Our review focused on plants, but several recently published studies suggest that the basic biogeographical principles outlined here apply across a wide range of taxa, including
plants and various groups of animals (Chown et al., 1998; Sax,2001; Sax et al., 2002; Sax & Gaines, 2003).
The absence of common definitions of naturalization and invasion for all taxa is hampering further generalization and the identification of important contrasts between taxa.