Only plant known to have survived Ice Age here found

Sat, Aug 18, 2012, 01:00

IT MUST surely rank as Ireland’s toughest plant. Researchers have discovered the only known survivor of the last Ice Age here, a rare herb that loves the cold.

Most scientists believe that the Ice Age that ended 15,000 years ago scraped away all plant and animal life in Ireland.

However, a team from NUI Maynooth led by ecologist Dr Conor Meade has discovered that this is not so. They used an advanced DNA sampling method to show that the herb, Fringed Sandwort, has lived here – ice or no ice – for up to 150,000 years.

Dr Meade and collaborator Dr Colin Kelleher, of the National Botanic Gardens, recovered samples of Fringed Sandwort from the top of Benbulben in Co Sligo. Fellow team members Xiaodong Dang and Emma Howard-Williams collected similar plants from mountain peaks all over Europe, from Spain up to Svalbard inside the Arctic Circle.

The analysis showed the plants were the same, whether they came from northern Norway or the highest peak in Italy. Science Foundation Ireland funded the work, which was published in Molecular Ecology Resources.

“The data was unambiguous. There can be no doubt what we have in Spain and Italy is what we have on Benbulben,” said Dr Meade, who heads the molecular ecology laboratory in Maynooth’s department of biology.

The plant sports attractive white flowers, belying its toughness. It thrives up mountain sides at 2,500m to 3,000m, he said.

The question was how did it survive the glacial maximum here between 23,000 and 15,000 years ago, when ice a kilometre deep blanketed the Irish midlands.

Effectively the plant exploited a niche, a place that the ice did not cover, Dr Meade said. One such place was the high slopes of Benbulben. The Inuit refer to such spots as nunataks, or rocky outcrops above ice. “There is some evidence for nunataks and there was one on Benbulben. The north face of Benbulben appears to have remained ice-free,” he said.

“If we are going to find an ancient survivor we will probably find it here and it will only be found here,” he added.

The team developed a new DNA analysis method that allowed them to show quickly that all the plants tested were effectively the same plant – strong evidence that those found here weren’t blow-ins that arrived once the glaciers had gone.

Dr Meade said if this plant survived, perhaps others did too.

Indeed, perhaps the odd mammal also survived. Such speculation is, as yet, still to be proven by science.