Twenty forests in Scotland could act as “natural strongholds” for native red squirrels, protecting them even if greys were to “run rampant across the country”, research suggests.
The modelling shows the current composition of the country’s forests would protect red squirrels without the side-effects of other conservation measures including culls of the invasive grey species or man-made havens for reds.
A computer model developed by Professor Andy White, a mathematical biologist at Heriot-Watt University, found that red squirrels could use the 20 strongholds even in a worst-case scenario, if greys are allowed to “run rampant around Scotland”.
He said: “Red squirrels dominate in coniferous forests, whereas grey squirrels do better in broadleaf and mixed forests.
“The current policy is to create 19 managed strongholds for the reds, where broadleaf trees are removed and replanted with conifers that would protect their red populations. However, this would reduce tree species diversity for other species.
“Our model shows that over 20 existing forests in Scotland would act as natural strongholds for the reds. This means we don’t have to remove broadleaf species like oak.
“Natural strongholds could conserve red squirrel populations while simultaneously maintaining forest diversity.”
Conifers are trees which grow needles instead of leaves and cones instead of flowers, and they tend to be evergreen.
Two of Scotland’s red squirrel havens are Eskdalemuir forest in Dumfries and Galloway in the south, and Newtyle forest in Moray in the north.
Scotland is currently home to about three-quarters of the UK’s estimated 140,000 red squirrels, which are smaller than their grey rivals, of which there are about 2.5 million in the UK, said the Wildlife Trusts.
The greys were introduced to the UK from North America by the Victorians in the 1800s.
Greys threaten the long-term future of red squirrels by carrying the disease Parapoxvirus which can kill reds and are more likely to eat green acorns, reducing food sources.
The research is published in the journal Nature Conservation.