Invasive species as driving factors for the structure of benthic communities in Lake Constance, Germany.

The composition of benthic macroinvertebrate communities is influenced by a variety of factors, including the introduction of invasive species. However, only few analyses of factors influencing benthic community structure exist, especially those including invasive species. Our aim was to examine the importance of biotic factors on spatial and temporal variations in the benthic community within one system (Lake Constance, Germany). We examined the dependence of benthic community structure on invasive species by non-metric multidimensional scaling and distance-based redundancy analysis based on Bray-Curtis similarities. The three significant biotic factors explained 40% of the community variability. The mayfly Centroptilum luteolum and the snail Potamopyrgus antipodarum were positively associated with the amount of Chara, whereas some caddisfly taxa and Chironomidae were positively associated with the density of Dreissena polymorpha, which is a pattern most likely caused by their different habitat preferences. Several benthic taxa especially indigenous gammarids and Asellus aquaticus tended to decline with increased densities of the invasive amphipod Dikerogammarus villosus. Furthermore, density of D. villosus explained 26% of the benthic variability, demonstrating the strong impact of this species. Overall, our study demonstrates the large impact of invasive species on the composition of benthic macroinvertebrates. [ABSTRACT FROM AUTHOR]