PARENT SESSION
Contributed Oral Session 144: Predator - Prey Ecology: Terrestrial Habitat and Food Webs
Thursday, August 11, 1:30 PM - 5:00 PM, Meeting Room 524 A, Level 5, Palais des congrès de Montréal
Landscape factors and wolf pack distribution influence the spatial variability of wolf predation on elk.
Kauffman, Matthew*,1, Varley, Nathan2, Smith, Douglas3, Stahler, Daniel3, Boyce, Mark2, 1 University of Montana, Missoula, MT2 University of Alberta, Edmonton, AB3 Yellowstone National Park, Mammoth, MT
ABSTRACT- Accurately quantifying the factors that control predation risk across a landscape is necessary to evaluate its influence on prey habitat selection, foraging behaviour, and the direct demographic consequences of predation. In this study, we assessed the spatial and temporal variation in winter wolf (Canis lupus) predation on elk (Cervus elaphus) from 1996 -2004 across the Northern Range of Yellowstone National Park. We evaluated how much of the spatial variability in wolf predation on elk was controlled by landscape attributes that influence elk vulnerability to predation, versus the annual distribution of wolf packs that influence predator-prey encounters. In a Resource Selection Function (RSF) framework, we used the locations of 1201 wolf-killed elk to test the explanatory variables controlling spatial variation in wolf predation while accounting for elk habitat selection. Comparisons between RSF models for the nine winters showed that probability of predation varied temporally among years and spatially across elk winter range. This variation in predation risk was controlled both by the expanding distribution of the wolf population and landscape attributes that influence the predator-prey interactions. A suite of landscape factors (e.g., distance to roads, elevation, and habitat openness) influenced predation risk. The strength of these landscape factors suggests that elk can potentially select habitat features (i.e., high elevation, forested habitat) that make them virtually invulnerable to predation by wolves, but to do so would severely limit their access to winter forage. The implications of such a strong influence of landscape factors over predator-prey dynamics in this system are discussed.
Key words: predator-prey, spatial structure, wolves, elk