The movement of species by climate change and invasion is having very basic consequences on the biosphere, which, depending on context, may be positive or negative. For instance, plant invasion is leading to increases in diversity nearly everywhere on Earth (Sax et al. 2002, American Naturalist). Furthermore, where pre-human ecosystems are most drastically affected by new arrivals, new communities are appearing - assemblages of species that have never before coexisted. Many of these “novel ecosystems” or “no-analog” communities span several million hectares. Novel forests and grasslands now cover huge areas of South Africa, Florida, California, Hawai’i, and Puerto Rico, and they appear to be increasing (e.g., Hobbs et al. 2006, Global Ecology and Biogeography). The purpose of the workshop will be to consider the ecological impacts of the formation of novel ecosystems. We will address the following questions: (1) Can invasion stabilize the functional properties of ecosystems in the face of other human impacts, such as climate change? (2) What do novel ecosystems imply for theories of community assembly and ecological fitting? (3) Are novel ecosystems better tuned to a rapidly changing climate and environment? (4) Does restoration of pre-settlement ecosystems make sense in areas where novel ecosystems readily appear on their own? The workshop will serve as a foundation for a future ESA symposium and book proposal.