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Friday 21 September 2018

Red squirrels at risk of dying out in the future

The pockets of red squirrels found throughout Ireland today are not well mixed and many of the populations appear to be genetically isolated
The pockets of red squirrels found throughout Ireland today are not well mixed and many of the populations appear to be genetically isolated

Jim Hurley - Nature Trail

The Red Squirrel is regarded a native Irish animal. If there were squirrels in Ireland before the last ice age, it is assumed that the ice, snow and cold wiped them out together with their host trees. It is also assumed that when the ice finally melted that Red Squirrels colonised our green and pleasant land under its own steam before rising sea levels cut us off as an island.

It is not known for certain if they did colonise naturally or if people brought them here. It is not known why people would want to import them. Their remains have never been reported from archaeological digs.

The earliest evidence of the Red Squirrel being present in Ireland is a reference in a historical document dated from about the year 655 AD. By medieval times they were abundant as evidenced by the historical records of an export trade in pelts.

Exports of squirrel pelts fell dramatically during the eighteenth century in tandem with the widespread destruction of native woodlands. The trade ceased, and it is believed that the Red Squirrel possibly became extinct.

Several landlords reintroduced Red Squirrels to their estates. At least ten introductions from England are documented during the period 1815-1876. These animals are believed to have thrived, multiplied and spread.

So, is the Red Squirrel a native? And if it is, are there any natives left or are they all descendants of later introductions?

In a new collaborative study, mammal researchers, led by Denise O'Meara of Waterford Institute of Technology, used DNA to unravel the complex history of the Red Squirrel. They found that the Irish population retains a genetic footprint of a mixed ancestry. The heritage of some animals can be traced to Britain, as expected, but others retain a heritage rooted in mainland Europe.

So, our population is made up of a mixed bunch. While it might appear beneficial to the species to have such a broad genetic background, the new study shows that the pockets of red squirrels found throughout Ireland today are not well mixed and many of the populations appear to be genetically isolated and at risk of dying out in the future.

The problem is that Ireland's level of forest cover is still one of the lowest in Europe. Clear-felling, over-thinning and the lack of substantial hedgerows to act as wildlife corridors linking plots of woodland, results in populations being isolated, bobbing like a fleet of arks in a sea of uncertainty.

Wexford People

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