Coastal Services Center

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For the Expert: National Review of Innovative and Successful Coastal Habitat Restoration

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< Monitoring | Dissemination of Information >

Adaptive Management

Because significant uncertainty exists on the effectiveness of habitat restoration, more and more projects are being designed and implemented in an adaptive management framework. Since 1995, the Corps of Engineers has directed that ecosystem restoration be done according to the principles of adaptive management to better ensure attainment of project goals and planning objectives (USACE 1995). A simple definition of adaptive management is "learning by doing" (Walters 1986). More formally, uncertainties about a project are acknowledged in the planning phase and steps are taken to deal with these uncertainties. These measures may include incremental project implementation, experimental studies in subareas of the restoration site, projects run in parallel that differ in one or more conditions, and implementation of full projects with the plan to evaluate the effectiveness of a restoration technique. Each of these techniques requires a project be monitored over time. This is done to assess the success or failure of different restoration techniques and determine what remedial action might be required if a restoration effort is not achieving project goals.

Some very large projects, such as the restoration of the Florida Everglades and the CWPPRA program in Louisiana, have embraced the adaptive management approach. The Everglades program has not been implemented as yet, but planners are adapting project designs using results of extensive modeling studies of hydrology to guide restoration planning. The program will use feedback from an extensive, long-term monitoring program to guide restoration, as well as to correct their conceptual model of the system.

The tidal marsh restoration conducted in Louisiana is employing numerous methods (e.g., water diversions using pumping stations, beneficial use of dredged material for marsh creation, and terracing) to restore the Mississippi River deltaic marshes (Louisiana Coastal Wetlands Conservation and Restoration Task Force and Wetlands Conservation and Restoration Authority 1998). The program managers readily admit that the outcomes of these projects are uncertain, and that some of their efforts have met with failure. Their conceptual model shows that the marshes are starved of nutrients and sediment, and that reintroduction of these materials should alleviate some losses. Their basic strategy is to introduce water, nutrients, and sediment into the marshes to promote marsh growth and development. To assess the success of over a hundred projects, they have strategically located monitoring stations. A scientific team meets regularly (annually) to evaluate a selected subset of the projects. The lessons learned are incorporated into revisions and the development of new project plans. This program benefits from a clear understanding of factors that control marsh development from decades of research on these systems, the ability to conduct experiments with untested technologies, a strong monitoring program, and a framework for evaluating the results and incorporating them into future project plans, as well as through modifications to existing projects.

Smaller project examples include those such as the tidal marsh restoration in South Slough, Coos Bay, Oregon and eelgrass restoration at the Clinton ferry terminal in Puget Sound, Washington. In South Slough, restoration of the Winchester Tidelands marsh (8.1 hectares) was set up to provide information on what elevations are best for marsh development. Here, prior to removal of dikes surrounding former tidal marshes, four areas within the marsh were graded to different elevations. Colonization of the areas is being allowed to progress naturally following dike removal. The information gained through monitoring will allow future projects to be built to maximize the rate and pattern of marsh development through manipulation of elevation.

At the Clinton ferry terminal, eelgrass is being restored in bare areas within and adjacent to an existing eelgrass meadow. An initial 2-year research effort partitioned the various sources of eelgrass disturbance from ferry terminals and ferryboat operations. Although it was clear from the research why eelgrass was absent from some of these plots, reasons were not as obvious for others. Because of the uncertainty regarding restoration potential, the plots were given a relative score indicating low, moderate, or high probability of success. Then monitoring was set up to assess the progress of eelgrass development and to evaluate factors contributing to success or failure. In addition, eelgrass was planted under the terminal in an area where glass blocks in the overhead walkway were installed to pass light to support eelgrass. The effectiveness of this method was evaluated and used along with information from other studies to help plan eelgrass restoration near other terminals in Puget Sound. Clinton, therefore, represents a place where the lessons learned from experimental manipulations can be applied to increase the effectiveness of projects elsewhere. For example, light enhancement technologies have been incorporated in dock design in Port Townsend, Washington (Diefenderfer et al. In Press). The results of the Clinton project are presented annually and discussed with resource agency scientists and modifications are made in both the approach to restoration and to the metrics used to evaluate success. Researchers recently realized that total shoot abundance (relative to eelgrass lost from terminal reconstruction) was a better measure of the goal for the project of no-net-loss of eelgrass habitat than was mean shoot density (Southard et al. 2003). Similar to projects in Louisiana, but on a much smaller scale, this program benefits from a focused research program, a monitoring program, and a management framework.

Adaptive restoration is a concept being put into action in the Tijuana Estuary (Crooks 2003). A 8-hectare portion of the 200-hectare area is being restored in an experimental design so that the lessons learned from the smaller area can be applied to the larger restoration project.

The concept of adaptive management - learning by doing - is generally intuitive, however many restoration projects fail to incorporate it in the overall plan. It was developed specifically to provide information where there is uncertainty and a need for a decision-making framework (Thom 1997;Thom 2000). Adaptive management plans should be developed in the planning phase of a project. The principles of adaptive management can be applied at various levels of intensity and using various strategies. The most important element is to learn from the project.