Restoration Outcomes and Reporting: An Assessment of Wetland Area Gains in Wisconsin, USA

Abstract

Billions of dollars have been spent to restore wetlands throughout the conterminous United States, leading to gains in wetland area nationwide. However, knowledge regarding the impact of these additions is limited, in part due to the lack of a centralized restoration database, varying definitions of restoration, and shifting protocols amongst restoration initiatives. This study used high-resolution photography to evaluate 430 wetland restoration projects in Wisconsin, US between 2003 and 2008. Aerial photo-interpretation and geospatial analysis were used to determine pre- and post-project status of wetland extent and habitat type(s). Wetland extent was mapped within project boundaries and wetland area gains were identified. Wetlands were classified by cover type and hydrology to record reestablished habitats, as well as document the prevailing land use setting of the project area and compare these results to data reported by the state. The majority of wetland area gains were classified as seasonally flooded emergent marshes, and restoration sites were primarily located within agricultural settings. We found 39% of wetland area gains reported by the Wisconsin Department of Natural Resources (WDNR) agreed with our geospatially derived data. Actual reestablished wetland area was 61% less than the reported reestablished area. These results are valuable for documenting discrepancies between restoration accomplishment reporting and change in wetland area observed, and understanding current trends in reestablishment, including habitat types, hydrologic regimes, and land use settings. These results are beneficial to resource managers by providing insight into restoration shortcomings and the over-reporting that can occur when GIS tracking is not employed.