Fate of Giants becomes hot topic
news.com.au
20jul01
TIM Flannery, director of the South Australian Museum and author of Future Eaters, claims
that his research shows the country's megafauna was wiped out 46,400 years ago which may
support his theory of a human blitzkrieg.
"I have a hypothesis that I keep testing and so far I have found nothing to disprove
it. Although I keep trying," he said.
(Flannery proposes that the first arrivals to Australia hunted and killed all the large
mammals such as giant flesh eating kangaroos and hippo-sized wombats to the point of
extinction a "blitzkrieg" similar to that which happened in Madagascar and North
America.)
What our research shows is that all Australian land mammals, reptiles and birds weighing
more than 100kg, and six of the seven genera with a body mass of 45kg to 100kg, perished
in a period around 46,400 years ago.
The timing and causes of these extinctions remain uncertain.
Our results rule out extreme aridity at the last Ice Age as the cause of extinction, but
not other climatic impacts; a "blitzkrieg" model of human-induced extinction; or
an extended period of anthro-pogenic (human caused) ecosystem disruption.
We dated a whole series of fossil sites across Australia using innovative techniques and
we were very rigorous about it.
We took a very conservative position and I have to say the results surprised me.
We found that at least seven genera, that is seven different kinds of megafauna, survived
until 46,400 years ago.
These include the megalania (a giant 5m lizard) and diprotodon (the hippopotamus -sized
wombat).
There is no evidence of them existing after that at all. It's quite conclusive.
It is also consistent with the only other published data on genyornis (a megafauna
species) which went extinct 50,000 years ago plus or minus 5000 years.
There is no good data that points to anything otherwise.
I originally had no idea when they became extinct.
I thought it could have been more than 50,000 years ago. I just didn't know.
Our paper doesn't speculate on what caused it.
All that it does say is that it excludes climatic changes as a causal factor.
It does point to it happening close to the arrival of human beings, but all it says is
that it is close to human arrival.
We don't know enough about how long exactly humans have been in Australia.
It might or it might not support the theory of blitzkrieg.
To have been caused by humans it would have had to have happened within 1000 years (of
their arrival).
But the paper does not prove it. On the other hand it hasn't disproved it either."END OF REPORT
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