Often a commitment to large ecosystem initiatives is linked both conceptually and legally with requirements for ecological monitoring as a means of evaluating the effectiveness of management actions. Programs to determine ecosystem status and trends can contribute significantly to the resolution of difficult and contentious management questions, and can playa key role both in sharpening the focus of research questions and in developing adaptive approaches to resource management. Monitoring Ecosystems brings together leading scientists and researchers to offer a groundbreaking synthesis of lessons learned about ecological monitoring in major ecoregional initiatives around the United States. Contributors-Donald L. DeAngelis, Lance H. Gunderson, Barry R. Noon, John C. Ogden, Craig J. Palmer, Keith M. Reynolds, Paul L. Ringold, John R. Sauer, Lawrence E. Stevens, and many others-present insights and experiences gained from their work in designing, developing, and implementing comprehensive ecosystem monitoring programs in the Pacific Northwest, the lower Colorado River Basin, and the Florida Everglades. The book: outlines the conceptual and scientific underpinnings for regional-scale ecosystem monitoring, examines the role and importance of data management, modeling, and integrative analyses, considers techniques for and experience with monitoring habitats, populations, and communities Chapters by the editors synthesize and expand on points made throughout the volume and present recommendations for establishing frameworks for monitoring across scales, from local to international. Monitoring Ecosystems presents a critical examination of the lessons learned from direct experience along with generalized conclusions that canbe applied to monitoring programs in the United States and around the world. It is a vital contribution to science-based monitoring efforts thatwill allow those responsible for developing and implementing ecoregional initiatives to make use of knowledge gained in previous efforts, enabling them to focus their energies on system-specific questions and problems.