Linear features impact predator-prey encounters: analysis with first passage time

Abstract

Landscapes are heterogeneous and animals respond to this heterogeneity by altering their movement patterns. This thesis was motivated by the need to understand the impact of a particular type of heterogeneity, anthropogenic linear features, on wolf (Canis lupus) movement in the central east slopes of the Rocky Mountains (Alberta, Canada). First passage time refers to the length of time taken to first encounter an object, such as a prey item. Novel first passage time analysis methods for animal movement were developed and applied to wolves in the presence of linear features. The underlying movement model was parameterized using paths obtained from GPS collars. These animal movement paths were confounded by measurement error. I developed a mechanistic, empirically-based method for buffering linear features that minimized the underestimation of animal use of linear features introduced by GPS measurement error. Mean first passage time analysis showed that wolves found prey faster in landscapes with higher densities of linear features, resulting in an increased functional response, which was most prominent at low prey densities. These findings have implications for management of species at risk in highly developed landscapes.