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2 BIOLOGICAL REPORT 90(3) +3 +2 +1 O.f N W cc U Q U. 0 z -' 0 J J 2 LEGEND ® PALUSTRINE OPEN WATER . PALUSTRINE FLAT '? ESTUARINE WETLAND 0 PALUSTRINE EMERGENT WETLAND ® PALUSTRINE SCRUB-SHRUB WETLAND PALUSTRINE FORESTED WETLAND Fig. 1. Wetlands gained and lost in the conterminous United States between the mid-1950's and the mid-1970's (from Tiner 1994 and Frayer et al. 1983). first, then minimization of impacts, and finally, com- pensation for unavoidable impacts. Wetland creation and restoration are often employed as mitigation for wetland loss, and while the success of such mitigation is often assumed, it is less often documented. If the success of such projects is not carefully evaluated in terms of wetland functions, wetland losses may con- tinue to occur despite creation and restoration efforts. A successful policy of no net loss of wetlands depends on project monitoring and success evaluation. It is often assumed that wetlands restored or cre- ated to replace those lost to construction, filling, drain- ing, or contamination are successfully constructed sys- tems that effectively duplicate the functional values and self-sustaining characteristics of the original (nat- ural) wetland. However, information gleaned from extensive review of existing literature (Golet 1986; Ischinger and Schneller-McDonald 1988; Kusler 1988; Larsen 1988; Quammen 1986; Tiner 1984) pertaining to wetland creation and restoration fails to support this assumption. The lack of consistent criteria for evaluating project success is also apparent from a review of the literature. Information needs pertaining to such evaluation in- clude (1) defining success, (2) defining project objec- tives, (3) modifying success criteria so that they can be applied to different wetland types in different regions, and (4) comparing restoration and creation and deter- mining whether each requires a separate set of criteria for success. Wetland restoration and creation can be complex endeavors; wetland creation is especially difficult be- cause of the complexities of creating the correct soil and hydrologic conditions. While a number of wetland res- toration or creation projects have been successful, at least in some aspects, others have failed outright or are non-functional. It is unclear from the literature whether created wetlands can functionally duplicate natural sys- tems and effectively replace wetland loss. Wetland creation is usually more difficult to achieve than wetland restoration. This is due mainly to the difficulty of creating a suitable, self-sustaining hydro- logic regime - the foundation on which any wetland is built. Some wetland types are more difficult to create or construct than others (e.g., bottomland hardwood wetlands vs. emergent freshwater marsh). Restoration success also varies among wetland types; some wet- lands can be restored relatively quickly if existing hy- drologic conditions are suitable (e.g., low salt marsh). Reasons for failure of wetland restoration and cre- ation projects include the following (Conservation Foundation 1988): • lack of clearly stated project goals WETLANDS GAINS