Managing Critical Source Areas For Enhancing Ecosystem Services In Agricultural Landscapes

Ecosystem degradation especially deterioration in water quality and biological conditions in streams is often attributed to land use changes in terrestrial landscape over a range of spatial and temporal scales. Healthy ecosystems and streams have to be achieved by deliberately managing the land use changes in landscapes. For example, stormwater management that mitigates urbanization impacts on stream integrity has been largely implemented to limit and diminish the impacts of impervious cover. Regardless of how the riparian zones are defined, riparian restoration and management has been pervasive from the federal riparian management initiative to the municipal ordinance. However, impervious cover and riparian zones alone are likely incomplete surrogates for evaluating stream health. A comprehensive strategy that integrates the thorough understanding of human disturbances on in-stream response coupled across multiple landscape scales would be required to improve the biological integrity of stream ecosystems. The project explores the interrelationship between land use changes in landscape and the downstream water quality and biological degradation by incorporating new advances in hydrological science and technology. The project conducts field monitoring and watershed modeling across different physiographic regions, natural conditions and gradient in hydro-ecological sensitivity to understand how the fundamental physical and/or biogeochemical processes that are primarily governed by the variable source area hydrology control the traNational Science Foundation ormation, movement, and storage of water, nitrogen, and phosphorus in agricultural landscapes and develop scientifically defensible threshold values that differentiate landscape in terms of hydro-ecological sensitivity. The project also develops a set of land use indicators including the percentage of urban and agricultural lands and impervious cover in the hydro-ecologically sensitive areas that quantifies agricultural landscape changes and develop a regional landscape model that quantify the relationship between landscape changes and the losses in ecosystem services in term of downstream water quality degradation and aquatic health impairment. Through the landscape model, this project tests the hypotheses that the critical source areas in landscapes disproportionally contribute to ecosystem degradation and identify the threshold in land use intensity in terms of the presence of critical source areas in landscapes that lead to ecosystem degradation and therefore to provide the empirical evidence for natural resource protection and critical source area management. The project results support more targeting-oriented conservation efforts or precision conservation to improve the cost-effectiveness of the conservation efforts that manage the landscape to enhance ecosystem services.