摘要：Our aim was to examine the nature of macroinvertebrate community variation across a set of streams in three drainage basins in Finland. We found that there were no clearly discrete community types, but rather macroinvertebrate communities varied continuously along environmental gradients. Local environmental factors and geographical location were strongly collinear and both were important in accounting for variation in macroinvertebrate community structure in the multivariate regression tree analysis and based on a combination of k-means clustering and discriminant analysis. We conclude (i) that geographical location and local environmental factors are strongly intertwined and both are associated with variation in macroinvertebrate communities across northern streams at the spatial scale of the three drainage basins studied; and (ii) that environmental assessment and conservation studies should not rely too much on delineating "community types", but rather acknowledge the continuous variation of stream macroinvertebrate communities.
