Controlling invasive alien species

Origin of alien species

Alien species are plants and animals that are not native to the Netherlands or Europe. They have been imported or have come here unintentionally, as ‘stowaways’ hitching a ride on board a ship or car. Alien species often have no natural enemies here, which is why their numbers can grow very quickly.

Invasive alien species cause damage to nature

Some alien species spread so prolifically that they threaten native biodiversity. These are called invasive species. The European Commission has drawn up a list of 37 plants and animals that damage:

• Natural ecosystems: invasive alien species crowd out native plants and animals.
• The economy: muskrats, for instance, burrow in dikes, weakening flood defences. It costs a lot of money to repair the dikes.
• Public health: invasive alien species can spread diseases that do not normally occur here. For instance, a tiger mosquito bite can spread dengue fever.

The European Commission’s website provides more information about EU measures against invasive alien species.

Examples of invasive alien species

Invasive alien plant and animal species include:

• Ambrosia: pollen from this plant aggravates hay fever symptoms.
• Floating pennywort: a fast-growing aquatic plant that can completely clog up drainage ditches, rivers and canals.
• Grey squirrel: native to North America, these squirrels carry diseases that threaten the native red squirrel.
• Stone moroko: a small fish native to Eastern Asia that has escaped from garden ponds and now threatens native fish species.
• Giant hogweed: a large plant that crowds out other plants. Contact with the plant’s sap causes major skin inflammations and blistering.

Measures against invasive alien species

There are 3 main strategies for controlling invasive alien species:

• Preventing their introduction in the first place. There is a European ban on intentionally keeping, breeding, cultivating, transporting, placing on the market and importing invasive alien plants and animals.
• When invasive alien species are introduced unintentionally, the animals must be removed from the environment as quickly as possible. Plants must be destroyed.
• If invasive alien populations are so big they can no longer be caught or eradicated, measures must be taken to stop them from spreading further.

EU measures against invasive alien species

Invasive alien species are a major threat to biodiversity and ecosystems around the world. International agreements have been made on controlling these species. In the European Union, measures are laid down in the Regulation on Invasive Alien Species, which applies to all EU member states, including the Netherlands.

The Regulation is limited to plants and animals that have an adverse impact on biodiversity and ecosystem services.

The Union list

A key part of the Regulation is the List of Invasive Alien Species of Union Concern. EU member states must eradicate or control invasive alien species on the List of Invasive Alien Species of Union Concern (‘the Union list’). Some of these species also occur in the Netherlands. The Union list is updated regularly.

Invasive alien species on the Union list may not be:

• imported;
• bred or cultivated;
• sold or exchanged;
• kept.

Pet shops and garden centres may not sell plants or animals on the Union list.

Transitional provisions in the Regulation on Invasive Alien Species

The EU Regulation on Invasive Alien Species sets out transitional provisions in articles 31 and 32 for pet owners and keepers of commercial stocks. This second group includes commercial breeders, pet shops and garden centres. The transitional provisions are as follows:

• Pet owners

  Owners of companion animals may keep their pet until it dies. The animal must not breed, And the owner must not let the animal escape or release it into the wild.

• Breeders, pet shops and garden centres

  Breeders, pet shops and garden centres may sell any listed plants or animals that they have in stock until a year after the species concerned was put on the Union list.