PYGANODON GRANDIS DOMINATES MUSSEL ASSEMBLAGES IN NORTHERN PRAIRIE POTHOLE LAKES AND RESERVOIRS
Native freshwater mussels (Family: Unionidae) have been described as the most imperiled group of freshwater animals on Earth. However, few studies have documented mussel occurrence and distribution from northern prairie lakes and reservoirs. We conducted the first survey of South Dakota prairie lakes and reservoirs to evaluate species occurrence and relative abundance. Two person-hour timed searches were conducted in 116 randomly selected lakes and reservoirs stratified by major river basin. Seven species of Unionidae and one species each of Dreissenidae and Corbiculidae were recorded from our survey. Pyganodon grandis comprised 80% (1,770 shells) of total species abundance across all sites and occurred within 38% of surveyed lakes. There were a large number of live P. grandis in reservoirs (45%) compared to natural lakes (27%). Frequency of P. grandis among major river basins ranged from 0-58%. P. grandis was both more common and size distribution larger from reservoirs versus natural lakes. Survey results suggest that northern prairie basins currently support only a few species of Unionidae, with assemblages dominated by the generalist P. grandis. Current efforts focus on P. grandis age and growth variation as a function of lake trophic status.
Katherine M. Wollman (Primary Presenter/Author), South Dakota State University, firstname.lastname@example.org;
Nels H. Troelstrup, Jr. (Co-Presenter/Co-Author), South Dakota State University Department of Natural Resource Management, email@example.com;