An agenda for invasion biology

Here I advocate a comparative and systematic approach in which invasion (the extension of species ranges to areas not previously occupied by that species) is studied from the perspective of individual species as well as of the regions and biotas that export and receive invaders. In order to go beyond the particulars of invasion, it is important to ask: (1) how invaders differ from noninvaders in the arrival, establishment, and integration phases of invasion; (2) how donor regions or communities that have produced many successful invaders differ from those in which few resident species have been able to extend their ranges; (3) how recipient ecosystems with many successfully established invaders differ from those in which few species have taken hold; and (4) how invasion affects evolution not only of the invader itself but of species in the recipient community with which the invader interacts. Copyright (C) 1996 Elsevier Science Limited