HABITAT PARTITIONING AMONG THE MAYFLY SPECIES (EPHEMEROPTERA) OF YUCCABINE CREEK, A TROPICAL AUSTRALIAN STREAM

This study examines the distributions among microhabitats of 12 detritivorous species of mayfly in Yuccabine Creek, an upland tropical rainforest stream. Analysis of data from regular benthic sampling and from in situ experiments using implanted substrata showed that although all species occurred in all the microhabitats examined, different species had significantly different peaks of abundance in different microhabitats, leading to distinct partitioning of the available habitat. The observed patterns of distribution were closely associated with the distribution of fine detritus deposits (FPOM). In the absence of FPOM in fast-flowing regions of the stream, leaf litter was the prime determinant of species distribution. Current velocity and substratum particle size influenced the distribution of the detritus and leaf litter. Abundance of mayflies was greatest in the pool habitat for all except two of the species.