The EPPO prioritization process for invasive alien plants

Although invasive alien plants are gaining increased attention within EPPO countries, there is no existing widely agreed method to identify those alien plants that are considered invasive and represent the highest priority for pest risk analysis. In the framework of the ad hoc Panel on Invasive Alien Species, EPPO proposes a prioritization process for invasive alien plants designed (i) to produce a list of invasive alien plants that are established or could potentially establish in the EPPO region and (ii) to determine which of these have the highest priority for an EPPO pest risk analysis. The process consists of compiling available information on alien plants according to pre-determined criteria, and can be run at the EPPO region level, or at a country or local area level. These criteria examine whether the species is alien in the area under study, and whether it is established or not. The criteria used primarily rely on observations in the EPPO region but, if the species is not established, the invasive behaviour of the species in other countries should be investigated, as well as the suitability of the ecoclimatic conditions in the area under consideration. The spread potential, the potential negative impacts on native species, habitats and ecosystems, as well as on agriculture, horticulture or forestry are considered. If the species qualifies as an invasive alien plant of major concern through this first set of questions, the process then investigates the efficiency of international measures (to be justified through a pest risk analysis) to prevent the entry and spread of the species. The second set of questions are designed to determine whether the species is internationally traded or enters new countries through international pathways for which the risk of introduction is superior to natural spread, and whether the species still has a significant suitable area for further spread. If used by several EPPO countries, this prioritization process represents an opportunity to provide consistent country lists of invasive alien plant species, as well as a tool for dialogue and exchange of information.