Genetic Diversity, Structure, and Recolonization Patterns of Kentucky Black Bears

Hast, John

ABSTRACT: The black bear (Ursus americanus) has successfully recolonized the Cumberland, Pine, and Black Mountains of southeast Kentucky without management intervention. It has been hypothesized that these bears represent the western extreme of a larger regional metapopulation that spans the neighboring states of Tennessee, West Virginia, and Virginia. A second population of bears occurs in south-central Kentucky and may be solely sourced from a limited translocation of 14 individuals in the late 1990s which may have been additionally supplemented by individuals from farther east. I hypothesized that these two regional bear populations separated by Interstate 75 and habitat fragmentation would be genetically distinct, and that the translocated population would exhibit lower heterozygosity as a result of founder effects compounded by a decade long absence of interchange of individuals with other bear populations. To test my hypotheses, I conducted a genetic analysis using 8 microsatellite loci from hair of individual black bears collected at two temporal time intervals (2000-2002 and 2006-2009). My findings indicated the occurrence of two distinct bear populations within Kentucky; Big South Fork and southeastern Kentucky. Divergence between these two populations suggested a small, yet significant separation, although heterozygosity of each was comparable to other bear populations that exhibited connectivity with larger regional metapopulations or that occurred within large, stable populations. I identified a minimal number of migrants between the two regional subpopulations, yet this number remained constant between the temporal data sets. My findings suggested these bear populations are expanding and were supportive of observational data outside this study. Collectively these data, and the noted exchange of individual bears between these two populations despite formidable landscape barriers, may dissuade concerns about a lingering founder effect in the Big South Fork bear population.