UK's most wanted...

Coming soon to an ecosystem near you?

22 September 2017 by Sylvie Kruiniger

You've probably heard of the harlequin ladybird and you've certainly seen a grey squirrel, but what about others that might be on their way?

Invasive non-native species are estimated to cost Britain around £1·7 billion a year, with 15% of new arrivals posing a threat to biodiversity, economy or society. In 2014, Professor Helen Roy at NERC's Centre for Ecology & Hydrology led a team that pinpointed invasive non-native species that could arrive and pose a serious threat to UK biodiversity.

Asian hornet


STORY. Spotted in 2016 in the Channel Islands and then in Gloucestershire. The nest was destroyed and time will tell if any queens survived the winter.

PROBLEM. It kills honeybees which could affect honey production.

FACT! Smaller than European hornets but a deadly attacker that raids hives and carries honeybees away to eat.

African sacred ibis


STORY. No colonies yet in the UK but individuals and small groups have been sighted on numerous occasions.

PROBLEM. It feeds on birds' eggs and rubbish. It could be a danger to scarce reptiles and amphibians.

FACT! Over 1,200 pairs are now breeding in France.

American lobster


STORY. First recorded in British waters in 1988 and increasingly sighted in the English Channel and North Sea. Probably released accidentally from the food industry as some found with bands still on their claws.

PROBLEM. It's big, aggressive and competes and breeds with native lobsters. Also carries diseases including one that eats away at lobster shells.

FACT! The world's heaviest crustacean, sometimes over 20kg.

Quagga mussel


STORY. Originally from Ukraine, the first UK sighting was in 2014 at Wraysbury reservoir, near Heathrow Airport. Now confirmed at several UK locations.

PROBLEM. It blocks water pipes and harms ecosystems by filtering out nutrients.

FACT! Each mussel can produce up to one million eggs every year.

Variable-leaved milfoil


STORY. This aquatic plant has spread relentlessly in the US and parts of Western Europe. Only two records so far in the UK and eradication is ongoing.

PROBLEM. It forms mats preventing water flow, restricting sunlight and harming water-based life.

FACT! Thought to have partly caused a 40% drop in property values in the US state of New Hampshire.

Asian shore crab


STORY. There have been regular sightings in the Channel Islands since 2009. It was also spotted in Wales and Kent in 2014 but nothing on the mainland since then.

PROBLEM. It's an omnivore with a particular taste for snails and invertebrates and could outcompete native crabs.

FACT! Each female produces up to 200,000 eggs per year.



STORY. It's from North America but is now at home in parts of Western Europe. Not yet in the UK despite some escapes.

PROBLEM. Opportunistic raider that settles into urban environments where it can carry diseases toxic to humans and dogs.

FACT! Surprisingly strong swimmer as well as a superb climber.


Don't try to kill it because all these species can be tricky to identify. Download the iRecord app - external link - to report a sighting and visit the non-native species secretariat website - external link - to find out how you can help prevent the spread of invasive non-native species.

Professor Helen Roy said:

Predicting the next new arrivals is hard. We gathered experts on many species across all environments and used consensus methods to list those we thought would arrive within ten years, establish themselves and harm biodiversity and ecosystems. By figuring this out we've been able to help limit the impact of their arrival and focus efforts to protect native species.

NERC-funded researchers empower government, business and local research and communities to prevent and control invasive species, saving money and protecting ecosystem services.