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STREAM FISH HABITAT SUITABILITY AND THE RISK OF POPULATION DECLINE
Rashleigh, B. STREAM FISH HABITAT SUITABILITY AND THE RISK OF POPULATION DECLINE. Presented at Science Forum 2003, Washington, DC, May 5-7, 2003.
The overall objective is to develop watershed modeling tools for the immediate client (CVI) and their stakeholders in the Mid-Atlantic Highlands. This research continues the contributions that REVA has made to the CVI toolset and adds modeling and decision support capabilities for more general use by managers. To facilitate the prediction and analysis of fish health issues by EPA Program and Regional Offices and other environmental agencies, process-based models that describe these processes will be implemented:
1. the expected trophic dynamics of the dominant fish species
2. the spawning and recruitment dynamics of the dominant fish species
3. the bioaccumulation of organic chemicals and metals in aquatic biota
4. how physical habitat and chemical water quality impact fish feeding, reproduction, survival, and migration
To facilitate the use and application of these models, graphical user interfaces (GUI), supporting databases, and libraries of management scenarios will also be developed. Models will be linkable to integrated water quality and hydrologic models that simulate habitat characteristics (e.g., water depth, current velocity, water temperature and sediment loadings) that determine the survival, reproduction, and recruitment of fish and aquatic invertebrates. Similar to what has been achieved in REVA, frameworks based on the biogeography of fish will be developed to apply these models spatially for regional assessments of important fish health issues.
Objectives of this task between FY03 and FY05:
To provide modeling and decision support capabilities for aquatic resources compatible with existing geographic information (GIS) frameworks to evaluate effectiveness (and ultimately cost-benefit) of restoration activities planned in Region 3, initially the Mid-Atlantic Highlands region. This includes the primary interests in evaluating riparian zone restoration (using Rosgen methods) and acid mine drainage remediation.
To develop methods that explicitly link process models and spatial analysis methods across spatial and temporal scales.
To identify knowledge and information gaps in the integration of REVA and process models that enable projections of future ecosystem state.
To create a new generation of quantitative environmental assessment tools that explicitly address issues of scale, are not restricted in extent of application, and enable efficient rescaling (both spatial and temporal).
This research supports long-term goals established in ORD's multi-year research plans for Both GPRA Goal 2 (Water Quality) and Goal 8.1.1 (Sound Science/Ecological Research). This research will provide the tools to assess and diagnose impairment in aquatic ecosystems and the sources of associated stressors and to forecast the ecological, economic and human health outcomes of alternative solutions. Central to this task (as described in Goal 8) is the development and demonstration of methods to the states, tribes and local managers to: (1) assess the condition of waterbodies in a scientifically-defensible and representative way while allowing for aggregation and assessment of trends at multiple scales, (2) diagnose cause and forecast future condition in a scientifically defensible fashion to more effectively protect and restore valued ecosystems, and (3) assess current and future ecological conditions, probable causes of impairments and management alternatives.
Over half of the streams in the Mid-Atlantic Highlands have fish communities that are in fair or poor condition, and the EPA concluded that physical habitat alteration represents the greatest potential stressor across this region. A quantitative method for relating habitat quality to biological endpoints is needed in order for managers and researchers to understand the link between this stressor and fish community condition. Here, a model of fish habitat suitability that was developed by the U.S. Fish and Wildlife Service is applied in this region. Longnose dace is used as an indicator species for the most sensitive component of the fish community. Habitat suitability for longnose dace is determined by stream depth, temperature, substrate type, and natural cover and shelter. Available stream data are used to calculate an overall measure of habitat suitability. The measure of habitat suitability is then incorporated into a stage-structured population dynamics model for longnose dace. It is assumed that habitat suitability affects the carrying capacity for fish in these streams. The longnose dace population model incorporates uncertainty to provide estimates of population size through time. The outcome of this work is a modeling tool that can forecast the risk of fish population decline, in response to habitat alteration, over various time frames. The general result from this work is important because it provides managers with a method to quantitatively incorporate biological endpoints into decision-making for TMDLs. Specific results for the Mid-Atlantic Highlands can allow managers, in particular the Canaan Valley Institute, an EPA partner, to evaluate the response of biological endpoints to stream management alternatives and restoration scenarios for streams of this region.