Scenarios used in EICAT and EICAT+ to assign alien taxa to impact categories.

Detailed description of the 5 semiquantitative scenarios used in EICAT [24] and EICAT+ to assess negative and positive impacts caused by alien taxa on native taxa at different levels of organization. The scenarios are used in EICAT and EICAT+ to assign alien taxa to one of 5 ascending categories of impact magnitude. Note that when there is no or inadequate information to classify an alien taxon to one of the 5 impact categories, the taxon should be classified as Data Deficient (DD).