This study explored the effects of landscape change on the provision of ecosystem services in a mountain area in northern Portugal, in particular the trade-offs and synergies between services in 2 categories: provisioning and regulating. Services were assessed for 1990 and 2006 and projected for 2020 under 3 scenarios, both biophysically and economically, based on modeling and published and unpublished statistics. We found that landscape changes in the 16-year period under study increased the total supply of ecosystem services, measured both biophysically and monetarily, but that agriculture production dropped dramatically. Both regulating and provisioning services increased in value, but only regulating services increased in biophysical units. Projections under 2 of our 3 scenarios indicated that both types of ecosystem services will continue to increase in both amount and monetary value and will function in synergy, whereas the third scenario predicted a decrease in services and trade-offs between the 2 categories. Because land use has a major impact on ecosystem service supply, an understanding of the changes and trade-offs described in this article can support planning and management, in particular in mountain areas and other regions with limited alternatives for income generation. Our findings suggest that regional development plans should include incentives to maximize regulating and provisioning ecosystem services. ; info:eu-repo/semantics/publishedVersion