A “lost world” beneath the North Sea was once full of forests

The study, published in Proceedings of the National Academy of Sciences (PNAS), used sedimentary ancient DNA to uncover evidence of temperate trees such as oak, elm, and hazel more than 16,000 years ago. Researchers also detected DNA from a tree genus thought to have disappeared from the region around 400,000 years ago. In addition, the results suggest that parts of Doggerland persisted through major flooding events, including the Storegga tsunami about 8,150 years ago, with some areas remaining above water until roughly 7,000 years ago.

Professor Robin Allaby at University of Warwick and lead author of this study says: “By analyzing sedaDNA from Southern Doggerland at a scale not seen before, we have reconstructed the environment of this lost land from the end of the last Ice Age until the North Sea arrived. We unexpectedly found trees thousands of years earlier than anyone expected — and evidence that the North Sea fully formed later than previously thought.

“From a human perspective, this is the best evidence that Doggerland’s wooded environment could have supported early Mesolithic communities prior to flooding and may help explain why relatively little early Mesolithic evidence survives on mainland Britain today.”

Reconstructing the Lost Landscape of Doggerland

Doggerland once formed a land bridge connecting Britain to mainland Europe before rising sea levels submerged it, creating the modern North Sea. While scientists have long known the region was eventually forested, the timing of when trees first took hold and how suitable the environment was for early humans has remained uncertain.

To investigate, researchers analyzed sedimentary ancient DNA from 252 samples taken from 41 marine cores along the prehistoric Southern River (chosen for its well-preserved sediments and potential to reveal past habitats). This approach allowed them to trace the ecological history of Doggerland from about 16,000 years ago until it disappeared beneath the sea.

Their findings show that temperate woodland species, including oak, elm, and hazel, were present much earlier than suggested by pollen records from Britain. Lime (Tilia), a tree that prefers warmer conditions, also appeared around 2,000 years earlier than previously recorded in mainland Britain, indicating that parts of Doggerland may have acted as a northern refuge during the last Ice Age.

In another unexpected result, the team identified DNA from Pterocarya, a relative of walnut believed to have vanished from north-western Europe about 400,000 years ago. This suggests the species survived in the region far longer than previously thought.

New Insights Into Ice Age Europe and Early Humans

The findings add to growing evidence that small, protected areas known as “microrefugia” allowed temperate plant species to survive harsh Ice Age conditions in northern Europe. These refuges may help explain Reid’s Paradox — how forests were able to spread so quickly across the region after the last Ice Age ended.

The presence of woodland ecosystems in southern Doggerland 16,000 years ago also suggests the area could have supported abundant wildlife and provided valuable resources for humans, including animals such as boars. This would place a rich environment in the region thousands of years before the appearance of early groups like the Maglemosian culture around 10,300 years ago.

Co-author, Professor Vincent Gaffney at University of Bradford says, “For many years, Doggerland was often described as a land bridge – only significant as a route for prehistoric settlement of the British Isles. Today, we understand that Doggerland was not only a heartland of early human settlement, but also that the presence of the land mass may have provided a refuge for plants and animals and acted as a fulcrum for how prehistoric communities settled and resettled northern Europe over millennia.”