‘We got evidence of boars, deer, bears, aurochs’: Ancient DNA reveals sunken realm Doggerland had habitable forests during the last ice age
A sunken landmass that connected Britain to mainland Europe until a few thousand years ago could have provided an excellent refuge for plants and animals, including humans, during the era. last ice agereveals a new study.
Parts of Doggerland, now submerged by the North Sea, were home to temperate forests as early as 16,000 years ago – long before these forests recolonized Britain and northwest Europe following the final retreat of glaciers around 11,700 years ago.
Article continues below
Oaks (Quercus), elms (Ulmus) and hazelnut trees (Coryl) thrived for millennia in southern Doggerland, where the new study was conducted, before the landmass disappeared. Previous estimates suggest Doggerland was completely flooded 7,000 years ago, but the new results indicate this may have happened more than 6,000 years ago. Researchers reconstructed the region’s long-lost terrestrial ecosystem using DNA which has been preserved in the land under the sea for thousands of years, known as ancient sedimentary DNA.
“We have evidence of wild boars, deer, bears and aurochs,” said the study’s lead author. Robin Allabyevolutionary geneticist and professor of genomics at the University of Warwick in the United Kingdom, told Live Science. “To my knowledge, this is the largest study of sedimentary DNA ever carried out.”
Allaby and his colleagues analyzed 252 samples from 41 cores they drilled under the North Sea, off the coast of England. Specifically, the researchers collected the cores along the 30-kilometer-long prehistoric Southern River, located in what was once southern Doggerland.
Researchers have long known that Doggerland was forested before it was flooded by the North Sea. But the age of these forests was unclear, so scientists assumed they appeared around the same time as Britain’s forests. The consensus before this new research was that 16,000 years ago, southern Doggerland was a tundra (a dry, treeless plain), not a forest, Allaby said. At that time, the ice sheets extended to what is now the border between Scotland and England, he added.
The researchers analyzed the sediment in the cores and separated them into two categories: safe and unsafe. The secured sediments were fine silts and clays containing ancient DNA from species living in the area where the core was collected. The unsecured sediments were coarser sand and gravel containing ancient DNA that was washed away far from where the core was extracted, meaning that this DNA was not useful for reconstructing the local ecosystem.
“This makes perfect sense,” Allaby said, because “DNA doesn’t survive long in water.” Sediments are typically transported and deposited in a fluid, with slow-moving waters picking up only fine sediments and fast-moving, higher-energy waters displacing coarser sediments. Slow-moving waters can transport DNA-carrying sediments only short distances before the DNA rapidly degrades. In contrast, fast-moving waters can carry DNA-containing sediments much further before they disintegrate.
This means that when researchers found fine sediments containing ancient DNA in the cores, that DNA had likely been spread locally. The DNA present in the coarse sediments likely came from upstream ecosystems. Therefore, “we might select samples that we don’t trust to tell us about the local environment,” Allaby said.
Ancient DNA in secure sediments showed that temperate forest trees and animals lived around the South River around 16,000 years ago, when much of northwest Europe and Britain was still covered in tundra. Remarkably, researchers identified DNA from a walnut relative (Pterocarya) thought to have disappeared from the region 400,000 years ago. The team also found evidence of heat-loving lime trees (Tilia), suggesting that southern Doggerland was milder than surrounding areas during the last ice age.
“It turns out our knowledge is very imprecise,” Allaby said. “It’s not pure tundra: there’s enough environment here to support something that looks like a forest.”
The results, published March 10 in the journal PNASindicate that Stone Age inhabitants would have had “plenty to live on” in southern Doggerland after the region’s ice sheets retreated about 21,000 years ago, Allaby said. “We can predict where good places to settle would be, and the mouths of rivers are usually the place to go, because you’re close to the resources.”
The findings could also help resolve Reid’s paradox, which describes the mismatch between seed dispersal rates and the speed with which trees like oaks recolonized northern regions from the south after the last ice age, the researchers said. Southern Doggerland or another nearby region, such as northern France, may have been a glacial “microrefuge” for temperate trees, allowing species to spread northward much more quickly than they could have done if they had survived only on the Iberian Peninsula, for example.
Finally, the study indicated that the North Sea completely submerged southern Doggerland around 6,000 years ago, at least 1,000 years earlier than previous estimates of when the landmass was inundated.
“It’s another culmination of how imprecise what our knowledge of this landscape is,” Allaby said. “It really is a boundary.”
Allaby, R.G., Ware, R., Cribdon, R., Hansford, T.A., Kinnaird, T., Hamilton, D., Kistler, L., Murgatroyd, P., Bates, R., Fitch, S., and Gaffney, V. (2026). Early pre-flood colonization consistent with northern glacial refugia of southern Doggerland revealed by ancient sedimentary DNA. Proceedings of the National Academy of Sciences, 123(11), e2508402123. https://doi.org/10.1073/pnas.2508402123
