Scotland’s wildlife and ecosystem is at risk of “catastrophe” from raccoons that escape from zoos or stow away on lorries entering the country from Europe, experts have said.
The predators have been named on the top ten watchlist of non-native invasive species which are likely to arrive in the country in the next decade.
Richard Broughton, an ecologist and ornithologist at the UK Centre for Ecology and Hydrology (UKCEH), has said that racoons would be “bad news” for Scotland and for humans but a “potential catastrophe for other wildlife because they have a big biodiversity and environmental impact”.
The watchlist was compiled by the UKCEH and NatureScot for the Scottish government to show the potential impact of non-native species and inform policy on environmental protection.
There are already more than 1,000 invasive plants and animals in Scotland, such as the grey squirrel, rhododendron, Japanese knotweed, mink and New Zealand flatworm, many of which pose a significant threat to native wildlife.
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To avoid additional pressures the new watchlist warns of the arrival of ten species including plants that cause flooding, mussels that clog up water pipes, several flatworm species, muntjac deer and racoons.
Even though there are no known racoon populations in Great Britain, the animals are very intelligent and adaptable and it is therefore “highly likely that a small number of racoons could establish a breeding population”, according to NatureScot.
Since 1970 at least 21 of the predators have been sighted in the wild and in 2018 a pet racoon was captured by the Scottish SPCA after being spotted in a field in South Lanarkshire. The most recent sighting occurred this year in the West Midlands, according to NBN Atlas, which records biodiversity information.
The animals are native to North America but have been deliberately introduced in several European countries during the 20th century for hunting or fur production.
In Germany two pairs of pet racoons were released in the 1930s and during the Second World War 25 escaped from a fur farm near Berlin during an airstrike. There are now estimated to be more than one million racoons in Germany and the animals have successfully established populations in France, the Netherlands and Italy.
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Broughton, who was the group lead for vertebrates on the study, said: “We know from Germany, France and the Netherlands that if racoons get to Scotland and they get a toehold here, it will be bad news.”
Racoons can transmit diseases such as rabies or parasites and are known to cause damage in urban areas by rummaging through bins or entering people’s attics where they can cause significant destruction.
They are also generalist predators and can prey on a wide range of native species, which is of particular concern in Scotland where they could attack amphibians, birds and their nests.
“If racoons get into the wild they can become quite a nuisance,” Broughton said. “They will be very bad for water birds and seabirds because they track the eggs and chicks. They’ll compete with pine martens and will attack capercaillie and grouse eggs.”
While the UK banned the import, keeping and breeding of racoons in 2016, zoos and specialist owners who already had racoons were allowed to keep them provided they did not let them breed.
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This may have reduced the likelihood of racoons entering the wild but since the animals can live up to 20 years in captivity and are notorious escape artists this could be wishful thinking, according to Broughton.
He added that there was no way of knowing how many were already in the wild and once they started breeding they would be impossible to get rid of.
The recent report on non-native species also identified freshwater environments as particularly susceptible to invasive species such as Asiatic clams, quagga mussels, zebra mussels, floating pennywort and parrot’s feather.
It states: “Freshwater environments are considered to be among the most vulnerable habitats to biological invasion and freshwater biodiversity is culturally and economically important in Scotland.”
It added that increased water sports and tourism could also increase pathways for invasive species to be transported into and throughout Scotland via vehicles, boats, equipment and clothing.
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Out of 171 possible new arrivals the study focused on ten of the most likely species and hopes that this will inform national strategy and action which will help to reduce the threat of “biological invasion”.
Stan Whitaker, NatureScot’s invasive and non-native species specialist, said: “Invasive non-native species are a serious threat to Scotland’s nature, damaging our environment, the economy and our health, and costing Scotland at least £499 million a year.
“The threat is increasing with the growth in international trade and travel. But we can all do something to help prevent these species from spreading by being plant-wise and composting invasive pond plants, like floating pennywort and parrot’s feather in our gardens, with care — or by reporting sightings of mammals like muntjac deer.”
Top 10 invasive species
Freshwater species
Asiatic clam
Quagga mussel
Zebra mussel
Submerged plant species
Floating pennywort
Parrot’s feather
Terrestrial plant species
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Highbush blueberry
Pheasant’s tail grass
Vertebrates
Muntjac deer
Racoon
Flatworms (four species grouped together)
