A researcher from the University of Southampton in the UK has discovered that the currently treeless and rugged grasslands of the Falkland Islands once hosted a lush and varied rainforest about 30 million years ago.
Dr. Zoë Thomas, who led an international group of scientists, revealed that the South Atlantic archipelago was once blanketed with cool, moist woodlands, resembling today’s rainforests in Tierra del Fuego, located at the southern tip of South America.
The research began after Dr. Thomas and her team received informal tips from the local community in Port Stanley, the capital of the Falklands, about possible buried remains of the ancient forest. Casual discussions eventually led them to the discovery of perfectly preserved prehistoric tree remnants and pollen at a construction site in early 2020.
“While we were in the Falklands for another research project, a local researcher mentioned hearing from a friend that something remarkable had been found by a builder they knew,” Dr. Thomas, a physical geography expert at the University of Southampton, explains.
She adds, “Excavators at a site for a new care home in Stanley had dug into a deep peat layer containing large tree trunks and branches. These finds were so well preserved that it appeared as though they had been buried only yesterday, although they were actually incredibly ancient.”
“We were instantly intrigued, as the presence of tree remnants here was surprising. For thousands, likely millions, of years, the Falkland Islands have been too windy with overly acidic soil to support trees. This led us to wonder just how old the wood was from this forest bed,” she reflects.
Assisted by the South Atlantic Environmental Research Institute (SAERI) in Port Stanley, the team extracted samples of the peat layers and deposits from the Tussac House site near Stanley Harbour. These samples were carefully sent to Australia for testing at the University of New South Wales, where the sediment was extensively sampled and the wood examined using specialized scanning electron microscopes.
Due to their age, the tree remains were too old for effective radiocarbon dating, so researchers turned to pollen spores instead. They analyzed several types of spores compacted and sealed within the same peat layers as the wood. This pollen analysis indicated that the tree trunks and branches were dated between 15 and 30 million years old.
The comprehensive research findings have recently been published in the journal Antarctic Science.
The Falkland Islands, a British territory located 8,000 miles from the UK in the South Atlantic, consist of two main islands and 778 smaller ones, covering an area slightly larger than half of Wales. The islands are characterized by wet, cold, and windy weather with rapidly changing conditions, resembling Dartmoor in the UK.
In the distant past, the climate in the South Atlantic was significantly warmer and wetter, capable of supporting rainforest-like environments. While these conditions were cooler than the tropical rainforests we often envision, such as the Amazon, they could still host a rich and diverse ecosystem comprising various plant and animal species.
Many tree species present on the Falklands when the Tussac House samples were taken have since become extinct. However, it is believed they arrived on the islands by being carried by prevailing westerly winds from the expansive rainforests that once spread across large areas of the southern hemisphere, including modern-day mainland South America.
Although researchers cannot definitively determine the cause of the rainforest’s decline and the subsequent transition to peatlands, a shift in climate toward colder and drier conditions is a plausible explanation.
Dr. Thomas remarks, “It’s fascinating to consider that if we hadn’t had the opportunity to converse and connect with the tight-knit community at that specific time, we might have never discovered these impeccably preserved tree samples.”
“Prior to our visit and the discovery by the construction worker, no one realized that six meters beneath their feet lay perfectly preserved relics of an ancient rainforest, along with exquisite fossilized pollen. I am extremely grateful to the welcoming Islanders, whose openness allowed us this rare chance to investigate.”
Looking to the future, Dr. Thomas believes the islands are unlikely to revert to a forested landscape soon: “Current forecasts indicate that the region will become warmer but also drier, raising concerns regarding the potential for erosion of the peatlands, which are sensitive to climate change.”
