Separation in habitat use and phylogenetic influence on habitat use among fishes in diverse temperate stream communities

The investigation of habitat use and its relationship to phylogeny among co-occurring species provides knowledge of ecological and evolutionary parameters important for the structuring and maintenance of communities. Among communities of benthic, riffle dwelling stream fishes in the Duck River, TN, USA, we tested for interspecific separations in habitat use (i.e., based on flow velocity, substrate composition, depth, and spatial position of occurrence) to elucidate processes influential in maintaining community structure. Furthermore, we incorporated phylogeny to test for influence of evolutionary history on patterns of contemporary habitat use. Multivariate analyses recovered two significant species clusters among communities, suggesting that separations in habitat use occurred between groups of species rather than among all individual species. Phylogenetic relationships among species did not significantly correlate with species habitat use; however, we recovered patterns of displacement in habitat use among the most closely related taxa. Our results suggest that group separations in habitat use, and displacement in habitat use between close phylogenetic relatives, can help explain how communities are structured and maintained. These findings are important for understanding ecological community organization, and we demonstrate the value of examining contemporary ecological relationships in the light of evolutionary relationships.