What are invasive non-native species? An invasive non-native species is one that has been transported outside of its natural range and that threatens environmental, agricultural or economic resources. Non-natives are considered by the World Conservation Union (IUCN) to be one of the primary threats to global biodiversity, second only to habitat destruction.

In the past, natural barriers such as oceans, mountain ranges and inhospitable climates have allowed unique ecosystems and species to evolve. Increasing levels of activities such as global trade, tourism and travel have resulted in an unprecedented dispersal of species into new habitats throughout the world.

In their new habitat these species are without their natural competitors or predators and they are able to dominate or out-compete other species. When invasive plants become dominant in the environment they may provide an unsuitable habitat for native insects, birds, and animals. Once established, invasive species are very difficult and costly to control or eradicate, and mechanical or chemical control (which in some cases may be the only viable option) can cause further damage to the environment. The problems caused by invasive non-native species are likely to increase in line with further globalisation, increased travel, and the effects of climate change.

What is the Scottish Executive doing? In March 2001 a working group was set up to review invasive non-native species policy throughout Great Britain. The group made 8 key recommendations for further action, which were set out in A Review of Non-Native Species Policy published in March 2003.

The Scottish Executive consulted on legislative measures (Key Recommendation 5 of the Review) during August and September 2003. A number of new provisions dealing with non-native species were subsequently incorporated into the Nature Conservation (Scotland) Act 2004. The remaining recommendations from the Review were consulted on, in a second exercise, between March and June 2004. The 2004 consultation also sought views on proposals to extend the list of "prohibited" non-native species on Schedule 9 of the Wildlife and Countryside Act 1981.

Following positive responses, the 13 species proposed were added to the 1981 Act by means of subordinate legislation on June 30 2005. This has the effect of making it an offence for any person to plant or cause to grow in the wild any plant of the species listed, or any hybrid of such a plant. On June 1 2005 a new Horticultural Code of Practice covering non-natives was launched - this was developed in co-operation with Defra, the Welsh Assembly Government, trade and environmental interests. It was designated under section 14B of the Wildlife and Countryside Act 1981 which allows the Scottish courts to take account of the Code when considering cases involving non-native species.