Benthic macroinvertebrate community structure in streams of different salinities

Abstract

The likely effect of salinization on stream invertebrates was studied by comparing macroinvertebrate community structure at nine sites in six lowland, perennially flowing streams. The salinity of these streams ranged from 51 to 1100 mg L-1 total dissolved solids (TDS) (and were historically higher, up to about 2000 mg L-1 TDS). There was no correlation between either number of taxa or faunal abundance with salinity. However, multivariate analyses showed distinct invertebrate communities associated with different salinities. Fidelity analysis identified groups of taxa associated with either low or high salinity. Existing information on the distribution of the common taxa within these groups indicated that they were tolerant of wider ranges in salinity than those found in this study. The rare taxa most clearly distinguished between sites of different salinities and are possibly more sensitive to changes in salinity.