In the 1980s, a hilltop in coastal Ecuador witnessed a devastating mass extinction event. Ninety unique plant species, some yet to be officially named, vanished as the last cloud forests of the Centinela range were cleared for agriculture. This cautionary tale has been a rallying cry in the battle to preserve rainforests worldwide.
However, a recent study published in Nature Plants challenges this narrative. After extensive research, an international team of botanists found no evidence of these extinctions. Instead, they discovered that Centinela’s flora persists in the remaining fragments of coastal Ecuador’s forests.
“It’s a miracle,” said lead author Dawson White, a postdoctoral researcher in the Department of Organismic and Evolutionary Biology at Harvard. “Many of Centinela’s plants are still on the brink of extinction, but fortunately, the reports of their demise were exaggerated. There’s still time to save them and turn this story around.”
The study uncovered a fascinating revelation about the earlier overestimation of extinction likelihood at Centinela. It turns out that the researchers at the time were discovering a plethora of new and unclassified species, with limited knowledge of the distribution of plant species in the world’s most diverse forests. Over the decades, these initial collections have yielded more than 50 new species.
Additionally, as botanists expanded their collections and natural history museums digitized their specimens, plants believed to have vanished at Centinela have been found in other South American locations, while some were rediscovered in situ by the team. Out of the 90 species initially presumed extinct, only one remains to be rediscovered or confirmed to exist elsewhere. This remarkable revelation underscores the importance of continued research and conservation efforts in these biodiverse regions.
“Understanding which plants are growing in a given Andean cloud forest is a monumental task because you will undoubtedly find new species,” said White. “What our investigation highlights is that it takes decades of work from taxonomic experts to describe new species in such forests. And only once we have names for these species that are then noted in our scientific networks can we begin to understand where else these plants grow and their risk of extinction.”
Ecuador, a small but incredibly diverse country, serves as a compelling example of the challenges scientists face in monitoring and protecting tropical biodiversity. With over 20,000 plant species, including 4,000 found nowhere else on Earth, many of which are still unnamed and unmapped, it’s clear that urgent action is needed. The study emphasizes the crucial role of herbaria collections in understanding and preserving plant diversity.
“Herbaria give us the fundamental ‘what’ and ‘where’ of plant biodiversity,” said co-author Juan Guevara, Universidad de Las Américas in Quito. “They are what made it possible to solve this mystery. They’re the basis of everything we know about which plants are threatened with extinction.”
Furthermore, the study revealed that Centinela’s forests are more resilient than previously believed. Recent fieldwork uncovered small, overlooked fragments of the original forest, some less than an acre in size, which are home to many species thought to be extinct. One such rediscovery is the Gasteranthus extinctus, a wildflower named after its own extinction, found by the team in 2021.
“Over the last two years, we’ve surveyed a dozen fragments in the region,” said co-author Andrea Fernández, Northwestern University and the Chicago Botanic Garden. “They’re tiny islands lost in a sea of plantations, but they’re still full of astonishing plants.”
The researchers were astounded to find a wealth of both familiar and previously undiscovered plant species in the old Centinela flora. Their discoveries over the past five years have led to the description or unearthing of eight new species, ranging from delicate wildflowers to majestic canopy trees.
“One of our most astonishing discoveries is a totally new species of canopy tree in the Cotton family,” said Fernández. “It’s one of the tallest trees we have encountered, but it’s extremely rare; there could be only 15 individuals alive in Centinela. It’s now being actively targeted by local loggers-s-o we are rushing to describe this new tree species and get its seeds growing in botanic gardens.”
Once shunned due to its troubled history, Centinela is now abuzz with scientists eager to explore its ravaged forests for potential research and conservation opportunities. In Ecuador, botanical gardens are creating collections of the region’s rarest and most endangered plants, while conservationists are gathering seeds for future reforestation efforts and seeking sustainable solutions to preserve the remaining fragments.
On a global scale, the revival of Centinela has sparked the launch of a new conservation initiative by Earth imaging company Planet Labs, offering high-quality satellite imagery to bolster conservation projects.
While the new study revises the record of a past mass extinction event, it does not diminish the urgency of the current biodiversity crisis worldwide. The IUCN Red List reports that over 45,000 species on Earth are currently at risk of extinction, with nearly half of all amphibians, a third of all corals, and a quarter of all mammals facing threats. Scientists at Kew Botanical Gardens have compiled a list of over 800 plant species presumed to have already become extinct.
“Plants in coastal Ecuador and a lot of other hard-hit places in the tropics are finding a way to hang on in the last nooks and crannies,” said co-author Nigel Pitman, the Field Museum of Natural History. “They won’t survive for long under those conditions, but we’ve still got time to act before they’re gone forever.”
Journal reference:
- Dawson M. White, Nigel C. A. Pitman, Kenneth J. Feeley, Gonzalo Rivas-Torres, Santiago Bravo-Sánchez, Francisco Sánchez-Parrales, John L. Clark, Carmen Ulloa Ulloa, Xavier Cornejo, Thomas L. P. Couvreur, Marcia Peñafiel, Gladys Benavides, Carmita Bonifaz, Juan Carlos Cerón, Andrea Fernández, Riley P. Fortier, Daniel Navas-Muñoz, Verónica Rojas M, J. Nicolás Zapata, Justin Williams & Juan Ernesto Guevara-Andino. Refuting the hypothesis of Centinelan extinction at its place of origin. Nature Plants, 2024; DOI: 10.1038/s41477-024-01832-7
