bernard Wrote:
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> I'm also of the opinion that the role of humans in
> the extinction of megafauna is exaggerated and
> that ecological changes were very important.
> However, the case for human role in Australia
> seems to better documented.
>
> Bernard

It doesn't seem possible that a few small groups of nomadic hunters could kill enough individuals of a specie to cause its' extinction on an entire continent unless that specie was already under severe stress from climate change or disease. However I suspect that human use of fire could under unusual circumstances virtually eliminate a specie in a region.

A severe drought over a large region could result in a virtual tinder box situation where a wild fire could destroy all forage over hundreds or thousands of square miles. In North America most native grass species go dormant in the fall and remain dormant all through the winter. Thus after a fire in the late fall there would be absolutely nothing edible above ground for the next 4 or 5 months. Any large grazing mammal that could not find another area with winter forage would starve to death before spring.