Food availability and grizzly bear (Ursus arctos) selection of post-fire and thinned forests in the mountain national parks of Canada

  • Author / Creator
    McLellan, Charles
  • Human-caused mortality and habitat loss have led to the extirpation of grizzly bears (Ursus arctos) across much of their North American range. Today, these factors continue to limit extant grizzly bear populations as productive habitats often occur in areas with elevated mortality risk creating ecological traps. Maintaining viable grizzly bear populations and preventing further range loss requires minimizing human-caused mortality and maintaining, or enhancing, productive habitats in secure locations.
    The objectives of this study were to evaluate the effects of post-fire and forest thinning on grizzly bear habitat quality in Banff, Yoho, and Kootenay national parks to assess whether these disturbances enhance grizzly bear habitat. Specifically, I first estimated grizzly bear selection of post-fire habitats across different spatial and temporal scales using data from 26 radio-collared grizzly bears. Factors that influenced grizzly bear selection of burns were then used to predict locations (map) where prescribed burning will most effectively create habitat attractive to bears. Second, I compared the presence and abundance of 25 known grizzly bear foods between burns, thinned forests, and adjacent undisturbed forests testing which factors (climate, terrain, or disturbance) most contributed to their occurrence thus informing future burn or thinning prescriptions.
    Grizzly bear selection of burns was scale dependant. Burns did not affect home range selection (placement) within the study area but were selected within their home range across the active season (April to November). Compared to thinned or forested areas, burns provided a greater abundance of important early spring, summer, and fall food resources, whereas thinned areas had more abundant green, herbaceous vegetation that is favoured by bears in late spring and early summer. This study provides a more comprehensive understanding of grizzly bear food resources and habitat use of burned and thinned areas and supports the use of prescribed fire and thinning for enhancements of grizzly bear habitat in remote, secure areas of the parks. Models from this thesis can assist with planning the locations of future prescribed fires and forest thinning treatments in the region.

  • Subjects / Keywords
  • Graduation date
    Fall 2018
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
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