Semester of Graduation
Summer 2026
Degree Type
Dissertation/Thesis
Degree Name
Masters in Integrative Biology
Department
Department of Ecology, Evolution, and Organismal Biology
Committee Chair/First Advisor
Nicholas Green
Second Advisor
Troy Mutchler
Third Advisor
Jun Tu
Abstract
Urbanization and climate change are altering streamflow and land cover across the southeastern United States, threatening freshwater biodiversity in rivers already burdened by impoundments and habitat loss. I investigated how changes in streamflow and land cover might affect fish community biodiversity in the Etowah River watershed of North Georgia. By combining a dataset of fish collections from 1999 through 2019 with contemporaneous land use and daily streamflow, I was able to model fish community responses to urbanization and climate-driven hydrologic changes and then forecast fish community structure under multiple CMIP6 global climate models and greenhouse gas emissions scenarios (SSP2-4.5 and SSP5-8.5) through 2100. The analysis found that historical biodiversity metrics were strongly influenced by average streamflow and urban land cover. Although species richness responded negatively to urbanization, life history groups (defined by clusters of life history traits) responded differently to urban land cover. Biodiversity metrics were generally positively correlated with average streamflow. Streamflow was projected to increase consistently under both emissions scenarios, driving projected increases in most biodiversity metrics, including overall richness, diversity, and Etowah darter (Etheostoma etowahae) presence. However, one life-history group (non-guarding serial spawners) and the Cherokee darter (E. scotti) are projected to decline in abundance or likelihood of presence, driven by continued urbanization rather than climate-driven flow change. My results highlight the importance of direct human impacts and land use on aquatic biodiversity and suggest that conservation efforts in the Atlanta metropolitan watersheds should consider these effects while planning for climate change adaptation.