Home ranges in adult Scandinavian brown bears (Ursus arctos): effect of mass, sex, reproductive category, population density and habitat type |
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| Authors: | Bjørn Dahle Jon E Swenson |
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| Institution: | Department of Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway;Department of Biology and Nature Conservation, Agricultural University of Norway, Post Box 5014, N-1432 Ås, Norway Norwegian Institute for Nature Research, Tungasletta 2, N-7485 Trondheim, Norway |
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| Abstract: | Annual home-range size indices for 36 male and 52 female adult brown bears Ursus arctos in two study areas in central and northern Scandinavia were estimated to evaluate factors believed to influence home-range size. Male home ranges were larger than home ranges of lone females after controlling for the sexual size dimorphism acting on metabolic needs. Further, home ranges of females with cubs were smaller than home ranges of lone females and females with yearlings. Thus, differences in metabolic need were not able to explain the variation in range size among females of different reproductive categories or between males and females, suggesting roaming behaviour of males in this promiscuous species. Home-range size in both males and females was inversely related to population density along a density gradient that was not linked to food availability. This contradicts the hypothesis that females use the minimum areas that sustain their energy requirements. However, on a large geographical scale a negative relationship between range size and food availability was evident. The annual home ranges in inland boreal environments in Scandinavia are the largest reported for brown bears in Eurasia, and similar to those in inland boreal and montane environments in North America. |
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| Keywords: | brown bear home-range size population density Ursus arctos |
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