A noninvasive, genetic, spatial-capture study of an expanding black bear population in southwestern New York. In the last several decades, the black bear population in New York has been growing due to conservative management. Of particular concern is the black bear population in the southern part of the state, where there has been a 500% increase in harvest in just the last 2 decades. To determine baseline population size and other population parameters, I conducted a non-invasive, genetic spatial capture-recapture (SCR) study in a c. 2,600 km^2 region of the Southern Black Bear Range in New York. Non-invasive, genetic methods identify individuals and examine population genetics from samples of genetic material that are passively deposited, including skin, feathers, hair,and scat samples.I collected hair samples with DNA from black bears to 1) estimate population density, 2) test for spatial patterns of range expansion related to landcover, and 3) identify patterns of genetic diversity. By including data about the locations of capture, SCR methods estimate populations as distributions across a study area. In this way populations density can be related to ecologically relevant covariates such as habitat and landcover types.
I estimated density of ~8 bears/100 km2 (i.e., ~1 bear / 1 mi 2), but bears were not uniformly distributed across the landscape. Bear densities were higher in areas with more forest landcover, and there were more bears in the south than in the north. Male bears had larger home ranges than female bears. Genetic diversity was similar to that of other studied populations, too. These results were consistent with our knowledge about black bears in New York, but the lack of avoidance of agricultural or roads suggest that black bears may continue to expand northward unless they are actively managed.