SCOTLAND'S moles are under threat from an underground alien invader from the other side of the world which is quietly wreaking havoc in the countryside, a leading scientist has warned.
While most farmers and greenkeepers may welcome the moles' plight, there is increasing concern among wildlife organisations about the mammal.
Experts yesterday said the moles' reputation as pests was undeserved. They play a vital role in drainage,
aerating the soil and dispersing nutrients.
But the problem for moles is that earthworms, which form the bulk of their diet, are being devoured by the invasive New Zealand flatworm (Arthurdendyus triangulatus).
Moles dig a network of tunnels as traps for earthworms to fall into. But moles will die within 12-24 hours without food, meaning the earthworm is vital to their existence.
Earthworms form part of a finely balanced food chain and it is possible their disappearance will affect not only moles but also other creatures such as badgers, hedgehogs and shrews.
Dr Brian Boag, a leading ecologist and the UK's foremost flatworm expert, who carried out a mole survey near Dunoon, said the absence of molehills in the test area was due to flatworms.
"This is an insidious problem which is not going to go away. It will get worse as time goes on," said Dr Boag, of the Scottish Crop Research Institute in Dundee.
"Passing by fields, you would expect around 70 per cent of them to have molehills. But when I surveyed 59 fields between Sandbank, near Dunoon, and Loch Eck, 55 of them had flatworms and no molehills.
"The New Zealand flatworms are predators who catch their prey at night and we don't yet have any method for destroying their advance."
Professor Stephen Harris, of the school of biological sciences at the University of Bristol, and an expert on moles, said: "There is recent evidence to suggest that there has been a decline in mole numbers across Britain.
"Last estimates in the mid-1990s put numbers at around 31 million but there is a distinct suspicion it is going down.
"We are not entirely sure why this is, but the New Zealand flatworm situation in Scotland may be a vital factor. Unfortunately the moles don't eat the flatworms."
Peter Cunningham, a biologist with the Wester Ross Fisheries Trust, who has a croft at Alltgrishan by Melvaig, near Gairloch in Wester Ross, said: "There are no moles on my croft though there were many within living memory in the last 20 years on my neighbour's.
"Moles were pests in the old days on the crofts, when their molehills in the long grass broke scythes, but they create drainage and let air in to stop the soil getting compacted and waterlogged. It looks like the flatworms are the cause."
Hannah Stockwell, promotions officer for the People's Trust for Endangered Species, which launched a UK-wide MoleWatch survey in January, said:
"There is so little information about moles and their population that a decline in numbers may go unnoticed.
"Through our annual mammal surveys, we detected a dramatic decline in hedgehog populations in some parts of Britain.
"As moles and hedgehogs both occupy similar habitats and have diets of earthworms and slugs, we decided to conduct a nationwide survey on moles in order to produce a distribution map so we can see where moles are present and absent from."
New Zealand flatworms were first spotted in Edinburgh and Belfast in the early 1960s and are believed to have been imported in a consignment of potplants from New Zealand.
They were initially seen as a curiosity but were eventually put on a government's "most wanted" hit list and scheduled under the Wildlife and Countryside Act 1981, making it an offence to release them or allow them into the wild.
FACT BOX• The European mole (Talpa europaea) is found in mainland Britain but not in Ireland. They have no UK legal protection.
• Its front feet are powerful and shovel-like "hands" that scoop earth, while the smaller hind feet kick it back behind the mole as it tunnels.
• Moles sometimes construct very large mounds containing an internal structure with one or more nests, a network of tunnels and even food stores.
• Males and females are solitary for most of the year. With the start of the breeding season, males enlarge their territories, seeking females.
• Most moles live up to three years, but they can make it to six. Their main predators are owls, buzzards, stoats, cats and dogs, and humans.
The full article contains 761 words and appears in The Scotsman newspaper.
