Ancient DNA Reveals Ice Age Forests Grew on the Lost Doggerland 16,000 Years Ago, Before It Was Swallowed by the North Sea

Thousands of years ago, forests stretched across a landscape linking Britain to mainland Europe. Rivers meandered through stands of oak and hazel, animals like wild boar probably moved through the undergrowth, and early humans may have traveled or settled along its waterways. Today, this lost land – Doggerland – lies beneath the North Sea.

Now a new study, published in Proceedings of the National Academy of Sciencesshows that the forests of Doggerland appeared thousands of years earlier than previously thought. By analyzing ancient DNA from sediment samples taken from seafloor cores in the southern North Sea, researchers found that temperate trees were already growing there more than 16,000 years ago.

“We reconstructed the environment of these lost lands from the end of the last ice age to the arrival of the North Sea. We unexpectedly discovered trees thousands of years earlier than expected – and evidence that the North Sea fully formed later than previously thought,” lead author Robin Allaby said in a press release.

Learn more: This WWII wreck spills pollutants into the North Sea

Rebuilding Doggerland

To reconstruct Doggerland’s ancient environment, researchers examined 252 sediment samples from 41 seafloor cores drilled along the course of a prehistoric river that once flowed through southern Doggerland.

DNA showed that temperate forest species – including oak, elm and hazel – grew there much earlier than pollen records from Britain suggested. Another heat-loving tree, the linden, also appeared around 2,000 years earlier than expected in mainland Britain.

These early trees suggest that parts of Doggerland may have served as small refuges at the end of the Ice Age, where forest species managed to survive further north than expected.

The Lost Trees of Doggerland

DNA also revealed a surprising survivor. Researchers found traces of Pterocarya, a relative of the walnut tree thought to have disappeared from northwest Europe around 400,000 years ago.

Its presence suggests that the tree may have survived in isolated pockets of suitable habitat much longer than previously thought after its disappearance.

These types of habitats are known as “microrefuges” – small areas where plants and animals manage to endure harsh climatic periods while surrounding areas become inhospitable. Such refuges may help explain Reid’s paradox, which asks how forests spread so quickly across northern Europe after the Ice Age.

A landscape for humans, plants and animals

Wooded environments would have supported diverse wildlife and provided resources such as food, shelter and fuel – conditions that could have attracted early human communities long before the documented Maglemosian culture appeared, around 10,300 years ago.

“From a human perspective, this is the best evidence that the wooded environment of Doggerland could have supported early Mesolithic communities before the floods and may help to explain why relatively little evidence of the early Mesolithic survives today on the British mainland,” Allaby said.

The DNA record also indicates that Doggerland did not disappear as quickly as previously thought. Parts of the landscape appear to have survived major floods, including the Storegga tsunami around 8,150 years ago, and may have remained above sea level until around 7,000 years ago.

“For many years, Doggerland has often been described as a land bridge. Today we understand that Doggerland was not only the heart of early human settlements, but also that the presence of this land mass could have provided a refuge for plants and animals and served as a fulcrum for how prehistoric communities settled and resettled across northern Europe over the millennia,” added co-author Vincent Gaffney, in the press release.

Much of this ancient history may now be hidden beneath the waters of the North Sea.

Learn more: Little-known and underwater: 5 cities submerged in European seas

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