Setting River Restoration Priorities: a Review of Approaches and a General Protocol for Identifying and Prioritizing Actions

—Implicit in the question, ‘‘How should I prioritize restoration actions?’’ is often the unstated question, ‘‘What should I restore?’’ Distinguishing between these questions helps clarify the restoration planning process, which has four distinct steps: (1) identify the restoration goal, (2) select a project prioritization approach that is consistent with the goal, (3) use watershed assessments to identify restoration actions, and (4) prioritize the list of actions. A well-crafted restoration goal identifies the biological objective of restoration, addresses underlying causes of habitat change, and recognizes that social, economic, and land use objectives may constrain restoration options. Once restoration goals are identified, one of six general approaches can be selected for prioritizing restoration actions: project type, refugia, decision support systems, single-species analysis, multispecies analysis, and cost effectiveness. Prioritizing by project type, refugia, or a decision support system requires the least quantitative information, and each approach is relatively easy to use. Single-species, multispecies, and cost effectiveness approaches require more information and effort but often most directly address legal requirements. Watershed assessments provide most of the information used to identify and prioritize actions and should be explicitly and carefully designed to support the goals and prioritization scheme. Watershed assessments identify causes of habitat degradation, habitat losses with the greatest effect on biota and ecosystems, and local land and water uses that may limit restoration opportunities. Results of assessments are translated into suites of restoration options, and analysis of land use and economic constraints helps to evaluate the feasibility of various options. Finally, actions are prioritized based on assessment results and the selected prioritization scheme. In general, we recommend the use of simple decision support systems for cases in which watershed assessments provide incomplete information; the cost effectiveness approach is recommended for cases in which watershed assessments identify (1) restoration actions needed to restore riverine habitats, (2) biological benefits associated with each action, and (3) costs of restoration actions. Dramatic declines of diadromous and freshwater fish populations have prompted substantial efforts to restore or rehabilitate riverine habitats. However, many river and watershed restoration projects fail to accomplish their objectives, and restoration efforts continue to achieve less than the desired outcomes (Bond and Lake 2003; Palmer et al. 2005; Roni et al. 2008, this issue). Specific causes of project failure vary, but include a misunderstanding of the natural potential of restoration sites (Muhar et al. 1995; Frissell 1997), a lack of understanding of geomorphological controls on habitat responses (Frissell and Nawa 1992; Kondolf 2000), nonnative species invasions (Klotzli and Grootjans 2001; Bond and Lake 2003), and presence of undetected water quality impairments (Cowx and Van Zyll de Jong 2004; Roni et al. 2008, this issue). Scientists and managers also have recognized that population declines are largely a result of attempts to manage individual species or habitat characteristics rather than whole ecosystems (Nehlsen et al. 1991; Doppelt et al. 1993; Frissell et al. 1997). Thus, scientists and managers now accept that river restoration is more likely to be successful at restoring individual or multiple species and preventing the demise of other species if there is careful consideration of the watershed or ecosystem context in which individual restoration actions are set (Lichatowich et al. 1995; Reeves et al. 1995; Beechie and Bolton 1999; Palmer et al. 2005). Nevertheless, legal mandates (e.g., Clean Water Act or Endangered Species Act in the United States) drive the continuing focus of restoration plans on single species or water quality attributes instead of watersheds or ecosystems (Karr 1991; Beechie et al. 2003a). Moreover, the scientific literature on stream restoration typically focuses on isolated steps in the planning * Corresponding author: [email protected] Received June 30, 2006; accepted February 15, 2007 Published online June 16, 2008 891 North American Journal of Fisheries Management 28:891–905, 2008 Copyright by the American Fisheries Society 2008 DOI: 10.1577/M06-174.1 [Article]