Benthic macroinvertebrate assemblages in north Swedish streams environmental relationships -Ecography 17 9-16 An analysis of the relationships between lotic macroinvertebrates and environmental vanables was earned out on matenal from 60 nffle sites in streams in northern Sweden The approach involved the use of TWINSPAN classification and canonical correspondence analysis on presence/absence data from two seasons (spnng and autumn) Variables most strongly associated with distribution patterns of assemblages were drainage area, elevation, water quality m terms of alkalinity, colour and phosphate and the presence of macrophytes The significance of affinities of different species to these vanables are discussed The eight clusters resulting from the TWINSPAN analysis could biologically be interpreted as classes of taxa related to stream size, chemical conditions and algae A multiple regression analysis for predicting species nchness using three independent vanables, viz drainage area amount or organic matter, and discharge was constructed The results of the study could be used as a starting point for further work on the community organization of benthic stream assemblages