TEMPORAL FLUCTUATIONS IN ABUNDANCES OF ANURAN AMPHIBIANS IN A SEASONAL AMAZONIAN RAIN-FOREST

Anuran amphibians were sampled over a period of 6 yr at a site in seasonal lowland tropical rainforest in southern Amazonian Peru. Three sampling periods were at the beginning of the rainy seasons in 1986, 1989, and 1991; two were in the middle of the rainy seasons of 1986 and 1990, and one was in the dry season of 1989. Temperature and rainfall were recorded throughout all sampling periods. Sampling was done along a system of trails and in four series of quadrats. A total of 5236 individuals of 61 species of anurans was recorded during the sampling period. Analysis of the data on the 20 most abundant species reveals that anuran activity is closely correlated with the occurrence of peaks of heavy rainfall and not total rainfall during a sampling period. There is no compelling evidence for declines in anuran populations at this site.