The programme we are proposing 'A hierarchical approach to the examination of the relationship between biodiversity and ecosystem service flows across coastal margins' (CBESS) will provide a large scale analysis of biodiversity stocks and the flows of ecosystem services from selected coastal systems. Our consortium of UK experts ranges from microbial ecologists, through environmental economists, to mathematical modellers, and practitioners belonging to the BTO and the RSPB, who have an immediate and vested interest in the sustainable use of coastal wetlands. Together, the CBESS consortium will create a study investigating how biodiversity stocks provide the following ecosystem services (defined according to the National Ecosystem Assessment as: - Supporting services- nutrient cycling, healthy habitat; Provisioning services- goods obtained from the landscape; Regulating services- coastal protection, climate regulation (greenhouse gas exchange, carbon sequestration); Cultural services- Recreation (walking, canoeing, angling, birding, hunting and aesthetic appeal). CBESS will combine the detailed study of two regional landscapes with a broad-scale UK-wide study to allow both specific and general conclusions to be drawn. The regional study will compare two areas of great local and national importance for England: Morecambe Bay on the west coast and the Essex coastline on the east coast. We will carry out biological and physical surveys at more than 600 stations and use these results to clarify how biodiversity can provide these important ecosystem functions. This information will be shared with those interested in using and managing coastal systems. From these studies we will develop practical methods and improved tools for the future analysis, management, and sustainability of the UK's coastal wetlands