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EFFECTS OF HABITAT DEGRADATION ON BIOLOGICAL ENDPOINTS IN THE SOUTH FORK BROAD RIVER BASIN, GEORGIA
Citation:
Rashleigh, B. EFFECTS OF HABITAT DEGRADATION ON BIOLOGICAL ENDPOINTS IN THE SOUTH FORK BROAD RIVER BASIN, GEORGIA. Presented at Georgia Water Resources Conference, Athens, GA, March 26-27, 2001.
Impact/Purpose:
This research project sets out to design and conduct an assessment of the long-term ecological consequences of alternative 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 BASE analysis to identify key research and data needs for address, to estimate timing, resource needs, etc., 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 BASE and other 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 of the Albemarle-Pamlico Basin.
Description:
Many of the streams of the lower Piedmont ecoregion in Georgia have been negatively impacted to some degree by habitat degradation due primarily to sedimentation. The South Fork of the Broad River watershed has been designated as sediment impacted under Section 303(d) of the Clean Water Act. A comprehensive field monitoring program has been established for the South Fork watershed including the development of relationships of sedimentation and biotic endpoints. Biotic endpoints are recognized as an important indicators of this degradation. In this assessment constrained ordination is used to examine the relation of fish and benthic macroinvertebrate sample data to selected habitat measures taken at 13 sites in and adjacent to the South Fork Broad river basin. Habitat degradation is reflected in benthic macroinvertebrate communities as a decrease in the Clingers/Burrowers ratio, as well as an increase in the abundance of Ephemeroptera and Odonata. Habitat degradation is reflected in fish communities as a increase in sunfish and a shift in the composition of minnow species. Both fish and benthic macroinvertebrates appear to be influenced primarily by natural gradients, and secondarily by habitat quality. A better understanding of the role of sedimentation and habitat in structuring communities improves our ability to use these communities as measurement endpoints in watershed assessment.