THE EFFECTS OF SEX, TERRAIN, WILDFIRE, WINTER SEVERITY, AND MATERNAL STATUS ON HABITAT SELECTION BY MOOSE IN NORTH-CENTRAL ALASKA

Abstract

Habitat selection is a central component of the ecology of individual animals as it affects body condition, survivorship, and reproductive output. We instrumented male and female moose (Alces alces) in north-central Alaska with GPS radio-collars to assess factors we hypothesized were important to their habitat selection. Using synoptic modeling techniques, we found that models with more covariates were better predictors of moose habitat selection than more simplistic models. As expected, moose selected for habitats with high canopy cover and/or that typically have abundant forage such as 11-30 year old burned areas. However, we detected differences in habitat selection between sexes, seasons (i.e., winter versus summer), during winters of varying severity, and females with differing maternal status. During winter males moved to lower elevation areas, presumably to avoid greater snow depths, whereas females remained at relatively similar elevations. Females selected burned habitat and areas that received higher amounts of solar radiation. We found that all moose selected for lower elevation habitats closer to rivers during moderate and severe winters, but elevation was not a strong influence during mild winters. We found that females with calves avoided riparian habitats and selected areas with more forested habitat than females without calves during both summer and winter. This suggests a trade-off between maximizing forage intake and reducing predation risk for their offspring. Our and similar data are useful to improve moose management strategies and provide a benchmark against which the impacts of climate change and industrial development are assessed in this rapidly-changing region.