Alien plants of Europe: introduction pathways, gateways and time trends

Abstract

The Convention on Biological Diversity (CBD) pathways classification framework used in the implementation of the European Union’s (EU) Regulation 1143/2014 on invasive alien species (IAS Regulation) has recently been adopted by the European Alien Species Information Network (EASIN), the official information system supporting the implementation of the IAS Regulation. In the current paper, the result of an alignment of the primary introduction pathways of all alien plants in Europe included in the EASIN catalogue is presented, based on the CBD framework. In total, 6,250 alien plant taxa (marine plants excluded), both alien to Europe (native range outside Europe) and alien in Europe (native range partially in Europe) are reported. Altogether 5,175 plant taxa had their primary introduction pathway aligned based on the CBD framework, while for the rest the pathway remains unknown. In addition, the taxonomy, year and country of its first record in the wild are provided for each taxon. Our analyses reveal that the main primary introduction pathways of alien plants into Europe are linked to accidental escapes from ornamental and horticultural activities. Northwestern European countries seem to act as the main gateway areas of alien plants into Europe. Recent first observations of new alien taxa growing spontaneously exhibit a contemporary accelerating trend for plants alien to Europe, particularly linked to ornamental and horticultural activities. On the other hand, the number of new plants alien in Europe seems to have stabilized over the last few decades. The present work can assist in the prioritization of introduction pathways control, with the target of slowing down the rate of alien plants introductions into Europe, following also the requirements of the IAS Regulation.

Italian Vascular Flora: New Findings, Updates and Exploration of Floristic Similarities between Regions

“…In addition to human activities, the large number of alien species reported as new for Italy and for its regions should be related to the recent greater attention of Italian botanists to this group of plants. In any event, our results are in line with the trend of increasing reports of alien species in Italy [46] and Europe [167].…”

“…Most of the 59 taxa reported for the first time for the Italian regions are escapees from cultivation (e.g., Actinidia deliciosa, Boerhavia coccinea, Campanula portenschlagiana and Elaeagnus × submacrophylla). This is fully in agreement with other authors according to whom agricultural activities and artificial green areas (gardens, parks and cultivated fields) represent starting points for the process of invasion [93,166,167]. In addition to human activities, the large number of alien species reported as new for Italy and for its regions should be related to the recent greater attention of Italian botanists to this group of plants.…”

The phytosanitary risks posed by seeds for sowing trade networks

“…Accidental introductions of commodity contaminants, including seed for sowing are believed to account for the establishment of an important proportion of invasive plant species in various jurisdictions e.g., 14% British Isles, 15% Galapagos, 7% United States, 25% New Zealand, ca. 20% Australia, and 13 to 37% in Europe [ 11 – 17 ]. Until 1950, most naturalized plants in New Zealand entered as crop seed contaminants, but since then deliberately introduced ornamental escapes have become increasingly important [ 12 , 18 , 19 ].…”

How Effective Are the Protected Areas of the Natura 2000 Network in Halting Biological Invasions? A Case Study in Greece

“…Comparing the life forms of alien and native flora [45,60], there were more alien taxa with phanerophytic life forms and less hemicryptophytic and chamaephytic plants, which was not the case for native flora, of which phanerophytes were the least popular life form. This observation could be related to the fact that the most common introduction pathway for alien plants is to escape from ornamental and horticultural activities [61,62].…”