Effects of hunting on the demographics, movement, and habitat selection of American black bears (Ursus americanus)

Abstract: I conducted a large-scale experiment to determine the effects of hunting on the demographics and behaviour of American black bears (Ursus americanus ). I monitored 290 bears, a subset of which were equipped with VHF and GPS radio-collars, in 2 hunted areas and an adjoining unhunted area in the boreal forest of Alberta, Canada, during a 4-year study (2002-2005). I implemented a modified before-after control-impact (BACI) design whereby bait sites for hunting were closed in 1 of the 2 hunted study areas in years 3 and 4 and adult males in an unhunted area were removed in year 3. I found population density to be the most important factor affecting population parameters and suggest that the potential effects of sexually selected infanticide (SSI), if it exists, are negligible in populations reduced below carrying capacity (K). I show that spatial and temporal movements of females with cubs were most influenced by the density of female neighbors. This differs from current interpretations of female movement where food availability and male avoidance are suggested as the main determinants. Lastly, I found that females with cubs adjusted their habitat selection in response to the probability of encountering a male and reduced their selection for high-quality habitats as the density of adult males increased. These results demonstrate that population density is the most important factor regulating behaviour and demographic parameters. Therefore, black bears can be harvested sustainably without concern for potential indirect effects such as increased infanticide and reduced productivity of females.