Polar Biology

, Volume 33, Issue 1, pp 31–40 | Cite as

Population-level resource selection by sympatric brown and American black bears in Alaska

  • Jerrold L. BelantEmail author
  • Brad Griffith
  • Yingte Zhang
  • Erich H. Follmann
  • Layne G. Adams
Original Paper


Distribution theory predicts that for two species living in sympatry, the subordinate species would be constrained from using the most suitable resources (e.g., habitat), resulting in its use of less suitable habitat and spatial segregation between species. We used negative binomial generalized linear mixed models with fixed effects to estimate seasonal population-level resource selection at two spatial resolutions for female brown bears (Ursus arctos) and female American black bears (U. americanus) in southcentral Alaska during May–September 2000. Black bears selected areas occupied by brown bears during spring which may be related to spatially restricted (i.e., restricted to low elevations) but dispersed or patchy availability of food. In contrast, black bears avoided areas occupied by brown bears during summer. Brown bears selected areas near salmon streams during summer, presumably to access spawning salmon. Use of areas with high berry production by black bears during summer appeared in response to avoidance of areas containing brown bears. Berries likely provided black bears a less nutritious, but adequate food source. We suggest that during summer, black bears were displaced by brown bears, which supports distribution theory in that black bears appeared to be partially constrained from areas containing salmon, resulting in their use of areas containing less nutritious forage. Spatial segregation of brown and American black bears apparently occurs when high-quality resources are spatially restricted and alternate resources are available to the subordinate species. This and previous work suggest that individual interactions between species can result in seasonal population-level responses.


American black bear Brown bear Interspecific competition Resource selection Ursus arctos Ursus americanus Alaska 



This study was a cooperative effort involving several agencies including the Alaska Department of Fish and Game, Alaska State Parks, National Park Service, US Geological Survey (Biological Resources Discipline), and University of Alaska Fairbanks. We thank K. Stahlnecker for ensuring initiation of this project. D. Bingham, J. Bryant, H. Griese, J. Kellam, J. Larrivee, M. Masteller, P. Owen, D. Porter, E. Shochat, K. Stahlnecker, and K. Wilson provided field and/or office assistance. Pilots J. (S.) Hamilton, J. Larrivee, H. McMahan, M. Meekin, and P. Walters were instrumental in safe and effective capture of study animals. D. Miller conducted the aerial salmon survey. P. Owen provided substantial assistance in all field aspects of this project. K. Kielland and K. Rode provided helpful comments on this manuscript. Funding for this study was provided by Denali National Park and Preserve, National Park Service Fee Demonstration Program, National Park Service Challenge Cost Share Program, and donations from Canon USA, Inc. through the National Park Foundation.


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Copyright information

© US Government 2009

Authors and Affiliations

  • Jerrold L. Belant
    • 1
  • Brad Griffith
    • 2
  • Yingte Zhang
    • 3
  • Erich H. Follmann
    • 4
  • Layne G. Adams
    • 5
  1. 1.Carnivore Ecology Laboratory, Forest and Wildlife Research CenterMississippi State UniversityMississippi StateUSA
  2. 2.US Geological Survey, Alaska Cooperative Fish and Wildlife Research UnitUniversity of AlaskaFairbanksUSA
  3. 3.Department of Mathematical SciencesUniversity of AlaskaFairbanksUSA
  4. 4.Institute of Arctic BiologyUniversity of AlaskaFairbanksUSA
  5. 5.US Geological SurveyAlaska Science CenterAnchorageUSA

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