Sexual segregation in North American elk: the role of density dependence |
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Authors: | Kelley M Stewart Danielle R Walsh John G Kie Brian L Dick R Terry Bowyer |
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Institution: | 1. Department of Natural Resources and Environmental Science, University of Nevada Reno, Reno, Nevada;2. Department of Biological Sciences, Idaho State University, Pocatello, Idaho;3. United States Forest Service, La Grande, Oregon |
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Abstract: | We investigated how density‐dependent processes and subsequent variation in nutritional condition of individuals influenced both timing and duration of sexual segregation and selection of resources. During 1999–2001, we experimentally created two population densities of North American elk (Cervus elaphus), a high‐density population at 20 elk/km2, and a low‐density population at 4 elk/km2 to test hypotheses relative to timing and duration of sexual segregation and variation in selection of resources. We used multi‐response permutation procedures to investigate patterns of sexual segregation, and resource selection functions to document differences in selection of resources by individuals in high‐ and low‐density populations during sexual segregation and aggregation. The duration of sexual segregation was 2 months longer in the high‐density population and likely was influenced by individuals in poorer nutritional condition, which corresponded with later conception and parturition, than at low density. Males and females in the high‐density population overlapped in selection of resources to a greater extent than in the low‐density population, probably resulting from density‐dependent effects of increased intraspecific competition and lower availability of resources. |
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Keywords: |
Cervus elaphus
density dependence experimental manipulation intrasexual competition North American elk resource selection sexual segregation |
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