Air Date: Week of March 12, 2004

Living on Earth’s Jennifer Chu reports that rising levels of carbon dioxide may be causing changes in the makeup of the Amazon.

Transcript

CURWOOD: Just ahead: how an effort to protect the public from cancer-causing agents in water went wrong. First, this Note on Emerging Science from Jennifer Chu.

CHU: For fauna and flora deep in the Amazon jungle, life has gone relatively undisturbed for centuries. These rainforests are among the most bio-diverse areas in the world, and home to more than 5,000 species of trees. But new research suggests the composition of these trees is changing. And the catalyst for this change may be rising levels of carbon dioxide, from industrial emissions around the world.

Scientists in Panama have seen what they call a dramatic change in the makeup of the forest. For the last two decades, they’ve studied 14,000 trees in the central Amazon. As they compiled their data, several trends caught their eye. The first is that most tree species began growing faster than normal. Second, there appeared to be a high turnover of old trees to younger saplings. And finally, and most surprisingly, larger, faster-growing trees seemed to be taking over areas where smaller, slower-growing ones would normally thrive.

Researchers worry that this carbon dioxide overload could decrease biodiversity by accelerating competition among trees. There could also be global implications. Forests are known to cut down the greenhouse effect by storing up carbon in tree roots. The smaller, denser trees that have more carbon capacity could lose out to taller, more competitive canopy species. Down the line, scientists also suggest that as the composition of the forest changes, so might the animals that live in it. That’s this week’s Note on Emerging Science, I’m Jennifer Chu.

CURWOOD: And you’re listening to Living on Earth.

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[MUSIC: The Pogues “A Pistol for Paddy Garcia” RUM, SODOMY & THE LASH (Wea International – 1985)]