Why 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.

You can find out more about the problems caused by invasive non-native species through our 'how do they effect me?' pages and by viewing the videos below:
Zebra Mussel (date recorded 18th November 2009)
Water Primrose (29th October 2009)
Chinese Mitten Crab (18th November 2009)
Floating Pennywort, filmed as part of the Be Plant Wise campaign

Thin strip of image show tree trunk and bark