Covariates Affecting Spatial Variability in Bison Travel Behavior

Understanding the mechanisms that influence an animal’s movement paths is essential for comprehending behavior and accurately predicting use of travel corridors. Researchers collected 121,380 locations from 14 female bison with GPS collars in central Yellowstone year-round to examine how topography, habitat type, roads, and elevation affected the probability of bison travel. They also conducted daily winter bison road use surveys (2003–2005) to quantify how topography and habitat type influenced spatial variability in the amount of bison road travel. Using model comparison techniques, they found the probability of bison travel and spatial distribution of travel locations were affected by multiple topographic and habitat type attributes, including slope, landscape roughness, habitat type, elevation, and distances to streams, foraging areas, forested habitats, and roads. Streams were the most influential natural landscape feature affecting bison travel, and results suggest that the bison travel network throughout central Yellowstone is spatially defined largely by the presence of streams that connect foraging areas. Also, the probability of bison travel was higher in regions of variable topography that constrain movements, such as canyons. Pronounced travel corridors existed both in close association with roads and distant from any roads; results indicate that roads may facilitate bison travel in certain areas. However, the findings suggest that many road segments used as travel corridors coincide with natural travel pathways because road segments receiving high amounts of bison travel had landscape features similar to those of natural travel corridors.