Abiotic factors affect microhabitat selection and community dynamics in a sandy-bottom lotic chironomid midge assemblage

Abstract

Research has established that there is a relationship between lotic macroinvertebrates and environmental variables; however, the sample is frequently large with a coarse mesh size, or sampling is broad in scope. My working hypothesis was that microhabitat variability affects habitat choice and community structure of larval chironomid midges, examined at a scale close to organismal size. Small benthic cores were taken monthly and divided vertically into 1 cm sections. Midge larvae were extracted from each section, and 14 environmental variables were assessed for each section. Partial canonical correspondence analysis indicated that a number of species showed unique microhabitat preferences. The species–environment relation was strong, in which several environmental variables contributed significantly to patterns of midge habitat structure, most notably current, depth in the sediment, and certain sediment fractions. This research demonstrated that small macroinvertebrates are selective in choosing microhabitats, measured at the rarely examined small scale close to organismal size, in a simple homogeneous sandy environment. Precision in defining an organism’s microhabitat can help us better to understand species habitat choices with a view to improve understanding of species interrelationships.