Rapid global change: implications for defining natives and aliens

ABSTRACT The ability to ascribe native or alien status to species in a rapidly changing world underpins diverse research fields that overlap with global change and biological invasions via biodiversity. Current definitions generally link alien status to anthropogenic dispersal events, but this can create conflicts for active management and global change adaptation strategies, such as managed relocation and restoration ecology. Here we propose a unifying approach that allows for the incorporation of rapid global change into biological invasion terminology. We introduce the concept of a projected dispersal envelope (PDE) to define the region where a species is or could be native, irrespective of human involvement. The PDE integrates biogeography and niche theory with existing invasion terminology to place a spatial and temporal context on species movements. We draw on a diverse suite of topical organism movements to illustrate these concepts. Our restructured definitions allow for native species to move into or with rapidly shifting climatic regions, as well as identifying the inappropriate introduction of alien species to new areas. Moreover, our definitions framework forms a timely and essential component of adaptation policies and responses for invasive species management and the enhancement of biodiversity in a rapidly changing world.