Suddenly the tree canopy below the twin-engine plane turns a mottled gray-brown, a sign of drought damage that he estimates may affect as many as half the trees.
Faced with warmer, drier conditions, trees have three options:
“Individuals can acclimate, species can adapt or migrate, or they go extinct,” says Kenneth Feeley, a biologist at Florida International University. A floral species can expand its range into a cooler region, but only as fast as seed dispersal allows. Feeley, who studies trees on the eastern slope of the Peruvian Andes, was surprised to see range changes there in just a few years. “Species are moving upslope about three vertical meters a year—that’s really fast,” he says, although perhaps not fast enough. “Based on the climate change that’s already happening, they need to move nine or 10 vertical meters a years.”
In the lowlands, deforestation reduces the areas to which species can move, and fields, pastures and roads create barriers to dispersal. Peru has some large protected areas, such as Manú National Park, where Feeley does his work, but scientists don’t know if they are big enough—or in the right places—to allow species to migrate in a rapidly changing climate.
As some species thrive and others fail to adapt, climate change will produce “winners and losers,” says Asner, who presented his preliminary findings on the drought damage on December 7 at the American Geophysical Union meeting in San Francisco.
