INFLUENCE OF ABIOTIC AND BIOTIC FACTORS ON AMPHIBIANS IN EPHEMERAL PONDS WITH SPECIAL REFERENCE TO LONG-TOED SALAMANDERS (AMBYSTOMA MACRODACTYLUM)

Abstract

Animals living in ephemeral habitats are subjected to various abiotic and biotic selection pressures that may not be present to the same degree in permanent habitats. For example, pond drying can lead to increased predation and competition as resources become limited and temperature and water quality undergo drastic fluctuations. Amphibians provide an excellent model for studying factors associated with survival in temporary habitats. Aquatic amphibians developing in ephemeral habitats must find food, avoid predators, and cope with potentially great fluctuations in abiotic parameters under increasingly harsh conditions. In Oregon (U.S.A.), larval long-toed salamanders (Ambystoma macrodactylum) often inhabit temporary ponds that gradually dry during the summer. We have been studying several factors that may influence long-toed salamander behavior, growth, and survival in ephemeral montane ponds in the Cascade Range. These include biotic interactions focusing on cannibalism and predation, and abiotic factor...