Crackdown on alien species


Experts from across Great Britain are joining forces to fend off unwanted species of plants and animals, it was announced today.

A new co-ordinating group, a partnership between the Scottish Executive, Welsh Assembly and Department for Environment, Food and Rural Affairs will seek out and advise on the best methods of controlling the least wanted alien invasive plant and animal species spreading through our countryside.

Species such as the American mink, which escaped from fur farms and threatens the survival of water voles and a number of ground nesting birds, and the Japanese Knotweed, whose roots have been known to burst through roads and house foundations, could be included on the hit list.

Deputy Environment Minister Lewis Macdonald said:

"The Scottish Executive is committed to protecting and enhancing the environment we live in.

"An increasing range of non-native invasive species pose a serious threat to our natural habitats, species and heritage.

"Although they have typically been introduced "innocently", many of these species are out-competing some of our most valuable and vulnerable native plants and animals, causing potentially irreversible damage.

"A cross-border approach to co-ordinating the way we deal with non-native species is crucial in order to ensure the protection of our wildlife and habitats."

An audit by Scottish Natural Heritage in 2001 found at least 988 alien species occurring in Scotland. These consisted mainly of higher plants, as well as mosses, mammals, birds, fish, insects and molluscs. They occur in all habitats from mountains to the marine environment

The Scottish Executive consulted during 2004 on a number of proposals arising from a GBreport (Review of Non-Native Species policy. Defra 2003)

3. Efforts to tackle invasive non-native species require cross-border co-ordination as they are best addressed on a "biogeographic" basis. i.e. within natural geographic and ecological boundaries.


  • Seemingly innocent plants such as the familiar rhododendron (Rhododendron ponticum) are toxic to other plants and cast dense shade making it difficult for other plants to grow. By rapidly spreading and preventing the regeneration of native woodlands it can wipe out natural tree cover and associated species dependent on native woodland for the right habitat and conditions.
  • Japanese Knotweed (Fallopia japonica) grows much larger in Scotland than it does in Japan and can burst through tarmac and on occasions can penetrate houses, as well as outcompeting almost all other vegetation. The extensive root system is very difficult to eradicate.
  • The ruffe (Gymnocephalus cernuus) is a fish which is native in England but does not occur naturally in Scotland. It feeds on fish eggs and, outside its natural range, is considered to be a threat to both commercial and sport fishing. It was unintentionally introduced into Loch Lomond in the early 1980s and is now thought to be one of the most common species in the loch. Ruffe have already changed the ecology of the loch, for example by destabilising normal predator-prey relationships and by impacting on rare species such as the native powan.
  • American mink (Mustela vision) are a predator of fish, birds, small mammals and crabs. They are implicated in the crash of water vole populations and threaten some populations of ground nesting birds. An EU Life project called The Hebridean Mink Project was set up in Novemebr 2001 to reduce levels of Mink on certain islands in the Western Isles.
  • The New Zealand Flatworm (Arthurdendyus triangulatus) is mainly found in the central belt and feeds almost exclusively on earthworms. It may threaten agriculture and the environment due to the adverse effects of earthworm eradication on soil quality. It is not controlled by many earthworm predators such as moles, badgers and birds which find it unpalatable.