Scottish forests offer red squirrels sanctuaries from invaders
Twenty Scottish forests could act as “natural strongholds” for native red squirrels, protecting them even if greys “run rampant”, research has suggested.
The modelling by Professor Andy White, a mathematical biologist at Heriot-Watt University, published in Nature Conservation, shows that the coniferous composition of the country’s forests would protect red squirrels without the side-effects of measures such as culls of invasive greys.
Scotland is home to three quarters of the UK’s 140,000 red squirrels, which are smaller than their rivals. Reds naturally dominate, however, in coniferous forests such as Newtyle in Moray and Eskdalemuir in Dumfries and Galloway.
The computer model found that red squirrels could use the 20 strongholds even in a worst-case scenario, if populations of greys are allowed to soar.
“This is great news for red squirrels,” said White. “When I started this research 10 years ago I was pretty pessimistic about the outcome for red squirrels in Scotland. Now I’m very optimistic. The work done by conservation bodies has prevented the spread of grey squirrels beyond certain boundaries over the last decade.”
The research, which is published in Nature Conservation, identifies havens within existing areas of non-native plantations, such as Eskdalemuir Forest in Dumfries and Galloway in southern Scotland and Newtyle Forest in Moray in the north. Ironically, the native red squirrel can survive in non-native plantations of species such as sitka spruce that are inhospitable for the broadleaved or mixed woodland-loving grey squirrel.
The co-author, Kenny Kortland, a wildlife ecologist for Forest and Land Scotland, the Scottish government’s forestry body, said that the study showed that Scotland’s timber industry supports one of the country’s most popular species.
The resurgence of pine martens has also improved the reds’ prospects, with the native carnivore proving effective at predating or dispersing grey squirrels. But last year a study showed that the pine marten will not live in urban areas, which remain a grey squirrel stronghold from where the species can expand.