The Falkland Islands were once home to a “lush, diverse rainforest” 30 million years ago, now uncovered thanks to a rare discovery 20 feet (or 6 metres) underground at a local building site.
Dr Zoe Thomas, from the University of Southampton, found that the South Atlantic archipelago was once covered in a cold and wet woodland, similar to the rainforests in Tierra del Fuego, off the tip of South America.
Working with a team of global scientists, Dr Thomas conducted the research after clues to the ancient forest’s buried remains reached her via word of mouth in Port Stanley, the Falklands’ capital.
“We were in the Falklands carrying out research for a different project when a fellow researcher, based on the Island, mentioned they’d heard from a friend that something interesting had been dug up by a builder they knew,” according to Dr Thomas, an expert in physical geography.
“We thought that’s weird because one of the things about the Falklands that everyone knows about is that no trees grow,” said Dr Thomas, lead author of a new study. “It’s very sort of windswept and barren.”
According to Dr Thomas, building excavators at the site of a new care home cut into a deep peat layer filled with large tree trunks and branches – with the trunks and branches so well preserved that they looked like they’d been buried the day before, but “were, in fact, extremely old.”
“Our interest was immediately piqued, as finding tree remains here was baffling. For at least thousands, probably millions of years, the Falkland Islands have been unable to sustain trees.”
“It’s too windy and the soil too acidic.”
“This raised the intriguing question of just how old the wood from this forest bed was?”
Speaking to CNN over the weekend, Dr Thomas and colleagues went to the site of the 1982 disputed UK and Argentina territory and began “picking up these big chunks of wood”—so well preserved that they “looked like driftwood.”
“The idea that they’d found tree trunks and branches made us think, how old can this stuff be? We were pretty sure that no trees had grown there in a long time,” she said – who published the findings in the Antarctic Science journal – revealing that the fossils predated radiocarbon dating, which can determine the age of organic matter up to 50,000 years old.
Instead, the scientists turned to microscopic pollen and spores found in the peat for answers. “Fossilised pollen indicates a particular span of geologic time, so its presence can help determine the age of a fossil site,” said Michael Donovan, paleobotany collections manager at Chicago’s Field Museum – who was not involved in the study.
The researchers then transported the remains and samples of the peat layers for testing at the University of New South Wales. There, they used an electron microscope that could produce highly detailed images of the wood and its cellular makeup – analysing a variety of spores compacted and sealed in the same layers of peat as the wood.
These pollen records led them to conclude that the tree trunks and branches are between 15 million and 30 million years old.
“The age limits for the study site were estimated based on age ranges of pollen species from Patagonian rocks and comparisons with similarly aged floras from southern Patagonia and Antarctica,” Donovan told CNN in an email.
Through analysis, they were able to identify the species of the trees, which belonged to a rainforest similar to what’s found in modern Patagonia – meaning the climate in the Falklands millions of years ago must have been wetter and warmer than it is today. At the same time, however, Dr Thomas said it would have been cooler than tropical rainforests such as the Amazon but still able to support a rich, diverse ecosystem of plant and animal life.
“A lot of tree species that are growing (in Patagonia) now hadn’t evolved yet, but we found close relatives (in the Falkland Islands samples), including species of beech and conifer,” she said.
“The Falkland Islands are currently covered by grasslands and lack native trees,” Donovan added. “The fossil pollen, spores, and wood presented in this study paint a much different picture of the ancient environment, providing direct evidence of the presence of cool, wet forests.”
The exact reason trees still don’t grow on the Falkland archipelago is unclear, according to the study, which added that trees flourish at the same latitude in other areas across South America. Dr Thomas said the strong winds the islands experience and the acidic peat-rich soil could be factors.
“Many of the tree species growing on the Falkland Islands are now extinct but would have seeded on the islands by being carried on the prevailing westerly winds from rainforests that covered much of the southern hemisphere, including mainland South America,” she said, adding that it “was reasonable to speculate” that the lack of tree life on the islands is due to a change in climate and a move to colder and drier conditions.
As for the future, Dr Thomas says the islands are unlikely to see a return to a forest landscape anytime soon: “Current projections suggest the region will get warmer, but also drier – leading to concerns about the risk of erosion to the peatlands, which are sensitive to climate change.”
- To learn more about ancient forests, including an ancient South Pole polar forest – covering areas of modern-day Australia, New Zealand and South America, click here for Wood Central’s special feature.
