How does landscape permeability affect the movement of eastern red-backed salamanders?

Demographic and genetic connectivity have important implications for population dynamics of wildlife and their ability to adapt to changing environments. Landscape features such as roads and streams can inhibit movement of species with poor dispersal capabilities and exacerbate the effects of habitat fragmentation. Terrestrial plethodontid salamanders are generally thought of as incapable of long-distance movement and may vary in their motivation to move across a landscape by sex and size classes. To examine landscape permeability to movement, we assessed how distance and natural or man-made landscape features affect recapture rates after displacement in red-backed salamanders (Plethodon cinereus). We randomly assigned marked salamanders from 6 plots at Camp Karoondinha in Millmont, Pennsylvania, USA, to a control (placed under the same cover board) or a treatment (displaced 25 m or 50 m through the forest or across a stream or road). Of 290 marked individuals, we recaptured 29.8%. We recaptured more individuals in the control treatment compared to displaced individuals, with recapture rates decreasing with the presence of a road or stream. Landscape feature type and sex did not affect the probability of recapture, but developmental stage did, with adult salamanders more likely to be recaptured than juvenile salamanders. Our results suggest that landscape permeability is reduced for terrestrial salamanders when a landscape feature is present compared to open forest. Narrow, dirt roads present a similar challenge to a natural stream for red-backed salamanders. Our study should be of value to land managers who are concerned about the negative effects of landscape permeability on terrestrial salamander populations.