ANU boffins say it wasn’t climate change that did for the megafauna

justin heywood said :

One journal article doth not a scientific fact make – and on this topic there hundreds of articles, mostly with a different point of view than that expressed by Field and Wroe.

There well may be “hundreds” of articles on the subject but that doesn’t change the fact that the archaeological record is so sparse as to be unable to differentiate between the competing hypothesis. I wouldn’t have thought it would be too outrageous to suggest that we just don’t know and probably will never know.

Thumper said :

Tiger Quolls the size of action buses!

Look at the Zygomaturus trilobus. That is Latin for ‘big as three ACTION buses, but not as old or orange.’

Gungahlin Al said :

thebrownstreak69 said :

We’re talking about wooley mammoths here, right?

No Mammoths were restricted to the Siberia/North America areas. When referring to Australian megafauna, scientists are talking about all the bigger animals – including current ones, but mostly talking about the extinct ones. Picture a 3m 2000kg wombat, a 500kg emu and a 7m goanna! Not actually those animals but they resembled the current species, just huge.

Pretty good summary of it all in Wikipedia: http://en.wikipedia.org/wiki/Australian_megafauna

Tiger Quolls the size of action buses!

thebrownstreak69 said :

We’re talking about wooley mammoths here, right?

No Mammoths were restricted to the Siberia/North America areas. When referring to Australian megafauna, scientists are talking about all the bigger animals – including current ones, but mostly talking about the extinct ones. Picture a 3m 2000kg wombat, a 500kg emu and a 7m goanna! Not actually those animals but they resembled the current species, just huge.

Pretty good summary of it all in Wikipedia: http://en.wikipedia.org/wiki/Australian_megafauna

justin heywood said :

howeph said :

Roundhead89 said :

Oh dear. Crash goes another climate change myth.

Roundhead89, you must be smarter than me, because I can’t see any climate change myth crashing down.

Please explain.

In fact, a change in the climate is one of the competing theories in explaining the disappearance of the megafauna. A very interesting topic, but a bit of a perfect storm of competing scientific theories unfortunately complicated by politics.

What do you mean by ‘complicated by politics’?

Whenever this topic comes up, respectful discourse between scientists degenerates into a childish sand-pit of denigration, ad homs, etc. There are only a few cases where this happens, usually with some underlying financial/political/or ideological contention.

I’m wondering what that political complication is in this case(??)

davo101 said :

CraigT said :

The problem with stating the obvious, “Humans arrives and hunted the megafauna to extinction”, is that it goes against the noble savage fantasy of the Aboriginals as “caretakers of the land” and similar rubbish such as trying to paint fire stick hunting as a land management technique instead of the destructive vandalism that it was.

No the problem is that there is not enough evidence to state this. To quote Field and Wroe (2012):

In our view the question remains wide open. Arguments for either a human- or climate- driven process remain based on major and currently untested assumptions. Notably, acceptance of a human-driven event assumes that the PGM and LGM were no more severe than the glacial maxima that preceded them and that a lack of evidence for most now extinct species post-PGM is a sampling artefact. Arguments for a climate-driven process may assume the reverse. Neither position is strongly supported by hard evidence at present, but it is increasingly clear that the climate was deteriorating at the time humans are thought to have arrived. The unknown number of megafaunal species present at human arrival faced possible direct or indirect influences from humans and increasingly arid and variable climate. Even with the advantage of far better resolved palaeoclimatic data and extinction chronologies than are presently available, it would be difficult to quantify the respective roles of either factor robustly.

One journal article doth not a scientific fact make – and on this topic there hundreds of articles, mostly with a different point of view than that expressed by Field and Wroe.

BimboGeek said :

I thought the collossal squid is bigger than a blue whale? I find normal tentacles terrifying, collossal ones can stay in the abyss!!

Just to give you a size comparison the blue whale can weigh up to 170 tonnes

http://www.heraldsun.com.au/leader/west/enormous-btriple-and-bdouble-trucks-may-soon-be-on-yarraville-streets/story-fngnvmj7-1226665461864

Spitfire3 said :

BimboGeek said :

I thought the collossal squid is bigger than a blue whale?

Nowhere near as big as blue whales.

Katy, we may need a skysquid for the next bash.

Beware the mighty Kraken!

BimboGeek said :

I thought the collossal squid is bigger than a blue whale?

Nowhere near as big as blue whales.

Katy, we may need a skysquid for the next bash.

BimboGeek said :

I thought the collossal squid is bigger than a blue whale? I find normal tentacles terrifying, collossal ones can stay in the abyss!!

Mmmmmm. Colossal salt and pepper squid!

So, would you describe Godzilla as megafauna, or ultramegafauna, or motherf*ckafauna, or gigafauna?

I thought the collossal squid is bigger than a blue whale? I find normal tentacles terrifying, collossal ones can stay in the abyss!!

CraigT said :

The problem with stating the obvious, “Humans arrives and hunted the megafauna to extinction”, is that it goes against the noble savage fantasy of the Aboriginals as “caretakers of the land” and similar rubbish such as trying to paint fire stick hunting as a land management technique instead of the destructive vandalism that it was.

No the problem is that there is not enough evidence to state this. To quote Field and Wroe (2012):

In our view the question remains wide open. Arguments for either a human- or climate- driven process remain based on major and currently untested assumptions. Notably, acceptance of a human-driven event assumes that the PGM and LGM were no more severe than the glacial maxima that preceded them and that a lack of evidence for most now extinct species post-PGM is a sampling artefact. Arguments for a climate-driven process may assume the reverse. Neither position is strongly supported by hard evidence at present, but it is increasingly clear that the climate was deteriorating at the time humans are thought to have arrived. The unknown number of megafaunal species present at human arrival faced possible direct or indirect influences from humans and increasingly arid and variable climate. Even with the advantage of far better resolved palaeoclimatic data and extinction chronologies than are presently available, it would be difficult to quantify the respective roles of either factor robustly.

CraigT said :

The problem with stating the obvious, “Humans arrives and hunted the Megafauna to extinction”, is that it goes against the noble savage fantasy of the aboriginals as “caretakers of the land” and similar rubbish such as trying to paint firestick hunting as a land management technique instead of the destructive vandalism that it was.

True indeed.

Mind you, there’s a subtle, though important, difference between destructive vandalism for the purpose of feeding yourself in ignorance of the consequences, and destructive vandalism for increased profits in the full and certain knowledge of the consequences.

justin heywood said :

There is a LOT of evidence pointing to a general extinction of megafauna at about the same time as the arrival of humans. These species had survived even ice ages before, but disappeared at a time when, relatively speaking, the climate was not changing rapidly.
This is certainly circumstantial evidence, but it would be a remarkable coincidence if humans were not the cause. They most certainly were the cause of mass extinctions on many other islands.

…as they are the cause of the current mass-extinction event that is in progress.

The problem with stating the obvious, “Humans arrives and hunted the Megafauna to extinction”, is that it goes against the noble savage fantasy of the aboriginals as “caretakers of the land” and similar rubbish such as trying to paint firestick hunting as a land management technique instead of the destructive vandalism that it was.

Roundhead89 said :

Oh dear. Crash goes another climate change myth.

Yeah, because we all know what really killed megafauna – it was feminists and their agenda….

Might have been Costco!

poetix said :

DrKoresh said :

johnboy said :

Don’t tell the elephants

That’s why I qualified my statement with the word “most”, smarty-pants :p

Whales are quite large, too.

Indeed and many of us would be aware that the Blue Whale is the largest creature that has ever existed..

DrKoresh said :

johnboy said :

Don’t tell the elephants

That’s why I qualified my statement with the word “most”, smarty-pants :p

Whales are quite large, too.

From Wikipedia:

New evidence based on accurate optically stimulated luminescence and uranium-thorium dating of megafaunal remains suggests that humans were the ultimate cause of the extinction of megafauna in Australia.[4] The dates derived show that all forms of megafauna on the Australian mainland became extinct in the same rapid timeframe — approximately 46,000 years ago[5] — the period of time in which humans first arrived in Australia. Analysis of oxygen and carbon isotopes from teeth of megafauna indicate the regional climates at the time of extinction were similar to arid regional climates of today, and that the megafauna were well adapted to arid climates.[4] The dates derived have been interpreted as suggesting that the main mechanism for extinction was human burning of a landscape that was then much less fire-adapted; oxygen and carbon isotopes of teeth indicate sudden, drastic, non-climate-related changes in vegetation and in the diet of surviving marsupial species. However, humans appear to have rapidly eliminated the megafauna of Tasmania about 41,000 years ago (following formation of a land bridge to Australia about 43,000 years ago as ice age sea levels declined) without using fire to modify the environment there,[6][7][8] implying that at least in this case hunting was the most important factor. It has also been suggested that the vegetational changes that occurred on the mainland were a consequence, rather than a cause, of the elimination of the megafauna.[6] This idea is supported by sediment cores from Lynch’s Crater in Queensland, which indicate that fire increased in the local ecosystem about a century after the disappearance of megafaunal browsers, leading to a subsequent transition to fire-tolerant sclerophyll vegetation