An invasive non-native species is any animal or plant that has been introduced (ie. by human action) outside its natural distribution (past or present) and has the ability to spread causing damage to the environment, the economy and the way we live.
Invasive non-native species are estimated to cost the British economy £1.7 billion a year. They are one of the greatest threats to the environment worldwide, and their impacts can be far reaching – they have adverse impacts on the native environment by predation, competition and spread of disease. They also threaten economic interests such as agriculture, forestry, fisheries and development.