Abstract
This thesis aims to understand the mechanisms through which Payments for Environmental Services (PES) emerge and influence the effective conservation of natural ecosystems in Cambodia. It also contributes to the operationalization of institutional conceptual frameworks for the analysis of PES, as it takes to the case of one of the world’s least developed countries. In Cambodia, PES appear to be the result of political processes (negotiations) influenced by pre-existing institutions and in which some stakeholders, such as the Government and NGOs,seek to influence decisions related to the definition of new rules for the use of natural resources so that they align with their interests. This explains why some types of PES schemes face political blockages at the national level. The thesis also seeks to measure and explain the environmental effectiveness of one community-PES. The case study leads to the effective conservation of forests even when the external pressure increases. However, this effect depends on some characteristics of the local socio-economic context, probably because they influence the likelihood of local collective management of forests, which the scheme aims to strengthen. In addition, the permanence of these effects is not guaranteed in the long run. The program has indeed eroded some perceptions of use values of forest conservation, which are, in a context of poverty and strong dependence of local communities on natural resources, the foundation for partially intrinsic motivation to conserve.