Since the last ice age and the arrival of man in Britain almost all new species of terrestrial animals, plants and fungi that have become established have been brought here by man, either intentionally or accidentally. These are all non-native species, but only a small proportion are invasive and pose a serious threat to our native species and environment. These are classified as invasive non-native species (INNS).
In addition to the more familiar terrestrial species, such as Rhododendron and Crocosmia (Montbretia), there are also marine invasive non-native species. These can also threaten our native marine flora and fauna and have a significant economic impact on marine industries and their associated infrastructure e.g. invasive marine algae (seaweed) can grow on piers, slipways, fish-farm cages, boat hulls and can become entangled in boat propellers.
The environmental problems they cause affect us all and in Britain cost us in the region of £1.7 billion each year. The impact of INNS on biodiversity, our environment and infra-structure are severe and growing. Once a species has been introduced the problems persist and escalate as the species spreads further. Control and eradication are often difficult and expensive, but there are steps that we can take to limit their spread.
Fortunately geography is on our side and the islands of the Outer Hebrides have only been affected by a limited number of terrestrial INNS, however the threat posed by marine species is potentially more significant. To safeguard our ecosystems and wildlife we need to know the extent of the distribution of these species and to be vigilant for the arrival of new species. You can help by submitting records of INNS and ensuring that you do not add to the problems by following the Be Plant Wise and Check, Clean, Dry codes.
Your INNS records can make a difference and to help you the descriptions of our target species include identification sheets for you to download.
If you have non-native plants growing on your land your are legally required to ensure that they do not spread into "the wild". Spread may occur naturally (for example by seed ) or dumping unwanted plant material or contaminated soil.
Further information is available from the GB non-native species secretariat.