The Effects of Human Disturbance on Carnivore Behavior

Abstract

Humans impact wildlife behavior in a variety of ways. Wild animals often modify their behavior in human-occupied landscapes, and studying this behavior can help us take effective conservation measures. For example, identifying how wildlife alter behavior near roads can help wildlife managers develop strategies to reduce mortality from vehicles. In the first chapter of my thesis, I determined how roads affect bobcat (Lynx rufus) movement by analyzing GPS data from bobcats using continuous-time movement analyses. I found that bobcats crossed roads less frequently than expected from random chance. I found little evidence that bobcats preferentially use culverts or underpasses to cross roads, or that bobcat movement behavior (i.e., speed and home range size) varies with road density, but daily distance traveled increased with road density. Managers interested in reducing bobcat mortality from vehicle collisions must do more than simply providing crossing structures. Fences to funnel bobcats toward crossing structures, rumble strips to scare bobcats from roads, reduced speed limits, and wildlife warning signs for drivers may be effective tools to reduce bobcat mortality from vehicle collisions. Human activity is another threat to wildlife. Species often modify their behavior out of fear of humans, but the extent to which human activity alters species interactions is poorly understood. In the second chapter of my thesis, I tested the influence of humans on spatial and temporal overlap between two apex predators and their prey using five years of camera trap data from a nationwide study. As human activity increased, pumas reduced temporal overlap with ungulates but increased temporal overlap with mesocarnivores. Wolves experienced changes in temporal overlap with all prey species, but with no consistent patterns. There were no significant changes in spatial overlap between apex predators and prey species as human activity increased. The divergent responses of pumas and wolves to human activity align with expectations of ambush and cursorial predators, which may necessitate different strategies for conservation of these two types of predators and their interactions with prey. Research extending these results to predation rates will be key to assessing impacts to community- and ecosystem-level processes such as risk effects and trophic cascades.