Comparing modified biological monitoring working party score system and several biological indices based on macroinvertebrates for water-quality assessment

Macroinvertebrate communities from the lower Nysa Kłodzka River catchment, southern Poland, were analyzed seasonally, in order to assess changes in their composition and structure, in relation to water quality. Two major groups of sites, differing in both morphological structure and taxonomical composition by cluster analysis, were identified within the catchment area. Wider and deeper sites, located along the Nysa Kłodzka River, were associated with the dominance of Chironomidae. Sites assigned along tributaries were characterized by a diversified structure of dominant taxa, including Oligochaeta, Hirudinea, Crustacea, Trichoptera, Ephemeroptera and Diptera. The performance of the modified procedure, named BMWP(PL) index, in accurately classifying 26 sites has been assessed through comparison with saprobic, diversity and biotic indices as well as chemical data. Due to diversified taxa richness and the presence or absence of specific indicator groups, values of the BMWP(PL) index varied from 27 to 93, and were correlated with the other biological indices and chemical variables. It has been stated that there is strong potential for application of the BMWP(PL) system in Poland, although some further testing is recommended.