of my Department or by h is representa t ives . It is understood that copying or p u b l i c a t i o n of th is thes is f o r f i n a n c i a l gain s h a l l not be allowed without my wri t ten permiss ion. Department of • — • u' — The Un ivers i ty of B r i t i s h Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 Date /?//?~73~ ABSTRACT An i n v e s t i g a t i o n was c a r r i e d out on a population of D a l l sheep and t h e i r range i n southwestern Yukon from 1969 to 1973. The r e s u l t s are presented i n two separate, d i s t i n c t portions. Part I deals with the geography, geology, g l a c i o l o g y , s o i l s and climate of the study area. I t describes i n d e t a i l the vegetation of the three biogeoclimatic zones and breaks i t down in t o 32 plant asso-c i a t i o n s , grouped into 23 a l l i a n c e s and 17 orders, following the Braun-Blanquet methods of phytosociology. Part II covers the sheep population, which has during the study period remained f a i r l y constant at a l e v e l of about 200 adults. Detailed population s t a t i s t i c s are presented on such parameters as: n a t a l i t y and m o r t a l i t y rates, p r o d u c t i v i t y , sex r a t i o s , d e n s i t i e s and h i s t o r i c a l information about t h i s herd i s reviewed. The range use pattern and the forages selected by t h i s population are discussed on a monthly bas i s . The response of sheep to some environmental v a r i a b l e s as temperature, wind, snow depths i s analysed. Based on a l i f e table and c l a s s i f i e d counts a model of the population structure i s presented which i s useful f o r management questions such as c a l c u l a t i n g "allowable" harvests. TABLE OF CONTENTS i i i Page LIST OF TABLES • . i x LIST OF FIGURES x v Part I INTRODUCTION 1 Location of Study Area . . . . . . . . . . . . . . 2 Physiography and Geology 4 Glaciology and S o i l s 12 Weather and Climate 20 Regional Climate 20 Local Modifications 23 Previous Botanical Work i n the Kluane Area 27 Methods and Materials . . . . . . 33 Analyses of Vegetation 34 Analyses of Environmental Factors . . . 35 Vegetation Tables . . . 37 Vegetation Map 39 CLASSIFICATION OF VEGETATION ON SHEEP MOUNTAIN 41 The boreal (montane) biogeoclimatic zone 42 The subalpine willow-birch biogeoclimatic zone 80 The alpine tundra biogeoclimatic zone 94 DISCUSSION 130 i v Page SUGGESTIONS FOR FURTHER SYNECOLOGICAL WORK 143 SUMMARY 145 LITERATURE CITED 149 APPENDIX . . .. 157 Synthesis Tables of Orders and t h e i r Lower Units 158 L i s t of Vascular Plants . 175 L i s t of Lichens . • . 185 L i s t of Mosses and Hepaticae 187 Standard E c o l o g i c a l Forms . . . 189 Condensed Table of F l o r i s t i c Structure of Plant Associations and t h e i r Higher Units 192 Vegetation Map of Sheep Mountain (in pocket) V' Z Part II INTRODUCTION . . . . . . . . 194 Methods and Materials . . . . . . . 196 Population Dynamics and Range U t i l i z a t i o n 197 Forage U t i l i z a t i o n 203 Direct Observations 204 Rumen Sample Analyses 205 Snow Conditions 206 Temperatures 207 Wind 208 Plant Phenology . . ' 209 V Page RESULTS AND DISCUSSIONS . 212 Numbers . . • • • 212 Range of the Population 216 Migration Pattern . . . . . 217 Population C h a r a c t e r i s t i c s 222 Densities 222 Sex Ratios . . . . . . . . . . . 225 Breeding Age and Longevity 228 Reproductive Performance . . 232 Pregnancy Rate; Twinning . 232 Lamb to Ewe Ratios; M o r t a l i t y During the F i r s t Year of L i f e 233 Yearling to Ewe Ratios; M o r t a l i t y During the Second Year of L i f e . 244 Prod u c t i v i t y of the Population . 248 Composition of Nursery Bands 250 Structure of the Ram Segment of the Population 251 Adult M o r t a l i t i e s ; M o r t a l i t y Factors 254 Man-inflicted M o r t a l i t i e s 257 Accidents 258 Predation . . . . . 261 Coyote 261 Eagles 262 Wolves . . 264 Wolverine . 267 v i Page Lynx 2 6 7 Cougar . . . 2 6 8 G r i z z l y Bear, Black Bear, Fox, Raven, and Magpie . . . . 269 Dispersal . 2 7 1 Diseases, Parasites, Toothwear 273 Weather . • • • • 278 Competition 280 L i f e Table 282 H i s t o r i c a l Review of the Population Trend i n t h i s Herd 290 RESPONSE.TO ENVIRONMENTAL FACTORS 297 Plant Phenology 297 Dates of F i r s t Flowering 297 Rates of Growth and Drying-up of Important Winter Range Forage Plants 299 The A l t i t u d i n a l Advance of Plant Development 302 Response to Snow Conditions 304 Response to Temperature 312 Response to Wind 319 V e r t i c a l Migration of Sheep Population . 328 Diurnal Feeding Rhythm 335 RANGE USE AND FORAGE . SELECTION 340 Range Use During January . 346 Forage Use During January . 349 v i i Page Range Use During February . .. 352 Forage Use During February . 355 Range Use During March 358 Forage Use During March. 361 Range Use During A p r i l 364 Forage Use During A p r i l 368 Range Use During May 370 Forage Use During May 374 Range Use During June 377 Forage Use During June 384 Range Use During July 387 Forage Use During July 391 Range Use. During August . 396 Forage Use During August 397 Range Use During September 402 Forage Use During September . 405-Range Use During October 409 Forage Use During October 411 Range Use During November. . 415 Forage Use During November 417 Range Use During December 419 Forage Use During;December 422 General Discussion on the U t i l i z a t i o n of Forages 424-Selection of Forages 427 v i i i Page U t i l i z a t i o n of Broad Forage Types . 430 Comparisons to Forage U t i l i z a t i o n Studies i n Other Areas . . . ... . 433 General Discussion on the Range U t i l i z a t i o n Oyer the Annual Cycle 439 Sex-Specifi"c Range Use 443 The Relationships of.This Sheep Population to i t s Winter Range 445 MANAGEMENT RECOMMENDATIONS 452 Sheep Censuses and C l a s s i f i c a t i o n s . 452 Horn Growth. Rates 459 Optimizing of Harvests 466 SUMMARY 473 LITERATURE CITED . . . . . . . 478 APPENDIX 491 Numbers of D a l l Sheep,(excluding new born lambs) Counted on Sheep Mountain "Winter Ranges" 492 Horn Data From the Kluane Game Sanctuary . . 495 i x LIST OF TABLES Table Page Part I 1. climate-logical data for stations i n the Kluane area 21 2. Synopsis of the synsystematic units of the study area . . . . 43 3. Sizes of the associations of the mapped area i n acres . . . . . . . . . . . . . . . 44 4. P u c c i n e l l i o (deschampsioidis) - Taraxacetum l a c e r i .... . . . . . . . 49 5. Astero (yukonensis) - Hordeo (jubati) -Puccinellietum deschampsioidis 50 6. Hordeo (jubati). - Asteretum yukonensis 51 7. Astero (yukonensis) - Deschampsietum caespitosae . . . . 52 8. Triglochino (palustris) - Juncetum a r c t i c i 56 9. Triglochino (palustris) - Caricetum a q u a t i l i s 57 10. Astero (yukonensis) - Junco ( a r t i c i ) -Salicetum brachycarpae 61 11. Eriophoro ( a n g u s t i f o l i i ) - Carico ( a q u a t i l i s ) -• Salicetum p l a n i f o l i a e 62 12. Dryadetum drummondii . 65 13. Roso ( a c i c u l a r i s ) - Shepherdio (canadensis) -Populetum balsamiferae . 67 14. Calamagrostido (purpurascentis) - Arctostaphyletum uvae - u r s i . 71 15. Hypno (procerrimi) - A b i e t i n e l l o (abietinae) -Piceetum glaucae 74 16. Pentstemono (gormanii) - Artemisio (frigidae) -Agropyretum yukonensis 81 X Table Page 17. Artemisio (frigidae) - Agropyro (yukonensis) -Eurotietum lanatae 82 18. Pentstemono (gormanii) - Artemisietum f r i g i d a e 83 19. Agropyro (yukonensis) - Artemisietum f r i g i d a e -r u p e s t r i s 84 20. Oxytropo ( v i s c i d a e ) . - Artemisio (hyperboreae -frig i d a e ) - Carieetum f i l i f o l i a e . . . . 85 21. Arctostaphylo (rubrae - uvae ursi) - Festuco (altaicae) - Salicetum r e t i c u l a t a e - glaucae . . . . . 8 9 22. Arctostaphylo (rubrae) - Cassiopo (tetragonae) -Salicetum r e t i c u l a t a e - lanatae - glaucae . . . . . . 90 23. Artemisietum alaskanae 95 24. Artemisio (hyperboreae - alaskanae) - Salicetum m y r t i l l i f o l i a e 96 25. S a l i c o (reticulatae) - Sileno (acaulis) - Carico (scirpoideae) - Dryadetum i n t e g r i f o l i a e . . . . . . . 101 26. S a l i c o . ( r e t i c u l a t a e ) - Cassiopo (tetragonae) -Dryadetum i n t e g r i f o l i a e 102 27. Oxytropo (viscidae) . Artemisio . (hyperboreae) -Festuco (brachyphyllae) - Trisetetum s p i c a t i . . . . . 107 28. Oxytropo (huddelsonii) - Salicetum dodgeanae 108 29'. Agropyretum v i o l a c e i . . . I l l 30. Artemisio' (arcticae) - S a l i c o (reticulatae) -Festucetum a l t a i c a e . . . . . . . 114 31. Salicetum barrattianae . 117 32. Saxifrago . ( o p p o s i t i f o l i a e ) - Oxyrio (digynae) -Salicetum p o l a r i s '. .. . . . . . . 122 33. Seneciono (lugentis) - Salicetum p o l a r i s -r e t i c u l a t a e 123 34. Oxyrio (digynae) - Artemisietum a r c t i c a e -t i l e s i i 127 x i Table Page 35. Saxifrago ( h i r c u l i ) - Caricetum membranaceae . . . . . . 128 36. PUCCINELLIO - SALICORNIETALIA 158 37. CARICETALIA AQUATILIS . 159 38. SALICETALIA PLANIFOLIAE . . . 160 39. DRYADETALIA DRUMMONDII . 161 40. POPULETALIA BALSAMIFERAE 162 41. CALAMAGROSTIDO (PURPURASCENTIS) - ARCTOSTAPHYLETALIA UVAE-URSI' . . . . . . . 163 42. PICEETALIA GLAUCAE - MARIANAE 164 43. ARTEMIS 10 (FRIGIDAE) .. - AGROPYRETALIA YUKONENSIS . . . . . 165 44. BETULETALIA GLANDULOSAE . 166 45. ARTEMISIETALIA ALASKANAE ... .. . . " 167 46. DRYADETALIA INTEGRIFOLIAE . . . . 168 47. OXYTROPO (VISCIDAE) - ARTEMIS10 (HYPERBOREAE) -FESTUCO (BRAGHYPHYLLAE) - TRISETETALIA SPICATI . . . . 169 48. AGROPYRETALIA VIOLACEI . . . . . . . . 170 49. FESTUCETALIA ALTAI CAE 171 50. SALICETALIA BARRATTIANAE 172 51. SALICETALIA POLARIS 173 52. PETASITETALIA FRIGIDI 174 53. Condensed table of f l o r i s t i c structure of plant associations and t h e i r higher units . . . . . . . . ±92~ fa pit V-2. Part II 1. Numbers of Dal.l sheep counted on. Sheep Mountain "winter ranges" . . 492 2. Highest numbers of sheep observed on Sheep Mountain . . . 213 x i i Table Page 3. Composition of the population 214 4. Migration distances of "northern" sheep 221 5. Densities of "northern" sheep 224 6. Sex r a t i o s of D a l l sheep . . . . 226 7a. Sur v i v a l of the 1971 lamb crop to ye a r l i n g s ' age . . . . 235 7b. Sur v i v a l of the 1972 lamb crop to ye a r l i n g s ' age . . . . 236 8a. Reproductive performance . 238 8b. Reproductive performance 239 9. C l a s s i f i c a t i o n of rams 251 10. Comparisons of c l a s s i f i c a t i o n of rams . . . . . . . . 253 11a. Adult mortality 1970 to 1971 255 l i b . Adult m o r t a l i t y 1971 to 1972 . 256 12. L i f e table f o r rams of the Sheep Mountain population . . . 285 13. Dates of f i r s t flowering of Sheep Mountain plants . . . . 298 14. Average temperatures at Sheep Mountain during 1970/71 . . . . . . . . . . . 313 15. A l t i t u d i n a l movement.of sheep i n response to temperature 315 16. Average monthly wind speed during 1970/71 320 17. Response of D a l l sheep to wind c h i l l 323 18. S t a t i s t i c s on v e r t i c a l migration 329 19. Origins of rumen samples 342 20. U t i l i z a t i o n of d i f f e r e n t habitat types (plant associations) over the annual cycle . .. 343 21. S t a t i s t i c s on range u t i l i z a t i o n 344 22. S t a t i s t i c s on forage u t i l i z a t i o n 345 x i i i Table Page 23. Feeding observations during late::winter and spring . 350 24. Rumen sample analyses for January . . 351 25. Rumen sample analyses for February 356 26. Rumen sample analyses for March 362 27. Rumen sample analyses f or A p r i l 369 28. Rumen sample analyses f or May 375 29. Feeding observations during summer and early f a l l . . . . . . . 385 30. Rumen sample analyses for.June . 386 31. Rumen sample analyses f or July 393 32. Rumen sample analyses for August 400 33. Rumen sample analyses for September . . . . 408 34. Rumen sample analyses for October and November . . . . . 413 35. Feeding observations during f a l l and early winter 414 36. Rumen sample analyses for December 423 37. Summary s t a t i s t i c s on range u t i l i z a t i o n 440 38. Summary of forage composition over the annual cycle 425 39. Horn data from the Kluane Game Sanctuary 495 40a. Horn s t a t i s t i c s (annual increments i n lengths) 454 40b. Horn s t a t i s t i c s (annual increments i n degree curl) 455 41. Horn s t a t i s t i c s f o r Dall . ewes 460 42. Comparisons of annual increments i n horn growth of D a l l rams 461 x i v Table Page 43. Numbers of "trophies" i n the l e g a l age classes of rams 469 44. Horn lengths of rams taken i n the 1973 hunting season i n southern Yukon 470 X V LIST OF FIGURES Figure Page Part I 1. Map of study area 3 2. Geology and physiography of study area 7 3. Generalized s o i l p r o f i l e of Kluane Lake basin 16 4. P u c c i n e l l i o (deschampsioidis) - Taraxacetum l a c e r i 48 5. Zonation of Slims River flood p l a i n 48 6. Triglochino (palustris) - Juncetum a r c t i c i . . . . . . 53 7. Triglochino (palustris) - Caricetum a q u a t i l i s 53 8. Astero (yukonensis) - Junco ( a r c t i c i ) -Salicetum brachycarpae . 59 9. Eriophoro ( a n g u s t i f o l i i ) - Carico ( a q u a t i l i s ) -Salicetum p l a n i f o l i a e 59 10. Dryadetum drummondii 64 11. Roso ( a c i c u l a r i s ) - Shepherdio (canadensis) -Populetum tremuloidis 64 12. Calamagrostido (purpurascentis) -Arctostaphyletum uvae-ursi 70 13. Hypno (procerrimi) - A b i e t i n e l l o (abietinae) -Piceetum glaucae . . . . . 70 14. General aspect of grassland d i s t r i b u t i o n 77 15. Ecotone i n grassland associations 77 16. Arctostaphylo (rubrae - uvae-ursi) - Festuco (altaicae) - Salicetum r e t i c u l a t a e - glaucae 88 17. Arctostaphylo (rubrae) - Cassiopo (tetragonae) -Salicetum r e t i c u l a t a e - lanatae - glaucae 88 xv i Figure Page 18. Artemisietum alaskanae . . . . 93 19. Artemisio (hyperboreae - alaskanae) -Salicetum m y r t i l l i f o l i a e 93 20. S a l i c o (reticulatae) - Sileno (acaulis) -Carico (scirpoideae) - Dryadetum i n t e g r i f o l i a e . . . . 100 21. S a l i c o (reticulatae) - Cassiopo (tetragonae) -Dryadetum i n t e g r i f o l i a e 100 22. Oxytropo (viseidae) - Artemisio (hyperboreae) -Festuco (brachyphyllae) - Trisetetum s p i c a t i . . . . . 105 23. Oxytropo (huddelsonii) - Salicetum dodgeanae . . . . . . 105 24. Agropyretum v i o l a c e i . . . . . . . 110 25. Artemisio (arcticae) - S a l i c o (reticulatae) -Festucetum a l t a i c a e . 113 26. Salicetum barrattianae ., 113 27. Saxifrago ( o p p o s i t i f o l i a e ) - Oxyrio (digynae) -Salicetum p o l a r i s 120 28. Seneciono (lugentis) - Salicetum p o l a r i s -r e t i c u l a t a e . . . . . . . . . 120 29. Oxyrio (digynae) - Artemisietum a r c t i c a e -t i l e s i i . . ' . . . . . ' 126 30. Saxifrago ( h i r c u l i ) - Caricetum membranaceae . 126 31. A l t i t u d i n a l range of plant associations . . 131 32. S o i l moisture c h a r a c t e r i s t i c s of plant associations 132 33. Duration of snow, cover and depths 133 Part II l a . Range of the Sheep Mountain population of D a l l Sheep . . . 199 l b . Sheep Mountain 200 x v i i Figure Page 2. Phenological sequence of growth and drying up of important winter range forage plants 300 3. Growth of Carex f i l i f o l i a at various a l t i t u d e s demonstrating v e r t i c a l phenological advance 303 4. Average and maximum snow depths during March 1971 305 5. Snow depths i n feeding areas 307 6. Photograph of Sheep Mountain from l a t e February showing extent of bare, wind-swept areas 309 7. Typical winter scene: sheep u t i l i z i n g wind-swept areas . . . . 309 8. Response of D a l l sheep to winter temperatures 317 9. Response of D a l l sheep to wind c h i l l . . . . . . . . 325 10. V e r t i c a l migration of sheep population 330 11. Diurnal feeding rhythm of sheep 336 12. D i s t r i b u t i o n of grazing s i t e s during January 1971 347 13. D i s t r i b u t i o n of grazing s i t e s during February 1971 354 14. D i s t r i b u t i o n of grazing s i t e s during March 1971 359 15. Photograph of sheep at mineral l i c k 365 16. D i s t r i b u t i o n of grazing s i t e s during A p r i l 1971 367 17. Sheep feeding on Galamagrostis and Artemisia . . . . . . 365 18. D i s t r i b u t i o n of grazing s i t e s during May 1971 372 19. Sheep feeding on Carex f i l i f o l i a . . . . 378 20ab. Grazed and ungrazed clump of Carex f i l i f o l i a 379 21ab. Grazed and ungrazed bunch of Calamagrostis purpurascens 380 x v i i i Figure Page 22. Sheep feeding on Agropyron yukoriense . . . . . . . . 378 23. D i s t r i b u t i o n of grazing s i t e s during June 1971 383 388 24abc. Sheep u t i l i z i n g browse species during June 25. D i s t r i b u t i o n of grazing s i t e s during July 1971 392 26. Goats using dry, alpine grasslands 395 27. Large nursery band of sheep using.Dryas s i t e s 395 28. Large nursery band grazing on moist, shady . north slope . 398 29. Nursery band on alpine meadow i n l a t e August/ early September, . . . . 398 30. D i s t r i b u t i o n of grazing s i t e s during August 1971 399 31. "S o c i a l gathering" of nursery sheep on large south-east facing slope during September 404 32. D i s t r i b u t i o n of grazing s i t e s during September . . . . . 406 33. Sheep feeding on S a l i x glauca . . 407 34. Sheep feeding on S a l i x m y r t i l l i f o l i a 407 35. D i s t r i b u t i o n of grazing s i t e s during October 1970 412 36. Distribution, of grazing s i t e s during November 1970 418 37. D i s t r i b u t i o n of grazing s i t e s during December 1970 421 38. D i s t r i b u t i o n of grazing s i t e s over 1970/71 431 39. D a l l sheep forage composition 432 40. Sheep Creek slopes - a heavily u t i l i z e d winter range 446 xix Figure Page 41. West flank of Mount Wallace and north slope of Sheep Mountain - a heavily u t i l i z e d summer range . . . . 446 42. Structure of the sheep population 457 43. Relation between age of rams and horn lengths 462 44. Relation between age of rams and horn bases 463 X X ACKNOWLEDGMENTS The study presented here i s i n two p a r t s — P a r t I i s the plant e c o l o g i c a l study as part of an i n v e s t i g a t i o n of D a l l Sheep and t h e i r habitat; and Part II presents the study of an i n v e s t i g a t i o n dealing with the ecology of D a l l Sheep and t h e i r h abitat—done at the University of B r i t i s h Columbia, Department of Zoology, under the guidance of Dr. I. McT. Cowan. I am.grateful to Dr. Cowan for h i s encouragement and support throughout the study period and for making funds a v a i l a b l e f or t h i s pro-j e c t through the University of B r i t i s h Columbia, the A r c t i c I n s t i t u t e of North America, the Canadian W i l d l i f e Service, the Boone and Crockett Club, and the National Research Council. Thanks are also due to Mr. J . B. F i t z g e r a l d , Director of the Yukon Game Branch, and Mr. S. Rolfson, Superintendent of Kluane National Park, for making a v a i l a b l e a d d i t i o n a l manpower and for providing l o g i s t i c support. The assistance of the following students during f i e l d work i s g r a t e f u l l y acknowledged: Cathy Young, B i l l Richards, Rob Gordon, Ken Summers, and Terry Kennedy. I am g r a t e f u l to the following experts for providing help with the i d e n t i f i c a t i o n of Plants: Dr. J . W. Thomson, University of Wisconsin, with lichens; Dr. W. B . S c h o f i e l d , University of B r i t i s h Columbia, with mosses and hepaticae; Dr. G. Argus, National Museum of Natural History, Ottawa, with many willow specimens; Dr. D. (Murray, University of Alaska, with many Carex spp.; and Dr. V. C. Brink, University of B r i t i s h Columbia. I am p a r t i c u l a r l y thankful to Dr. V. Krajina, University of B r i t i s h Columbia, who provided indispensable assistance throughout t h i s x x i study with f i e l d work, plant i d e n t i f i c a t i o n s and c l a s s i f i c a t i o n of syneco-l o g i c a l u n i t s . L a s t l y , the write r benefitted greatly from frequent correspon-dence with the following two 'sheep experts': Dr. V. Geist, University of Calgary; and Dr. N. Simmonds, Canadian W i l d l i f e Service. To a l l the above-mentioned i n d i v i d u a l s and agencies, and to a l l others who i n d i r e c t l y contributed to t h i s i n v e s t i g a t i o n , I extend my most sincere gratitude. PART I PHYTOSOCIOLOGICAL ANALYSIS AND SYNTHESIS OF SHEEP MOUNTAIN, S.W. YUKON TERRITORY, CANADA by MANFRED HOEFS INTRODUCTION The p h y t o s o c i o l o g i c a l a n a l y s i s and t h e v e g e t a t i o n map p r e s e n t e d i n t h i s work a r e p o r t i o n s o f a l a r g e r i n v e s t i g a t i o n d e a l i n g w i t h t h e e c o l o g y o f a D a l l Sheep p o p u l a t i o n . T h r o u g h o u t t h e Yukon t h e s t u d y a r e a i s known t o s u p p o r t a v e r y h i g h d e n s i t y o f D a l l Sheep and t h e u n o f f i c i a l name "Sheep M o u n t a i n " was g i v e n t o t h e a r e a f o r t h a t r e a s o n . Our i n v e s t i g a t i o n t r i e d t o a s s e s s t h e s t a t u s o f t h e D a l l Sheep p o p u l a t i o n o f t h e a r e a , compare i t t o p o p u l a t i o n s r e p o r t e d on f r o m o t h e r a r e a s , and e v a l u a t e some o f t h e e n v i r o n m e n t a l f a c t o r s w h i c h may be r e s p o n s i b l e t o e x p l a i n t h e h i g h sheep d e n s i t i e s e n c o u n t e r e d . Sheep M o u n t a i n s u p p o r t s up t o 200 D a l l Sheep d u r i n g t h e w i n t e r months on i t s 9 . 3 s q u a r e m i l e a r e a , o f w h i c h l e s s t h a n 6 . 5 s q u a r e m i l e s a r e a c t u a l l y sheep h a b i t a t . When t r y i n g t o e x p l a i n t h e p e r f o r m a n c e o f an u n g u l a t e p o p u l a t i o n a number o f f a c t o r s need t o be l o o k e d i n t o ; t h e s e i n c l u d e t h e q u a n t i t y and q u a l i t y o f i t s r a n g e , p a r t i c u l a r l y i t s w i n t e r r a n g e , t h e t y p e o f w e a t h e r e n c o u n t e r e d d u r i n g w i n t e r , t h e p o s s i b l e i m p a c t s o f p r e d a t o r s , p a r a s i t e s and d i s e a s e s as w e l l a s t h e i m p a c t o f man t h r o u g h h u n t i n g o r o t h e r t y p e s o f a c t i v i t i e s . W h i l e a l l t h e s e p o t e n t i a l l i m i t i n g f a c t o r s were l o o k e d i n t o i n some d e t a i l t h e m a j o r e m p h a s i s was p l a c e d on t h e i n v e s t i g a t i o n o f t h i s sheep p o p u l a t i o n ' s r a n g e , p a r t i c u l a r l y i t s w i n t e r r a n g e . O n l y l i m i t e d b o t a n i c a l i n f o r m a t i o n was a v a i l a b l e f o r t h e a r e a when t h i s s t u d y s t a r t e d , and i t c o n s i s t e d a l m o s t e n t i r e l y o f p l a n t c o l l e c t i o n s . No q u a n t i t a t i v e s y n e c o l o g i c a l ujork had been done . I t was t h e r e f o r e d e c i d e d t o do a p h y t o s o c i o l o g i c a l i n v e s t i g a t i o n on Sheep M o u n t a i n u s i n g c o n v e n t i o n a l s y n e c o l o g i c a l methods o f t h e Z u r i c h -M o n t p e l l i e r S c h o o l . T h i s v e g e t a t i o n a n a l y s i s was meant t o h e l p i n t h e e v a l u a t i o n o f t h e p e r f o r m a n c e o f t h i s sheep p o p u l a t i o n ; t h e E u r o p e a n method was c h o s e n t o e n a b l e s y n e c o l o g i s t t o compare and i n t e g r a t e t h i s s t u d y w i t h s i m i l a r o n e s c a r r i e d o u t i n a number o f l o c a t i o n s o f w e s t e r n and a r c t i c C a n a d a , w h i c h u s e d t h e same a n a l y t i c a l methods [ B e c k i n g ( 1 9 5 4 ) ; O r l o c i ( 1 9 6 4 ) ; K r a j i n a ( 1 9 6 5 ) ; B r o o k e ( 1 9 6 6 ) ; L a m b e r t ( 1 9 6 8 ) ; B r o o k e , P e t e r s o n & K r a j i n a ( 1 9 7 0 ) ; B a r r e t t ( 1 9 7 2 ) ] . Even t h o u g h t h e r a n g e o f t h e D a l l Sheep p o p u l a t i o n e x t e n d s beyond t h e b o u n d a r i e s o f Sheep M o u n t a i n , t h e l a t t e r has r e p r e s e n t a t i v e s t a n d s o f a l l m a j o r a s s o c i a t i o n s f o u n d i n t h e r e g i o n t h a t a r e u t i l i z e d by s h e e p . One o f t h e m a j o r o b j e c t i v e s o f t h i s p h y t o s o c i o l o g i c a l i n v e s t i g a t i o n was t o o b t a i n b a s e l i n e d a t a f o r t h e c o n s t r u c t i o n o f a v e g e t a t i o n map o f t h i s a r e a . T h i s map was meant t o be u s e d t o e v a l u a t e t h e d i s t r i b u t i o n p a t t e r n s and g r a z i n g " s t r a t e g i e s " o f sheep o v e r t h e a n n u a l c y c l e . L o c a t i o n o f S t u d y A r e a The s t u d y a r e a i s l o c a t e d i n t h e c e n t r e o f t h e n e w l y - e s t a b l i s h e d K l u a n e N a t i o n a l P a r k , s o u t h w e s t Yukon. T e r r i t o r y ( T i g . l ) . The name "Sheep M o u n t a i n " was g i v e n t o i t by l o c a l p e o p l e b e c a u s e o f i t s i m p o r t a n c e as a D a l l Sheep w i n t e r r a n g e . The name i s n o t o f f i c i a l , b u t i t i s commonly u s e d i n t h e Yukon T e r r i t o r y and i t w i l l be u s e d i n t h i s t h e s i s . I t s e x a c t l o c a t i o n i s t h e s o u t h w e s t c o r n e r o f K l u a n e L a k e , where t h e S l i m s R i v e r i s b u i l d i n g a d e l t a ( F i g . l ) . As f a r as f l o r i s t i c c o m p o s i t i o n i s H O 50 •> w j(r i(y 1 » ' '^"S^t^^ l ^ ^ ^ ^ - ^ ^ ^ J . ^ P ^ ^ t ^ ^ - i ^ )j^:^-^J^l^-{ '}'; \C -<•-. }XN-.-6347. . :^.^J c •-.61° - 30'2 M M f il 1/ .. *^-~ ."""r ;7;fyr^p^^'^'"i^71 / r ^ " - ^ ' ^ ' l ; '•J02iai'.<"';« ':>•<••'-vvr 4 _"7-:';-~^X.yU, f 'j SM1IHMSI MBH scut b 10 IS 30 ••v;:.v'-;;'-i.^";7r-;^;; !'•>.'\( ;.7'\ /' -'.':f (V.:-7.",A ;N;%'-V-7^,I u r ^ : ^ . c ^ - - r ^ ^ f , - -7 l - ^ ' ^ v . - . - . - 4 -c o n c e r n e d , Sheep M o u n t a i n i s r e p r e s e n t a t i v e f o r D a l l Sheep r a n g e s f o r t h e n o r t h e r n h a l f o f K l u a n e N a t i o n a l P a r k , a p p r o x i m a t e l y f rom t h e S l i m s R i v e r v a l l e y t o t h e D o n j e