'Humans killed off Australia's giant beasts'

[xchrom]

http://www.bbc.co.uk/news/science-environment-17488447


Scientists have linked a dramatic decrease in spores found in herbivore dung to the arrival of humans in Australia 41,000 years ago

Humans hunted Australia's giant vertebrates to extinction about 40,000 years ago, the latest research published in Science has concluded.

The cause of the widespread extinction has provoked much debate, with climate change being one theory.

However, scientists studied dung samples from 130,000 and 41,000 years ago, when humans arrived, and concluded hunting and fire were the cause.

The extinction in turn caused major ecological changes to the landscape.

[JackintheGreen]

1. I thought we sorta already knew this

The moa in New Zealand is an obvious example of large fauna extinguished by man (though a bird), and the diprotodon disappeared only 45,000 years or so ago after surviving the 1.5 million years prior.

[Hawkowl]

2. I don't buy it

I simply think it is ludicrous that 5 foot tall humans armed with sticks hunted 9 foot tall kangaroos and giant marsupial lions to extinction and THAT changed the climate. That is equivalent to saying that primitive humans hunted mammoths to extinction and that caused the ice age.

I think it much more likely that the climate changed which caused specific vegetation to die off which then caused the mega fauna to die off. Volcanoes, meteors, are much more likely to cause such massive climate change. If human fossil remains were found with the dinosaurs, some scientists would claim humans hunted them to extinction!

The Sahara desert is a much more recent example of heavy duty climate change. About 10,000 years ago the Sahara region resembled central Africa with all the associated fauna. I don't see any ludicrous explanations of how the Sahara desert was caused by humans exterminating all the lions, hippos, elephants and giraffes from northern Africa resulting in the Sahara desert!

[muriel_volestrangler]

3. They're not saying this caused climate change

They're saying humans hunting the megafauna caused their extinction; and that this (because the type of grazing changes the relative ecological fitness of plants), and human-set fire, then changed the vegetation.

You may think there are other reasons, but no-one has found evidence of climate change, volcanoes or meteors in Autstralia at that time. It's up to you to look for evidence to support your claim; the scientists have done it with theirs.

[NickB79]

4. There is ample evidence that humans applied extreme pressures on megafauna

And mammoth extinctions HAVE been tied to human overhunting: http://www.livescience.com/6984-prehistoric-humans-wiped-elephants.html

And the story isn't saying that hunting CAUSED climate change; it's saying that hunting was the PRIMARY driver of megafauna extinction, with naturally occurring climate change occurring AFTER the hunter-induced extinctions had swept over the continent.

IMO, the one thing that shows a clear human impact is the fact that these animal populations had survived largely intact for the previous 1 million years before Cro-Magnon man spread across the planet. There were numerous other warming cycles before the one we are currently in, but only in this most recent one did all these species around the globe go extinct.