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BEYOND THE INDICES: RELATIONS OF HABITAT AND FISH CHARACTERISTICS IN THE GEORGIA PIEDMONT
Citation:
Rashleigh, B AND J. G. Kennen. BEYOND THE INDICES: RELATIONS OF HABITAT AND FISH CHARACTERISTICS IN THE GEORGIA PIEDMONT. Presented at Georgia Water Resources Conference, Athens, GA, April 23-24, 2003.
Impact/Purpose:
This research project sets out to design and conduct an assessment of the long-term ecological consequences of alternative watershed management choices. As the first project to be done at this scale using predictive ecological endpoints, we will seek to identify the appropriate components of such an analysis. We will use experience gained in the conduct of this analysis to identify key research and data needs for future analyses. We will extend this analysis beyond previous and ongoing studies in two ways: by incorporating biological endpoints, primarily properties of fish communities, and by introducing the concept of sustainability of ecological state under future scenarios contrasted with the present state of those same ecological resources. Requirements that are identified during the course of this study will permit the recommendation of specific capabilities that should be incorporated in a general modeling system currently under development to support environmental assessments. Finally, the analysis is intended to be of value for establishing environmental management choices that will be beneficial and those that would be detrimental to the sustainability of ecological resources. Specific objectives are listed below:
1. Develop watershed-based modeling systems to forecast the effectiveness of alternative management plans in meeting sediment-related, nutrient-related, pathogen-related, and toxics-related criteria and standards, and biologically-based criteria and standards; and
2. Develop and maintain a comprehensive technical support capability that directly links environmental TMDL exposure research activities and products for the EPA Office of Water, EPA Regional Offices, and the States to be used for implementation of policy, regulatory development, remediation, and enforcement needs.
Description:
The Georgia Department of Natural Resources has conducted biological sampling at 180 stream sites in the Georgia Piedmont (1998-99) and recorded several trophic and abundance characteristics of the fish assemblages and habitat at each site. These characteristics were combined to form an index that provides a screening tool for multiple sites across the Piedmont. In this analysis we focus at the level of the individual characteristics to gain additional insight about ecological variability and the dominant environmental gradients across sites sampled. Data were stratified to control for variation associated with basin area, which resulted in a subset of 88 sites that ranged in size from 8 to 39 km2. Principal Components Analysis (PCA) indicated that important patterns in fish data were related to the number of benthic invertivore, cyprinid, and simple lithophilic species; and pioneering vs. sunfish species. In addition, PCA indicated that habitat variability was related to riffle amount, sediment deposition and embeddedness, and bank stability, and stream width and depth. Multiple regression indicated that the number of benthic invertivore, cyprinid, and lithophilic species appeared to be primarily associated with substrate characteristics. These results can be used to guide protection and management activities in the Georgia Piedmont, and support restoration efforts of impaired streams in the state.