Ecological issues in wetland mitigation: An introduction to the forum

Wetland mitigation projects are changing the nation's landscapes, with habitat in one area being created or restored to compensate for damages in another. Ecologists are beginning to document substantial differences between what is lost and gained in the process, and the balance sheet often comes up short. Of great concern is whether either wetland area or wetland functions are sustained by such trades. The following papers comprise a forum of responses to mitigation policies and projects. The authors are scientists who have conducted research on mitigation sites, followed mitigation projects, and/or reviewed literature on the subject. This introductory paper defines mitigation in the regulatory context; identifies ecological issues under four headings relative to our ability to create specific ecosystems at will: predictability, structure and function, limiting factors, and landscape issues; and points out the declining status of wetlands and their nationally recognized value. The subsequent six forum papers are: Simenstad and Them's long-term performance evaluation of a constructed tidal wetland, Bedford's discussion of hydrologic equivalence for freshwater wetland mitigation, Brinson's advice on reference wetlands, Mitsch and Wilson's reflections on how to improve functioning of mitigation wetlands, Zedler's call for regional mitigation planning in southern California, and Race and Fonseca's long-term perspective on mitigation policy.