'Extinction Debt': Reaping What We've Bulldozed

Humanity's debt collectors may be coming soon to collect on the 'extinction debt' owed due to massive deforestation in the Brazilian Amazon, with dozens of species slated for extinction mere decades from now.

As a group of scientists explain in a new study in Science, 80% of extinctions due to historical habitat loss in the Brazilian Amazon are yet to come.

Describing this extinction IOU, the Guardian's Ian Sample writes that the destruction of the large swaths of land "has turned scores of rare species into the walking dead, doomed to disappear even if deforestation were halted in the region overnight."

"Realistic deforestation scenarios suggest that local regions will lose an average of nine vertebrate species and have a further 16 committed to extinction by 2050," wrote the researchers. "There is a window of opportunity to dilute the legacy of historical deforestation by concentrating conservation efforts in areas with greatest debt."

"Now that we know where the extinction debt is likely to be, we can go to the ground to restore habitat and take remedial actions to try to regenerate new habitats," said study lead author Robert Ewers, an ecologist at Imperial College London in the U.K.. "We can try to put off ever having to pay that debt."

"This problem has been building, and it will soon roll over and crash like a wave," warns Ewers.

Speaking to the Guardian, Ewers added, "For now, the problem is along the arc of deforestation in the south and east where there is a long history of forest loss. But that is going to move in the future. We expect most of the species there to go extinct, and we'll pick up more extinction debt along the big, paved highways which are now cutting into the heart of the Amazon."

Thiago Rangel, an ecologist at the Federal University of Goias in Brazil, writing in an accompanying article in Science, says, "Extinction debts in the Brazilian Amazon are one debt that should be defaulted on."

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