Socio-ecological research provides a new paradigm for understanding linkages between social and ecological systems. Environmental sustainability depends on this understanding -- without it, the development of workable policy solutions to some of the most recalcitrant environmental problems of today, ranging from fisheries depletion to invasive species, will remain difficult to design and even more difficult to achieve. New frameworks are needed to help us understand how humans perceive the critical services provided by ecosystems, how these perceptions change behavior and institutions, and how behavioral and institutional change in turn feeds back to affect ecosystem structure and function and thereby the ability of ecosystems to deliver future services. Scientists in the U.S. Long-Term Ecological Research Network, now in its 30th year, have developed such a framework to understand society and environment linkages in ecosystems as disparate as arctic tundra, eastern forests, deserts, croplands, and cities. In this symposium, we will provide three examples of how such a framework can provide insights not otherwise available into how ecosystems and society interact. Marine, urban, and rangeland studies demonstrate the value of an integrated, long-term, comparative research program in socio-ecological research and point to new policy options for managing environmental change.