Date of Award





Earth and Space Science - Environmental Science Track


Earth & Space Science

First Advisor

William S. Birkhead


An ichthyological survey was conducted within the lower Piedmont and upper Coastal Plain physiographic regions of the middle Chattahoochee River drainage basin between August 1998 and September 2000. Sampling was conducted by Columbus State University (CSU) under contract to Columbus Water Works for the purpose of obtaining biological measurements of watershed health. Objectives of the survey were the establishment of a data baseline of IBI scores for this ecoregion and to ascertain if there was a correlation between the IBI score and human influence. The thesis to be tested is: 'Fish community IBI scores of different watersheds within the Middle Chattahoochee drainage basin will reflect varying degrees of anthropogenic impact on habitat quality.' Samples were taken twice per year during Spring and Fall over a time span of two years in order to obtain representative samples during periods of normal and low seasonal flow, respectively. Samples were obtained using backpack and boat-borne electroshocking equipment following standard protocol. Fish assemblages collected at stream sites were analyzed using scoring criteria for an Index of Biotic Integrity developed by Georgia Department of Natural Resources for wadeable streams in the Apalachicola drainage basins of the Piedmont Ecoregion of Georgia. A total of 7715 individuals of 48 species were collected from the tributary streams and a total of 8322 individuals of 43 species were collected from the mainstem of the Chattahoochee River during this survey. No correlation could be detected between IBI score and chemical water quality in the tributary streams. The IBI scores exhibited significant positive correlation with physical stream habitat features as measured using the Habitat Assessment Index during three of the four sampling seasons. The only land use feature that the IBI score appeared correlated with was urbanization, which exhibited significant negative correlation during the first two sampling seasons. Finally, the IBI scores of three of the streams appeared to be positively influenced by a period of prolonged drought in the Middle Chattahoochee drainage basin. Drought conditions may have reduced negative impacts on habitat quality that are reflected in IBI scores. The three streams that exhibited the greatest improvement in IBI score as the drought progressed were in watersheds with urban/suburban development that would be expected to suffer greater impact from storm-water runoff than streams in more rural areas. During the second two seasons, as the drought progressed, IBI scores no longer reflected a significant effect from urbanization. Additionally, streams with higher IBI scores exhibited low variability in their scores while streams with lower IBI scores exhibited highly variable scores. The conclusion was reached that fish community IBI scores are indicative of anthropogenic impacts to habitat quality with the caveat that climatic anomalies, such as drought, may lead to temporarily inflated IBI scores in the more impacted streams that do not accurately reflect true watershed health.