Towards a National Evaluation of Compensatory Mitigation Sites: A Proposed Study Methodology

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Each year more than 40,000 acres of wetlands are restored, established, enhanced, and preserved to compensate for the approximately 20,000 acres of losses permitted through the federal wetlands regulatory program. Nationwide, an estimated $2.9 billion is spent annually on these compensatory mitigation projects. However, it is not clear whether this significant investment in compensation yields projects that are effectively replacing lost wetlands. State and regional studies on wetland compensatory mitigation suggest that a significant proportion of compensation sites are failing to meet administrative and ecological performance standards. In response, some studies have suggested that consolidating mitigation at fewer larger mitigation banks may help improve overall mitigation success; however, this assertion has never been rigorously tested. A national study is needed to comprehensively evaluate compensatory mitigation. Here we present a protocol, developed by a team of wetland experts, to assess the ecological outcomes of the three compensatory mitigation mechanisms – mitigation banking, inlieu fee mitigation, and permittee-responsible mitigation – in a manner that will enable comparisons of the three mechanisms nationwide. The design is also meant to help establish a protocol for the on-going national assessment of mitigation sites.