Scientists recently analyzed sedimentary ancient DNA (sedaDNA) from 252 seabed samples taken from 41 marine cores in the southern North Sea (part of the submerged prehistoric landmass known as Doggerland). The findings, published in the Proceedings of the National Academy of Sciences (PNAS) and led by researchers from the University of Warwick, reveal that temperate forests thrived there more than 16,000 years ago — thousands of years earlier than previously indicated by pollen records from mainland Britain.

This places the forests deep into the Last Glacial Maximum aftermath, when much of northwestern Europe and Britain was still dominated by tundra and ice sheets had only recently begun retreating around 20,000 years ago. The discovery suggests Doggerland served as an early refuge or “microrefugia” for woodland species, allowing faster recolonization than models based on terrestrial evidence alone had predicted. It also implies that the full formation of the modern North Sea occurred later than some earlier estimates.

Key Findings from the DNA Evidence

Temperate trees: DNA from oak, elm, hazel, and lime (linden) appeared earlier than expected. These species formed a mosaic of woodlands along a prehistoric river system in southern Doggerland.

Associated wildlife: Traces of animals including boars, deer, bears, aurochs (wild cattle), and beavers indicate a habitable, resource-rich ecosystem capable of supporting early human populations during the late Ice Age / early Mesolithic transition.

The Pterocarya surprise: Most headline-grabbing was the detection of DNA from Pterocarya (a genus of walnut relatives, sometimes called wingnuts or Caucasian wingnut). Pollen and fossil records had indicated this tree disappeared from northwestern Europe around 400,000 years ago during earlier glacial-interglacial cycles. Its presence in these ~16,000-year-old sediments shows the species survived much longer in isolated pockets—likely due to favorable local conditions in Doggerland—challenging assumptions about its regional extinction timeline. The DNA clusters with modern Asian species like Pterocarya stenoptera.

Doggerland was a vast, low-lying plain connecting Britain to continental Europe until rising post-glacial sea levels gradually flooded it, with final submergence around 7,000–8,000 years ago (turning it into islands before full inundation). Fishermen and researchers have long dredged up mammoth bones, antler tools, and peat-preserved wood from the area, but this sedaDNA approach provides a high-resolution ecological snapshot without relying solely on visible fossils.

Buried Ecosystem

The study highlights the power of sedimentary ancient DNA for reconstructing lost landscapes where traditional pollen analysis falls short (pollen can degrade or travel). It refines our understanding of post-Ice Age vegetation migration, helps explain “Reid’s Paradox” (how forests seemed to spread faster than seed dispersal rates would allow), and suggests Doggerland may have been a key corridor for early human and animal movement—potentially explaining sparse early Mesolithic evidence on mainland Britain.

This discovery adds to the growing body of evidence that Doggerland was not a barren wasteland but a dynamic, productive landscape during a time of rapid climatic change. It underscores how much of Earth’s history remains hidden beneath the seas—and how new techniques like sedaDNA continue to rewrite timelines of ecological resilience and survival.

The research was published in March 2026, with coverage picking up in April. For the full paper, search for the PNAS article by the University of Warwick team (lead author Robin Allaby and colleagues).

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Early colonization before inundation consistent with northern glacial refugia in Southern Doggerland revealed by sedimentary ancient DNA

A new peer-reviewed study published in Proceedings of the National Academy of Sciences (PNAS) in early 2026 (March 2026 online) and led by researchers from the University of Warwick reveal that temperate forests thrived there more than 16,000 years ago.

Researchers analyzed 252 sedaDNA samples from 41 marine sediment cores along the course of a prehistoric river system in southern Doggerland (the submerged landmass that once connected Britain to continental Europe).

The full open-access paper is available on the PNAS site. (peer reviewed)

National Academy of Sciences (PNAS)

Lead author: Robin G. Allaby (University of Warwick)

March 10, 2026

Vol. 123 | No. 11

Early colonization before inundation consistent with northern glacial refugia in Southern Doggerland revealed by sedimentary ancient DNA

DOI: https://doi.org/10.1073/pnas.2508402123

Prior to the formation of the present-day North Sea during the mid-Holocene, North-Western Europe was connected through the Doggerland landmass. While it has been known for the past century that Doggerland was forested, it has not been clear when the onset of forestation occurred or whether the environment was more habitable for humans than surrounding European areas. In this study, we reconstruct the paleoecology of a river system, the Southern River, from the late Late Pleistocene to the late Holocene using sedimentary ancient DNA (sedaDNA) from 252 sediment samples from 41 cores spanning the length of the river system and headwater area. We identify secure and insecure sedaDNA signals by integrating sedimentological and sedaDNA data into a taphonomic model. Secure sedaDNA signals are found in silty and fine sand deposits where 95 to 98% originates from local deposition, but coarse sands and gravels are insecure with 60 to 70% of the sedaDNA associated with mixed ecosystem signals from reworked and influxed sediments. Secure sediments reveal the presence of several temperate tree genera such as Quercus, Ulmus, and Corylus over 16,000 y ago in the Late Pleniglacial, and thermal indicator genus Tilia several thousand years earlier than has been recorded for surrounding European areas. In this area, we also detect an anomalous signal of the genus Pterocarya, considered extinct in the region since the Hoxnian Stage (~400 ka). These observations are consistent with colonization from nearby northern glacial refugia, suggesting a favorable environment in which the cultural Mesolithic could develop.

Press coverage (ScienceDaily, EurekAlert, Warwick University, Live Science, etc.) from March–April 2026 emphasized the “lost world” forests and the surprising Pterocarya survival, but the title’s focus is on the early colonization/refugia implications.