When assessing ecosystem services, it is essential to identify which services are relevant to different stakeholders as well as their perception of those services, in order to make informed decisions about land use management. Divergent social interests may lead to conflicts over the use of a territory, stressing the tension between conservation needs and economic activities, which may be productive but nevertheless threatening the achievement of conservation goals. In this chapter, we present an assessment of social preferences for ecosystem services in a globally relevant biosphere reserve in South America; a region that requires more research on how to conserve ecosystems while incorporating human needs and values. Using a semi-structured approach, we found differences among stakeholders about the importance they attribute to different ecosystem services. On one side, local farmers and members of local organizations give higher value to provisioning services and cultural services of symbolic plants. On the other, scientists, environmentally concerned people, teachers, NGOs, and employees of the local government lend more importance to regulating and cultural services, revealing contrasting preferences for ecosystem services.