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Saturday, August 18, 2012

Extinction Rates Hike In The Brazilian Forests

Brazil’s Amazon rainforest has many accolades to its name: It is the largest tropical rainforest in the world covering over five and a half a million square kilometers, it is the home to 10 percent of the world’s known species and 20 percents of the world’s known bird species, and it is that 2.5 million different insect species and over 40,000 plant species live in the Amazon rain forest. Tragically enough, the diversity seen in the Amazon rainforest has been threatened for years due to human activity. It has been estimated that almost 90 percent of the rain forest is now gone, having been replaced with roads and cities, and as a result, the biodiversity has also taken a hit.
In 2007, the National Geographic shared the concerns the Amazon was facing:
During the past 40 years, close to 20 percent of the Amazon rain forest has been cut down—more than in all the previous 450 years since European colonization began. The percentage could well be far higher; the figure fails to account for selective logging, which causes significant damage but is less easily observable than clear-cuts. Scientists fear that an additional 20 percent of the trees will be lost over the next two decades. If that happens, the forest’s ecology will begin to unravel. Intact, the Amazon produces half its own rainfall through the moisture it releases into the atmosphere. Eliminate enough of that rain through clearing, and the remaining trees dry out and die. When desiccation is worsened by global warming, severe droughts raise the specter of wildfires that could ravage the forest. Such a drought afflicted the Amazon in 2005, reducing river levels as much as 40 feet and stranding hundreds of communities.
Unfortunately, the news only gets worst. A recent study, which appeared in the journal Plos ONE, found that the rainforest which once was known for its biodiversity is currently the poster child of extinction. The biologists found that numbers to be shocking — for instance, only 767 populations of mammals of 3,528 still existed. Other species facing extinction include jaguars, lowland tapirs, woolly spider monkeys and giant anteaters.
The study states:
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[.]
While the study brought bad news, it also shared some good news that shed light on how the biodiversity in the Amazon can be protected. The study found that the areas of the rainforest that have ecological protection also showed the highest rates of biodiversity. This means that all hope is not gone and that if we work towards protecting what is left, via hunting and constructions bans, of the rainforest then we still stand a chance to save the species that face extinction.

Original article:  http://www.greenerideal.com/science/0817-extinction-in-the-brazilian-forests/

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