Chironomid Taxa Richness: Natural Variation and Use in Pollution Assessment

Taxa richness of the benthic macroinvertebrate community is often used as a simple and reliable water quality indicator. However, taxa richness for Chironomidae (SC) may be less effective. SC in unstressed ecosystems may vary with differences in stream size and season. A diverse chironomid community may be present in some moderately polluted environments. A comparison of SC with taxa richness for the intolerant Ephemeroptera, Plecoptera and Trichoptera (SEPT) showed no significant relationship. Also, the effects of sediment may complicate use of SC in water quality work. SEPT was consistently found to decline with sediment addition, but the response of SC was flow dependent.