Many Amazon tree species may survive man-made warming, a new genetic analysis has revealed, overturning findings that a temperature rise may cause them to die. However, researchers warn that extreme drought and forest fires will impact the Amazon region as temperatures rise and the over-exploitation of the region's resources continues to be a major threat to its future.
The conservation policy for the Amazon should remain focused on reducing global greenhouse-gas emissions and preventing deforestation, they said, the journal Ecology and Evolution reported.
The study by University of Michigan evolutionary biologist Christopher Dick and colleagues shows the surprising age of some Amazonian tree species — more than eight million years — and thereby shows that they have survived previous periods as warm as many of the global warming scenarios forecast for the year 2100.
The new study is at odds with earlier papers, based on ecological niche-modelling scenarios, which predicted tree species extinctions in response to relatively small increases in global average air temperatures, according to an university statement.
"Our paper provides evidence that common Amazon tree species endured climates warmer than the present, implying that — in the absence of other major environmental changes — they could tolerate near-term future warming under climate change," said Dick, associate professor of ecology and evolutionary biology at Michigan.
But study co-author Simon Lewis of University College London and the University of Leeds cautioned that "the past cannot be compared directly with the future."
"While tree species seem likely to tolerate higher air temperatures than today, the Amazon forest is being converted for agriculture and mining, and what remains is being degraded by logging and increasingly fragmented by fields and roads," Lewis said.