348 



Alaska — Oni Liviiifi Rcsiiiirces 



Figure. Wolf and caribou popula- 

 tion trends in Denali National 

 Park, Alaska, 1984-93. 



For further information: 



Layne G. Adams 

 National Biological Service 

 National Park Service-Alaska 



Region 



2525 Gambell St.. Room 107 



Anchorage. AK 99503 



our research began (Adams et al. in press; 

 Figure). About 46 wolves inhabited the 1 ().()()()- 

 km- (3.860-mi-) range of the caribou herd in the 

 early years of our study (Meier et al. in press). 

 The nuinber of wolves was lower than we 

 expected based on the abundance of large prey 

 species in Denali. Light snowfalls were favor- 

 able to caribou, and few died. Wolves preyed 

 primarily on moose; the few caribou they took 

 were usually very young or very old (Mech et 

 al. in press). Times were tough for wolves, with 

 poor production of pups and high dispersal rates 

 for young wolves. Also, fights between packs 

 resulted in the deaths of several wolves. 



With the onset of more severe winters, 

 beginning with winter 1988-89, wolf numbers 

 rapidly increased to 81 wolves in just 2 years 

 (Meier et al. in press; Figure), primarily because 

 of higher pup production and less dispersal of 

 young wolves. Caribou were more vulnerable to 

 predation in the deep snow and replaced moose 



— Caribou 



— Wolves 



ii; Above-average snowfall 



100 



80 



60 



40 



84 85 86 87 88 89 90 91 92 93 



Year 



as the most important prey species for wolves. 

 Losses of adult cows increased eight-fold to 

 nearly 20% per year. Fewer than 9% of the 

 calves survived to 4 months old, compared to 

 nearly 60% following the light snow winters 

 (Adams et al. in press). The caribou herd 

 stopped growing in 1990 at about 3,300 and 

 plummeted to KTOO by 1993, a 50% decline in 

 only 3 years (Figure). With declining prey, the 

 wolves also declined to about 60 wolves within 

 the caribou herd's range, a 23% reduction 

 between March 1990 and March 1993. 



The fluctuations in wolf and caribou num- 

 bers observed in Denali National Park are prob- 

 ably indicative of normal adjustments to the 



highly variable winter weather of the region. 

 Within 8 years, the caribou herd increased by 

 36% and declined by 50%. At the same time, 

 the wolves almost doubled in number and then 

 declined halfway back to their original num- 

 bers. 



The trends noted for the Denali caribou herd 

 are representative of population trends of sever- 

 al mountain caribou herds throughout central 

 Alaska, including ihc Chisana and Mentasta 

 herds in the Wrangell Mountains, and the Delta 

 and Macomb herds east of Denali Park in the 

 Alaska Range. Unlike the Denali herd, which 

 has been closed to hunting for nearly 20 years, 

 these other caribou herds are important 

 resources for subsistence and sport hunters 

 alike. Hunting seasons have been closed for all 

 four caribou herds because of the declines in the 

 last few years. 



These reductions in hunting opportunities 

 have led to debates over the merits of wolf con- 

 trol to provide more caribou for human harvest. 

 Arguments regarding allocation of harvestable 

 wildlife between subsistence and sport hunters 

 will intensify when hunting seasons are 

 reopened. Although the future of wolves and 

 caribou in interior Alaska is secure, natural tluc- 

 tuations like those described here can be expect- 

 ed to generate continued controversy over the 

 management and allocation of these important 

 wildlife resources. 



References 



Adams, L.G., B.W. Dale, and L.D. Mech. Wolf predation on 

 caribou calves in Denali National Park. Alaska. In L. 

 Carbyn. S. Fritts. and D. Seip. eds. Ecology and conser- 

 vation of wolves in a changing world. Canadian 

 Circumpolar Institute, University of Alberta, Edmonton. 

 In press. 



Harbo. S.J., Jr. and F.C. Dean. 1983. Historical and current 

 perspectives on wolf management in Alaska. Pages 51-64 

 in L.N. Carbyn, ed. Wolves in Canada and Alaska: their 

 status, biology, and management. Canadian Wildlife 

 Service Rep. Series 45. 135 pp. 



Mech. L.D. 1973. Wolf numbers in the Superior National 

 Forest of Minnesota. USDA Forest Service Res. Paper 

 NC-97. 10 pp. 



Mech. L.D. 1975. Current techniques in the study of elusive 

 wilderness carnivores. Pages 315-322 in Proceedings 

 11th International Congress Game Biologists. National 

 Swedish Environment Protection Board. Stockholm. 



Mech. L.D.. T.J. Meier. J.W. Burch, and L.G. Adams. 

 Patterns of prey selection by wolves in Denali National 

 Park. Alaska. In L. Carbyn. S. Fritts. and D. Seip, eds. 

 Ecology and conservation of wolves in a changing world. 

 Canadian Circumpolar Institute. University of Alberta. 

 Edmonton. In press. 



Meier. T.J.. J.W. Burch. L.D. Mech. and L.G. Adams. Pack 

 structure dynamics and genetic relatedness among wolf 

 packs in a naturally regulated population. In L. Carbyn. 

 S. Fritts. and D. Seip. eds. Ecology and conservation of 

 wolves in a changing world. Canadian Circumpolar 

 Institute. University of Alberta. Edmonton. In press. 



