Quantifying the value of ecosystem services is important for the social recognition and acceptance of ecosystem management across multiple geographic scales. Yet, the data required to perform such quantifications and the dynamic models that allow the projection of policy changes into the future are currently scattered, incomplete, and difficult to use. We describe the design of the Ecosystem Services Database (ESD), an integrated, web-accessible knowledge base that links a relational database for temporally and spatially explicit data to dynamic simulation models. The ESD architecture supports unit standardization, scale translation in space and time, and statistical analysis. Process-based dynamic models and valuation methods can be run by end users either through a web-based simulation engine or on their own computers by means of open-source software. The knowledge base will serve as: (1) a communication tool for use by researchers in several fields; (2) an analytical tool for meta-analysis, synthesis, and prediction; (3) an educational tool to disseminate knowledge on ecosystem services and their valuation; (4) a collaborative tool for institutions involved in different aspects of ecosystem service valuation; and (5) a prototype for linking databases and dynamic models. (C) 2002 Elsevier Science B.V. All rights reserved.