Document: NAT-3-52-39

Distribution and coexistence of two terrestrial salamander species: A difference in desiccation physiology.

MURPHY, N.* and C.E.NELSON

Indiana University, Bloomington, IN 47405, U.S.A. ¹

Abstract:
Plethodontids are small, lungless, terrestrial salamanders that must keep their skin moist for respiration. This makes them especially susceptible to desiccation. Cover objects on the forest floor that provide moist, cool refugia are aggressively defended by resident individuals. In previous work where two similar species compete for cover objects, local areas of competitive exclusion are the result. Plot sampling in the springs of 1997 and 1998 demonstrated that Plethodon cinereus and P. dorsalis coexist broadly and syntopically in south-central Indiana. P. dorsalis was captured significantly less frequently in dryer habitats and during the drier of the two years. These data suggested that P. dorsalis was more sensitive to desiccation. In lab experiments, P. dorsalis did desiccate more quickly than P. cinereus. The field and lab data together suggest that P. dorsalis probably retreats underground sooner than P. cinereus to avoid desiccation. This may provide a temporal release from competition for P. cinereus allowing these two species to coexist syntopically.

Keywords: Plethodon, terrestrial salamander, competition

This abstract is being presented at: 9:45 AM in session:
Oral Session #27: Salamanders, Lizards, and Tortoises.