Join the Battle Against Alien Invaders!

Tuesday 20th June 2017

American MinkAmerican Mink

July is Invasive Species Month and Surrey’s wildlife needs your help to win the war against problem pests that are threatening the county’s environment. Surrey Wildlife Trust is joining forces with environment organisations, local authorities and volunteer groups across the county for a month-long campaign to tackle the problem head on.

“Invasive Species Month is all about creating awareness in local communities about what the issues are and how best to eradicate these problem pests,” said Glen Skelton, Surrey Wildlife Trust’s RiverSearch Co-ordinator.

“One area’s invasive species soon become another’s by travelling along our rivers, roads and rail networks,” added Glen. “We want to create a network of community groups across the whole of Surrey which systematically tackle the ever increasing presence of some of these invasive species along our rivers and wetlands. We hope that by collaborating with groups on a county scale, we stand some chance of getting on top of this problem.”

Surrey has more than its fair share of invasive species and here are the Trust’s top five most wanted alien invaders:

Mink - American Mink escaped from UK fur farms in the 1950s and quickly became established in the wild. These active predators kill many of our native wild creatures, including the water vole, which is now extinct in Surrey.

Signal Crayfish – Introduced to the UK in 1976 and now present in many of Surrey’s waterways. This North American invader is a voracious predator, feeding on fish, frogs, invertebrates and plants. As a carrier of crayfish plague, the signal crayfish is a major threat to our smaller native white clawed species.

Himalayan Balsam – Tall pink flowering plant introduced to the UK in 1839 and now a familiar sight on Surrey’s waterways. It smothers smaller native plants and its roots can erode riverbanks. Each plant produces almost 1,000 seeds, which explode out into the water, spreading the problem downstream.

Demon Shrimp – From south east Europe, this non-native shrimp is a voracious predator and has a varied diet, including our native freshwater shrimps, young fish, fish eggs and insect larvae. Highly invasive in freshwater and now present in the Wey navigation.

Quagga Mussel - This freshwater mollusc spreads rapidly and will smother and kill our native mussels, block water pipes and foul boat hulls. Originating from south east Europe, the mussels have been found in the River Wraysbury in Staines.

A series of work parties to mark Invasive Species Month are being run by the Trust and partner organisations in July. Volunteers can sign up to help target invasive plants such as Himalayan balsam, ragwort and bracken – events are being held across Surrey, from Woking to Wisley and Farnham to Leatherhead.

“Himalayan balsam might look pretty but it is actually pretty awful stuff – it shades out our native plants which are vital for bees and its roots can damage riverbanks,” added Glen. 

“Our aim is to empower people across the whole county to get out and do their bit in the fight against these alien invaders and ‘balsam bashing’ is a great way to start!”

Find your nearest work party here >>  If you belong to a community group and would like to run a task with your group to eradicate an invasive species in your area, contact Glen by emailing:

You can also keep up to date during July by following our RiverSearch Facebook and Twitter pages for alerts about new invaders in Surrey, as well as tips for reducing their spread. To find out more about the Trust’s RiverSearch project and to sign up as a citizen science volunteer, visit our RiverSearch page  here >>

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