HABITAT-SPECIFIC LIFE-HISTORIES AND FORAGING BY STREAM-DWELLING AMERICAN TOADS

This study examined the relative performance of larval American toads (Bufo americanus) inhabiting different habitats (isolated pools and th e main channel) of an intermittent third-order stream in west-central Kentucky. Larval mortality was 100% in six of eight isolated pools bec ause of habitat drying, mortality was similar to 98% in each of tile t wo longer lasting pools. None of the cohorts tracked in the main chann el died from desiccation. Density effects on larval diets and life-his tory traits also varied between habitats. Algal (food) standing crops were significantly negatively correlated with larval densities in isol ated pools but not in the main channel. As epilithic chlorophyll a con centrations decreased in isolated pools, larvae proportionally include d more detritus in their diets. Associated with these patterns, larvae inhabiting isolated. pools metamorphosed at a significantly smaller s ize than those in the main channel. These results suggest that intrasp ecific competition for periphyton is more likely to occur in isolated pools than in the main channel. Between-habitat variation in larval pe rformance may have major effects on the dynamics of natural load popul ations.