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Fires wiped out' ancient mammals
By Helen Briggs
BBC News science reporter
The first humans to arrive in Australia destroyed the pristine landscape, probably by lighting huge fires, the latest research suggests.
The evidence, published in Science magazine, comes from ancient eggshells.
These show birds changed their diets drastically when humans came on the scene, switching from grass to the type of plants that thrive on scrubland.
The study supports others that have blamed humans for mass extinctions across the world 10-50,000 years ago.
Many scientists believe the causes are actually more complex and relate to climate changes during that period, but, according to Dr Marilyn Fogel, of the Carnegie Institution in Washington, US, chemical clues gleaned from the eggshells suggest otherwise.
"Humans are the major suspect," she said. "However, we don't think that over-hunting or new diseases are to blame for the extinctions, because our research sees the ecological transition at the base of the food chain.
"Bands of people set large-scale fires for a variety of reasons including hunting, clearing and signalling other bands.
"Based on the evidence, human-induced change in the vegetation is the best fit to explain what happened at that critical juncture."
Dalje
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