PS 31-90 - Patterns of seasonal migration in a terrestrial salamander, Plethodon websteri: Using hatchling distribution to locate subterranean nursery habitat

Thursday, August 11, 2016
ESA Exhibit Hall, Ft Lauderdale Convention Center
Debora L. Mann, Biology Department, Millsaps College, Jackson, MS and Tom M. Mann, Mississippi Natural Heritage Program, Mississippi Museum of Natural Science, Jackson, MS
Background/Question/Methods

One of the southernmost Plethodon species in the United States, Webster’s Salamanders, P. websteri, forage in forest leaf litter between October and May and retreat underground during the warmer months. Oviposition has not been observed but is assumed to occur while they are underground. Using drift fence captures and mark-recapture with visual implant elastomer at our study site in central Mississippi, we have previously documented the seasonal migration of Webster’s Salamanders away from a limestone outcrop to the surrounding forest upon their emergence in the fall and early winter, and a return to the outcrop in spring. We suggest that the outcrop provides access to subterranean refugia and oviposition sites deep enough to afford  protection from heat and desiccation in summer. Here we describe the temporal and spatial distribution of salamanders in relation to the outcrop using monthly surveys beneath 552 flagged cover objects (small limbs) in the forest surrounding the outcrop from November 2012 to May 2013 and in October 2013. Sex and age classes of captured salamanders were determined from ventral photographs. Salamanders were photographed on-site and released immediately at their point of capture.

Results/Conclusions

Limb survey data support results from other survey methods. First-year juveniles were found closer to the outcrop (X = 6 m; range 0-28 m; n = 71)  than adults (X = 33 m; range 1-109 m; n = 57). They also emerged later in fall and returned to the outcrop  later in spring than adults. Since they do not migrate as far as older individuals, we  suggest that surveys for first-year juveniles undertaken when they first emerge in November, or when they approach summer retreats in May, can be used to identify critical locations where salamanders access summer refugia and oviposition sites. P. websteri  is ranked as imperiled or critically imperiled in four of the five states in which it is found. Effective conservation of Webster’s Salamanders requires protection of not only the forests where they forage but also the subterranean habitat required for their survival and reproduction in summer.