Highways as Potential Barriers to Movement and Genetic Exchange in Small Mammals

摘要

Small mammal populations separated by highways may be partially or completely isolated from one another due to low dispersal capabilities, low probability of surviving highway crossing attempts, and/or avoidance of areas adjacent to highways. The authors' objective was to determine how population connectivity is influenced by highways of different widths and traffic levels for several small mammal species that may experience varying success in crossing highways. The authors used mark-recapture techniques to compare movement adjacent to highways to movement across highways for southern red-backed voles (Clethrionomys gapperi), deer mice (peromyscus maniculatus), yellow pine chimpmunks (Tamias amoenus), and red-tailed chipmunks (Tamias ruficaudus) in forested areas of western Montana. In addition, the authors used genetic techniques to compare gene flow (movement plus reproduction) adjacent to highways to gene flow across highways for red-backed voles, deer mice, and vagrant shrews (Sorex vagrans).