The Nebulous Ecology of Native Invasions

In the Anthropocene, alien species are no longer the only category of biological organism establishing and rapidly spreading beyond historical boundaries. We review evidence showing that invasions by native species are a global phenomenon and present case studies from Southern Africa, and elsewhere, that reveal how climate-mediated expansions of native plants into adjacent communities can emulate the functional and structural changes associated with invasions by alien plant species. We conclude that integrating native invasions into ecological practice and theory will improve mechanistic models and better inform policy and adaptive ecological management in the 21st century.