The team looked at how far red squirrels had retreated on a landscape scale, and found the annual distance was 76 square kilometres in Cumbria and 96 sq km in Norfolk. In contrast, the annual retreat in Italy was just 3.6 sq km and 4.4 sq km in Scotland. The red squirrel decline - measured in terms of the area they inhabit rather than population numbers - was 17-25 times higher in Cumbria and Norfolk where the virus was present than in Italy and Scotland where it was absent. (It is believed that red squirrels became extinct in Norfolk in the last ten years).
The team then simulated various management strategies using a computer model. Although results suggested that a continuous cull of more than 60 per cent of greys would be needed to save red squirrels on a landscape scale, researchers reasoned this approach would be costly, require complete coverage, long-term commitment and is unrealistic.
The team therefore recommend in the Biological Conservation study that the only practical and humane way forward is the strategy of red squirrel refuge areas where control of grey squirrels bringing the disease could be targeted locally along likely entry points.
In this second study, the team describes how it is applying computer technology to develop recommendations for England's biggest red squirrel refuge, Kielder Forest, Northumberland. The forest has played a leading role in developing conservation strategies for the red squirrel. The team identified four potential 'gateways' for grey squirrels and developed a strategy to manage the disease threat. So far there has been no reports of the virus or the disease in the forest. There are now plans to apply the ap
Source:University of Newcastle upon Tyne