Sunday, March 25, 2012

Australian Megafauna hunted to death



Megafauna hunted to death, says new data by: Leigh Dayton, Science writer From: The Australian
March 23, 2012 5:00AM

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An artist's illustration of the giant extinct kangaroo Procoptodon goliah,which stood approximately 3 metres tall. Picture: The Australian Source: The Australian

NEW data from Australian scientists adds to the growing body of evidence that blames people for the demise of the continent's giant plant-eating animals.

According to findings reported today in Science, most of Australia's so-called megafauna vanished about 40,000 years ago following the arrival of humans.



After analysing a 130,000-year-long record of pollen and charcoal from two sediment cores from Lynch's Crater, in northeast Australia, the team led by Susan Rule of Canberra's Australian National University concluded: "Our results suggest that human arrival rather than climate caused megafaunal extinction."



Among the victims are fearsome claw-footed kangaroos, Sthenurines, that weighed in at 300kg; enormous Genyoris newtoni, at 200kg the heaviest bird known; and the leopard-sized marsupial lion, Thylacoleo carnifex.



..."The debate really should be over now," said John Alroy, a paleobiologist with Sydney's Macquarie University. "Hunting did it, end of story."



But as the team's report helps end the long-running whodunnit - humans or climate change - it has ignited another: did the extinction of the mighty beasts transform the landscape or did human firing convert the drought-adapted mosaic of trees, shrubs and nutritious grasslands into the modern fire-adapted, scrubby "sclerophyll" vegetation?



According to Dr Rule and her colleagues at the ANU, the universities of NSW, Adelaide and Tasmania and Melbourne's Monash University, after people hunted most megafauna to extinction grazing on vegetation decreased, the fuel load increased and fire triggered the ecosystem changes.



Not so, countered Gifford Miller, a geochronologist with the University of Colorado, Boulder, in the US, who told The Australian the new data did not support the notion.



He stood by findings he and US and Australian colleagues reported in 2005, also in Science, showing that when humans fired the landscape they changed the vegetation, and animals that could not adapt died out.



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Taken from: http://www.theaustralian.com.au/news/health-science/megafauna-hunted-to-death-says-new-data/story-e6frg8y6-1226307723634

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