Term of Award

Summer 2024

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

J. Checo Colón-Gaud

Committee Member 1

Stephen Vives

Committee Member 2

Aaron Schrey

Abstract

The southeastern United States is a hotspot for aquatic biodiversity; yet this region is also considered vulnerable to climate and land–use changes. The Ogeechee River is an unimpeded blackwater river in Georgia that drains into the Atlantic Ocean and a unique ecosystem due to the preservation of its natural state; Historically, research conducted in the river establishes a baseline for long-term ecological studies. The aim of this study is to compare aquatic macroinvertebrate and fish community composition data collected in 2014 to 2017 to a recently collected dataset from 2023 and document temporal changes. Water quality monitoring was performed throughout the year either daily or monthly dependent upon site. Aquatic macroinvertebrates and fishes were collected seasonally using standardized methods. Macroinvertebrates were assessed using rapid bioassessment protocols (RBP), permutational multivariate analysis of variance (PERMANOVA), and non–metric multidimensional scaling (NMDS) plots based on abundance and functional traits. Fishes were assessed using the index of biotic integrity (IBI), PERMANOVA, and NMDS based on abundance and trophic characteristics. Macroinvertebrate and fish communities improved in RBP and IBI scores, respectively in 2023 compared to 2014–2017. Macroinvertebrate communities differed across years and seasons, including differences between seasonal communities within a single year. Macroinvertebrate relative abundance appears to be influenced by seasonal flood pulse patterns. Site-specific macroinvertebrate communities sampled in 2023 were similar within the community; however, the 2023 communities were different from the historical dataset. Fish communities differed across sampling years with partial overlap in relative abundances between sites. The community abundance and feeding guild abundance differed in community composition in 2014 samples compared to all other years. The results from this study emphasize the importance of community analysis over time. Long-term datasets like the one generated in this study can provide meaningful insights for conservation scientists.

OCLC Number

1446519450

Research Data and Supplementary Material

No

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