Semester of Graduation
Summer 2026
Degree
Master of Science (MS)
Department
Renewable Natural Resources
Document Type
Thesis
Abstract
Understanding the distributional patterns of organisms and the consequential ecosystem functions mediated by those organisms is a fundamental goal of ecology. Freshwater mussels (hereafter mussels) are a diverse group of filter-feeding bivalves with various adaptations to a large range of environmental conditions. Mussels can form high biomass aggregations and create biogeochemical hotspots where high rates of nutrient cycling can alleviate nutrient limitation that promotes biological diversity. However, mussels are a highly imperiled fauna with loss of species and precipitous declines in abundance occurring in recent decades. Thus, the risk of mussel-mediated ecosystem functions being lost is heightened. Investigating how species’ functional traits are distributed and how associated functional effect traits influence ecosystem processes, like nutrient cycling, can improve scientific understanding of mussel-habitat associations and consequential influences that species have on their ecosystems. Here, I evaluated the relationship between habitat variability, assemblage structure and life history strategy composition of freshwater mussel assemblages in the Pearl River, a southeastern coastal plain watershed. At a subset of sites, I quantified interspecific differences in nutrient cycling traits and estimated mussel biomass to understand how variation in mussel assemblage structure contributes to fluxes and stoichiometry of locally available nutrients. Mussel species richness increased with watershed area, and species characterized by slow growth, late maturation and long lifespans were negatively associated with areas that experienced more low flows and more flow reversals. Species better adapted to colonizing disturbed environments were associated with high salinity and were found in higher abundances downstream where saltwater intrusion and dynamic backwater habitats are common. Species-specific nutrient cycling trait variation coupled with differences in biomass distribution and assemblage structure altered the ratio of dissolved nitrogen and phosphorus released by mussel beds. However, when scaled to the ecosystem-level mussel nutrient excretion never exceeded background concentrations, suggesting mussel effects in this system are concentrated at fine spatial scales. Altogether, this research addresses fundamental questions about mussel-habitat associations and consequential nutrient cycling effects that can inform freshwater mussel conservation and stream ecosystem management.
Date
7-30-2026
Recommended Citation
Kuczek, Madison P., "Hydrologic and Biogeochemical Variability in Streams Influences Assemblage Structure and Ecosystem Function of Freshwater Mussels" (2026). LSU Master's Theses. 6435.
https://repository.lsu.edu/gradschool_theses/6435
Committee Chair
Hopper, Garrett W.
LSU Acknowledgement
1
LSU Accessibility Acknowledgment
1
Included in
Biochemistry Commons, Biodiversity Commons, Biogeochemistry Commons, Hydrology Commons, Natural Resources and Conservation Commons, Natural Resources Management and Policy Commons, Other Ecology and Evolutionary Biology Commons, Population Biology Commons