Background/Question/Methods In recent years agricultural areas have gained visibility and acceptance as an important frontier in biodiversity conservation. Agriculture is the largest driver of land-use change worldwide, including biodiversity hotspots in Mesoamerica. In addition to their economic value, agricultural lands now host much of the biodiversity endemic to threatened tropical ecosystems. Conservation policies, such as Costa Rica’s Payment for Ecosystem Services (PES) program, aim to balance economic and production needs with conservation goals. Current PES payments and program evaluation rely heavily upon indices of land use types, focusing on associated carbon sequestration and biodiversity values. However, they do not systematically incorporate ecological monitoring data or spatial relationships. Consequently, the existing indices may not be the most appropriate tool for predicting and planning for the multiple services provided by agricultural ecosystems. Land use changes are evaluated 2002-2006 in the Global Environmental Facility PES pilot program in Costa Rica’s Esparza region. We explore the degree to which incorporating additional ecological data into the indices would alter program evaluation results and enhance prediction of ecosystem service availability.
Results/Conclusions It was determined that refining index categories to reflect the identity, composition, and evenness of tree species incorporated through PES reforestation would have a significant effect on monitoring results and prediction of service availability. Based on preliminary farmer interviews, it was also determined that a significant number of families reduced or eliminated subsistence crop production during PES participation. Management of subsistence crop areas is not currently included in the indices. Given the potential for un-accounted for diversity reduction, it is recommended to include three on-farm measurements: crop diversity; overall floral diversity; and faunal diversity response.  It was found that evaluation of tradeoffs between multiple services in agricultural lands will require refining the indices used to evaluate the conservation value of various land use types.