Resource availability and anthropogenic disturbance alter how wolves move and feed: comparing two populations.

Abstract

Animals behave 'optimally' when they minimize their costs while maximizing their energetic gain. Optimal foraging theory predicts that with decreasing resource abundance, animals will increase 1) niche breadth, 2) territory size and movement distance, and 3) time spent at resource patches. We used optimal foraging as a guiding framework to test what drives differences in behaviour of GPS collared wolves in two predator populations. As expected, niche breadth and territory sizes were larger, movement rates were greater and cluster durations were longer in the study area with relatively lower resource abundance Our comparative test through the lens of optimal foraging theory led to some unexpected discoveries. Specifically, differences in these responses were not explained by the density of the large primary prey (moose) but instead anthropogenic disturbance (linear feature density) was a ubiquitous influence on wolf behaviours. Wolves in higher linear feature density responded by reducing their cluster residency and increased step lengths and territory sizes with increases in linear feature density. Our work provides evidence that large carnivores can mediate changes in resources by adjusting their space use and time budgets in a way that corresponds with optimal behaviour - maximizing their energy gain and minimizing costs.