| Summary: | Water chemistry, habitat quality, and channel stability interact to influence a streams biological integrity. The goal of this project was to assess how channel stability, together with other physicochemical stream measurements, are associated with the structure and abundance of resident macroinvertebrate communities. I recorded multiple physicochemical parameters and calculated a Pfankuch habitat stability index monthly for a year at potential reference streams in southeastern Louisiana. I assessed the relationships of channels stability with measured physicochemical parameters with multiple regression and principle components analysis. Mixed model multivariate analysis of variance was used to determine associations of habitat characteristics with resident macroinvertebrate genera and communities.
In the September woody debris sample, macroinvertebrate abundance was generally determined by habitat factors that describe stream metabolism and woody debris habitat, in the May woody debris sample, abundances of xylophilic macroinvertebrates appeared to be more associated with geomorphologic components of a stream rather than stream productivity. The PSI was associated with multiple habitat variables, and variability in channel stability between streams was found to affect macroinvertebrate genera and community abundances in both seasons regardless of stream size or stream productivity. Because of the high correlations between the PSI, other habitat variables, and macroinvertebrate abundance, I believe the PSI should be used in future studies that focus on developing a biotic index in low gradient Louisiana streams. Integrating biological monitoring, more precise habitat measurements, and current physicochemical monitoring protocols will result in managers having more tools to evaluate stream degradation and protect Louisianas waterways.
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