How was the EPPO List of invasive alien plants created?
A preliminary list of approximately 500 Invasive Alien Plants in the EPPO region was assembled from scientific and technical literature, from web sites and from official contacts in EPPO member countries with a questionnaire survey. A preliminary prioritization of these species was done by expert judgment based on the following factors:
- whether the plant is considered invasive or potentially invasive by several EPPO countries,
- whether the plant is absent or still containable by appropriate measures in several EPPO countries,
- the potential of the plant for further spread and damage into significant areas where it is absent,
- whether the plant is reported to be actively spreading or becoming more damaging in its current distribution area.
Additional information was then gathered from official contacts in EPPO member countries about the plants’: typical habitats, geographical distribution within countries, identification of areas where a species is creating most problems, abundance, existence of current pathways, mode(s) of spread, type of spread, cultivation, official control, etc.
The species were reconsidered in the light of this information to score them for:
- general invasiveness,
- damage to crop, natural flora and habitats, and man-made disturbed areas,
- current spreading trends.