Specimens from the Brazil nut, Lecythidacene family, are displayed inside the Herbarium at The New York Botanical Garden, in the Bronx borough of New York. () (AP Photo/Ed Bailey/File/Thinkstock)
Amazon forests may lose thousands of tree species
November 30, 2015
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A first-of-its-kind examination of the Amazon's trees found that as many as half the species may be threatened with extinction. Or they could be heading that way. It is because of massive deforestation. Among the more than 5,000 tree species in deep trouble are the ones that produce Brazil nuts and mahogany.
An international team of 158 scientists examined the trees. The scientists found that between 36 and 57 percent of the 16,000 tree species in the tropical rainforest area would be considered threatened. The actual number depends on the degree to which deforestation comes under control in the next 35 years. The scientists' study is published in Science Advances.
The range rests on whether cutting down the region's forest continues at the rate of the late 20th and early 21st centuries or slows down to lesser levels proposed in 2006, study authors said. If deforestation continues at the same pace, nearly 8,700 tree types are in trouble. But the number of species at risk could be as low as 5,500. That is if nations are able to cut back as planned, said study co-author Nigel Pitman. He is from the Field Museum in Chicago.
"We've never had a good idea of how many species are threatened in the Amazon," Pitman said. "Now with this study, we have an estimate."
About 15 years ago, the Amazon was losing about 11,600 square miles of forest a year, said Tim Killeen. He is a scientist from Agteca Amazonica in Bolivia. That figure has dropped to about 3,800 square miles a year, he said.
Killeen said the tree that produces Brazil nuts is seriously under threat. And "mahogany is commercially extinct throughout the Amazon." He said that means there's no more industry harvesting the wood. But some trees exist.
Duke University ecologist Stuart Pimm praised the work as sensible and important. He was not part of the study.
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CRITICAL THINKING QUESTION
Why have scientists not known how many species are threatened in the Amazon, until now?
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