Abstract

I examined how the distributions of the plethodontid salamanders Desmognathus monticola, D. fuscus, Eurycea cirrigera, Plethodon cinereus, and P. glutinosus were related to interspecific differences in the characteristics of their retreats and differences in their dehydration and rehydration rates. There was little spatial overlap between the terrestrial species, Plethodon cinereus and P. glutinosus, and the largest two semiaquatic species, Desmognathus monticola and D. fuscus. Terrestrial species occupied retreats that were considerably drier than those of semiaquatic species, but they selected larger cover objects. Body size appeared to influence microhabitat use as well. Among both the terrestrial and the semiaquatic salamanders, large species used wider cover objects, deeper retreats, and occupied cooler retreat sites than smaller species. Among the semiaquatic salamanders, larger species were found closer to water than smaller species. Rehydration rates paralleled habitat use. Species found farther from water on searches of transects rehydrated faster than species inhabiting wetter habitats closer to water. Salamanders were found significantly farther from water on transects where the large aquatic salamander Desmognathus quadramaculatus was present than on transects where it was absent. The findings of this study are consistent with the hypothesis that species distributions along environmental gradients are frequently determined by opposing gradients in the influence of limiting environmental factors and the influence of dominant competitors and predators.