Participatory assessment to define indicators for monitoring water-based payment of ecosystem services programs in Brazil

The cascade model is a commonly applied framework to evaluate ecosystem services provision, highlighting their benefits to society and assigning non-monetary and monetary values to these services. Adapting this model, we present a methodology to establish the most suitable indicators for monitoring Payment for Ecosystem Services (PES) programs related to water resources in Brazil. Through a participatory process, a set of ecosystem functions indicators were assigned for each ecosystem service (ES) considered in the study. The indicators were then classified following these criteria: clarity, viability, sensitivity, and relevance. The indicators were organized by their final score according to each evaluated criterion. The results demonstrated that “clarity” and “relevance” criteria were those most important for the experts to choose an indicator. In general, we could also observe a preference for analytical and well-established indicators in the literature for all ES evaluated. The indicators list presented can support the PES program monitoring in Brazil. Additionally, the methodology developed can be easily applied in other areas and provide the definition of the most suitable indicators to monitor water-based PES in different Brazilian contexts. Keywords:cascade model, ecosystem functions, ecosystem service indicators, tropical areas.