[url=http://www.abc.net.au/science/articles/2011/05/11/3211825.htm]How did the Aboriginal population of Australia rise and fall over the millennia? [/url]
A new mathematical model could fuel a long-standing debate over the nature of Aboriginal population growth in Australia prior to European settlement.
The model supports the idea that there was a marked increase in the growth of the continent’s Aboriginal population towards the end of the Holocene says ecologist Professor Christopher Johnson of the University of Tasmania.
Johnson says radiocarbon dating shows an increase in the number of sites occupied by Aboriginal people in the past 10000 years particularly in the past 4000 years.
“The number builds up exponentially towards the present” says Johnson whose work is published online this week in the Proceedings of the Royal Society B.
However some archaeologists argue that while there was an initial spurt of population growth after Aboriginal people first colonised Australia around 45000 years ago it then maintained a stable level until Europeans arrived.
Such archaeologists argue that the apparent increase seen in the archaeological record is actually due to the fact that older evidence gets destroyed or washed away through time.
Johnson together with Professor Barry Brook of University of Adelaide developed a mathematical model in an effort to help settle this question.
The model simulates what happens when a stable population occupies sites and then moves on. When a site is abandoned the evidence for occupation of that site gradually disappears.
Johnson says the model shows that the decay of evidence from abandoned sites can not account for a stable population appearing to increase exponentially.
He says the Aboriginal population grew at about 40 per cent every 1000 years over the past 5000 years and about 10 to 15 per cent in the 5000 years before that.
“It’s not a particularly fast growth rate in itself” he says. “But when our time scale is 10000 years it’s very dramatic.”