Extent-Dependent Habitat Selection in a Migratory Large Herbivore: Road Avoidance Across Scales
Context In southwestern Alberta, human development, including roads, is encroaching on the landscape and into the range of a partially migratory population of elk (Cervus elaphus). Objectives To quantify factors influencing among- and within-home-range selection of winter range in this population. Methods We studied individual habitat selection and road avoidance at two biologically relevant spatial scales. We outlined availability extents for 107 individual elk-years based on observed fall migration distance, and based on a minimum convex polygon around winter telemetry relocations. To model the response by elk to road disturbance, we fit a habitat-selection model to each elk-year at each of the two availability extents, and examined population-level and individual variation in space-use. We then evaluated the relationship between inferred selection at the two scales and the functional response in selection. Results Roads had a ubiquitous influence on elk across scales. Elk, individually and as a population, avoided roads when migrating to their winter range and within this seasonal home range. Individual elk that avoided roads more strongly relative to the population did so at both scales of analysis.Further, the avoidance of low-use roads decreased with increasing road density. These results support bottom-up habitat-selection patterns (i.e., scale-independent) and functional response in habitat selection. Conclusions Overall, using a multi-scale habitat selection analysis, we show that road avoidance is a major determinant of elk space-use behaviour across multiple scales. Consequently, any new road construction or increases in road-use intensity could have detrimental effects on migratory elk populations by restricting space-use.
Prokopenko, C., M.S. Boyce, and T. Avgar (2017) Extent-Dependent Habitat Selection in a Migratory Large Herbivore: Road Avoidance Across Scales. Landscape Ecology, 32: 313-325.