MEASURING THE RESPONSES OF MACROINVERTEBRATE COMMUNITIES TO WATER-POLLUTION - A COMPARISON OF MULTIVARIATE APPROACHES, BIOTIC AND DIVERSITYINDEXES

The responses of macroinvertebrate communities to pollution by sewage effluent in the River Trent system (UK) were investigated using a vari ety of multivariate approaches, biotic indices and diversity indices. It was found that multivariate analyses clearly illuminated the change of community structure along the pollution gradient. CY Dissimilarity Measure (CYD)-based Non-Metric Multidimensional Scaling (NMDS) appear ed to perform better than DCA and clustering. Species richness, the BM WP, BMWP-ASPT, the Chandler Score, Chandler-ASPT could detect the effe cts of major pollution. However, these indices showed varying sensitiv ity to different ranges of pollution, for example, Chandler-ASPT and B MWP-ASPT are more sensitive to the change in clean/slightly polluted r ange than in the moderate/very polluted range. The diversity indices w ere the least informative. The advantages and disadvantages of the var ious approaches were discussed.