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SIMULATION COASTAL PLAIN STREAM FISH COMMUNITY RESPONSE TO NONPOINT SOURCE POLLUTION USING LINKED HYDROLOGIC-ECOLOGICAL MODELS
Citation:
Rashleigh, B AND J M. Johnston. SIMULATION COASTAL PLAIN STREAM FISH COMMUNITY RESPONSE TO NONPOINT SOURCE POLLUTION USING LINKED HYDROLOGIC-ECOLOGICAL MODELS. Presented at Ecological Society of America Meeting, Madison, WI, August 5-10, 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:
Nonpoint source pollution is the primary stress in many streams. Characteristic declines in stream fish communities are recognized in streams influenced by nonpoint source pollution, but the processes by which these declines occur are not well understood. Here, predicted time series of flow, sediment, nutrients, and temperature from the HSPF watershed model were used as input to the Aquatox ecological model to simulate effects of nonpoint source stressors on fish assemblages. The models were calibrated to Contentnea Creek in the coastal plain of North Carolina. Stream fish assemblages were most sensitive to changes in flow and temperature, and less sensitive to changes in sediment and nutrient loading. Increased flow lead to increased population sizes for algae and insects but decreased settling of detritus, which reduced food available to omnivores. Increased temperature altered seasonal abundance patterns of all taxa. Linked hydrologic-ecological models are useful for integrating multiple stresses with ecological interactions, assessing the response of stream fish communities, and projecting the outcomes of future landuse scenarios.