Rising Carbon Dioxide Levels Messing With Amazon Ecology

Researchers have discovered that areas of the Amazon rainforest previously considered pristine are in fact undergoing drastic changes, likely due to increased levels of carbon dioxide in the atmosphere. The discovery was a bit of an accident — researchers tracked changes in plots of isolated rainforest to use them as “controls” against which to measure other areas directly affected by humans. “But suddenly the controls weren’t acting like controls,” said William Laurance of the Smithsonian Tropical Research Institute, whose findings were published in the latest issue of the journal Nature. Tall, fast-growing trees were accelerating their growth, while denser, shorter, slower-growing trees beneath the forest canopy were declining. Laurence speculates that the changes are fueled by atmospheric CO2. The results could be dire: As forest composition changes, dramatic changes in biodiversity could follow. Worse yet, the trees that are flourishing absorb less CO2, which means the forests’ ability to serve as a “carbon sink,” absorbing excess CO2, could be curtailed. Laurence urges a full-scale study of the problem.