Human activity is rapidly altering ecosystems across the globe in unprecedented ways. However, collecting ecological data required to detect, understand and forecast changes occurring over large spatial and temporal scales is difficult or impossible for individual researchers or universities. To meet these challenges, scientists from diverse disciplines are turning increasingly to self-organized research networks that span entire oceans or continents to yield unparalleled views of ecosystem patterns and dynamics. How are global ecosystems changing? To what extent are these changes the result of local impacts, natural climate cycles (El Niño/Southern Oscillation, Pacific Decadal Oscillation), and global climate change? Can changes in ecosystems be predicted, and, if so, are they likely to reverse, continue, or accelerate? How will people and their livelihoods be affected? What can be done to mitigate impacts on ecosystems and the people who depend on them? This symposium brings together leading researchers who are successfully addressing these important questions through large-scale collaborative ecological research in terrestrial and marine ecosystems. They will share the current state of the science, the important advances made possible only through collaborative research networks, as well as lessons learned and visions for the future of these networks.