Land conversion, climate change and species invasions are contributing to the widespread emergence of novel ecosystems, which demand a shift in how we think about traditional approaches to conservation, restoration and environmental management. They are novel because they exist without historical precedents and are self-sustaining. Traditional approaches emphasizing native species and historical continuity are challenged by novel ecosystems that deliver critical ecosystems services or are simply immune to practical restorative efforts. Some fear that, by raising the issue of novel...