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Sex and scale: implications for habitat selection by Alaskan moose Alces alces gigas

TitleSex and scale: implications for habitat selection by Alaskan moose Alces alces gigas
Publication TypeJournal Article
Year of Publication2011
AuthorsOehlers, SA, R. Bowyer, T, Huettmann, F, Kessler, WB
JournalWildlife Biology

We examined the roles of sex and spatial scale in habitat selection by Alaskan moose Alces alces gigas. We GPScollared11 female and seven male adult moose in the Tongass National Forest, Alaska, USA, during 2002-2004.We predicted that adult male and female moose would be spatially separated outside of the mating season,consistent with hypotheses attributing sexual segregation among sexually dimorphic ruminants to allometricdifferences in body and gastrointestinal size, and resulting differential needs for nutrient requirements by the sexes(the gastrocentric hypothesis), and varying risks of predation (the predation hypothesis) between sexes, especiallyfor females with young. We predicted that habitat selection would be similar between sexes during the matingseason, but dissimilar and occur at different scales during periods of late gestation and lactation. We expected thatduring segregation, females would select for a higher percentage of forested cover and a higher edge density thanmales to reduce predation risk on their young. Furthermore, we examined whether differences in scale of habitatselected between the sexes was related to home-range size. Multi-response Permutation Procedures (MRPP)analysis indicated that the spatial distributions of adult males and females differed, particularly near or duringparturition. The sexes selected habitats similarly during the mating season (rut), when sexes generally were aggregated,whereas sexes exhibited differential habitat selection during spring, when sexes were segregated. Habitatselection by both sexes was best explained by vegetation and landscape composition tabulated within 1,000-mradii centered on GPS locations of moose. The sexes did not differ in the scale at which they selected habitats.Mean size of the annual home range was 76 km2 for females and 125 km2 for males, but size of home range was notrelated to scale of habitat selection by moose. Our results indicate that females were likely selecting habitat withhigh-quality forage while minimizing predation risk during periods of sexual segregation, whereas males wereselecting habitat that allowed high forage intake, which together provide support for both the gastrocentric andthe predation hypotheses.

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