Climate change killed megafauna

[walkinTas]

In the Australian today, a new study on the extinction of megafauna suggests it was all due to climate change.

[Swifty]

Jared Diamond has noted that the extinction of megafauna globally has occurred soon after humans arrived on the scene - in Australia, Asia, North and South America, and particularly in New Zealand.
Also, these fauna had lived through multiple glacial cycles over the previous hundreds of thousands of years. Why the sudden extinction just after people showed up? Because the people killed and ate them.

[FatCanyoner]

For those blocked by the paywall of copied the text below. Interesting theory. Worth noting is the fact that aboriginals did not colonise the whole of Australia in one go. It took thousands of years before it was fully occupied, making it hard to wipe out many species continent wide in a short period of time.

A NEW study has vindicated Aboriginal people over the extinction of Australia's megafauna, finding wild climate fluctuations killed off most of the giant species well before humans arrived.

The idea that early Aborigines wiped out the megafauna – which included a ferocious marsupial lion, a hippopotamus-sized wombat, a five-metre goanna and a 230 kilogram kangaroo – was popularised in palaeontologist Tim Flannery’s 1994 book Future Eaters.

But a scientific review has found fewer than 15 of the 90-odd giant species in Australia and New Guinea still existed by the time people arrived.

“There’s no uncontested archaeological evidence that a single human ever ate a single individual from a single megafaunal species,” said lead author Stephen Wroe of the universities of NSW and Newcastle.

“Not only is there no clear evidence of that, there’s no uncontested evidence anywhere of humans and megafauna even being in the same place at the same time.”

Proponents of the “blitzkrieg theory” – that the Aborigines killed off the megafauna soon after they arrived – say the lack of authenticated “kill sites” doesn’t disprove the theory, because such sites would be very few and hard to find.

But Professor Wroe said new dating evidence suggested as few as eight megafauna species coexisted with humans. And Antarctic ice core records showed that glacial cycles had become increasingly severe over at least the past 350,000 years, draining Australia of water and slashing average temperatures by 9 degrees Celsius.

“It’s very clear that there was a long-term loss of species through the last 150,000 to 300,000 years. When humans arrived, things were already going from bad to worse,” Professor Wroe said.

He said very low population estimates for early Aborigines, and evidence that they were fisherman rather than big-game hunters, suggested they would not have had the means to “wipe out 90 species in the blink of an eye”.

And charcoal evidence indicated that an upsurge in the frequency of fires, sometimes attributed to “firestick farming” by Aborigines, had preceded their arrival by many thousands of years.

Professor Wroe said there was no doubt that Maoris had driven New Zealand’s giant moa bird to extinction, and some evidence that North American settlers had done the same to mammoths. But it was fanciful to assume something similar had happened much earlier in Australia.

“Perhaps at some point it was reasonable to invoke humans as a driving force. But why would you, given that there is no direct evidence whatsoever?”

The study, which also involved researchers from the universities of Queensland, New England and Washington, is published today in the US journal Proceedings of the National Academy of Sciences.

[doogs]

In the Australian today, a new study on the extinction of megafauna suggests it was all due to climate change.

Don't be daft, climate change doesn't exist... they were hunted to extinction by the indigenous population

[Nuts]

a ferocious marsupial lion, a hippopotamus-sized wombat, a five-metre goanna and a 230 kilogram kangaroo

A hippo sized wombat would be kinda cool. But yes, good luck fitting that in a dilly bag.

[Davidf61]

Sad there not here anymore, apart from drop bears . Can you just imagine bumping into some of these thing as you turned the corner on a remote track....

[photonaturally]

Pack hiking will be a lot less fun with hippo sized wombats. They do not need to break into tents to get food. Just swallow the it whole.

[walkinTas]

Jared Diamond has noted that the extinction of megafauna globally has occurred soon after humans arrived on the scene - in Australia, Asia, North and South America, and particularly in New Zealand.
Also, these fauna had lived through multiple glacial cycles over the previous hundreds of thousands of years. Why the sudden extinction just after people showed up? Because the people killed and ate them.

That has long been the established theory Swifty, but this article refutes the idea suggesting that only 15 such species still existed when man arrived. And, in so doing, adds another opinion to the mix. My understanding - it isn't a matter of climate change or climate extremes per se, but rapid (in evolutionary time frames) and multiple changes/fluctuations that defeated the ability of species to adapt.

IMHO, the fact that no one has found camp fires, spit roasts and megafauna bones in the same spot does not 'prove' anything. However, if it can be reliably established that most megafauna were already extinct when man arrived in Australia, then that must change the story. One would think if man and megafauna co-existed there should be cave painting to testify to this - unless cave painters became the preferred diet of some megafauna.

[doogs]

This page sums it up pretty well, there were probably several different factors that led to their demise. http://www.abc.net.au/science/features/megafauna/

[jackhinde]

Tim Flannery addressed the Australian Archaeological Society last year, he believes his hypothesis regarding the extinctions now warrants theory status. At this time it is truely impossible to determine one way or the other. I will just point out that in regard to species numbers, megafauna have at least a 25 million year history on this continent, and therefore many hundreds of species we may never find evidence of would have been extinct prior to humanity arriving here... and in regards to people arriving here we still don't even know when that was- it is all guess work past the known date for willandra lakes.

[walkinTas]

This page sums it up pretty well...

Yep, that about sums it up.

I think the only one that still exists is the drop bear - I should say rumoured to still exist.

[climberman]

Great info !

One of the authors was my honours supervisor, back in the dark ages.

[Happy Pirate]

Actually it wasn't a new study; merely another rehash of old papers. It added nothing new to the debate.

This is one of those issues which are almost impossible to "prove" by scientific evidence and are fraught with opinion, agendas and even the dreaded PC.

Personally I think its worth noting that, as Diamond was mentioned, megafauna has gone extinct coincidentally with the arrival of human populations at many periods and locations across the globe.

It seems to me as if some people want to preserve the cliche of the "noble savage" who lives in perfect harmony with the environment. Its a very 19th century Romantic European construct.
The truth I suspect is more along the lines of 'hey - we're all human - we stuff things up to fill our own needs because we can and because we tend to look only at short term changes.'
Some cultures are just more efficient (or greedy or ruthless) than others.

Steve

[nq111]

Ac
The truth I suspect is more along the lines of 'hey - we're all human - we stuff things up to fill our own needs because we can and because we tend to look only at short term changes.'

I think the same is true of every species on the planet. We are just better at it and able to generate bigger impacts.

How many species did the evolution of cyanobacteria wipe out billions of years ago? Nearly every current species at the time.

[Clusterpod]

It seems to me as if some people want to preserve the cliche of the "noble savage" who lives in perfect harmony with the environment. Its a very 19th century Romantic European construct.

A construct that is nevertheless far closer than the Hobbesian : ""In such condition there is no place for industry, because the fruit thereof is uncertain, and consequently, not culture of the earth, no navigation, nor the use of commodities that may be imported by sea, no commodious building, no instruments of moving and removing such things as require much force, no knowledge of the face of the earth, no account of time, no arts, no letters, no society, and which is worst of all, continual fear and danger of violent death, and the life of man, solitary, poor, nasty, brutish, and short."

I know which construct I prefer.

[puredingo]

OK, I'll come clean I killed them....They were threatening my sheep and getting all through my garden.

[walkinTas]

On evolutionary time scales, humans arrived in Australia very recently - about half way through the "late Pleistocene".

Actually it wasn't a new study; merely another rehash of old papers. It added nothing new to the debate.
This is one of those issues which are almost impossible to "prove" by scientific evidence and are fraught with opinion, agendas and even the dreaded PC.
Personally I think its worth noting that, as Diamond was mentioned, megafauna has gone extinct coincidentally with the arrival of human populations at many periods and locations across the globe.

You are right in saying the opinion isn't new. And you are also right that megafauna have gone extinct coincidentally with the arrival of human populations across the globe. Still, it is worth asking if science can provide evidence to support the current theories, or even provide evidence it was more than a coincidence. Particularly, is the Australian experience in any way different or unique. From what I have read, it would appear science generally believes there was a large, global collapse of megafauna population in the late Pleistocene leading to the extinction of many species and that humans played a role in this. The problem is, this mostly took place between 100,000 and 50,000 years ago and was pretty much all over by 46,000 ya. Was the population of humans in Australia at the time significant enough to have wiped out so many species? Science rightly asks questions and looks for answers. One simplistic answer is probably not the full story. So did humans alone kill off the megafauna, or did they partially contribute to the extinctions, or did they only end the last renascence of an already failing fauna?

Some might find this paper - (Late-surviving megafauna in Tasmania, Australia, implicate human involvement in their extinction) - interesting because it has a Tassie flavour.

[doogs]

I think the figure is around 90% of megafauna being extinct by the time man came along. The rest were on their way out and man probably gave them a final shove from hunting and their burning practices which helped to alter the vegetation.
But.... A lot of the theory blaming man comes from the extinction of the Moa bird in New Zealand, which is well documented, and if it happened there surely the same fate befell the Australian Megafauna? As for a large global collapse at the same time, that appears to be true except for one glaring example: Madagascar! Man didn't arrive in Madagascar until about 2000 years ago and it was then that the megafauna on the island started to become extinct; Giant lemurs, pygmy hippopotamus, elephant birds etc..it is quite obvious the megafauna was killed off by man. Another pointer to the possibility that man was the cause of the extinction in Australia?

[roysta]

In the Australian today, a new study on the extinction of megafauna suggests it was all due to climate change.

Please don't get me started on this one !!!!!

[Happy Pirate]

Ac
The truth I suspect is more along the lines of 'hey - we're all human - we stuff things up to fill our own needs because we can and because we tend to look only at short term changes.'

I think the same is true of every species on the planet. We are just better at it and able to generate bigger impacts.

How many species did the evolution of cyanobacteria wipe out billions of years ago? Nearly every current species at the time.

Exactly, My point is that we are all driven by exactly the same motivations as every other species on the planet. We are ALL (European, Indigenous etc) just better than other species at getting what we want.
And we folk are also better than all other species at seeing the consequences of our actions. Modern western Humans are especially good at this.
Unfortunately it would seem that this is no stimulus toward remedial action and we are no better than any other species at restraining ourselves against our most base nature.
This is our great flaw I think - a lack of self restraint against our greedy nature. In that sense I think modern Western culture exceeds indidgenous culture. We lack a culture of moderation.

[Happy Pirate]

It seems to me as if some people want to preserve the cliche of the "noble savage" who lives in perfect harmony with the environment. Its a very 19th century Romantic European construct.

A construct that is nevertheless far closer than the Hobbesian : ""In such condition there is no place for industry, because the fruit thereof is uncertain, and consequently, not culture of the earth, no navigation, nor the use of commodities that may be imported by sea, no commodious building, no instruments of moving and removing such things as require much force, no knowledge of the face of the earth, no account of time, no arts, no letters, no society, and which is worst of all, continual fear and danger of violent death, and the life of man, solitary, poor, nasty, brutish, and short."

I know which construct I prefer.

Hey Clusterpod
I think what you wrote here is important and I want to say, before I attempt to tear it apart that I agree with you. Hobbes was a stooge for the past and future industrialists and gets no sympathy from me.
I suspect that like me you feel a deep and powerful yearning for natural areas and like me you want to uphold indigenous cultures as the paradigm of the closest we humans have ever got to perfect harmony with nature.
But the truth is that both you and I DO live in the dominant Western based "civilised" paradigm. If you didn't you wouldn't be on this forum.
So the problem is that we who talk about nature hold our ideal from a position of being so alienated from the natural world that we uphold nature as some sort of "other" beyond our own lives. So in effect our baseline position is problematic to start with. Our entire relationship with nature is a construct starting with the term "Nature" and finishing with the idea of National Parks and the exclusion of subsistance activities therein. We believe ourselves to be separate and our activities to opperate outside of nature rather than within areas of spoil.

When I say something like "Indigenous people, like Europeans, exploited and changed the landscape" there is a tendency to lump the two together as "bad"
The difference in levels of exploitation can be seen in the fact that it only took 200 years for Europeans to effect more change than Aboriginees in 50,000.
So my point is that in some sense it's just a matter of classification. European culture affected the the world they interacted with. Indigenous culture affected the world they interacted with. Between cultures there is a difference in degree (and within those cultural differences there are valid differences in the level of engagement with and acculturisation of nature). But to treat indigenous cultures as if they were above the laws of nature is a mis-representation of indigenous culture just as bad as those who sought to portray them as in some way less than human.
I know this is a touchy subject and I hope that my brash, unconsidered opinions will not be taken as offensive beyond the level of normal discussion.
cheers
Steve

[Happy Pirate]

Homo_Evo.png

On evolutionary time scales, humans arrived in Australia very recently - about half way through the "late Pleistocene".

Actually it wasn't a new study; merely another rehash of old papers. It added nothing new to the debate.
This is one of those issues which are almost impossible to "prove" by scientific evidence and are fraught with opinion, agendas and even the dreaded PC.
Personally I think its worth noting that, as Diamond was mentioned, megafauna has gone extinct coincidentally with the arrival of human populations at many periods and locations across the globe.

You are right in saying the opinion isn't new. And you are also right that megafauna have gone extinct coincidentally with the arrival of human populations across the globe. Still, it is worth asking if science can provide evidence to support the current theories, or even provide evidence it was more than a coincidence. Particularly, is the Australian experience in any way different or unique. From what I have read, it would appear science generally believes there was a large, global collapse of megafauna population in the late Pleistocene leading to the extinction of many species and that humans played a role in this. The problem is, this mostly took place between 100,000 and 50,000 years ago and was pretty much all over by 46,000 ya. Was the population of humans in Australia at the time significant enough to have wiped out so many species? Science rightly asks questions and looks for answers. One simplistic answer is probably not the full story. So did humans alone kill off the megafauna, or did they partially contribute to the extinctions, or did they only end the last renascence of an already failing fauna?

Some might find this paper - (Late-surviving megafauna in Tasmania, Australia, implicate human involvement in their extinction) - interesting because it has a Tassie flavour.

Hi walkintas
like I said, Its not an issue I expect to be ever provable one way or t'other. Part of the problem is that the occurence of a fossil in one era in no way delineates it's temporal range. So timelines are vague at best.
There are only certain positions in science discussion that are ever provable. One of the the first signs of quackary is to demand "proof" from science where logic dictates that proof is not possible. BTW I am not accusing you of quackary.
The issue in Tas is very separate from the mainland because of the different time-lines and the separations involved. I am always very careful about including data from Tasmania that is supposed to reresent the mainlaind.

I tend to agree with your inclination that it was a combination of the two.
It's what I have called (colloquially) the Greek Fisherman Decline. I won't describe that now (too many wine) but ask me if you're interested.
I think half of the danger is the black or white debate thate tends to ensue as researchers and their 'groupies' take absolute sides against each other where none exists in the research.
best wishes
Steve

[walkinTas]

I tend to agree with your inclination that it was a combination of the two.

The post by doogs earlier summarised the popular thinking - i.e. man or climate or a combination of the two. (unless of course you believe they were wiped out by "teasers" using them for random target practice!)

Problem one that science has is that it is very difficult to offer definitive proof. We agree there. The more complex the problem the harder it is, because no one has all the facts. No one can know everything. The next group of people to study any area of interest can always make another observation, take another or different measure, add another ounce of evidence, reveal something as yet not considered. And that might change the collective understanding. Problem two that science has is that some people close their minds to alternative possibilities, and then no amount of evidence will suffice.

That said, it doesn't mean that science can't offer plausible explanations to help us better understand. We shouldn't always need definitive proof before we can entertain the possibility. And sometimes with the help of science, we might even be able to reach a situation where there is little doubt or reasonable certainty. The more evidence available the more likely it is this will happen, but, because of 'problem two' that is not always true - for some people anyway.

In questions like this I tend to keep a very open mind, entertain all the possibilities, even to the point of swinging with the breeze a little. I am equally interested in all sides of the discussion.

I think there are a lot of enduring, romantic myths about indigenous live styles. For hunter-gatherer populations, the so called harmony with the land can perhaps be explained by the Lotka–Volterra equation (your Greek fishermen). The fact that man is an omnivore only slightly changes that equation. The theory has it that hunter-gatherer populations (in places like Tasmania) had reached the predicted equalibrium point - stabilised at a level that the environment could sustain. Of course, there is that proof thing again - and as usual, science has an alternative point of view.

I am well aware that some people believe that "fire-stick farming" disproves the natural balance theory, but does it? Or does it simply change the dynamics a little and thereby actually prove the Lotka–Volterra equation. If the population stable point had been reached, even with "fire-stick farming", then isn't the equation proved? But "fire-stick farming" is another topic, and one where science is still collecting the evidence.

[Happy Pirate]

I tend to agree with your inclination that it was a combination of the two.

The post by doogs earlier summarised the popular thinking - i.e. man or climate or a combination of the two. (unless of course you believe they were wiped out by "teasers" using them for random target practice!)

Brilliant!!!
I had completely forgotten to consider Teasers (beep beep beep). Of course it was them. So much more of paleo-ecology makes sense now.

[Happy Pirate]

Problem one that science has is that it is very difficult to offer definitive proof. We agree there. The more complex the problem the harder it is, because no one has all the facts. No one can know everything. The next group of people to study any area of interest can always make another observation, take another or different measure, add another ounce of evidence, reveal something as yet not considered. And that might change the collective understanding. Problem two that science has is that some people close their minds to alternative possibilities, and then no amount of evidence will suffice.

That said, it doesn't mean that science can't offer plausible explanations to help us better understand. We shouldn't always need definitive proof before we can entertain the possibility. And sometimes with the help of science, we might even be able to reach a situation where there is little doubt or reasonable certainty. The more evidence available the more likely it is this will happen, but, because of 'problem two' that is not always true - for some people anyway.

I think there are a lot of enduring, romantic myths about indigenous live styles. For hunter-gatherer populations, the so called harmony with the land can perhaps be explained by the Lotka–Volterra equation (your Greek fishermen). The fact that man is an omnivore only slightly changes that equation. The theory has it that hunter-gatherer populations (in places like Tasmania) had reached the predicted equalibrium point - stabilised at a level that the environment could sustain. Of course, there is that proof thing again - and as usual, science has an alternative point of view.

I am well aware that some people believe that "fire-stick farming" disproves the natural balance theory, but does it? Or does it simply change the dynamics a little and thereby actually prove the Lotka–Volterra equation. If the population stable point had been reached, even with "fire-stick farming", then isn't the equation proved? But "fire-stick farming" is another topic, and one where science is still collecting the evidence.

Hey WalkinTas
How is Tas at the moment? Damn I miss the place and all the current joy of Maggie Island can't expunge the loss.
I envy you there at the moment.

**Ahem**

I don't want to go too much further with this argument because I know it can be a passionate topic and the place for such arguments is probably better left to peer reviewed journals; so forgive me that I haven't read and responded to all of your references. I"m sure you can keep listing objections and I'm happy to keep responding but in truth I hate pissing matches which is what using uncertain data or opinion often degenerates into eventually and there's not much that's more uncertain than this subject.
Still, at least we're not arguing about vacinations or UFOs But that's not science's problem but the media's.

As I said you can never prove anything in science, only disprove. This is not a problem with a lack of data, its a problem with the process of logic. Science can only offer empirical evidence (the sun has risen so many times in the east we expect it to keep happening) but a single anomalous occurrence can disprove a lifetime of observation (damn- the sun just rose in the west- there goes physics). That doesn't suggest that there isn't a valid reason for hanging onto observational based science.

Now just when you thought we had that sorted, our problem in paleo-ecology is not one of complexity initially, it's one of data.

With this topic the data (mainly fossil, pollen or charcoal records) is so patchy and fossil record can only ever partially describe a spatio-temporal species range and can very rarely delineate actual extinction boundaries anyway (i.e. we know when they did live but we don't know for sure when or where they didn't live). So in paleo-ecology we have the aditional error of patchy and unevenly distributed data. Algorithms in ecology (such as you quoted) are usually so coarse and idealistic that you wouldn't use them to temporally extract predictive data anyway even if the data was better that the current Paleo-record. To try to impose 'ideal' algorithms on such a coarse dataset will never be a valid argument.

"We shouldn't always need definitive proof before we can entertain the possibility"

We can entertain any possibility from telling stories and using imagination is always useful to flesh out the range of possibilities but science is where we reign in fantasy to the realm of the possible. Definitive proof is always either a tautology (in mathematics) or an oxymoron (in science and everything else).

The next group of people to study any area of interest can always make another observation, take another or different measure, add another ounce of evidence, reveal something as yet not considered.

You would expect any further observations to fall within the range of all previous observations. Beyond that would be genuine reason to take notice.
The problem here primarily is that with the the study in question they didn't make any new studies or observations. This is one of those annoying papers that make use of the popular press for it's argument potential (like so) but offers science nothing new.

My 'Greek Fisherman" reference is actually the opposite of a Lotka–Volterra equation and is about the escalation of resource extraction due to technological advance vs. resource depletion. I will describe my idea if requested but I'm such a slow typer that I consolidate wherever possible. (you wouldn't believe how long it me to took to type this - oh is it still 2013?)
To tell the truth the the Lotka–Volterra equation doesn't explain human development at all as it's a predictor more for ecological equilibrium than for imbalance and advancement and the study of human and pre-human interaction with paleolithic ecosysytems is one of continual imbalance. At least what we know so far.

I'm not sure what the"'Natural Balance theory" is but don't get me started on the current "Proof" http://www.sciencedirect.com/science/article/pii/S0277379110003768 about fire-stick farming (unless you REALLY feel like an argument ). His data is was so shonky it was embarrassing. (Once again, willing to share if interested).
It's one of those cases of 'If your data won't hold up to peer review - run to the popular press'. Worse than the current article in question.
As someone with a very close interest in Paleo-Fire Ecology I kinda want to challenge said author to trial by hand to hand combat - as is the traditional method of resolving dispute amongst Palero-Fire-ecologists!

Sorry for the rambling - I guess it touched my Paleo-nervous system
I'll go to bed now (for a thousand years or more)
cheers
Steve