In northern Colombia, in a semi-desert region that juts into the Caribbean Sea, its dusty roads traveled by the Wayúu people with their blankets and colorful backpacks, is Cerrejón — one of the largest open-pit coal mines in the world. Excavated for more than 30 years, its huge craters and twisted paths down which the trucks descend give the impression of a tropical hell.
But for the trained eyes of Carlos Jaramillo, that hell is a paradise he always dreamed of finding. There, while working for the Colombian Petroleum Institute more than 20 years ago, Jaramillo, a paleontologist and pollen expert, began with other colleagues to unearth the lost history of the Neotropical forests of the Americas — and to challenge some of the paradigms of paleontology.
Fossil after fossil, these scientists have been reconstructing a history that was thought to be impossible to discover. “For many years, it was believed that almost no fossils had been preserved in the tropics because of the high rates of weathering — the decomposition of minerals and rocks — and, if they did exist, it would be very difficult to find them because of the current forest cover,” says Jaramillo, now a researcher at the Smithsonian Tropical Research Institute in Panama.
While the geology textbooks that Jaramillo and his colleagues learned from said that tropical forests, just like temperate forests, had remained more or less stable in their plant composition for at least 120 million years, recent palaeobotanical findings suggest a very different story.
For the entire Cenozoic, the current geological era that began some 66 million years ago with the meteorite impact that wiped out dinosaurs and many of the planet’s other species, “the climate and geology of the Neotropics have been far from stable,” note ecologist Christopher W. Dick and botanist R. Toby Pennington in a review of the history and geography of Neotropical tree diversity in the 2019 Annual Review of Ecology, Evolution, and Systematics. In addition to the meteorite impact, which marked a before and after in this ecosystem, the rise of the Isthmus of Panama, the formation of the Amazon River and the uplift of the northern Andes, for example, have profoundly influenced the region’s climate, species formation and migration.
