Responses of a Pond-breeding Amphibian Community to the Experimental Removal of Predatory Fish

Introduced species have become one of the most important anthropogenic impacts in aquatic ecosystems and are implicated in the declines of many native amphibian populations. Despite the effects of introduced fish species on amphibian communities, there is little information concerning the responses of amphibians following the removal of introduced predatory fish. We present results of a 4-y field experiment designed to determine the amphibian community- and population-level responses to the removal of introduced predatory fish from two experimental ponds. We observed an increase in amphibian species diversity in experimental ponds following the removal of fish. We also observed temporal changes in smallmouth salamander (Ambystoma texanum) population dynamics. Although A. texanum size at metamorphosis was unaffected by introduced fish in experimental ponds, fish removal resulted in prolonged A. texanum larval period and improved reproductive success. We attribute these responses to increases in A. texanum larval densities, as we caught considerably more metamorphosed A. texanum juveniles from experimental ponds following the removal of fish. Collectively, these observations support previous studies indicating that introductions of predatory fish have adverse effects on amphibians at both the community and population levels. Furthermore, our results suggest that amphibian communities are capable of recovering from environmental perturbations.