The Tamar Catchment Partnership have adopted an ecosystem services approach to their catchment management planning activities. During this participatory process, stakeholders and technical specialists worked with a broker/facilitator to identify areas within their catchment which play, or have the potential to play, a particularly important role in the delivery of a range of benefits (ecosystem services) to society. To ensure that the resulting synthesis is robust, all of the data and evidence relating to each ecosystem service (and the environmental infrastructure that provides it) has been collated and scrutinised by the stakeholders during the discussions. Once the evidence had been evaluated, the partnership then worked to develop a series of conceptual models or ‘rules’ which could be used to define areas of the catchment most likely to play a critical role in the provision of the different ecosystem services.