Black Bear Landscape Genetics
Population Genetic Analysis of Black Bears (Ursus americanus) in California
An estimated 30,000 black bears (Ursus americanus) occupy a variety of habitats in California. California Department of Fish and Game (CDFG) management population units are currently designated by habitat type, and consist of: North Coast/Cascade, Sierra, and Central Western/Southwestern. The goal of this project was to determine the population genetic structure of black bears in California.
In an analysis of DNA of 540 black bears across California, we discovered distinct population structure and genetic evidence of 2 historic colonization events. First, DNA types (genotypes) of bears sampled in southern California are most related to those from the Yosemite National Park region and not with spatially intervening populations. Historical records recount the translocation of 28 black bears from the Yosemite National Park area of the central Sierra Nevada to the San Bernardino Mountains in southern California in the 1930s.
Second, before colonization of California by Europeans, the Central Coast region was inhabited by the now extinct California grizzly bear (Ursus arctos californiensis), but not black bears. Following an apparent competitive release and range expansion during the past century, black bears now inhabit the Central Coast region of California. Black bears in California's Central Coast display lower genetic diversity (founder effect) and a genetic signature most closely allied with black bears from the southern Sierra Nevada. In both these cases, molecular genetic techniques allowed historical reconstruction of anthropogenic events leading to changes in animal distributions.
Read more in our journal paper:
Brown SK, Hull JM, Updike D, Fain S, Ernest HB. 2009. Black Bear Population Genetics in California: Signatures of Population Structure, Competitive Release and Historical Translocation. Journal of Mammalogy. 90:1066–1074.
Information from this research will aid black bear management and conservation. We collaborated with California Department of Fish and Game, US Fish and Wildlife Service Forensic Laboratory, United States Department of Agriculture-Wildlife Services, National Park Service (NPS) and independent researchers.
For more information about Black Bears in California, see the Outdoor California magazine Bear issue, 2002.