Invasive species such as Japanese knotweed, the grey squirrel and the European rabbit have cost the UK economy more than £5 billion over the past five decades, Queen’s University Belfast (QUB) research has revealed.
It amounts to one of the highest costs to the economy in Europe and costs are only set to increase, as invasive species represent a growing threat to the environment worldwide.
The study, which has been published in the journal NeoBiota, is one of the largest of its kind and one of the few to measure the true economic impact posed by invasive species. It’s led to calls for better biosecurity investment to prevent the arrival of these species on UK shores in the first place.
Dr Ross Cuthbert, research associate from the School of Biological Sciences at Queen’s University, who first authored the study, said the majority of the costs are caused by direct damages “such as reductions in agricultural productivity and infrastructure repair costs, whereas very little was spent on the actual management of invasive species, and especially prevention of future invasions”.
Dr Cuthbert, who is also a postdoctoral research fellow from GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany, said: “Worryingly, we also found that invasion costs are increasing rapidly over time and are likely to continue rising in future as more invasive species arrive in the UK.”
Invasive rabbits cause severe damage to agricultural areas by overgrazing, which affects both the growth and yield of key crops, especially considering grasslands and cereals. Their burrowing can also impact the quality of pastures.
Japanese knotweed causes structural damage to property that is expensive to remediate and reduces house values substantially.
Invasive waterweeds can clog waterways, blocking access by watercraft, worsening flood risk and impeding recreational activities such as angling.
The costs were measured mostly through their effect on agriculture and property over the last 40 to 50 years, where they have the biggest impact. An international team of researchers built the first global database of invasion costs named InvaCost, led by a team at Paris-Saclay University, as a result.
Economic costs are “severely” underestimated as less than 10% of the known invasive species here have reported costs due to a lack of research efforts.
To conduct their study, the researchers examined how costs in the UK were distributed across different invasive species, environments and cost types and how they have changed through time.
The researchers said they hope this study will raise awareness of the huge economic burden invasive species have on the UK economy for policy makers and society and promote greater management spending to prevent damage to the economy and ecosystems.
Dr Cuthbert said: “Investing in better biosecurity to prevent invasive species from arriving in the first place could reduce future economic impacts and be much cheaper than future damages or long-term control.”
The research was funded by the French National Research Agency (ANR-14-CE02-0021), the Alexander von Humboldt Foundation, AXA Research Fund Chair of Invasion Biology and the BNP-Paribas Foundation Climate Initiative.