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The Brazilian Amazon has been racking up debt — and not the financial kind. This heavily-logged region has accumulated a large “extinction debt,” meaning that many of the species extinctions expected to be triggered by deforestation are still looming.

While we often hear about the threat of driving plants and animals in the Amazon extinct, we don’t know exactly when those extinctions will happen. A species might linger for years or decades after part of its habitat has been destroyed. Eventually, though, the effects of deforestation may catch up and the species will disappear.

In a study published in Science, researchers calculated how extinctions might play out over the next several decades. So far, most bird, mammal, and amphibian species that rely on forest habitat are still present in the Amazon; only about 1 percent have gone missing. Eighty to 90 percent of local extinctions due to forest loss “have yet to be realized”, the team writes.

Each 2500-square-kilometer region in the Amazon could lose roughly 5 percent of its mammal, bird, and amphibian species by 2050. But people could try to stave off future extinctions by taking steps to preserve the forest. “Extinction debts in the Brazilian Amazon are one debt that should be defaulted on,” writes researcher Thiago Rangel of the Federal University of Goias in Brazil in an accompanying article. Roberta Kwok | 12 July 2012

Source: Wearn, O.R., D.C. Reumen, and R.M. Ewers. 2012. Extinction debt and windows of conservation opportunity in the Brazilian Amazon. Science doi: 10.1126/science.1219013.

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