Distribution of subadult grizzly bears in relation to human development in the Bow River Watershed, Alberta

Abstract

We studied the relationship between human development and activity, and subadult grizzly bears (Ursus arctos) by comparing the distribution of radiotelemetry locations from 23 subadult versus 29 adult grizzly bears during 1994–2000 in the Bow River Watershed of Alberta, Canada. We used logistic regression to model significant differences in the spatial distribution of subadult and adult grizzly bears and analysis of variance (ANOVA) to test for significant differences in temporal distribution. Subadult bears were significantly closer to high-use roads and at lower elevations than adult bears. Both subadult and adult bears were significantly closer to high-use roads and at lower elevations during human inactive periods (1800–0700) than during human active periods (0700–1800). Subadult bears were closer to high-use roads regardless of the time of day, and therefore predisposed to greater encounter rates with humans. Consequently, subadult bears had a greater chance of becoming habituated to humans and of being killed or removed from the population by humans than adult bears. In areas with high levels of human use, we recommend that grizzly bear managers consider the population effects of these losses.