#SIWISofa: Payments for watershed services
Payments for ecosystem services (PES) are a relatively new economic policy instrument. The factors that drive and explain their environmental performance are still poorly understood. Existing reviews of PES schemes and assessments of success and fail factors are mainly qualitative in nature. There is limited evidence of the impacts of Payments for Watershed Services (PWS) on sustainable levels of land-water management due to the absence of reliable longer-term scientific data and adequate cross-evaluation. In a global review of 50 PWS schemes, key institutional- economic factors were identified that drive and explain the environmental performance of existing PWS schemes. Despite efforts to find quantitative information on their environmental performance, such empirical evidence is lacking in many of the studies PWS schemes. International monitoring guidelines are needed to facilitate comparisons, identify success factors and support the future design of cost-effective PWS schemes.