Using existing scientific capacity to set targets for ecosystem-based management: A Puget Sound case study

Human actions have altered the structure and function of coastal ecosystems worldwide. In many locations, the overall portfolio of goods, cultural amenities, and supporting services provided by the marine environment has deteriorated. Ecosystem-based management (EBM) offers significant promise for addressing these issues because it is a comprehensive and integrated approach designed to reconcile conflicts and trade-offs among users of marine resources. A key step in the implementation of EBM is the establishment of target reference levels, or desired states, for indicators that reflect the status of the ecosystem. This paper reviews five approaches, borrowed from a variety of disciplines, to establish target reference levels for EBM. The approaches include the use of existing reference levels, reference directions, and reference levels based on nonlinear functional relationships, baselines, or social norms. Each approach is particularly suitable for EBM because it can be used alone or in combination with others to contextualize status for a diverse suite of ecosystem goals influenced by a wide variety of human activities. Perhaps most importantly, these approaches offer a prospectus for moving forward with EBM by using readily available information, motivating existing scientific capacity, and addressing trade-offs implicit to the setting of targets. This last point is articulated via examples of how each type of reference level might be applied in Puget Sound, WA, USA, where the efforts of scientists, managers, and policy makers have aligned recently in the interest of EBM implementation.