Which Species Threaten UK Biodiversity?

At the end of last year, the EU published its first ever list of invasive alien species (IAS) which are predicted to threaten biodiversity across the bloc, including the UK. Of course, the potential impacts of the arrival and spread of these species will be detrimental to British wildlife regardless of the outcome of the Brexit debate, as animals are not known for their respect for political wrangling.

From a longlist of 329 species, the panel of EU experts whittled the IAS list down to 66. Eight in particular are deemed to be of particular concern, including the northern snakehead, the black striped mussel and the rusty crayfish. While none of these animals have yet be discovered in the wild in the EU, the panel behind the report say they must be included in any forthcoming legislation.

Creating the shortlist

In compiling the final shortlist, the experts used a technique called “horizon scanning”. This involved them taking the initial longlist of 329 species and ranking each one in four different categories: a) the likelihood of them arriving in the EU; b) the likelihood of their population establishing itself; c) the likelihood of them spreading amongst native species and d) the size of the impact their presence is projected to have on biodiversity.

It is the first time that horizon scanning has been used to predict IAS threats on a continent-wide scale and highlights the wide number of species which may cause problems for European and British biodiversity. Although none of the species are yet found in the EU (apart from in captivity), it’s feared that they may be able to stowaway on boats or flights or escape from laboratories and zoos.

Top of the pile

While the EU experts identified a total of 66 species which could threaten EU and UK biodiversity, they have earmarked eight that are of particular concern. These are comprised of:

• Black striped mussel. Native to the Caribbean and the Gulf of Mexico, the black striped mussel could overwhelm local populations and have a detrimental impact on fisheries.
• Fox squirrel. Native to North America, the fox squirrel could outcompete existing squirrel species (similar to how the grey squirrel has marginalised the red squirrel in the UK).
• Golden mussel. Native to China and parts of southeast Asia, the golden mussel could overwhelm local populations.
• Green seaweed. Native to the Red Sea, green seaweed could outcompete local seaweed species and disrupt entire ecosystems as a result.
• Northern snakehead. Native to China, Russia and both North and South Korea, the northern snakehead is aggressive to other species and has been wreaking havoc in the US for the last 20 years.
• Onyx slippersnail. Native to the Americas, the onyx slippersnail could quickly proliferate and overwhelm local populations.
• Rusty crayfish. Native to North America, the rusty crayfish is a transmitter of disease and fungus and could decimate local populations.
• Striped eel catfish. Native to the western Pacific and the Indian Ocean, the striped eel catfish could disrupt water quality and prey on local populations.

It’s no coincidence that six of the eight IAS are water-dwelling animals. With that in mind, high-resolution monitoring of rivers and waterways will be imperative to ensure that none of the above scenarios occur.