Wetland Losses Due to Row Crop Expansion in the Dakota Prairie Pothole Region

Agriculture is the greatest source of wetland loss in the Prairie Pothole Region of North and South Dakota (Dakota PPR). Demand for corn ethanol, expiration of agricultural conservation contracts, and increasing commodity prices may have stimulated alteration of wetlands for row crop production. The purpose of this study was to determine recent wetland-to-row-crop transition rates within the Dakota PPR, using GIS analysis to intersect the 2011 National Agricultural Statistics Service’s Cropland Data Layer (CDL) with wetlands mapped by the U.S. Fish & Wildlife Service’s National Wetlands Inventory (NWI) and the U.S. Geological Survey’s National Land Cover Database (NLCD). The NWI depicts wetlands as they existed in the 1980s, whereas the NLCD depicts wetlands as of 2001. On an annualized basis, the NWI wetland loss rate was 0.28 % (−5,203 ha/yr) and the NLCD wetland loss rate was 0.35 % (−6,223 ha/yr). Fewer losses occurred along the western and northern edges of the Dakota PPR, which are less conducive to row crops due to climate and topographic limitations. The map of apparent wetland losses generated by this study provides a means for monitoring and enforcement agencies to quickly identify potential violations of compliance with Swampbuster or other wetland regulations.