Graduate Exit Seminar

Clarissa Bey will present her Graduate Exit Seminar at 10:00 a.m. in 333C Kottman Hall. Her presentation is Scale-dependent Environmental Influcences on Freshwater Mussel Assemblages in Big Darby Creek, Ohio.  

Freshwater mussels are considered to be the most imperiled group of animals in North America, yet the environmental factors that influence mussel assemblage structure and distribution are not fully resolved. The life cycle of freshwater mussels - whereby larvae are obligate ectoparasites on fishes and adults are benthic and sedentary - suggests that dispersal of mussels is linked to fish movement whereas growth and reproduction might be expected to be controlled by broad-scale environmental processes, thus adding complexity to mussel-environment relationships. A more thorough understanding of the responses of linked stream mussel-fish assemblages to scale-dependent environmental characteristics is expected to improve both current ecological understanding as well as inform conservation and management. I investigated the relationships between (1) stream hydrogeomorphology and mussel and darter assemblages and (2) the relative influences of local- and catchment (i.e., landscape)-scale environmental factors on mussel assemblages at 20 reaches in Big Darby Creek, Ohio. Overall, my results suggest that local-scale (i.e., reach level) environmental characteristics can be valuable in predicting mussel assemblage distribution and structure. Whereas coarse-level geomorphic classifications may be meaningful for fish, they appear to be less so for mussels. Finer-resolution quantitative geomorphic variables provided substantially more information for both fish and mussel assemblages. However, findings from my thesis also indicate that a singular focus on local-scale environmental variables may underestimate the importance of broad-scale processes (e.g., dispersal, catchment-scale hydrology, land use and land cover). Collectively, my results show a strong influence of scale-dependent environmental factors on freshwater mussel assemblages, suggesting that conservation and management schemes will benefit from approaches that combine reach- and catchment-level assessments, as well as the dynamics of cohabitating fish assemblages.