8 invasive species to look out for in the UK

Find out about some invasive non-native species that could cause big problems if they become established. 


The Non-native Species Secretariat (NNSS) has responsibility for helping to coordinate the approach to invasive non-native species in Great Britain.


The following species are examples of plants and animals which could cause a significant negative impact if they were to become widely established in the UK. If you see one, you can send in your record to alertnonnative@ceh.ac.uk (preferably accompanied by a photo). 

1. Quagga mussel 


Quagga mussel © David Aldridge, Cambridge University

This tiny freshwater mussel from eastern Europe breeds extremely fast and grows in dense colonies, which can be an expensive nuisance when clogging water treatment pipes. 

Anglers, boaters and other water users should remember to Check Clean Dry after leaving the water to help prevent this mussel, and other invasive aquatic species, from spreading via clothing and equipment. 

2. Water primrose


Water primrose © Trevor Renals

This highly invasive freshwater weed from South America was originally introduced to Europe for its attractive yellow flowers. In France (where it has now become widespread) it blocks waterways and takes over ponds and lakes, forcing out native wildlife and causing flooding.

Water primrose is currently only established in a small number of sites in England and Wales, but if it were to establish widely in Great Britain, it would cost millions to manage.

The Environment Agency is working to eradicate existing populations, and gardeners are asked to Be Plant Wise and avoid dumping aquarium or pond plants in the wild. 

3. Asian hornet


Asian hornet © Jean Haxaire

This invasive non-native insect is from Asia and is a voracious predator of honeybees and other insects. It was detected in the UK for the first time in September 2016.

The Animal and Plant Health Agency quickly located and destroyed the hornet nest, but it is possible this that species could reappear.

There is a new app available with detailed guidance on identifying the Asian hornet, and the common species that it could be confused with, and to submit any suspected records.

4. American bullfrog


American bullfrog © GB NNSS

This American native has earned the reputation as one of the most harmful invasive amphibian species. Not only does it feed day and night on a wide range of prey, but also carries a disease that has led to worldwide amphibian decline and several global extinctions.

In the past bullfrogs have been kept as pets and deliberately released into the wild – it is advised not to release any unwanted pets as it could be bad for the animal and could harm native wildlife.

5. Sacred ibis


Sacred ibis © GB NNSS

These striking African birds were very popular in European zoos in the 1970s and 80s, and there were established free-flying colonies within their grounds. Unfortunately this led to escapes, which are a serious problem for other wildlife. 

In France, where they are established, their diet includes fish, small rodents, amphibians, and the eggs and young of other bird species including terns. A number of individuals have been spotted wild in Britain.

6. Topmouth gudgeon


Topmouth gudgeon © Matt Brazier/Environment Agency

Originally from eastern Asia, this small fish breeds very quickly. It harms both native and farmed fish by eating other young fish and eggs, and spreading disease.

The Environment Agency is trying to eradicate topmouth gudgeon from a small number of ponds where it has been introduced.

7. Pitcher plant


Pitcher plant © CEH

This strange looking North American plant is a threat to our bog communities as it reduces the cover of native plant species, including mosses, which can impact on peat formation.

Pitcher plants are carnivorous, feeding on insects that are trapped in their pitchers, which may impact on insect communities. Volunteers from the New Forest Non-native Plants Project are helping to clear this plant from the New Forest.

8. Raccoon


Raccoon © Ruthanne Annaloro

This distinctive American animal is not established in Great Britain, but individuals do occasionally escape from private collections.

While they may look cute in cartoons, raccoons may threaten native wildlife, including vulnerable bird species. They can also carry rabies and other nasty diseases which can harm humans and animals.

Discover which non-native invasive species are already established and causing problems.


Read more about the GB non-native species secretariat