Extinction Rates Soar in Brazil's Fragmented Forests

© Stephen Messenger

While much is made about pervasive threats faced by Brazil's Amazon rainforest (and rightfully so), the nation is home to another biologically diverse region that's even more imperiled. After centuries of deforestation in the Atlantic Forest, an ecosystem which once stretched unbroken for over 500,000 square miles along the eastern coast of South America, now only a small fraction remains. And, in this now fragmented forest, researchers say the species struggling for survival there are disappearing at an equally alarming rate.

In a recent study which appeared in the journal Plos ONE, researchers surveyed wildlife populations in 196 isolated patches of Atlantic Forests. But sadly, the formerly thriving hotspot of biodiversity was found to be hotbed of extinction.

Biologists say that they "uncovered a staggering rate of local extinctions in the mammal fauna, with only 767 from a possible 3,528 populations still persisting."

On average, forest patches retained 3.9 out of 18 potential species occupancies, and geographic ranges had contracted to 0–14.4% of their former distributions, including five large-bodied species that had been extirpated at a regional scale. Forest fragments were highly accessible to hunters and exposed to edge effects and fires, thereby severely diminishing the predictive power of species-area relationships[.]

Among the species found to be virtually extinct from these forests were jaguars, lowland tapirs, woolly spider monkeys and giant anteaters.

Although there is little chance of recovery for the Atlantic Forest, researchers say that some hope remains for the few persisting species clinging to life in the fragmented ecosystem. Until now, the true extent of extinctions within these patches of wilderness was not fully known, leading to some complacency on the part of government officials charged with conservation. Researchers are hoping their study will change that:

"This paper is a very big positive endorsement of more protected areas."

Tags: Biodiversity | Brazil | Extinction

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