Plant species threatened by invasive alien species

763 European plant taxa are considered as extinct or close to extinction, of which 75 no longer exist in the wild according to the IUCN global red list and national red lists. The geographical area under study is Pan-European as covered by Flora Europaea, i.e. including the Northern part of the Mediterranean and Black Seas, the Greek islands, Cyprus, Madeira and Canary Islands. These species are mostly endemic or sub-endemic. The highest numbers of extinct or critically endangered taxa are from the following areas: 162 in the Iberian Peninsula (representing 21.2%), 160 in the Balkan Peninsula (21%), 159 in Macaronesian islands (20.8%), and 135 in the Italian Peninsula (17.7%). The rest of Europe only gathers 147 extinct or critically endangered taxa (19.3%). Endemicity in Central and Western Europe is low and limited to coastal areas (cliffs, dunes, estuaries), rocks and lake shores. Although endemic species are found in Scandinavian and Baltic countries, only one has been found to be threatened. This may be due to a very low number of endemic species in northern countries.

The main factors threatening these rare plant species are listed below; it can be noted that they usually act in combination:

destruction of habitats is identified as the main driver of species decline, representing 53.4% of known causes of extinctions. It includes: agricultural practices (48.5%); infrastructure development and urbanisation (44.4%); as well as other causes such as management of non agricultural areas (8.5%)
intrinsic factors account for 53.9% of cases, including the extremely restricted range of species, limited reproduction, regeneration and dispersion capacities
climate change, although difficult to assess, is likely to influence reproduction/regeneration capacity of certain taxa. It is estimated that 73 taxa are at risk from climate change
invasive alien species, pollutions and other factors are additional drivers of species decline. They are difficult to assess, and often under-estimated.

Of particular interest are the plants recorded as threatened by invasive alien species:

Species	Family	Origin
Andryala crithmifolia	Asteraceae	Madeira (PT)
Apium graveolens subsp. butronensis	Apiaceae	ES
Apollonias barbujana subsp. ceballosi	Lauraceae	Las Canarias (ES)
Argyranthemum adauctum subsp. palmensis	Asteraceae	Las Canarias (ES)
Bencomia brachystachya	Rosaceae	Las Canarias (ES)
Cheirolophus massonianus	Asteraceae	Madeira (PT)
Convolvulus subauriculatus	Convolvulaceae	Las Canarias (ES)
Crambe tamadabensis	Brassicaceae	Las Canarias (ES)
Crambe wildprettii	Brassicaceae	Las Canarias (ES)
Dianthus arenarius subsp. bohemicus	Caryophyllaceae	CZ
Dorycnium broussonetii	Fabaceae	Las Canarias (ES)
Echium acanthocarpum	Boraginaceae	Las Canarias (ES)
Goniolimon italicum	Plumbaginaceae	IT
Helianthemum bystropogophyllum	Cistaceae	Las Canarias (ES)
Helianthemum cirae	Cistaceae	Las Canarias (ES)
Helianthemum juliae	Cistaceae	Las Canarias (ES)
Hypericum coadunatum	Clusiaceae	Las Canarias (ES)
Iberis intermedia subsp. beugesiaca	Brassicaceae	FR
Isoplexis chalcantha	Scrophulariaceae	Las Canarias (ES)
Lotus pyranthus	Fabaceae	Las Canarias (ES)
Myosotis azorica	Boraginaceae	Açores (PT)
Onopordum nogalesii	Asteraceae	Las Canarias (ES)
Sideritis discolor	Lamiaceae	Las Canarias (ES)
Silene nocteolens	Caryophyllaceae	Las Canarias (ES)
Sonchus wildprettii	Asteraceae	Las Canarias (ES)
Sorbus leyana	Rosaceae	GB
Sorbus wilmottiana	Rosaceae	GB
Teucrium heterophyllum subsp. heterophyllum	Lamiaceae	Madeira (PT)
Tolpis crassiuscula	Asteraceae	Las Canarias (ES)

Sources

Data supplied from the Most Threatened European endemic and sub-endemic Plants Database, Museum National d’Histoire Naturelle/European Topic Centre on Biological Diversity ; Conservatoire Botanique National de Brest, 2006.

Buord S, Lesouëf JY (2006) Consolidating knowledge on plant species in need for urgent attention at European level. Centre thématique Européen pour la Protection de la nature et de la Biodiversité. Muséum National d’Histoire Naturelle. European Environmental Agency. 50 p.