Amazon forest species face extinction danger
A paper published at Science magazine, says the vast majority of species extinctions in the Brazilian Amazon are yet to come., becaseu of the deforestation.According to Scientific American’s article taken from the Nature magazine, a paper published today says the vast majority of species extinctions in the Brazilian Amazon are yet to come.
Deforestation has declined to record lows in recent years, and just over 50 percent of Brazil’s rainforest now falls under some form of protected status. But the effects of habitat loss take time to become clear. “Cutting down trees doesn’t kill a bird directly. It takes a lot of time for those birds to actually die. They’re all crammed into the habitat that’s left. Then gradually you’ll have this increased mortality,” says Robert Ewers, an ecologist at Imperial College London and the study’s leader, said the Scientific American article.
Previous models of how deforestation affects biodiversity have assumed that deforestation happens in one swoop. But that’s not how it works. Deforestation tends to occur in fits and spurts, and as it continues, the number of species headed for extinction — the “extinction debt” — rises, according to Scientific American article.
“If you cut down a patch of habitat and, before the effects are felt, you cut down more habitat, you’ve got some outstanding debt,” explains Daniel Reuman, a mathematician at Imperial College, who also worked on the project. “We wanted to figure out how it happens with multiple instances over time instead of just one instance. It’s an amazingly simple model extension that has big implications.”
So, Ewers, Reuman and their colleague Oliver Wearn came up with a formula that relates species extinction to the timing and amount of habitat loss. “It sorts out the bookkeeping of all these different deforestation events and extinction debts,” explains Reuman. When they plugged individual species data for vertebrates that depend on the tropical forest for food and shelter and deforestation patterns from 1970 to 2008 into their model, it projected that 80 to 90 percent of extinctions caused by previous rainforest loss are yet to come. Brazil still owes the grim reaper an average of two mammals, five birds and one amphibian per 2500 square kilometers.