Aquatic water weeds like floating pennyworts and Japanese knotweeds may seem innocuous enough, as may gray squirrels, minks and parakeets. Yet invasive species such as these cost the United Kingdom some £4 billion a year in economic losses.
This is according to researchers at the nonprofit CABI, who have found a 135% increase in comparable costs since their last assessment in 2010. “Annual estimated costs in 2021 were £3.02bn, £499m, £343m and £150m to England, Scotland, Wales and Northern Ireland respectively,” the scientists say in a statement on their findings.
“The cost to forestry increased eightfold, the cost to aquaculture and agriculture increased by 139.5% and 112.7%, respectively, and the cost of most of the other sectors increased roughly in line with inflation (47.6% for GB and 55.7% for Northern Ireland),” they continue.
Agriculture is the worst-affected industry with annual losses of ocer £1 billion, followed by construction, development and infrastructure at £270 million as well as tourism and recreation at £136m. The impact upon forestry is estimated to be £123m.
There are around 2,000 invasive non-native species (INNS) in the UK with between 10 and 12 new species becoming established on the islands every year. “The list includes well-known established species such as gray squirrel, killer shrimp, giant hogweed, mink and parakeets, as well as recently arrived, but highly impactful species such as the sea squirt Didemnum vexillum and ash dieback,” the scientists say.
“The fungus Hymenoscyphus fraxineus, which causes ash dieback disease, has become the costliest species in the past decade in the UK at an estimated £883.5m followed by followed by Japanese knotweed (£246.5m), rabbits (£169.7m), rats and mice (£84.4m), cockroaches (£69.8m) and deer (£62.9m),” they observe,
When it comes to groups of invasive species fungi are the costliest, accounting for nearly 53% of the total estimated costs, followed by mammals, plants and terrestrial arthropods (21.9%, 15.5% and 7.5% of the total, respectively).
“This assessment again shows the important costs of INNS to the UK economy,” says Richard Shaw, senior regional director for Europe and the Americas. “Few effects of INNS specific management efforts can be seen in these results. However, they highlight the need to continue prevention and early detection, followed by eradication of the highest-risk species prior to establishment.”
To tackle the scourge of invasive species, biological control and other long-term solutions are need, the experts say. Comprehensive action by the government will also be key.
“Invasive non-native species pose a serious threat to our natural environment and this government is taking action through the recently launched GB Invasive Non-Native Species strategy, to protect our native animals and plants from INNS,” says Niall Moore, head of GB Non-Native Secretariat.
“CABI’s research reveals the significant financial impact of INNS. It is vital that we work together with researchers, scientists, and others, who are working to tackle INNS, to prevent their entry into and establishment in Great Britain and, when they do become established, to mitigate their negative impacts,” Moore stresses.
