Correspondence between aquatic ecoregions and the distribution of fish communities of eastern Oklahoma

I assessed fish community data collected by the Oklahoma Conservation Commission from 97 minimally impaired wadeable reference streams in eastern Oklahoma to determine whether existing aquatic ecoregions provide the best framework for spatial classification for the development of biological assessment methods and biocriteria. I used indirect ordination and classification to identify areas that support similar fish communities. A general correspondence was observed between fish assemblages and most ecoregions, although at least two ecoregions need to be split into subregions to adequately partition variance in key measures of biological integrity. Results from canonical correspondence analysis indicated that substrate size and habitat type were the primary physical habitat variables that influenced the fish species composition and community structure.