Ecosystem management links human activities with the functioning of natural environments over large spatial and temporal scales. Our examination of Greater Yellowstone and Georges Bank shows similarities exist between human uses, administrative characteristics, and some biophysical features. Each region faces growing pressures to replace traditional extractive uses with more sustainable extractive or noncommodity uses coupled with concern about endangered species. Ecosystem management as a set of practical guidelines for making decisions under evolving expectations is far from complete, and it embodies new demands on individuals and institutions. In each system these challenges are considered relative to: the public's symbolic understanding of the management challenge, ecosystem management ambiguities, information availability, information use, administrative setting, and learning capabilities of governance organizations Progress in making ecosystem management operational may occur as refinements in content and approach make it an increasingly attractive option for resource users, the public, and government officials.