Dispersal and Colonization Through Open Fields by a Terrestrial, Woodland Salamander

The ability of animal species to disperse through matrix habitats is likely to have important implications for species' responses to habitat fragmentation. Within fragmented forests, open fields are among the most common matrix habitats. However, few empirical studies have measured the effects of open habitats on dispersal success of forest-dwelling species. We used two experiments to determine the effects of open habitats and distance on dispersal and colonization by red-backed salamanders, Plethodon cinereus. In the first experiment, salamanders were displaced from habitat edges 25 m and 55 m into an open field and farther into the forest. Return rates from salamanders crossing the field vs. the forest were then used to determine the barrier effects of open habitats. Although return rate declined with distance, salamanders returned successfully through open habitat as often as they returned successfully through forest. In the second experiment, we constructed “islands” of forest-like habitat within an open field. As in the previous experiment, colonization declined with distance. However, salamanders did colonize most of these field plots within one year. Initial colonists tended to be in the size range of young adults, suggesting that there may be a distinct dispersal phase for terrestrial salamanders. Collectively, these results suggest that even relatively sedentary species may be able to move through matrix habitats that are otherwise little used. Given that red-backed salamanders appear to be relatively abundant in fragmented forests, we suggest that movement through open habitats could help to offset some of the negative effects of habitat fragmentation.