Compliance with Regulatory Performance Standards in Wetland Mitigation Banks

The U.S. Army Corps of Engineers, under Sect. 404 of the Clean Water Act, requires that development projects that discharge fill to Waters of the United States, including wetlands, must provide compensation through the wetland mitigation process. The Army Corps prefers that compensation is provided through purchase of credits from wetland mitigation banks, which are large wetland restoration projects constructed by third-party bank sponsors for the purpose of selling wetland mitigation credits for a profit. We assessed the regulatory outcomes of banks in the Chicago, USA, region, which possesses one of the country’s most well-developed banking markets. We used data from 22 wetland mitigation banks in the Chicago District of the Army Corps to determine how successful banks were at meeting mandatory ecological performance standards by the end of a required monitoring period. We found that banks typically struggled to meet performance standards limiting dominance by non-native species, although they often met standards related to native species richness and dominance. Perennial plant species richness and floristic quality metrics generally increased during the banks’ five-year monitoring period. The results of this study can serve as a useful resource for the continued adaptation and improvement of performance standards and mitigation assessment.