Using genetics in the conservation management of the American black bear (Ursus americanus) in Missouri


By the early 1900s, black bears were believed to be almost extinct in Missouri and Arkansas, presumably due to extensive logging and overharvest. To reestablish Arkansas populations, the Arkansas Game and Fish Commission conducted a translocation program from 1958 to 1968, moving 254 bears from Minnesota and Manitoba, Canada, to the Ozark and Ouachita National Forests. This remains one of the most successful large mammal translocations ever conducted, and the Arkansas population grew rapidly into the thousands. However, bear sightings and nuisance reports suggested that 50 years after the translocations, populations in Missouri were small, and densities were low. We conducted a spatially explicit genetic capture-recapture study to estimate the size and density of the black bear population in south-centralMissouri.We genotyped hair samples collected over two years using 15 microsatellite loci and estimated the population size at 279 ± 54 (SE) and the density at 1.7 bears/km2. To infer the source of bears colonizing Missouri, we analyzed the resulting genotypes in the Bayesian clustering program STRUCTURE along with genotypes from Arkansas, Oklahoma, and source populations. The results revealed unique genetic clusters in the Ouachitas, the Ozarks, and the source populations and found that Missouri bears were divided between those that clustered with the Ozarks and a unique cluster. The presence of the unique cluster in Missouri supports the hypothesis that black bears in the Missouri Ozarks were not extirpated but were reduced to very low densities during European settlement and have subsequently become admixed with bears that trace their ancestry to the reintroduction. While some might suggest that the unique Missouri population should be designated as a separate management unit, we caution that this might not be beneficial to the preservation of the Missouri bear population as we have no evidence that it is ecologically or geographically distinct, it has low genetic diversity, and the genetic differentiation may not be related to adaptive differences.

Publication Title

Conservation Genetics in Mammals: Integrative Research Using Novel Approaches