Getting to the root of the matter: grizzly bears and alpine sweetvetch in west-central Alberta, Canada

Abstract

Wildlife habitat selection is influenced by gender, offspring-dependency, resource availability, and spatiotemporal variation in resource nutrition. In consideration of these factors, this thesis examines alpine sweetvetch (Hedysarum alpinum) root and its relationship to grizzly bears (Ursus arctos) in west-central Alberta, Canada. I observed sexually segregated, offspring-dependent functional responses in selection for sweetvetch habitat that was further affected by inter-annual patterns in spring climate (i.e., Pacific Decadal Oscillation). Selection patterns suggested that habitat segregation was due to differences in nutritional requirements between sexes and offspring predation risk. Nutritional analyses of roots indicated that temporal patterns in protein content were influenced by spatial variations in temperature and soil. This spatiotemporal heterogeneity benefits grizzly bears by prolonging the availability of nutritious roots, and may explain why sweetvetch habitats in the mountains were relied upon throughout the spring and how bears could rely on a root digging (habitat) strategy.