A spatial landscape scale approach for estimating erosion, water quantity, and quality in response to South Dakota grassland conversion

Abstract

AbstractConversion of grassland to cropland has been linked to many complex environmental challenges in natural resource systems. South Dakota is a mosaic of grasslands, wetlands, and cropland that has experienced tremendous land use change over the past 10 years and is expected to continue for the next 50 years. The rate of future conversion may vary greatly depending on economic, policy, and social factors. Land conversion influences cumulative erosion from arable soils which could impact hydrologic flow and water quality. Quantifying future changes for these three externalities is important to understand the possible long‐term consequences of grassland conversion. A system dynamics model was developed to address the dynamic complexity of these natural resource systems by capturing its structure and behavior and was able to adequately replicate historical changes in erosion, discharge, and total suspended solids from 1947 to 2012.Recommendations for resource managers Resource managers should apply this tool for problems that require quantitative assessment of environmental consequences to be coupled with economic, policy, and social factors that influence long‐term land‐use change decisions. The model can be used to evaluate alternative policies and indicate the magnitude of change for three critical environmental factors using different long‐term grassland conversion, climate, and tillage (conservation and conventional) patterns. Model output of four spatially explicit water‐catchments that span South Dakota from east to west: Big Sioux, James, Bad, and Belle Fourche rivers can be used to quantify differences between unique natural resource systems. The model is adequate for the purpose of generating forecast for future annual erosion (t·ha−1·year−1), discharge (million cubic meters), and total suspended solids (mg/L) under different potential future grassland conversion rates and should be leveraged by managers to gain insight into future landscape scale consequences of grassland conversion in South Dakota. Potential for additional natural resource applications.