Assessing the capacity of European regional seas to supply ecosystem services using marine status assessments

In this paper we describe work that progresses the understanding of socio-ecological systems from the perspective of exploring how the supply of ecosystem services might vary with changes in the state of ecosystem components. We developed and tested a new assessment approach (concept, framework and methodology) to assess the capacity of marine ecosystems to supply services, which could be carried out using available policyreported assessment information on marine biodiversity and ecosystem status. The starting point was an assessment that drew on an understanding of ecosystem state-service relationships, and that was extended to incorporate operational, policy-relevant ecosystem assessment information at European regional sea scales in response to the requirements of the EU Biodiversity Strategy to 2020. The assessment consists of three key steps: (1) identifying all the instances where a marine ecosystem component can potentially contribute to the supply of a marine ecosystem service; (2) developing a critical pathway analysis to identify the major ecosystem component(s) contributing to the supply of a given service; (3) interpreting available information on the state and trends of these major contributing components with knowledge of the ecosystem state-service relationship, to assess the ecosystem's capacity for service supply and its direction of change. The assessment provides a common approach that can be applied across marine regions, and in data rich or data poor situations. This approach captures the sustainability of ecosystem service supply capacity through retaining the connection with the state of the ecosystem and can help to inform management decisions and track the effectiveness of environmental policies.