What are Black and White Lists?

The Risk Assessment process evaluates the invasive potential of an alien species in an area. During this process, depending on the results of the Risk Assessment, the species are placed in certain categories or lists. The most common are the Black and the White list.

The Black list contains species whose introduction in a certain area is strictly limited, since these species are proven to be extremely invasive in the given area or its surroundings. Also, the black list contains species that are not yet present in a certain area but may cause problems if introduced.

Unlike the Black list, the White list contains species that do not, according to their risk assessment or long-term experience, represent a risk. Introduction of these species may be allowed in certain conditions and with limitations, although their uncontrolled release in nature may not be encouraged.

On occasion, the Grey list may be used. It contains species that are not on either of the previous lists – species that have not yet been placed on the Black or the White list, but are in taxonomic relations with species on either of the list.