Term of Award

Summer 2019

Degree Name

Master of Science in Biology (M.S.)

Document Type and Release Option

Thesis (open access)

Copyright Statement / License for Reuse

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Department

Department of Biology

Committee Chair

Checo Colon-Gaud

Committee Member 1

RAY CHANDLER

Committee Member 2

LANCE DURDEN

Committee Member 3

KERRIE SENDALL

Committee Member 3 Email

ksendall@georgiasouthern.edu

Abstract

The Intergovernmental Panel for Climate Change (IPCC) predicts a rise in temperatures and changes to precipitation patterns for the 21st century. These changes are expected to lead to a higher frequency of extreme events such as drought and floods which lead to the alteration of the hydrology, communities, and processes of freshwater ecosystems. Leaf litter decomposition in stream ecosystems is an important component of the energy and nutrient cycle representing a food source for aquatic organisms. This has made it a tool for assessing long term responses to disturbance due to changes in the assemblage of macroinvertebrates that colonize leaf packs. My objective is to use long-term data to evaluate 5 years of leaf litter decomposition data at the Ogeechee River from 2013 through 2017 after a 3-year drought period (2010 - 2012) to assess the leaf decomposition process and the macroinvertebrate community associated with it. We predicted that disturbances due to climate variability, specifically drought and flood disturbances, will have an impact in the process and that factors such as temperature, discharge and potentially the shredder functional feeding group will drive these changes. Additionally, we predicted these types of disturbances will impact macroinvertebrate abundance and richness negatively. This study reveals changes in the rate of decomposition in a post-drought in 2013 and the subsequent years that are explained by fluctuations in temperature, discharge and potentially shredders. Additionally, we detected a shift in the species composition after the post-drought year into a more stable period alluding to a lag effect in species richness. In conclusion, we can predict an increase in decomposition rates during disturbance events, especially drought as well as a decrease in both abundance and richness.

Research Data and Supplementary Material

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