Environmental influences on macroinvertebrate assemblages in headwater streams of northeastern Ohio

We determined composition and trophic structure of macroinvertebrate assemblages, and also examined how environmental factors, such as riparian forest, aquatic habitat, and vertebrate predators, influenced these assemblages in relatively undisturbed headwater streams of northeastern Ohio. Using canonical correspondence analysis, we examined the relationships between macroinvertebrate assemblages, both compositional and trophic structure, and the environment. Ordination analyses showed a distinct separation of upstream and downstream macroinvertebrate faunas, while variance partitioning suggested that this may be because of the strong effects that predatory fishes and salamanders had in upstream areas. Aquatic habitat may be a strong determinant of macroinvertebrate composition and structure in these headwater streams, though this may be a reflection of site fidelity. Riparian forest habitat also explained a large portion of variation in macroinvertebrate functional feeding guild structure, emphasizing the connection between terrestrial and aquatic ecosystems in these headwater stream systems.