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Invasive alien species in Europe (SEBI 010) - Assessment published May 2010

Indicator Assessment Created 17 Sep 2009 Published 21 May 2010 Last modified 16 Feb 2015, 05:56 PM
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Generic metadata


Biodiversity Biodiversity (Primary topic)

biodiversity | baseline | alien species | invasive species | ecosystems | freshwater
DPSIR: Pressure
Typology: N/A
Indicator codes
  • SEBI 010
Temporal coverage:
Geographic coverage:
Albania, Andorra, Armenia, Austria, Azerbaijan, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Europa, Finland, France, Georgia, Germany, Greece, Hungary, Iceland, Ireland, Italy, Kazakhstan, Latvia, Liechtenstein, Lithuania, Luxembourg, Macedonia (FYR), Malta, Moldova, Monaco, Montenegro, Netherlands, Norway, Poland, Portugal, Romania, Russia, San Marino, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey, Ukraine, United Kingdom

Key policy question: Is the number of alien species in Europe increasing? Which invasive alien species should be targeted by management actions? (5)

Key messages

The cumulative number of alien species introduced has been constantly increasing since the 1900s . While the increase may be slowing down or levelling off for terrestrial and freshwater species, this is certainly not the case for marine and estuarine species. A relatively constant proportion of the alien species establishedcause significant damage to native biodiversity, i.e. can be classified as invasive alien species according to the Convention on Biological Diversity. This increase in the number of alien species established thus implies a growing potential risk of damage to native biodiversity caused by invasive alien species.

While the majority of the approximately 10 000 alien species recorded in Europe (DAISIE project) have not (yet) been found to have major impacts, some are highly invasive. To identify the most problematic species to help prioritise monitoring, research and management actions, a list of 'Worst invasive alien species threatening biodiversity in Europe' (15), presently comprising 163 species/species groups, has been established.

While invasive alien species are recognised as a major driver of biodiversity loss, the issue of 'alien species' may in the future need to be considered in the context of climate change and particularly adaptation. For example, as agricultural food production adapts to a changing climate, farmers may welcome the arrival of pollinator species that match the new plant varieties that are used. Indeed, the movement of plant and animal species together may be necessary to facilitate adaptation.

(5) A species, subspecies or lower taxon, introduced outside its natural past or present distribution; includes any part, gametes, seeds, eggs or propagules of such species that might survive and subsequently reproduce. An invasive alien species is an alien species whose introduction and/or spread threaten biological diversity, accessed on 2 December 2008).

(15) Based on expert opinion in the SEBI 2010 expert group on invasive alien species.

Cumulative number of alien species established in terrestrial environment in 11 countries

Note: How to read the graph: in the 1990s, the total number of terrestrial alien species reached more than 3 500 Species

Data source:
Downloads and more info

Cumulative number of alien species established in freshwater environment in 11 countries

Note: How to read the graph: in the 1990s, the total number of freshwater alien species reached around 140 species

Data source:


SEBI indicators, 2010 - SEBI indicator 10.

Downloads and more info

Alien species in European marine/estuarine waters (October 2008)

Note: How to read the graph: In the 1990s, the total number of alien marine species increased to around 1 000

Data source:

SEBI 2010 Expert Group on invasive alien species, based on national data sets (Belgium, Denmark, Germany, Malta and the United Kingdom) available online; review papers (Netherlands and Turkey); NEMO database for the Baltic; Black Sea database; HCMR data base for the Mediterranean; project reports (ALIENS, DAISIE); and the contributions of experts from France, Spain and Russia made during a dedicated workshop.

SEBI indicators, 2010 - SEBI indicator 10.

Downloads and more info

Number of the listed 'worst' terrestrial and freshwater invasive alien species threatening biodiversity in Europe

Note: The numbers on the map indicate how many species from the list are present in each country. Of the list of 163 'worst' invasive alien species', 34 are present in Portugal.

Data source:

EEA/SEBI2010, 2006 Expert Group on trends in invasive alien species.

SEBI indicators, 2010 - SEBI indicator 10.

Downloads and more info

Key assessment

The trend in establishment of new species indicates that the problem is far from under control, with impacts on biodiversity expected to increase because of the growing number of species involved, and an increasing vulnerability of ecosystems to invasions, which results from other pressures such as habitat loss, degradation, fragmentation, over-exploitation and climate change. Particularly worrying is the situation in marine and island ecosystems.

The indicator on the cumulative number of alien species established in Europe includes data from all European countries with marine/estuarine waters (and non European countries bordering European seas). For terrestrial and freshwater ecosystems, however, data are currently available for 11 European countries. Nevertheless the indicator may be considered fairly representative for the European area. Data coverage on the cumulative numbers of alien species established in Europe will be expanded to cover more European countries in the near future.

The number of invasive alien species establishing themselves in Europe should be minimized and management actions should be taken to reduce the impact of at least the worst invasive alien species to acceptable levels. There is, however, no quantitative target for this indicator. The list of 'worst invasive alien species threatening biodiversity'(16) identifies species that should be a priority for more detailed monitoring, research and management. The 163 species/species groups on the present list, of which vascular plants are the biggest taxonomic group with 39 species, are judged to have a significant impact on native biodiversity through competition with other species. They may also affect human health and damage economic activities. Map 1 shows a preliminary estimate of the number of worst invasive species in European countries. The main conclusion to draw from the map is that fairly high numbers of listed species can be found in all European countries. These country figures are only rough indications of the actual impact, which may differ markedly between species and regions.

There is a consensus (e.g. in the context of the Convention on Biological Diversity) that the best strategy of addressing invasive alien species would be through control of pathways of introduction to prevent establishment of new alien species. The opportunities for eradicating established alien species are best at an early stage (or in limited areas such as small islands). An early warning system identifying potentially invasive alien species, including newly established ones and/or species expected to spread, would be of high value in this context. This indicator, therefore, will need to be complemented by information on developing and implementing strategies to manage the problem of invasive alien species.

(16) Based on expert opinion expressed at the SEBI 2010 expert group on invasive alien species.


Data sources

More information about this indicator

See this indicator specification for more details.

Contacts and ownership

EEA Contact Info

Katarzyna Biala


EEA Management Plan

2010 1.2.2 (note: EEA internal system)


Frequency of updates

Updates are scheduled every 5 years in October-December (Q4)
European Environment Agency (EEA)
Kongens Nytorv 6
1050 Copenhagen K
Phone: +45 3336 7100