AN AGENDA FOR INVASION BIOLOGY

Here I advocate a comparative and systematic approach in which invasio n (the extension of species ranges to areas not previously occupied by that species) is studied from the perspective of individual species a s 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, establis hment, and integration phases of invasion; (2) how donor regions or co mmunities that have produced many successful invaders differ from thos e in which few resident species have been able to extend their ranges; (3) how recipient ecosystems with many successfully established invad ers differ from those in which few species have taken hold; and (4) ho w invasion affects evolution not only of the invader itself but of spe cies in the recipient community with which the invader interacts. Copy right (C) 1996 Elsevier Science Limited