Effects of channel stability on benthic macroinvertebrate communities in southeastern Louisiana Coastal Plain streams

Physical disturbance is common in streams and have been found to be important in structuring lotic communities.  Streams with different geomorphologic attributes vary in their ability to resist changes in channel structure and composition, which in turn influence the range of habitat conditions available to resident macroinvertebrate communities.  In this study, we sampled several streams with different geomorphologic characteristics to assess the relative importance of channel stability in determining benthic macroinvertebrate community composition.  Although within geographic proximity and affected by similar weather events, we have detected a gradient of channel stability among streams based on a Pfankuch stability index and differences in physicochemistry and primary production.  Macroinvertebrates have been collected in each stream, and we will relate macroinvertebrate community composition to stream characteristics with common factor analysis (stream characteristics) and MANOVA.  In addition to examining the extent of channel stability influence on macroinvertebrate community structure, results will also be used to quantify reference conditions for coastal plain streams in the Terrace Upland ecoregion in southeastern Louisiana.