Food and cover resources for small mammals on an industrially logged landscape in the Sierra Nevada of California

Abstract

The presence and abundance of organisms within an ecosystem often correlate with habitat variables that may have few, or unknown, functional values. Understanding the functional role of these variables is especially important for organisms occupying landscapes managed for timber production and containing diverse habitat patches of different quantities and structures of vegetation. We investigated the strength of associations reported in the literature between small mammal generalists and vegetation. On an industrially logged landscape in northern CA, we used occupancy and mark-recapture analyses across three years to estimate the presence and total numbers for woodrats ( Neotoma fuscipes Baird, 1858) and deer mice ( Peromyscus maniculatus (Wagner, 1845)) related to vegetative attributes on coniferous and non-coniferous sites. Abundances of the small mammals correlated positively with shrub cover and hardwoods for woodrats and with shrubs and masting species for deer mice. Indices describing the value of vegetation features for both food and cover, but not these resources independently, described both species’ presence and abundances best. We demonstrated that shrubs and non-coniferous trees are particularly important for small mammals and should be of particular focus to forest managers in the Sierras and mountains with similar forest structures.