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Terrestrial Invasive Non-Native Species (INNS)

As with marine and freshwater species, terrestrial INNS present a significant threat to native habitats and biodiversity. Not only can INNS out-compete and debilitate native wildlife populations, damage habitats and their functionality and introduce or spread disease, but in the case of plants like Japanese knotweed, which is fast growing and extremely tough, they can also cause significant damage to commercial and environmental infrastructure.

The main means of spread of terrestrial INNS into the wild is via:

  • Accidental escape, e.g. the importation and spread of exotic garden plants into the wild;
  • Direct release, e.g. the release of terrapins or fish into forest ponds;
  • Irresponsible plant disposal methods, e.g. disposing of garden waste in the wild;
  • Poor biosecurity measures, e.g. the illegal importation of certain bee keeping equipment and products onto the Isle of Man.

Once established, INNS can take many years of determined effort and significant amounts of money to eradicate. The best defence against INNS is to not allow them to establish in the first place.

On the Isle of Man the release of non-native plants and animals into the wild is prohibited under Section 14 of the Wildlife Act 1990. This prevents the introduction into the wild of any animal which is not ordinarily resident, or a regular visitor, to the Isle of Man in a wild state, or any species of animal or plant listed in Schedule 8 to the Act.

Schedule 8 includes both terrestrial and freshwater non-native species

Unfortunately, a number of terrestrial INNS species, particularly plants, are already well established across the Isle of Man. It is vital for the preservation of our native species that, where possible, responsible methods should be used to halt their spread, remove them from the wild and stop further invasive species becoming established.

It is the responsibility of landowners to eradicate INNS on their own land, but DEFA would encourage prior consultation for advice on the most effective control methods.

Contact Details (Terrestrial INNS)

DEFA (Ecosystem Policy)
Telephone: +44 1624 685963

DEFA (Agriculture Directorate)
Phone: +44 1624 685844

DEFA (Forestry, Amenity and Lands Directorate)
Telephone: +44 1624 685835

Further information about introduced species

The UK Non-Native Species Secretariat was developed to meet the challenge posed by invasive non-native species in Great Britain. Its website provides useful tools and information.

UK Non-Native Species Secretariat website

Potentially harmful invasive New Zealand and Australian flatworms in the Isle of Man

These invasive species eat earthworms. In certain areas of the British Isles these predators have have had a large impact on earthworms, and in some cases the New Zealand flatworm has been shown to cause local extinction of native earthworm populations. The implications for both agriculture and wildlife in the Isle of Man make these invasive species a cause for concern. Spreading from gardens where they have been introduced may have an impact on the natural food chains and soil structure and could become costly or impossible to eliminate.

Please look out for these flatworms and report sightings to DEFA at, and follow the measures recommended in the Flatworm Information Sheet.

Asian hornet response plan

Asian hornets have reached the UK and are being eradicated when detected. They are a significant threat to beekeeping. Identification and further information can be found at the GB Non-Native Species Secretariat. Updates and news are available from the National Bee Unit.

A response plan has been specifically created for the Isle of Man and any Asian hornets found here should be reported immediately to DEFA or the Bee Inspector.

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