title: Sexual segregation in North American elk: the role of density dependence.
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/km(2), and a low-density population at 4 elk/km(2) 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.
authors.affiliation: Department of Natural Resources and Environmental Science, University of Nevada Reno Reno, Nevada, 89557.
authors.forename: Kelley M
authors.initials: KM
authors.lastname: Stewart
authors.affiliation: Department of Natural Resources and Environmental Science, University of Nevada Reno Reno, Nevada, 89557.
authors.forename: Danielle R
authors.initials: DR
authors.lastname: Walsh
authors.affiliation: Department of Biological Sciences, Idaho State University Stop 8007, 921 South 8th Avenue, Pocatello, Idaho, 83209.
authors.forename: John G
authors.initials: JG
authors.lastname: Kie
authors.affiliation: United States Forest Service Pacific Northwest Research Station, 1401 Gekeler Lane, La Grande, Oregon, 97850.
authors.forename: Brian L
authors.initials: BL
authors.lastname: Dick
authors.affiliation: Department of Biological Sciences, Idaho State University Stop 8007, 921 South 8th Avenue, Pocatello, Idaho, 83209.
authors.forename: R Terry
authors.initials: RT
authors.lastname: Bowyer
keywords: Cervus elaphus; North American elk; density dependence; experimental manipulation; intrasexual competition; resource selection; sexual segregation