Table 1 Categorization scheme for the stages in the invasion process, modified from Blackburn et al. [8]

A

Not transported beyond limits of native range

B

Individuals transported beyond limits of native range, but not released in the wild

C0

Individuals released in the wild, but incapable of surviving for a significant period

C1

Individuals surviving in the wild in location where introduced, no reproduction

C2

Individuals surviving in the wild in location where introduced, reproduction occurring, but population not self-sustaining

C3

Individuals surviving in the wild in location where introduced, population self-sustaining

D1

Self-sustaining population in the wild, with individuals surviving a significant distance from the original point of introduction

D2

Self-sustaining population in the wild, with individuals surviving and reproducing a significant distance from the original point of introduction

E

Fully invasive, with individuals dispersing, surviving and reproducing at multiple sites across a significant spectrum of habitats