Recent reports at the Scottish and global levels reveal the scale of the threat to nature and the economy from invasive species, a threat that is only growing as our climate changes.
An invasive non-native species (INNS) is defined as a species intentionally or unintentionally introduced outside its native range by human actions. These species tend to be opportunists, exploiting any chance to spread, and cause damage to the environment, the economy, our health or the way we live.
The multi-national Intergovernmental Panel on Biodiversity and Ecosystem Services’ Invasive Alien Species Assessment was published in February and brings together more than 13,000 scientific studies and indigenous and traditional knowledge. It concludes that INNS are spreading around the world at unprecedented and increasing rates, predicting that their number will increase by more than a third by 2050. Humans have introduced more than 37,000 non-native species around the world and at least 3,500 create problems for nature.
Globally INNS are one of the top five biggest threats to nature, including driving extinctions. The assessment concludes that INNS cost the world more than $420bn a year. UK work estimates the cost to the British economy at £1.9 billion every year.
Well-known examples of invasive non-native species that are causing damage in Scotland include Giant Hogweed, Japanese Knotweed and Signal Crayfish. There are already 2,000 non-native species in Britain and about 200 of these are considered invasive. Around a dozen new non-native species establish themselves in the UK every year.
A 2023 Scottish Government study identified 30 invasive non-native species with a high risk of becoming a problem in Scotland in the next decade – including raccoons, which would compete for food with our native foxes and badgers.
Scotland has a long-term goal to eliminate the impacts of INNS by 2045. There is a UK goal to halve the number of new species arriving by 2030 and there is a similar global target. There was also an international target for strong action by 2020 but progress in Scotland has been slow.
Despite efforts to tackle them the threat and impact of these species is on the rise, driven by climate change and growing global movement of people and goods.
Last month Scottish Environment Link published a proposed action plan for tackling INNS, including 10 INNS response principles developed by environmental and conservation groups, These include acting early, at sufficient scale and, where possible, making those responsible pay to deal with the problem. They also call for specific strategies to deal with rhododendron and to prevent grey squirrels advancing into the Highlands.
Environmental Standards Scotland, of which I am Acting Chair, is reviewing the scale of the problem, the success of current strategies and what more could be done. It will also be looking at gaps in existing data. To get started it has issued a call for evidence on invasive non-native species. This closes on the 11th of July.
Invasive non-native species are a serious and growing threat to nature and the economy, here and around the globe. The increased attention being paid to what more we should do to combat this problem is very welcome.
A version of this article appeared in the Scotsman newspaper on the 12th June 2024.
Image: Giant hogweed. Image made by nature protector Natubico www.vivism.info
