Warm spell spurred tropical biodiversity
Some like it hot, including the plants living in South America's tropical rain forests 56 million years ago. As global average temperatures spiked 5 degrees Celsius over a period of 10,000 years — a geologic blink of an eye — plant diversity in northern South America also soared, researchers report in the Nov. 12 Science.
"We were expecting to find rapid extinction, a total change in the forest," says study leader Carlos Jaramillo, a biologist at the Smithsonian Tropical Research Institute in Balboa, Panama. "What we found was just the opposite — a very fast addition of many new species, and a huge spike in the diversity of tropical plants."
The study raises new questions about how tropical rain forests might respond as atmospheric carbon dioxide levels rise because of fossil fuel burning and other industrial activities. The researchers say that today's forests may not respond to warming in the same way that ancient forests did, but the findings do suggest that at least some plants are surprisingly adaptable.
"This kind of work is critically important," says Scott Wing, a paleobotanist at the Smithsonian Institution in Washington, D.C., who was not involved in the study. "We're beginning to map out what happened in different places during this huge perturbation of the carbon cycle and climate system. It's our best bet at seeing the results of something that's already happened."