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result. In these cases, a pre-disturbance condition may not represent the best solution, when the objective is to maximize an ecosystem service, function, or aesthetic. Rather than focus on restoring to some primeval state, a more profitable approach would be to accept that ecosystems are dynamic and focus on repairing damaged systems to the extent possible (Hobbs and Harris 2001). The Carbon Copy myth prevails in extractive resource industries, such as forestry and mining, and its foundations are used as arguments to justify access to resources in undisturbed environments- the beliefbeing that these systems will return to their previous state after disturbance. Although few ecologists pretend that the more destructive forms of mining can be fully restored, the belief in this ability is promoted by those backing the extraction industries. Despite limited success, the Carbon Copy myth has resurged in the USA in the form of the "No Net Loss" paradigm of wetland protection policy and mitigation (Zedler 1996), which assumes that created or restored wetlands provide equivalent ecological services, function, and value as those destroyed. Although success stories exist, many now consider the assumptions invalid because few created or restored wetlands have achieved structure or function equivalent to existing wetlands (Zedler and Callaway 1999, National Research Council 2001, Seabloom and van der Valk 2003), and natural wetlands continue to disappear without equivalent replacement (Whigham 1999). An alternative to creating a carbon copy of species complement is to create a system equivalent in function to the pre-disturbance state. Restored systems can be functionally superior to pre- disturbance systems, as in the case of wetlands engineered for nutrient removal (e.g., Peterson 1998). The growing field of ecological engineering is rich with examples of such enhanced systems (Ansola et al. 1995, Kadlec and Knight 1996, Knowlton et al. 2002, Kangas 2003), and will become ever more important to society as we continue to degrade natural systems. Functional replacement could be more easily accomplished than replacement of taxonomic composition because of the shared ecological function of many species (Stanturf et al. 2001). The danger in this approach is that some functions may be enhanced yet more subtle functions (e.g., species' habitats) or indirect interactions (e.g., heightened predation due to habitat differences) may suffer. Questions that remain include the resilience of functional Ecology and Society 10(1): 19 J/ htto:/ /www.ecolol!.Vandsocietv.orl!/voII0/issl/artI9/ replacements to disturbances and their acceptability to society. The heightened public awareness of invasive species modifying ecosystems and the potentially foreign look of a functional replacement may be socially unpalatable. TIlE MYTH OF TIlE FIELD OF DREAMS The Field of Dreams stems from the notion that all one needs is the physical structure for a particular ecosystem, and biotic composition and function will self-assemble-if you build it, they will come. Similarly, restoration of a process, such as ftre or hydrologic regime, is expected to re-create pre- disturbance structure. Although re-creating the physical template and drivers are a necessary ftrst step, it is rarely a final step and sometimes a misstep (e.g., Smith 1997). A fundamental assumption of this myth is that the community and ecosystem assembly process follow a repeatable trajectory, and uncertainty is implicitly ignored. Although there are some encouraging generalizations emerging about community assembly (Christensen and Peet 1984, Drake 1990, Keddy 1999), community assembly is in many ways reminiscent of Rudyard Kipling's (1902) Just So Stories: communities are historically contingent products (Parker 1997), and much uncertainty still exists given the influences of initial conditions (Grace 1987) and stochastic or neutral assembly (Hubbell 2001). Failure to accept uncertainty and the dynamic nature of community assembly can lead to the traps of the Carbon Copy myth. The Field of Dreams approach is common in both wetland and stream restoration, where emphasis is often on re-creating physical attributes with little attention paid to biotic responses. For example, the Rosgen approach (Rosgen 1994, 1998) is probably the most widely used stream restoration method in North America, but it deals almost exclusively with geomorphic attributes of stream channels. Restoration goals in systems such as urban watersheds often involve preventing streambed erosion and destruction of buried utilities, such as sewer and water lines. Although stabilization of the stream channel is quite important, stopping at a geomorphic end point is similar to ensuring that mining excavations in terrestrial landscapes are filled after a job is completed, and then not proceeding with revegetation. Similar examples exist for wetland restorations (van der Valk 1998), where the concept of self-design (Mitsch and