NOBLE GREEN MAY HAVE HUNTED MEGAFAUNA TO EXTINCTION

The Australian, 3 May 2006
 HYPERLINK "http://www.theaustralian.news.com.au/story/0" \t "linkWin" http://www.theaustralian.news.com.au/story/0,20867,19004166-30417,00.html

Hunt widens for megafauna killer

New evidence shows Aborigines may have hunted our giant beasts to extinction, writes Brendan O'Keefe

A CLAIM that disturbed sediments at an archeological site in western NSW point the finger at humans for the extinction of Australia's megafauna has reignited the debate about what killed the giant beasts.

Scientists have long argued about the fate of the animals, which included the two-tonne wombat-like Diprotodon, the two-metre-tall flightless bird Genyornis and giant kangaroos.

A team led by archeologist Judith Field of the University of Sydney, who found megafauna bones and stone tools at Cuddie Springs in western NSW in the early 1990s, say climate change - Ice Age aridity - killed the megafauna, about 30,000 years ago.

But others, such as Richard Gillespie and Barry Brook, who have made the latest claim, say that Aborigines caused the mass extinction either by hunting or by habitat destruction, about 45,000 years ago.

Gillespie, a radiocarbon dating expert and a visiting fellow at the Australian National University, and Brook, a population ecologist and senior research fellow in the school of environmental research at Charles Darwin University, say the animal bones, artefacts and charcoal in the sediments at Cuddie Springs do not age with depth.

They say this suggests the sediments have been mixed.

University of Sydney archeologist Richard Fullagar, a colleague of Field's, concedes there is "some interesting discussion on radiocarbon dating statistics", but says "the explanation they put forward is fundamentally flawed. It's wrong".

"It's not like a city in the Middle East; you've got sediments where Aboriginal people have been camping for long periods of time, the artefacts are going to be scuffed around and moved around a bit," he says.

Field's people say there was a 15,000-year overlap between the time of arrival of humans and the extinction of the megafauna, suggesting long co-existence before a natural death for the animals.

Gillespie, Brook and others say the overlap is about 5000 years. "The coincidence of the time of arrival [of humans] to the megafauna extinction to us looks horribly suspicious," Gillespie says.

Gillespie and Brook, in the journal Archaeology in Oceania, say the sediments have been mixed over time, probably in floods.

They studied 20 published datings on material from the layers bearing bones, artefacts and charcoal. If the layers were undisturbed, as the excavators say, the ages should increase with depth.

But Gillespie and Brook found that all the charcoal dates were statistically the same age, about 36,000 years old. And sand in the two upper layers was much younger than charcoal from the same levels, suggesting that the sediments had been mixed, and that some of the charcoal had been redeposited.

They also studied the animal bones for traces of protein, which have been found in stone tools at the site.

"The bones from Cuddie Springs that we looked at ... there wasn't any protein there," Gillespie says. "This suggests that the bones are very old. Some of the stone tools have got hair and blood residues on them where the protein has survived ... this is anomalous if you don't find any protein in the bones in the same layer."

Gillespie says the animals were probably hunted into oblivion - "You don't have to kill every one of them for them to go extinct" - and that "people altered the landscape a bit when they turned up".

Fullagar places himself in the "multi-causal" camp but rules out hunting: "There's certainly scavenging but there's no spear points or spears stuck in bones.

"Hunting is very difficult and potentially dangerous," Fullagar says. "Hunters are not very successful and the chance of it causing extinction is very low.

"It seems a mix of things have caused it and climate is probably standing out."

The debate goes on. Gillespie says: "It's getting to a point where two camps are down in their bunkers and there's a fair bit of heat about but nobody wants to give in.

"Some people are never going to change their opinion but I think a consensus will probably be reached. It will turn up soon ... the evidence is mounting for our side.

"They don't want to see the Aborigines as anything except the 'noble green'."