23 Mar 2012:
Australian Mammal Extinctions
Tied to Human Hunting, Not Climate Change
The disappearance roughly 40,000 years ago of dozens of large mammals in Australia — including rhinoceros-sized wombats and tapir-like marsupials — was caused by human hunting and not by climate change
, according to a new study by Australian scientists. Researchers at the University of
©Science/AAAS/Drawing by Peter Murray
Tasmania reached that conclusion after analyzing two mud core samples dating back as far as 130,000 years. By examining the cores for the Sporomiella
fungus — which only releases its spores when in the dung of plant-eating animals — the scientists concluded that megafauna survived periods of climate change over the last 100,000 years. But when humans arrived in sizeable numbers, the presence of the spores dropped “almost to zero” around 41,000 years ago, indicating that hunting was the main reason for the extinction of these large animals, according to the paper, published in Science
. Not long after the megafauna was hunted to extinction, grasses and trees began to grow more profusely because of the decline of grazing animals, setting the stage for large fires. The Australian research parallels other, similar findings worldwide showing that human hunting was crucial in large-animal extinctions.
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