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Europe’s first invasive species inventory

Between 2005 and 2008, INRA participated in the first inventory of invasive plant and animal species in Europe and the creation of a database of 10,000 species.

The Siberian chipmunk, also known as the common chipmunk. © INRA, Maud Marsot
By Pascale Mollier, translated by Teri Jones-Villeneuve
Updated on 06/30/2017
Published on 05/04/2016

Biological invasions (1) can cause major economic and ecological impacts. However, until the end of the 1990s, very little research had dealt with the issue and only a handful of species had been studied. From 2005 to 2008, a large European project (2) was undertaken to create the first inventory of exotic species introduced to the continent.

Plants account for a majority of introduced species

Ragweed. © INRA, UMR Agroécologie, Dijon
Ragweed © INRA, UMR Agroécologie, Dijon

Plants account for most of the 10,000 plus invasive species identified, followed by invertebrates, and to a lesser degree, marine species, fungi and vertebrates.

The inventory includes species introduced to Europe both directly and indirectly by people since the discovery of America by Christopher Columbus in 1492 (3). Fifteen European institutions, including five teams from INRA, participated in the inventory. INRA headed up the coordination of the studies on land invertebrates and fungi.

This project led to the creation of a free database that provides information about these species and lists numerous European specialists on invasive species. Database users can also focus their searches on one of 70 land regions and 48 marine or coastal species that were studied.

 

A spike in biological invasions

The harlequin ladybird (harmonia axyridis), which preys on aphids, is now considered harmful to many native coccinellid species as it tends outcompete them.. © INRA, © INRA / SOPHIA ANTIPOLIS
The harlequin ladybird (harmonia axyridis), which preys on aphids, is now considered harmful to many native coccinellid species as it tends outcompete them. © INRA, © INRA / SOPHIA ANTIPOLIS

Over the past fifty years, there has been an unprecedented rise in biological invasions. For example, 17 new exotic insect species have appeared every year in Europe since 2000, compared to just 8 per year over the 1950–1974 period. The growth of trade and transport is largely responsible for this increase, as most species hitch a ride on imported goods. However, certain species were introduced deliberately, such as butterflies, fish and turtles, cage birds and ornamental plants such as water primroses or Japanese knotweed.

The top 100 worst invaders

Following this inventory, a European study looked at the impacts of invasive species. These impacts, which can be major and even irreversible, were observed for just 15% of the more than 10,000 species.

The 100 most dangerous species in terms of impacts are identified in the database. These pests include the tiger mosquito (which carries Chikungunya), barnacles, the Siberian chipmunk, the African sacred ibis and the acacia.

An adult female Western corn rootworm beetle (Diabrotica virgifera virgifera LeConte) preparing to fly. © INRA, Dr. Joseph L. Spencer, University of Illinois
An adult female Western corn rootworm beetle (Diabrotica virgifera virgifera LeConte) preparing to fly © INRA, Dr. Joseph L. Spencer, University of Illinois

Vertebrates and plants appear to have the most significant ecological impact, causing native species to die out and decreasing the diversity of flora and fauna. Examples of such species are the Canada goose, zebra mussels, Sika deer, coypu and Louisiana crawfish. The most harmful species include a toxic algae in Norway, water hyacinth in Spain, the coypu and muskrat. These species – which do not include several crop and forest pests – have caused problems in fifty different European regions.  
This research provides an important source of data for the field of evolutionary biology, shedding light on how invasive species arrive, how they spread and ecosystem resilience. It will also help inform prevention policies.

  

(1) Biological invasion (or bioinvasion): The sustained expansion of a species, subspecies or population outside its distribution area.
(2) Daisie Project: Delivering Alien Invasive Species Inventories in Europe, 2005–2008.
(3) Species that have expanded into new regions due to climate change were excluded from this inventory.