A Generalist Rodent Benefits from Logging Regardless of Deer Density

Landscape homogenization resulting from high browsing pressure or forest management practices can impact plant and animal diversity. Large herbivores and logging may therefore influence small mammal populations, which are known to strongly respond to forest disturbances. We assessed the influence of white-tailed deer (Odocoileus virginianus) density and forest harvesting on deer mice (Peromyscus maniculatus) in the boreal forest of Anticosti Island (Quebec, Canada). We expected mice to be favoured by logging and thus that their abundance and body mass would increase in cutblocks, due to a greater availability of grasses providing food, shelter from predators, and improved thermoregulation. Mice may also benefit from an increase in deer density, especially at intermediate densities, where food (insects and seeds) availability is the highest. In 2 consecutive summers, we live-captured mice within a large, controlled deer browsing experiment where deer were maintained at 4 different densities (0, 7.5, and 15 deer.km(-2) and ambient density, 27 to 56 deer.km(-2)) in forest and in cutblocks. We found higher mice abundance in logged habitat regardless of deer density, but body mass was unaffected by deer density and forest harvesting. While plant, insect, and bird communities have all been shown to respond to deer density reduction, the interspecific relationships between deer and mice appear neutral in this system.