Animal dung reveals secrets of the past

BALLYVAUGHAN, Ireland — The Burren in County Clare in the west of Ireland has long delighted tourists and intrigued scientists and botanists.

It consists of 135 square miles of bare limestone hills, its gray and pink rock contrasting with the emerald green fields on its horizons. It had long been assumed that the stripping action of glaciers long ago removed the top soil, and that only the arctic plant life for which the Burren is famous survived. Now new research has established that this "stony place" as the word burren (or boireann) means in Gaelic, was once a forest of pines and hazel trees that survived long after the Ice Age ended 12,000 years ago.

A team from National University of Ireland Galway came to this conclusion by examining ancient cattle and sheep excrement found deep in nearby peat deposits to establish grazing habits. To be more precise, they studied the spores of a fungus found on the animal dung, and were able to draw conclusions about the original plant cover.

Research published in the Journal of Ecology in London and carried out by Michael O’Connell and Ingo Fesser shows that the Burren supported woody vegetation and grasslands from around 1500 B.C. until possibly as late as the 17th century. The trees were cleared or burned by farmers to facilitate cultivation and grazing and the arctic flora that coexisted with the pine and hazel forests survived the clearances.

What the farmers lost through soil erosion is today Ireland’s gain. It has made a small corner of the country an area of spell-binding scenery, composed of terraced limestone rock and cracked pavements underneath which are hidden rivers and large caves.

On a recent drive along the coastal road from the beautiful village of Ballyvaughan in Galway Bay to Fanore on the windswept Atlantic coast, I found tiny orchids and arctic berries in crevasses of the rocks just a few paces from the roadside. I could see wild goats climb the steeper stone ridges.

Home to more than 700 species of plant life, the Burren is one of Europe’s richest botanical sites. A giant rock garden, it covers only 1 percent of the country’s landmass but is home to three quarters of Ireland’s native species. It is also one of the densest archaeological sites in northern Europe, with holy wells, ring forts and Neolithic and Bronze Age tombs, as well as early Christian churches and medieval abbeys.

The Burren is the only place in the world where cattle are moved to lowlands in summer and highlands in winter: In winter the lowlands are often waterlogged, while grass grows during the winter in the Burren. The limestone acts as a giant storage heater and releases its summer heat in the winter months.

Edmund Ludlow, the English officer who campaigned against small bands of guerrilla rebels on the Burren in 1651-52, memorably described it as a country where there is not enough water to drown a man, wood enough to hang one, nor earth enough to bury him, and yet their cattle are very fat — the grass growing in turfs of earth, of two- or three-foot square, that lie between the rocks is very sweet and nourishing.

The winter grazing is hugely important for the survival of the Burren's unique ecosystem. It leaves the grass short and allows the unique alpine and arctic flora to flourish without competing for space, light and nutrients.

While it looks rugged, the Burren's is a fragile ecosystem. In the 1990s there was an outcry from preservations and lovers of the region against a plan by the local government to build a new road and an interpretive center in the Burren to cater to an expected increase in tourists. The Irish planning board ruled against the scheme and today the Burren is treated as a national treasure by locals and visitors alike, and as a rich source for scientific research that tells the Irish more about their ancestors and the Ireland of long ago.