Road effects on amphibian movements in a forested landscape

Forested landscapes are often dissected by an extensive network of primary and secondary logging roads, which may constitute a relatively permanent change in habitat structure for surrounding wildlife populations. We collected data on eight species of amphibians in central Maine (USA) in an effort to better understand the influence of logging roads on their movements and roadside habitat use in a forested landscape. The effects of a wide (12 m), heavily used logging road were compared to those of a narrower (5 m), less used forest track. Generally, anuran habitat use and movements were unaffected by even the larger road. In contrast, salamander abundance (i.e., Ambystoma spp., Plethodon cinereus, and Notopthalmus viridescens) was 2.3 times higher at forest control sites than at roadside sites. Furthermore, captures in roadside traps (road crossings) were only 25.9% of similarly oriented captures in paired forested controls, suggesting that the larger road significantly inhibited movement by salamanders. The importance of barrier effects from the larger road also varied depending upon the specific type of movement being made, with a greater proportion of natal dispersal movements taking place across roads (22.1%) than either migratory movements (17.0%) or home-range movements (9.2%). Forest roads apparently can serve as a partial filter to the movements of some amphibian species.