Climate warming unlikely to cause extinction of ancient Amazon trees
January 28, 2013
Trees in the Amazon are likely to survive human-caused climate warming, according Chris Dick, STRI research associate and professor at the University of Michigan
Trees in the Amazon are likely to survive human-caused climate warming, according Chris Dick, STRI research associate and professor at the University of Michigan. Chris and colleagues determined the ages of tree species by extracting and sequencing DNA and analyzing the number of genetic mutations in the sequences. By estimating how long it would take for each tree population to accumulate the observed number of mutations researchers arrived at a minimum age for each species.
“We were surprised to find that nine of the tree species have been around for at least 2.6 million years, seven for at least 5.6 million years, and three for more than 8 million years, indicating they have survived previous periods as warm as many of the global warming scenarios forecast for the year 2100,” Chris commented. The results challenge earlier publications predicting species extinctions in response to relatively small increases in average global air temperatures.
Chris points out an important caveat: “Because we've been in a cold period over the past 2 million years some of the trees' adaptations to warmth tolerance may have been lost.” Study co-author Simon Lewis of University College London and the University of Leeds cautions that “the past cannot be compared directly with the future… direct human impacts, such as forest clearance for agriculture or mining, should remain a focus of conservation policy.” Finally, Eldredge Bermingham, co-author of the study concludes: “The most lasting finding of our study may be the discovery of ancient geographic variation within widespread species, indicating that many rainforest tree species were widely distributed before the major uplift of the northern Andes.”
This article is available online.