Implications of a Hierarchical Relationship Among Channel Form, Instream Habitat, and Stream Communities for Restoration of Channelized Streams

Abstract

Hierarchy theory provides a conceptual framework for understanding the influence of differently scaled processes on the structure of stream communities. Channel form, instream habitat, and stream communities appear to be hierarchically related, but the strength of the relationships among all components of this hypothesized hierarchy have not been examined. We sampled channel form, instream habitat, fishes, and macroinvertebrates in a channelized stream in Mississippi and Alabama to examine the hypothesis that a hierarchical relationship exists among channel form, instream habitat, and stream communities. Instream habitat, fishes, and macroinvertebrates were sampled in May, July, and September 2000. Measurements of channel form were obtained in July 2000. Mantel tests, multiple regressions, and correlation analyses were used to assess strength of the relationships among channel form, instream habitat, and stream communities. Positive correlations were observed between channel form and instream habitat, and correlations observed between these factors were the greatest observed in our study. Overall, fish and macroinvertebrate communities exhibited stronger relationships with instream habitat than with channel form. Species richness, evenness, and abundance tended to exhibit greater correlations with instream habitat, while species composition had greater correlations with channel form. We concluded that channel form, instream habitat, and stream communities were hierarchically related.