Scientists from the University of Newcastle upon Tyne's School of Biology have found that small number of red squirrels found in Cumbria, North West England, have a unique genetic make-up which sets them aside from those found in other areas of Britain and the continent.
But probably less than a thousand of these animals still survive and are dwindling in number due to an invasion by the American grey squirrel, which out-competes reds for food and passes on a deadly pox virus which can kill reds within two weeks.
Although Cumbria is benefiting from a red squirrel conservation programme, researchers say this may not be enough, and argue that these animals should be included in a captive breeding programme as an additional measure to ensure the animals survive.
The Cumbrian red squirrels could represent the last surviving members of an originally described subspecies for Britain, although other populations may exist in Scotland.
It is important they survive because previous research has suggested that more genetically diverse a species is, the less likely it is to become extinct.
The Newcastle University research team, who analysed squirrel hides from Holland, Italy, Spain, Sweden and the UK, publish their report in the current edition of the academic journal Conservation Genetics *.
Cumbria, along with North East England and parts of Scotland, is one of the last strongholds of the red squirrel in the UK. Populations of the species are declining nationally, mainly due to the continued spread of the grey squirrel.
Conservationists are working with landowners in Cumbria to introduce a series of refuges to red squirrel areas, which involves shaping a friendly environment for the animals within the local landscape.
However, the researchers are concerned there is a risk that the programme may not succeed. Landscape structure and composition in the region favour the grey squirrel and this, combined with the disease threat, means that it will be a difficult task to save red squirrels there.
For their study, the team analysed DNA samples from the pelts of more than 200 British and European squirrels held in museum collections dating back to 1861 to determine their genetic constitution.
The research suggested red squirrels in the North-east have adapted really well to the man-made conifer plantations of the region. It also showed many squirrels have recent European ancestry due to introductions of continental squirrels to the UK over the last 150 years.
However, there is no evidence of these introductions occurring in Cumbria, where many squirrels were found to resemble 18th century descriptions of the species.
Red squirrels came to Britain during the last ice age, 10,000 years ago. They colonised the UK from the European mainland, as forest cover followed the retreat of the ice sheets.
Researcher Dr Peter Lurz said: "Our research shows Cumbrian squirrels are very special. However, with the continuing spread of the grey squirrels in this region we are likely to lose them. Although we applaud the current conservation efforts to build refuges for the red squirrels, we think these may not be enough.
"A captive breeding programme needs to be introduced as an additional conservation measure, just in case the refuge programme does not work. This will guarantee these unique animals are not lost forever.
"We are not saying the Cumbrian squirrels are more important but we believe it is crucial to try and conserve them."
Dr Lurz paid tribute to the museums who supplied material for the research – Tullie House Museum in Carlisle, the Hancock Museum in Newcastle upon Tyne and British and Swedish Museums of Natural History. He said: "This kind of work would be impossible without their collections and support."
* Patterns of genetic diversity in the red squirrel. Hale, Lurz and Wolff, Conservation Genetics 5:2, pp.167-179 2004.
CONTACT: Dr Peter Lurz, tel. 44-191-222-5359
p.w.w.lurz@ncl.ac.uk
Availability: 10-4pm Tuesday and Wednesday April 6/7 2004.
Notes to editors:
1. The Newcastle University team has worked closely with Forest Enterprise (Kielder Forest) and the Mammals Trust UK over the last few years to help save red squirrels in conservation areas in Northumberland. See: http://www.ncl.ac.uk/press.office/newslink/index.html?ref=1065000922
USEFUL WEB LINKS:
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http://www.ncl.ac.uk/biol/
Up to date information on red squirrel projects:
http://www.squirrelweb.co.uk/
Squirrel facts and figures:
http://www.wildlifetrust.org.uk/durham/RedAlert/
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Journal
Conservation Genetics