Today, Northern Ireland’s uplands may seem wild and barren, but in fact, they were occupied and farmed for centuries, enduring crises including the Great Famine, the Little Ice Age, and the Black Death. To researchers, there has been an air of uncertainty around the long-term effects of these stressors on the region’s remote, “marginal” communities compared to those in towns and cities like Dublin.
Slieveanorra is an isolated nature reserve in Northern Ireland’s Antrim Plateau. From as early as the 12th century, however, the area was home to several family units engaged in farming and shepherding, although researchers are unsure if residents were permanent or seasonal. Sparse human occupation of Slieveanorra continued until the early 20th century, when the area’s lack of infrastructure and professional opportunities contributed to the last residents permanently abandoning the site.
Gill Plunkett and Graeme Swindles, archaeologists affiliated with Queen’s University Belfast in Northern Ireland, dug at Slieveanorra to see how the environment had changed since 1000 CE. After a core of peat was taken from the local bog, they analyzed it for patterns in the prevalence of microbes, pollen, and plant fossils, all proxies for land use. Volcanic ash layers (left by eruptions in Iceland) and organic remains were used to date the layers and mark historically significant periods like the Black Death, Little Ice Age, and Great Famine.
In their PLoS ONE study, the researchers present a high-resolution record of Slieveanorra’s occupation across a thousand years. Proxies show indigenous woodland replaced by grassland cultivation of cereals throughout Slieveanorra’s occupied history, until its contemporary uses for recreation and commercial forestry.
Surprisingly, the patterns showed no drastic changes during historical catastrophes. “Had the population been severely impacted by climate or other calamities to the point that its survival in the area was compromised,” Plunkett explained, “we would expect to see a cessation of farming indicators, such as cereals, and a recovery of tree pollen as woodland spread out into abandoned areas.”
Slieveanorra’s Secret to Survival Success
Plunkett and Swindles speculate that the people of Slieveanorra must have been able to either avoid environmental and societal calamities or quickly adapt to them. This observation was unexpected because the Slieveanorra population was quite remote and relatively economically unproductive. Researchers suggest that the cause for such societal robustness comes down to factors like agricultural methods (including the harvesting of both food and fiber crops) and trade.
“We think the population was practicing subsistence farming,” Plunkett explained, “including mixed crop cultivation and some animal husbandry. A mixed economy, coupled with the likely availability of supplementary wild resources in the surrounding woodland and rivers, may have helped tide them over during lean years (for example, if a crop failed because of a bad summer). The low population density in the wider area would have minimized the risk of transmission of infectious diseases.”
Benjamin Gearey, a lecturer in environmental archaeology at University College Cork, Ireland, said that the new study contributes to a more robust understanding of how different communities have adapted to climate change in the past. “Reconstructing the impact of past climate change on human societies has long been something of a holy grail for paleoenvironmental and archaeological research,” he said. “This study is an important step forward, providing much food for thought, especially as we confront the contemporary impact of climatic change and ecological crisis.”
—Clarissa Wright (@ClarissaWrights), Science Writer