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

摘要

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.