Global change is causing the reorganization of the earth’s biota. For example, species are being moved around the globe through trade and traffic, and species are shifting their ranges in response to climate change. Interacting species are not moving in concert, however, resulting in altered and novel community associations. This reshuffling of species’ distributions can affect biodiversity as co-evolved relationships become disrupted and as new communities of organisms with no evolutionary history form. Understanding the outcome of these novel and altered associations is essential to predict and mitigate the effects of global change on biodiversity. In this session, research will be presented on the influence that novel or altered community associations have on introduced or range-expanding species and on the effect that these novel species can have on their recipient communities.