UC Berkeley

In many of the world’s natural areas, humans now play, work, or live alongside large-bodied species of wildlife including ungulates, meso-carnivores, and even apex predators. The behavioral adjustments of these species to human activities have implications for individual fitness, population persistence, and community structure, as well as for human safety. Theory suggests that wildlife in human-dominated landscapes should modify their habitat use to avoid interactions with people, but that such avoidance may occur only in response to fine-scale spatial and temporal variation in human activity. Yet studies of the impacts of human disturbance on wildlife rarely quantify the fine-scale dynamics of human use. In this dissertation, I seek to link wildlife avoidance behavior more directly to the type, timing, intensity, and spatial distribution of human activity, thereby informing efforts to preserve relatively undisturbed spaces for large mammals in natural ecosystems regularly used by people.

I first consider spatiotemporal use of the landscape by grizzly bears (Ursos arctos) in areas of high recreation in Kananaskis Country, Alberta, Canada. For each day of the active bear season, I quantified numbers of people and vehicles using all trails, roads, and facilities located within the home ranges of GPS-collared bears. I estimated human disturbance at bear GPS positions as a function of both distance to human-use features and the average daily use on those features. Analyses revealed that when bears were in habitats adjacent to recreation infrastructure, they modified their behavior in response to daily, weekly, and seasonal fluctuations in human activity, avoiding the times and places of highest recreation. Bears responded to recreation patterns that were spatially and temporally consistent, highlighting the need to preserve predictable patterns of human use in the study area. This research demonstrates the value of quantifying fine-scale dynamics of human activity and focusing on areas of high overlap between wildlife and people to elucidate avoidance behavior of wild animals in human-dominated landscapes.

Further, I evaluate the effect of incorporating fine-scale estimates of recreation intensity on the predictive accuracy of resource selection function models developed to quantify habitat use of GPS-collared grizzly bears. Models that included static proxies for human disturbance were compared against those that estimated daily numbers of recreationists and vehicles within bear home ranges. When bears were in close proximity to trails, roads, and facilities, top models were those that rigorously quantified human use, indicating that bear habitat selection was significantly influenced by the fine-scale dynamics of recreation activity. My results suggest that when spatial overlap between human activity and wildlife is high, static representations of human disturbance may be less effective for describing wildlife behavior.

Last, I expand my focus to multiple species. Spatiotemporal patterns of occurrence of large mammals, recreationists, and domestic dogs were assessed using camera traps deployed within critical wildlife habitat bordering the town of Canmore, Alberta. Recreation was categorized by type of user, and daily numbers of recreationists and domestic dogs were quantified over a twenty-month period. Coyotes (Canis latrans) demonstrated the clearest temporal shifts in response to recreation intensity, and hikers and off-leash dogs spatially displaced several species. Results also suggested that study species responded most to past rather than current levels of human activity. My findings underscore the importance of spatial scale in recreation impact studies and indicate that recreation can have measurable effects on fine-scale habitat use and diel activity of large mammals.

The research presented in this dissertation adds to the growing body of literature on wildlife behavioral responses to human disturbance in general and outdoor recreation in particular. Human activity is increasing in most natural ecosystems, and my work suggests timely new approaches for quantifying human use and measuring its impacts on wildlife behavior in landscapes where presence of people is widespread.