Deer Vigilance and Movement Behavior Are Affected by Edge Density and Connectivity

Abstract

Animal behavior is an important component of individual, population, and community responses to anthropogenic habitat alteration. For example, antipredator behavior (e.g., vigilance) and animal movement behavior may both be important behavioral responses to the increased density of habitat edges and changes in patch connectivity that characterize highly modified habitats. Importantly, edge density and connectivity might interact, and this interaction is likely to mediate animal behavior: linear, edge-rich landscape features often provide structural connectivity between patches, but the functional connectedness of patches for animal use could depend upon how edge density modifies animal vigilance and movement. Using remote cameras in large-scale experimental landscapes that manipulate edge density (high- vs. low-density edges) and patch connectivity (isolated or connected patches), we examined the effects of edge density and connectivity on the antipredator behavior and movement behavior of white-tailed deer (Odocoileus virginianus). Deer vigilance was 1.38 times greater near high-density edges compared to low-density edges, regardless of whether patches were connected or isolated. Deer were also more likely to move parallel to connected high-density edges than all other edge types, suggesting that connectivity promotes movement along high-density edges. These results suggest that increases in edge density that accompany human fragmentation of existing habitats may give rise to large-scale changes in the antipredator behavior of deer. These results also suggest that conservation strategies that simultaneously manipulate edge density and connectivity (i.e., habitat corridors) may have multiple effects on different aspects of deer behavior: linear habitat corridors were areas of high vigilance, but also areas where deer movement behavior implied increased movement along the habitat edge.