Study: Half of Amazon Tree Species Could Become Extinct

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By Nora Macaluso

Nov. 20 — More than half of the tree species in the Amazon, the world's most diverse forest, could become extinct if not protected from threats ranging from mining to climate-related fires and droughts, according to a study released Nov. 20 by Chicago's Field Museum.

Some 36 percent to 57 percent of the Amazon's estimated 15,000 tree species probably qualify as “globally threatened” under International Union for Conservation of Nature criteria, said the study, published Nov. 20 in the journal Science Advances. Species including the Brazil nut, cacao and acai palm are among those potentially at risk, researchers said.

The study, involving 158 researchers from 21 countries, is the first to quantify the number of threatened species in the Amazon, the largest river basin in the world, the study's authors said.

“The story isn't that before this study we thought only a handful were threatened, and now we think there are quite a lot,” Nigel Pitman, an ecologist and conservationist with the Field Museum, said on a conference call. “The story is we've never had a good idea about how many species are threatened in the Amazon. Now we have an estimate.”

Largest River Basin

The Amazon basin drainage area covers more than a third of the South American continent in Brazil, Bolivia, Peru, Ecuador, Colombia, Venezuela and Guyana.

The researchers looked at deforestation trends and projected tree-species losses through 2050 under two scenarios: business-as-usual, which assumes current practices continue, and improved governance.

Under the business-as-usual case, 57 percent of species likely qualify as globally threatened, while if policies such as limiting illegal logging were to be enforced, the figure drops to 36 percent, they said. Both scenarios indicate threats to rare species, particularly in southern and eastern Amazonia, the study found.

The good news is about half the Amazon forest is in some form of protected area, lead author Hans ter Steege of Naturalis Biodiversity Center in the Netherlands, said during the call. If policies are put in place so that those areas remain protected, “the Amazon could be a showcase of large-scale conservation worldwide,” he said.

Underlying Causes Remain

On the other hand, a “return to past land-clearing practices remains very much a possibility,” said co-author Tim Killeen, a botanist and ecologist from Agteca-Amazonica, a Santa Cruz, Bolivia–based conservation group. “The underlying causes of deforestation have not gone away.”

Countries still have legal mechanisms that permit land-clearing for agriculture, and investment in mining continues while demand for commodities is projected to rise, he said.

To contact the reporter on this story: Nora Macaluso in Lansing, Mich., at nmacaluso@bna.com

To contact the editor responsible for this story: Greg Henderson at ghenderson@bna.com

For More Information 
The Field Museum study is available at http://advances.sciencemag.org/content/1/10/e1500936.