Why are non-native invasive species are a problem?

Invasive aquatic species can have a devastating impact on British plants, animals and ecosystems. As well as preying on, out-competing and displacing native wildlife, they can spread disease and block waterways. Their presence can sometimes be so damaging it can lead to significant changes to the entire ecology of a water body.

Recreational facilities can suffer as a result of invasive species. Fish populations may reduce or change. Invasive plants may restrict navigation through waterways, clog up propellers and add significantly to the management costs of our waterways.

As a water user, you could unknowingly help to spread invasive plants and animals from one water body to another. Animals, eggs, larvae and plant fragments are easily transported in or on equipment, shoes, clothing and other damp places and can survive for a long time. For example, new research from the Environment Agency shows that a killer shrimp can survive in the moist fold of a wader for up to 15 days.

The financial costs of invasive species can run into millions of pounds, as well as the irreplaceable cost to wildlife. The problems can be started with just a few individuals or small fragments of plants introduced into suitable habitat which in time can become a huge and permanent problem for everyone.

Report on the economic cost of invasive non-native species to the British economy
Case studies showing the impacts of invasive non-native species

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