Seasonal Migration by a Terrestrial Salamander, Plethodon websteri (Webster’s Salamander)

Mann, Thomas; Mann, Debora

We report seasonal, horizontal migration by a winter-active, terrestrial salamander, Plethodon websteri, away from a limestone outcrop upon their emergence in the fall and toward the outcrop in spring. We made 3,597 captures (including recaptures) using a series of three drift fences erected at 9 m, 65 m, and 84 m from the outcrop. Peak months for travel were November, when 98% of captures were on the sides of the fences facing the outcrop, and March, when 96% of captures were on the sides facing away from the outcrop, as expected if salamanders were moving away from the outcrop in fall and returning in spring. Recapture of salamanders that we marked with visual implant elastomer confirmed that animals move from the outcrop in fall and initiated movement toward the outcrop in spring from as much as 150 m. To our knowledge this is the third report of horizontal migration in a Plethodon species and the first to be confirmed by mark-recapture. We suggest that crevices in rocks provide refugia and oviposition sites deep enough to afford protection from heat and desiccation in summer for P. websteri, which is among the southernmost members of its genus. The requirement for rock outcrops for summer survival and nesting is relevant to management for P. websteri, which is ranked as imperiled or critically imperiled in four of five states in the USA in which it occurs. Effective conservation requires protection of forest habitat where salamanders forage, summer refugia, and migration routes between them.