ERCCIS has run a series of projects to monitor and record the spread of non-native species across the terrestrial, freshwater and marine habtiats of Cornwall.
Non-native (alien) species are plants and animals which have been transported to regions beyond their natural range, usually by human activities. Once a species arrives in a new location, several things can happen; it can find its new habitat inhospitable and die off, it can survive with little environmental impact, or it may thrive and can become invasive.
Non-native species often arrive without their natural predators which would have kept them in check within their native range. Some display traits which allow them to out-compete native species for essential resources such as food, space and light. This may be by their being bigger and stronger, more vigorous and quicker to grow, or by breeding at a time which is advantageous over native species. Some species also directly prey on native wildlife and/or can carry diseases from which native species have no immunity.
Due to the increasing threat there are now a large number of international, national and local agreements, conventions, legislation and strategies pertaining to invasive non native species. Defra launched The Invasive Non-Native Species Framework Strategy for Great Britain in May 2008.