This project will help to meet the vital need for empirical research into the theory and practice of Payments for Environmental Services (PES). PES approaches to conservation have become rapidly more popular in the last few years, driven by compelling evidence of their effectiveness compared with indirect approaches to financing conservation. This research will exploit a current opportunity to build robust research protocols into the initial design of a PES scheme, thus allowing credible research into its outcomes. This will be undertaken through work with selected communities around the Nyungwe National Park in Rwanda. Communities will be offered cash transfers, contingent on their performance in relation to a set of conservation indicators. One of the great advantages of this project location is the availability of high quality ranger monitoring that, for example, provides regular geo-referenced data on the location of snares, tree-felling and other illicit activities. The outcomes of this experiment will be investigated through interdisciplinary research based on four main types of data. Firstly, data on forest user behaviour, based on the ranger data and additional transect studies; secondly, livelihood surveys that build an understanding of relationships between communities and park resources; thirdly, qualitative data, based on interviews and focus groups, to build an understanding of the social dynamics arising from introduction of the PES scheme; fourthly, public goods games to elicit data on attitudes towards the Park. The research findings will be of use to a wide range of African and international agencies with an interest in better understanding ways of reconciling biodiversity conservation and poverty alleviation. The results will provide a timely input to our understanding of the theory and practice of PES schemes.