Proceedings of the Seventh Mountain Lion Workshop

GENETIC STRUCTURE OF COUGAR POPULATIONS ACROSS THE WYOMING
BASIN: METAPOPULATION OR MEGAPOPULATION
CHUCK R. ANDERSON, JR., Zoology and Physiology Department, University of Wyoming,
Box 3166, University Station, Laramie, WY 82071, USA, email: cander@uwyo.edu
FRED G. LINDZEY, Wyoming Cooperative Fish and Wildlife Research Unit, Box 3166,
University Station, Laramie, WY 82071, USA, email: flindzey@uwyo.edu
DAVE B. McDONALD, Zoology and Physiology Department, University of Wyoming,
Bioscience Room 413, University Station, Laramie, WY 82071, USA, email:
dbmcd@uwyo.edu
Abstract: Using microsatellite DNA analyses at 9 loci, we examined genetic structure of 5
geographically distinct cougar (Puma concolor) populations separated by the Wyoming Basin
and a distant cougar population from southwest Colorado. Observed heterozygosity was similar
among populations (Hobs = 0.49-0.59) and intermediate to that of other large carnivores.
Estimates of genetic structure (FST = 0.029, RST = 0.028) and number of migrants per generation
(Nem) suggested high gene flow across the central Rocky Mountains. Estimates of the number of
migrants per generation were lowest between the southwest Colorado cougar population and
cougar populations north of the Wyoming Basin (northwest WY, north-central WY, and the
Black Hills, SD; Nem = 2.9-3.0) and highest among cougar populations from adjacent mountain
ranges (Nem = 10.2-30.2), suggesting an effect of both isolation by distance and of habitat
matrix. We applied a model-based clustering method to infer population structure from
individual genotypes and noted that both males and females from throughout the region were
best described as a single panmictic population. Estimates of relatedness (rxy) did not differ (P >
0.05) between males and females. Estimated relative effective population size did not differ
significantly among populations (P > 0.05), but the higher estimates were from contiguous
mountain ranges (i.e., northwest WY, southwest WY, and southwest CO) and lower estimates
were from less contiguous terminal mountain ranges (i.e., north-central WY and Snowy Range
WY). Based on measures of gene flow we examined, extinction risk in the near future appears
extremely low, even for the relatively isolated Black Hills cougar population. Cougars in the
central Rocky Mountains appear to constitute a large panmictic population rather than a
metapopulation. Estimated effective population size for cougars in the central Rocky Mountains
ranged from 1,797 to 4,532 depending on analysis method and the mutation model assumed.
PROCEEDINGS OF THE SEVENTH MOUNTAIN LION WORKSHOP
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