What is an Invasive non-native species (INNS)?

In the UK, we give the term non-native species (NNS) to any species or race that does not occur naturally in an area. The term alien species is used in many other countries for non-native species. A  species that becomes so abundant after arrival that it damages biodiversity and often causes substantial economic or health problems is termed an invasive non native (INNS) or alien species. The term  applies to invasive plant/animal diseases.


In some cases non-native plants and animals do not pose a problem for a period of time before their numbers increase and cause damage, possibly because of changed circumstances (climate change or habitat transformation) that favour their ecology. So it is important to consider potential risks posed by all non-native species.