Term of Award

Spring 2023

Degree Name

Master of Science in Biology (M.S.)

Document Type and Release Option

Thesis (restricted to Georgia Southern)

Copyright Statement / License for Reuse

Digital Commons@Georgia Southern License

Department

Department of Biology

Committee Chair

Jose Checo Colon-Gaud

Committee Member 1

John Carroll

Committee Member 2

Ray Chandler

Abstract

The Southeastern U.S. has experienced record-breaking droughts since the 1980's. Climate models predict that droughts will become increasingly frequent and severe as temperatures and precipitation inputs continue to fluctuate within the region. Given the potential for change, many of the important functions that wetlands provide, and the aquatic organisms that facilitate these functions, will likely be impacted as wetland ecosystems become less stable. To understand the effects of climate-induced drought disturbances on wetlands of the southeastern US, this study examined leaf litter breakdown rates and macroinvertebrate community structure in permanently flooded (>365d) versus temporarily flooded (~60-90d) wetlands. To do so, a series of replicate ponds at the former USFWS Bo Ginn National Fish Hatchery in Jenkins County, GA were manipulated to simulate the effects of drought disturbance. Leaf litter bags were deployed in experimental ponds and allowed to be colonized by macroinvertebrates. I predicted that permanent wetlands would provide stable (i.e., less disturbed) conditions, supporting greater diversity in macroinvertebrate communities, and in doing so, greater diversity would yield faster turnover rates in leaf decomposition. Whereas macroinvertebrate communities in temporary wetlands would be less diverse as they would be exposed to harsher conditions, thus resulting in slower turnover rates of leaf decomposition. When assessed, permanent wetlands supported greater macroinvertebrate abundance and biomass than temporary wetlands. Leaf decomposition rates were consistently faster in permanent wetlands than temporary wetlands. However, temporary wetlands also supported diverse macroinvertebrate communities and functions, suggesting these habitats will be important sites of carbon turnover and harbors of biological diversity in the face of predicted drought disturbances.

Research Data and Supplementary Material

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