A LANDSCAPE-SCALE APPROACH TO WETLAND MITIGATION OF NON-POINT SOURCE AGRICULTURAL RUNOFF

This project will provide fundamental insights into the spatial and temporal variability in the mediation of nutrients and sediment runoff by GIWs, ultimately improving farm economics and enhancing environmental quality for farm communities. Ourlong-term goalis to provide the scientific foundation needed to prioritize the conservation and restoration of individual GIWs on agricultural lands to balance mitigation of non-point source runoff with agricultural productivity.To achieve this goal, we have the followingsupporting objectivesto characterize spatial and temporal variability in GIW function, extend our findings to management, and communicate with stakeholders about our findings:1.Spatial:Characterize nutrient content and form across the upland-to-wetland continuum.We will determine how water level and quality dynamics vary across a representative sample of GIWs to determine the range of variability in hydrologic and biogeochemical function. We will combine sediment fingerprinting with event-scale sediment yield modeling to determine how different soil and land use types contribute sediment to GIWs.This work will also refine parameters for the Universal Soil Loss Equation (USLE) and Modified Universal Soil Loss Equation (MUSLE), which are used to address Objective 2.2.Temporal:Investigate the trajectory of nutrient deposition during agricultural expansion.We will combine paleolimnological techniques with decadal-scale sediment yield modeling using USLE to quantitatively reconstruct soil and sediment biogeochemical dynamics throughout the historical agricultural expansion period.3.Integration:Develop a prioritization framework for conserving and/or restoring individual GIWs on marginal agricultural lands to protect water quality.We will develop conceptual models to prioritize individual GIWs for restoration and conservation. Our approach builds on an existing method that is popular for regional-scale wetland restoration planning and has been used extensively in the study region (Vellidis et al. 2003; Jang et al. 2013) by extending it to finer scales to promote continuity of restoration planning across scales. The models integrate information from Objectives 1 and 2, professional judgement, and general understanding of relevant ecological principles and processes to guide planning of wetland restoration and conservation.4.Outreach:Collaborate with stakeholders to understand the value of GIWs on agricultural lands.We will involve local stakeholders in research activities and integrate the project with agricultural sciences coursework at Auburn University.We will document this collaborative process by producing a video, "Discovering Isolated Wetlands," for wider distribution.