'Alien' threat to iconic red deer

Published on Wednesday 21 January 2009 21:30

SCOTLAND'S most iconic animal is under threat because it is breeding with an alien species, scientists have discovered.

Red deer could disappear from mainland Scotland because they are breeding with the Japanese sika deer, according to researchers at the University of Edinburgh.

And they warn that because the Japanese sika reproduces when it is younger than our native animal, usually in its first year, this could result in a rapid growth in the population of deer in Scotland. Already landowners struggle to control the high numbers.

Researchers studied the DNA of 735 deer from the Kintyre region. The results showed for the first time that there was extensive cross-breeding between red and sika deer, which were brought to Scotland in the 19th century.

In one area of forest more than 40 per cent of deer were found to be a mix of the two species.

Helen Senn, of the University of Edinburgh's School of Biological Sciences, said: "The extent of cross-breeding we uncovered is worrying, and suggests that similar populations of red-sika hybrids could exist undetected elsewhere in the UK.

"This cross-breeding represents a serious threat to wild red deer on mainland Scotland. Thankfully, legislation already exists to protect the red deer on many of the Scottish Islands from cross-breeding with sika deer, but the mainland red deer remain at risk."

She said although it is not known what the ecological impact of the cross-breeding could be, it could affect the rate the deer reproduce. "Sika deer give birth at a younger age, so it could form a population of deer that would be able to reproduce faster," she said.

"Given the management problems we have at the moment, that could make it worse.

"We don't know if that could happen but it's a possibility."

Ms Senn believes the extent of cross-breeding could change Scotland's wild deer population irretrievably. The cross-breed deer resemble a mix of the two species. The Japanese sika deer is spotty and smaller than the red, which is plain in colour.

Caroline Warburton, manager of Wild Scotland, said the research was worrying. "Red deer are probably the most iconic animal of Scotland. If the red deer populations was being threatened by cross-breeding then I think it would be quite serious. It would have implications for the wildlife tourism industry but also the country sport industry, I would imagine.

"There's also the conservation issue in terms of it being a native species and sika deer are not."

The research, funded by the Natural Environment Research Council and the Macaulay Institute, is published in the journal Molecular Ecology.