Anthropogenic effects on spatiotemporal activity patterns and interactions in a predator-prey assemblage

Evidence is accumulating that human presence and anthropogenic features in the environment impact the spatiotemporal activity patterns of both predators and prey. This is liable to affect predator-prey interactions, one of the central themes in wildlife ecology. Predator-prey interactions are complex to begin with, and disentangling anthropogenic impacts remains a substantial challenge. Yet, understanding such effects is essential in today’s increasingly human-dominated landscapes. The aim of this thesis was to test for anthropogenic effects on spatial and temporal patterns of activity in a system with two carnivores and one herbivore. I used camera trap data on Eurasian lynx (Lynx lynx), red fox (Vulpes vulpes) and Eurasian roe deer (Capreolus capreolus) collected continuously in southern Norway between 2012 and 2015. I fitted Bayesian co-occupancy models and Kernel density functions to estimate co-occupancy and the degree of overlap in diel activity patterns, respectively. The results supported the notion that sympatric predators use temporal partitioning in order to avoid humans. Further, it was revealed season-specific effects of human density on the spatiotemporal activity patterns in the study species. High human density increased the activity overlap between roe deer and red fox, likely as a result of increased temporal avoidance of humans. During winter this pattern was reversed; human density decreased the activity overlap between roe deer and red fox, indicating that roe deer might use humans as a shield in time towards red fox predation. This thesis suggests that human activity and human density are able to alter the spatiotemporal activity patterns in a predator-prey assemblage and are likely to influence their interactions. Furthermore, it highlights the importance of seasonality in factors constraining single species as well as modulating predator-prey interactions, which should be considered in future studies of predator-prey interactions.