Ecological novelty is typically defined in terms of dissimilarity from some predetermined baseline (e.g., modern or historic), and may refer either to species assemblages (“novel communities”) or to some function of interest (“novel ecosystems”). Such novelty may represent a significant challenge to researchers and conservationists, as new associations of species emerge in response to global change. As taxonomic composition changes, it is expected that a new assembly will also express novel ecosystem function, but this does not always prove the case. To date, the relationship between community and functional novelty remains poorly understood. As novel communities emerge in response to climate change, land use change, and invasions, to what extent do novel associations of species represent novel ecosystems? Answering this question is of critical interest as we enter the Anthropocene, as human activities have irreversibly altered biodiversity patterns. Are novel ecosystems a “new world order” to be embraced? Do they represent threats to biodiversity and ecosystem services? Is ecological novelty a useful framework, or a red herring? In this symposium, we seek to advance the theory and mechanistic understanding of ecological novelty by exploring the linkages between community, trait, and functional turnover through time. While these "novel community" and "novel ecosystem" are often used interchangeably, they in fact relate to different frameworks. Novel communities may be the result of individualistic shifts in species’ ranges and abundances in response to changes in climate, disturbance, or human activity. Such communities may differ from a historical equilibrium due to novel associations, changes in abundance, or losses of species. In contrast, novel ecosystems may emerge from community-driven changes in ecosystem processes or from altered function due to changes in abiotic conditions (e.g., climate) with or without compositional change. Changes in community structure or composition have resulted in numerous documented changes in ecosystem function. Conversely, in some cases, even substantial changes in community composition may not result in measurable functional change. This symposium brings together researchers working across systems and spatiotemporal scales, including trait-based ecology, paleontology, invasion ecology, urban ecology, landscape ecology, and global change ecology from land to sea, and the tropics to the temperate zone.