Chironomid species as indicators of freshwater habitat quality

Chironomid species responses to environmental factors were investigated because knowledge of species optima and tolerance is needed to develop an effective method for assessing the ecol. quality of freshwater ecosystem. The focus of the present study was on the optima at the species level for which environmental data are available with the objective of assigning each chironomid species to an appropriate quality class. The database used for the anal. includes samples collected predominantly in northern Italian lakes and running waters since the 1970s. Environmental response was quantified for 315 species with mean and std. deviation of variables weighted for taxa abundance. The 25 species with the most numerous data points available were arranged according to quality class values detd. by variable weighted means. Many species were found in class 1 waters (best water quality) while few species occurred in class 4 and 5 waters. The same species often occurred in waters that indicated poor and good water quality. Nitrate-N was the variable that most often placed species in low quality classes, whereas both dissolved oxygen and PO4-P usually placed species in class 1. Different species of the same genus often have different optima. [on SciFinder (R)]