EVALUATING THE DISTRIBUTION OF LARGE WOOD AND ITS IMPACT ON FISH COMMUNITY COMPOSITION IN THE UPPER MISSISSIPPI RIVER
Large wood is geomorphically and ecologically important in streams and rivers and is often used for restoration. However, we know little about its distribution and ecological role in great rivers. Our study sought to 1) understand the spatial distribution of large wood in the Upper Mississippi River (UMR) as it relates to river hydrogeomorphology and 2) characterize the relationship between wood and fish community composition across riverine habitats. We analyzed a long-term dataset of wood occurrence and fish assemblages in three reaches of the UMR using random forest and mixed-effects models and t-tests. We found strong relationships between wood presence and aquatic habitat type, water depth, and wing dam or revetment presence--indicating that wood transport- and source-related variables, as well as river infrastructure, are important to understanding wood dynamics in great rivers. Large wood presence was associated with significantly higher fish species abundance, richness, and diversity, although this varied across habitats. Of all groups, Centrarchids (sunfish family) showed strongest preference for wood. Our results suggest large wood as a useful restoration tool in UMR fish communities, but hydrogeomorphic factors should be considered when evaluating its effectiveness and longevity.
Serenity Budd (Co-Presenter/Co-Author), Vassar College, email@example.com;
Kaija Gahm (Primary Presenter/Author), Yale University , firstname.lastname@example.org;