Biodiversity: Alien invasions

The EU needs to urgently adopt an integrated policy on invasive alien species, urges Michl Ebner MEP.

Invasions by alien plant and animal species are now widely recognised as one of the most significant components of global environmental change, with far reaching and often harmful effects on biodiversity, ecosystems and the economy as well as acting as vectors for new diseases. There are many thousands of invasive alien species in Europe.

The EU is currently funding a strategic targeted project called DAISIE involving a number of international organisations, which will collate, analyse and disseminate the first pan-European inventory of aquatic and terrestrial invasive species.

There is no doubt that invasive alien species have a significant impact on the economy. The American oyster drill is a serious pest of the cultured oyster industry and muskrat and coypu have damaged riverbanks and increased the risk and severity of floods in many southern European countries.

Invasive alien species affect human health too; giant hogweed causes skin diseases, the brown rat causes leptospirosis and Egyptian geese cause pollution and pose a health hazard to swimmers. Invasive alien species also have a profound effect on the environment and our natural eco-systems.

These range from wholesale changes, such as the colonisation of sand dunes by Acacia plant species, to the extensive invasion by rhododendrons. The American mink is also held partially responsible for the decline in Europe’s water vole population.

The American grey squirrel, identified by the World Conservation Union (IUCN) as one of the 100 worst invasive alien species in the world, is now present in Ireland, Italy and the UK. The grey squirrel has a devastating impact on Europe’s native red squirrel; it damages trees, and preys on nesting birds, causing a
significant impact on biodiversity.

Displacement of red squirrels by grey squirrels happens primarily through competition for food and nesting sites. In Britain the greys also carry squirrel pox, which is deadly to reds. The grey squirrel damages trees by stripping off bark. This causes death or serious deformity. Large sums of EU money have already been spent on planting broadleaved trees.

Grey squirrels are now attacking many of these new plantations and destroying their economic value. As a result of the damage being done to the next generation of tall trees, grey squirrels are changing the landscape. In 150 years as the tall trees of today die or are felled, we could be left with mainly scrubby bushes to take their place.

The introduction of grey squirrels into Italy 58 years ago means that they now have a strong foothold on mainland Europe. Research carried out by the University of Turin due to be published in May 2006 shows that grey squirrels are spreading rapidly through Italy towards France and Switzerland. The research indicates that they will cross the Alps within 30 years, leaving much of Europe’s woodlands and wildlife at their mercy.

A recently formed organisation, the European Squirrel Initiative (ESI), has been active throughout Europe, highlighting the plight of the red squirrel and drawing attention to the significant impact that the grey squirrel
will have on the EU’s forestry and biodiversity.

The problem of invasive alien species was dealt with by the sustainable hunting, biodiversity and countryside activities intergroup during a meeting last December, with the participation of ESI. The intergroup adopted a resolution underlining that invasive alien animal species represent a major threat to biodiversity, second only to habitat destruction, encouraging further scientific research to assess their ecological and socio-economic impact and calling on the EU institutions to adopt an integrated policy on invasive alien species, following the example of the Council of Europe.

The resolution also highlights the threat posed by the grey squirrel for the survival of the European red squirrel in Ireland, Italy and the UK and asks for funding to develop a humane and effective method for its eradication.

There is no doubt, though, that some impacts of past invasions could have been reduced if European countries had applied relevant rules and codes of practice. Several biological invasions now threatening Europe might have been prevented.

European governments already have a commitment to “eradicate those alien species which threaten ecosystems, habitat or species” (UN convention on biological diversity), to “ensure that the deliberate introduction into the wild of any species which is not native to their territory is regulated so as not to prejudice natural habitats within their range or the wild fauna and flora and, if they consider it necessary, prohibit such introduction” (EU Habitats Directive) and to “strictly control the introduction of non-indigenous species” (Bern convention on the conservation of European wildlife & natural habitats).

The European commission needs to accelerate the development of an EU policy on invasive alien species and give support and encouragement to national governments to deal with their particular problems. Invasive alien species are a time bomb waiting to explode. Only action now will prevent devastating and far reaching consequences to the EU’s biodiversity, environment and economy.

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