Long term changes in benthic community structure in the English Midlands

Benthic community structure varies through time partly due to abiotic environmental changes and the understanding of such patterns is a major goal of ecological research. However, long term river research studies, especially those with a spatial component, are still rare. We collated a dataset of climatic, chemical and biological monitoring data from 1975-2000 for 9 sites in the River Dove catchment, a tributary of the Trent in the English Midlands. Macroinvertebrate samples were harmonised as abundance classes of families. Climate data consisted of water and air temperature, precipitation and river flow, we also included 10 water quality parameters (e.g. Oxygen, pH, organic and inorganic nutrients and metal concentrations). The aim of the analyses was to understand community trends and compare these with the abiotic data. A multivariate principal components analysis on the abiotic data allowed the identification of major drivers of variability, chiefly temperature, flow and N-NO₃. A partial CCA on the biological samples showed that climatic variation (mainly temperature and flow) accounted for a significant part of the community variance, while water quality changes only for a restricted share. Preliminary bioindicators of these climate change related parameters were thus derived.