Monash University, CU-Boulder show steep decline in megafauna shortly after 45,000 years ago
From the UNIVERSITY OF COLORADO AT BOULDER
New evidence involving the ancient poop of some of the huge and astonishing creatures that once roamed Australia indicates the primary cause of their extinction around 45,000 years ago was likely a result of humans, not climate change.
Led by Monash University in Victoria, Australia and the University of Colorado Boulder, the team used information from a sediment core drilled in the Indian Ocean off the coast of southwest Australia to help reconstruct past climate and ecosystems on the continent. The core contains chronological layers of material blown and washed into the ocean, including dust, pollen, ash and spores from a fungus called Sporormiella that thrived on the dung of plant-eating mammals, said CU Boulder Professor Gifford Miller.
Miller, who participated in the study led by Sander van der Kaars of Monash University, said the sediment core allowed scientists to look back in time, in this case more than 150,000 years, spanning Earth’s last full glacial cycle. Fungal spores from plant-eating mammal dung were abundant in the sediment core layers from 150,000 years ago to about 45,000 years ago, when they went into a nosedive, said Miller, a professor in the Department of Geological Sciences.
“The abundance of these spores is good evidence for a lot of large mammals on the southwestern Australian landscape up until about 45,000 years ago,” he said. “Then, in a window of time lasting just a few thousand years, the megafauna population collapsed.”
A paper on the subject was published online Jan. 20 in Nature Communications.
The Australian collection of megafauna some 50,000 years ago included 1,000-pound kangaroos, 2-ton wombats, 25-foot-long lizards, 400-pound flightless birds, 300-pound marsupial lions and Volkswagen-sized tortoises. More than 85 percent of Australia’s mammals, birds and reptiles weighing over 100 pounds went extinct shortly after the arrival of the first humans, said Miller.
The ocean sediment core showed the southwest is one of the few regions on the Australian continent that had dense forests both 45,000 years ago and today, making it a hotbed for biodiversity, said Miller, also associate director of CU Boulder’s Institute of Arctic and Alpine Research.
“It’s a region with some of the earliest evidence of humans on the continent, and where we would expect a lot of animals to have lived,” Miller said. “Because of the density of trees and shrubs, it could have been one of their last holdouts some 45,000 years ago. There is no evidence of significant climate change during the time of the megafauna extinction.”
Scientists have been debating the causes of the Australian megafauna extinctions for decades. Some claim the animals could not have survived changes in climate, including a shift some 70,000 years ago when much of the southwestern Australia landscape went from a wooded eucalyptus tree environment to an arid, sparsely vegetated landscape.
Others have suggested the animals were hunted to extinction by Australia’s earliest immigrants who had colonized most of the continent by 50,000 years ago, or a combination of overhunting and climate change, said Miller.
Miller said the extinction may have been caused by “imperceptible overkill.” A 2006 study by Australian researchers indicates that even low-intensity hunting of Australian megafauna – like the killing of one juvenile mammal per person per decade – could have resulted in the extinction of a species in just a few hundred years.
“The results of this study are of significant interest across the archaeological and Earth science communities and to the general public who remain fascinated by the menagerie of now extinct giant animals that roamed the planet – and the cause of their extinction – as our own species began its persistent colonization of Earth,” said van der Kaars.
In 2016 Miller used burned eggshells of the 400-pound bird, Genyornis, as the first direct evidence that humans actually preyed on the Australian megafauna.
The new study also included Research Professor Scott Lehman of INSTAAR. The study was funded in part by the U.S. National Science Foundation and the German Research Foundation.
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I’m so tired of getting blamed for everything….
Yep. If you grab the Vostok Ice Core data off the NOAA site (ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/vostok), the deuterium data is effectively a positively correlated proxy for temperature. The 45,000 BP period is one of the major glacial maxima during the last glacial. Humans had probably fully colonized Australia by that time since they had already reached Sydney by 45,000 to 50,000 BP. So, not only are humans present, but a dramatic climate shift is in the works (genuine global warming in fact), so the argument once more appears to be one of correlation rather than causation. There is no need to invoke magical processes like “imperceptible overkill.”
So according to this logic, the existence of any predator of any species, even in very small numbers will lead to extinction.
This bunk is just more left-wing, moralising pseudo-science which appears to be driven by an ideology that we should all become vegan and that even eating one chicken per decade is not “sustainable”.
Total corruption of science.
” The 45,000 BP period is one of the major glacial maxima during the last glacial. ”
Sorry but no. 45 000 BP is right in the middle of the mild MIS 3 with very reduced ice cover. The Glacial maxima were MIS 4 70 000 BP and MIS 2 20 000 BP
” Humans had probably fully colonized Australia by that time since they had already reached Sydney by 45,000 to 50,000 BP.”
Essentially all sites with dates >45 000 BP are extremely shaky.’
“So according to this logic, the existence of any predator of any species, even in very small numbers will lead to extinction.”
No. We are talking about megafauna i e quite large animals that bred very slowly and were essentally never predated as adults before humans arrived. There were never any very formidable predators in Australia before humans, Thylacoleo or Megalania are hardly in the same class as tigers or lions (or wolves for that matter).
I wondered why the Aboriginal arrival was getting pushed so far back. It’s so they can blame them.
Hmmm. So they could either try to catch 100 or so small agile animals – or get the same amount of meat by killing one large slow beast. And 50,000 years later we are trying to figure out which choice they made…
Or they could eat plants and spend their free time virtue signalling.
Well they could try try to eat plants.
Koalas did and their brains shrank
Not enough food crops in the SW Australian flora for people to survive on.
“Vegetables” were a part of the indigineous diet, but only a part,
And in reply to…” according to this logic, the existence of any predator of any species, even in very small numbers will lead to extinction.
No. You have large slow breeding vegetarian mammals [eg diprotodon] that have not evolved to avoid humans.
Before they can evolve a strategy to deal with humans they’re gone.
The predators that preyed on the vegetarians [eg Thylacoleo aka https://en.wikipedia.org/wiki/Marsupial_lion ] have nothing to eat.
They linger a while longer then they’re gone
So in this case people done it, not the climate
Perhaps it is worth mentioning that in Australia it is politically incorrect to say anything bad about the indigenous population – so saying they caused extinctions would cause quite a stir here. This story is quite interesting from that perspective – especially so as a US university appears to have co-authored the paper.
“so saying they caused extinctions would cause quite a stir here.”
I doubt that would even how up on their radar screens. They are too busy overcoming the daily effects of racial discrimination.
What passes for scientific research today is astounding. Humanity is blamed for every extinction by default,
without any real thought as to another cause. The “we deserve to be punished meme” underpins the anti-human ideology of the left, the environmental establishment, and the climate establishment. Not surprisingly, most of the human planners and drivers of these negative ideas also believe there are too many people on the planet. What better way to slow the progress and number of people on Earth than to deny the developing world affordable energy?
holly
But it works the other way around.
The more prosperous the nation (affordable energy) the fewer children they have.
The poorer the nation the greater the child birth.
The left does not understand this.
Not to mention all the bushmeat they eat.
They never will.
Hi Hans,
Sorry I don’t know how to place this reply right after your comment. To reply to your comment, although it is true developing nations tend to have more children, they also have high infant and child mortality. And, they are also prevented from”polluting the environment” or producing carbon emmisions, as long as their development is delayed.
My theory is that the base driver of the effort to reduce carbon emmissions, is humanity’s natural instinct to restrict or cripple the rise of a new human group ( China or Africa), not out of racism, but out of fear of being dominated by this new group, and fear of a shift to a new cultures’ values, language, and other practises. Human groups have been attacking each other for survival reasons, as other species do as well, since the beginning of our existence. Neandethals died out because they were dominated and assimilated. People fear the rise and potential dominance of other groups.
It can’t climate that killed them off, climate change isn’t that bad – more lefty bs
It can’t be human what done it either – more self-loathing, human-hating lefty bs.
Hmmm… “Miller said the extinction may have been caused by “imperceptible overkill.”” Then again, maybe it was the fleas that that came along for the ride… or the pathogens that rode along on the fleas…
Or perhaps the plunging levels of CO2 at the end of the last ice age got low enough that the plants supporting the megafauna enviroment could not survive.
I guess those early ancestors of the aborigines just did not burn enough stuff to keep it all going.
So there we go… humans are responsible!
They had to kill all the animals because of the global warming.
Humans are also responsible for the widespread fire adapted flora across the continent as they used fire to sculpt the landscape to suit their hunting and gathering. By the time the English arrived that transformation was long complete and the landscape looked ‘like and English gentleman’s park’ as so many writers of the late 18th and early 19th century recorded.
Of course the settlers, in their ignorance and arrogance never even considered that possibility and assumed that was its natural state. A couple of centuries later and the regular burning regime long abandoned has meant that the fire prone understorey has become a constant problem and when fires get into the tops of the eucalypts the expression ‘firestorm’ hadly does justice to what insues.
Wildfires are a constant threat to urban fringes and isolated settlements and farms. This is one aspect of thge Australian environment that is directly attributable to ‘western’ culture. It has SFA to do with alleged climate change although the climate scientist celebrities and their media papanazi followers keep that idea as far from the public eye as possible. Not good for business that sort of factual approach.
@M Seward
January 20, 2017 at 4:54 pm: We settlers produced a lightly-wooded grassland ie savannah. Somewhat similar to the aborigines. It is only arrogant ignorant townies who cause over-fuelling and stupid building inside that fuel. With predictable results. Same idiots gave us CAGW and much other trouble.
Yup. Sharped tipped spears from hungry humans will do that. As the sharp pointed bullet evolved spears are doing to large Africa fauna today. An overabundance of top preditor problem. Nithing to do with CAGW.
Ruud
What happened to your spell-checker?
Or are you trying to affect an antipodean accent?
Australian Clue – “The New Archaeology WhoDunIt game!
(The aborigines did it, in Australia, with spears n fire…)
“Miller said the extinction may have been caused by “imperceptible overkill.” A 2006 study by Australian researchers indicates that even low-intensity hunting of Australian megafauna – like the killing of one juvenile mammal per person per decade – could have resulted in the extinction of a species in just a few hundred years.”
Sooooo …. the species in Q. must have been marginal anyway if “the killing of one juvenile mammal per person per decade – could have resulted in the extinction of a species in just a few hundred years.”
Sooooo … another piece of hair-shirt misanthropist crap.
I can see this becoming the next fund-seeking game in town to keep these over-opinionated, sinecure-retentive, public-troughing, so-called scientists from being laid-off. “What extinct species can we blame on anthropogenicity so as to keep the media-driven angst alive and well?”
And where’s the pay-back for all the taxpayers’ money poured into such retrospective research? Donald …. show ’em the door!
@ Ross King January 20,2017
Well a similar thing happened in NZ with the Moa hunters – (NZ’a mega fauna) The early Maori hunted these large birds to extinction in short enough order p the breeding replacement capacity would be no match for the huntsmen with spears – note the Wikipedia extract below. In your terms their population would have been marginal in any event.
The moa were nine species (in six genera) of flightless birds endemic to New Zealand. The two largest species, Dinornis robustus and Dinornis novaezelandiae, reached about 3.6 m (12 ft) in height with neck outstretched, and weighed about 230 kg (510 lb). When Polynesians settled New Zealand around CE 1280, the moa population was about 58,000
They were the dominant herbivores in New Zealand’s forest, shrubland and subalpine ecosystems for thousands of years, and until the arrival of the Māori were hunted only by the Haast’s eagle. Moa extinction occurred around CE 1300] – CE 1440 ± 20 years, primarily due to overhunting by Māori
@Ross King
Actually a lot of them are employed by universities, so they wouldn’t get laid off. Instead they’d have to actually start teaching more students instead of getting released time for all the grant money they’re bringing in to their institutions. The institutions in turn take a very healthy cut of the grants, so they’re happy hire adjuncts at much lower wages to deal with those students.
Actually, Ross, if Australia’s indigenous folk did kill off the megafauna, that is a good thing to know. It shows they are not the wonderful protectors of the environment that our modern Aboriginal industry claims them to be. In fact it makes them no better then the “invading” British settlers over the last 200 years.
Jeez Ross, have a cup of tea and a good lie down mate.
Animals that evolved separately from humans have no fear – for example penguins in antarctica do not fear humans – so African megafauna survived, but elsewhere not so much.
Jeez, I just wish i could get a little fear reaction from the white-tail deer when I drive down my lane. The does and yearlings seem to like to mingle with the livestock during hunting seasons, maybe it’s my imagination.
Finding the bones of these extinct animals in ancient middens would certainly be some form of evidence that the locals were preying on them but it doesn’t mean that they directly had a hand in the extinction of all megafauna .
A few burnt egg shells does not causation make .
I follow you. Correct me, but AU doesn’t seem to be as conducive to growing megafauna as the African continent.
It isn’t. It is a continent with geologically very old landscape with little relief and heavily eroded, nutrient-poor soils. And marsupials never evolved digestive systems nearly as efficient as ruminants for extracting nourishment from low-quality forage. There never were any really big marsupials. The largest weighed about a ton.
Or was a change in wind direction cause the change in results. Or… Or….
This is impossible. The aboriginal inhabitants of Australia, like those of the Americas lived in harmony with nature. They could not possibly have caused an extinction. It must be the white Europeans who did it. It must be.
Readers should realise that this news, unlike climate scare stories, will never appear in the Australian media. You need to understand that, unlike all other humans, the Australian Aborigine is perfect in every way including land and animal management. Professor Tim Flannery, of climate alarmism fame, was once a paleontologist specializing in early Australian mega fauna. In his book, The Future Eaters, he explained how the early aboriginals exterminated the mega-fauna and changed the landscape with firestick farming. The latter was a replacement for the former but resulted in the destruction of the conifers and the ascendancy of the eucalypt. The indigenous industry here found the hypothesis outrageous and may explain Tim’s ardent support of the leftist CC meme as a way of doing penance. It has also been extremely profitable for him
“In his book, The Future Eaters, he explained how the early aboriginals exterminated the mega-fauna and changed the landscape with firestick farming. The latter was a replacement for the former…”
The mega-fauna was a replacement for the early aboriginals? That doesn’t make sense.
Firestick farming was a replacement for early aboriginals? Um, dubious.
Changing the landscape was a replacement for exterminating the mega-fauna? Does not compute, Captain Ayres.
Or the firestick was a replacement for Flannely’s book, The Future Eaters? That must be it.
The way I read it, is that after the easily hunted mega fauna had gone the aboriginals had to concentrate on prey more difficult to catch. Fire was the solution, which was used to flush out fauna and also to loosely farm them by the subsequent growth of green pick.
With the extinction of the mega fauna the bush was no longer controlled. The large browsers had kept the understory clear allowing grasses to grow which in turn supported the smaller marsupials. Without the browsers and grazers the bush became overgrown and stifled the grasses. Fire was used to clear the bush and encourage the grasses. In other words the fire stick replaced the mega fauna to do a similar job.
BTW I was a Lt Colonel.
I am also an Aussie. I find the whole noble savage idea a nonsense and frankly quite racist. I personally think that all humans are the same whether white, black or any other colour we exploit a resource until it is gone or severely depleted, sometimes we get lucky and begin to manage resource in a sustainable way!
Agree. The Zulu in South Africa complain about the arrival of white Europeans. I think the Hottentot the original residents of South Africa would have felt the same way about the Zulu with one important difference, there are no Hottentot alive today.
Please remove my previous post, I think I may have jumped the gun.
Rex, there were no ‘native inhabitants’ of South Africa. The Hottentots were farther north.
Actually the Khoi and San (sometimes called bushmen) were in South Africa looong before anyone else…
I often find it remarkable what proxies people come up with that contain information of the distant past. Then comes the next part, assembling the data. A glimpse here, a glimmer of a fact there, and eventually a picture emerges. And best of all, it is not all hypothesis and conjecture. There is actual physical material which can be examined.
Perhaps species with a low annual birth rate and a long lifespan would be susceptible. This part seems to fit, as well.
Actually fungi living on dung (particularly Sporormiella )are a very good proxy for large animals. They show the disappearance of the megafauna in Madagascar and New Zealand quite clearly at the historically correct times. In New Zealand they even show the expansion of introduced red deer in the twentieth century.
Pretty sad. But it is also obvious from the museum exhibits in Sydney that these animals were basically defenseless against human packs.
Oooh! The climate saved from those Mega Methane Making Mammals (and Birds and Reptiles)!
It was a man-caused extinction not a climate caused extinction, so we are not to blame!
Some years back I wrote an article called “Firestick Farming” which outlined the practice used regularly by modern aboriginals when they migrated to this continent. This practice is known to have decimated large swathes of bushland and forests, it also killed large populations of slow moving animals. Animals referred to as “Mega Fauna”.
My article caught the ire of one Dr Stephen Wroe whom was a lecturer at Sydney University. Dr Wroe’s argument was that there was no proof that aboriginals used Firestick Farming in the same way as Australia’s first people. Now think about what he just said. “in the same way as Australia’s first people”.
My response was obvious. I said “Maybe not, but at least you’ve now acknowledged there were humans on this continent before the aboriginals”.
Either way, we know the practice of ignighting forests and bushland had a significant impact on both flora and fauna.
“there were humans on this continent before the aboriginals”.
Who were they Scott?
The most notable was the ‘Mungo’ people. Named solely on the location or the skeletons when found by Jim Bowler. Mungo man had no DNA similarities with any other humans, including aboriginals, and the mitochondrial DNA from Mungo man is now extinct.
There’s the Kow Swamp people. There’s also conjecture over the people in Tasmania whom were isolated from mainland aboriginals fro more than 10,000 years. Australia also had a population of pygmies in northern Queensland that in recent times seems to have been either ‘wiped’ or simply excluded from Australian anthropological history.
There are plenty of examples of climate change affecting Australia’s Mega Fauna, Alcoota near the Aussie center is but one example of severe drought wiping out thousands upon thousands of animals as they became stranded at water holes due to a lack of food in the surrounding landscape during the late Miocene.
This paper smells like another attempt to paint a picture of Mankind = Bad , Nature = Blameless.
Firestick farming may have had some role to play, but the Australian landscape has been shaped by fire for around thirty million years due to natural lightning strikes and alternating periods of aridity and wet as the climate varied through cyclical ice ages and interglacial’s.
Compare vegetation during this interglacial and previous ones. There is a huge increase of eucalypts and an equally huge decrease of conifers and vine forests.
It would be nice to have an explantion of what people regard as “a CAUSE “….
Humans quite systematically overkill when they arrived in a new place…it does lead systematically to extinction…
anythings that causes a generation to have less than two descents can lead to an extinction ,as long as it lasts…
Aborigines had a heathy respect for conservation hunting , their dream time stories are full of lessons about over harvesting a particular plant,animal or even water .
Given the small time frame all these animals went extinct and the size of Australia I find it hard to believe that the aboriginals could be solely responsible for the extinction of all the megafauna .
In my experience “conservation hunting” is almost always invented by PC anthropologists, not bu hunter-gatherers.
tty, not sure of what your experience is or is based on but I am a conservation hunter , nothing I do is pc but I only take what I’m going to eat !
Y’all become “conservation hunter[s]” once you decimated the herds!
It’s called learning from experience. They kept a balance with the surviving fauna because they learned from getting it wrong the first time, and the fauna they kept a balance with were the once that had managed to survive them anyway.
“Pleistocene overkill” has been a debated topic for what, fifty years? There is a LOT of evidence about it. As is typical in the real world, some of the evidence is for it and some is against it and a lot of it is probably wrong anyway.
Australian aboriginal people had over 50,000 years to learn their lessons……..after they wiped out most of the big stuff, albeit inadvertently. They had to become conservationists. There were very few plants that were amenable to agriculture as easily as were the ancestors of wheat, rice, barley, oats etc
In general If you have to walk more than half a day from your camp to get a feed you have to shift camp to the next place where you have to walk less than half a day to get a feed.
You are unlikely to wipe out all the resources in that half day radius from your first camp and by the time you return a month or a year later the resources will have recovered to the point you can exploit them again.
In heavily populated areas where people get most of their food from intensive agriculture [ say rice farmers in Java] the local natural resources are often stripped to almost nothing. It’s instructive to watch local people harvest accessible reefs at low tide.Not a lot of thought about conservation there. If you don’t get that tiny clam your neighbour will.
Sure thing Robert. I presume from your comment you have first hand knowledge of what the first Australians actually did to feed themselves 45,000 years ago?
I’m interested in how such a precise figure for the megafauna numbers is arrived at – must be some pretty impressive evidence and statistical work involved here. It would be useful to know the estimate or precise figure for how many Aboriginie people are believed to be present. Imperceptible overkill may not be an unreasonable idea but it could have causes other than just people. Slow or imperceptible climate change etc etc could be equally put in the frame.
Except that 50 to 45 Ka the climate wasn’t changing any more than it had during the prior 50,000 years of the last glacial interval, and much less than during the previous interglacial, the Eemian. Climate change isn’t an option. Humans are not just the best explanation, but the only one supported by evidence.
Perhaps I should clarify … if you claim 85 per cent of the megafauna goes out quickly, then presumably you must have a good handle on the original numbers.
If Mann – sorry, Man was responsible, perhaps Mr Trump should publish an apology on behalf of the human race?
Population is the key.
Take today for example. We could never go straight back to hunter gatherers today because there are too many of us. Let’s say hunter gatherer starts tomorrow. Within a few weeks people are going to bed hungry and getting some meat for the family becomes the number 1 concern. Everybody is out hunting within a few weeks besides all other kinds of conflict.
Within a year, we have killed off just about all the animals and cut down every tree for firewood and cooking.
If the aborigines grew rapidly in population 45,000 years ago due to the abundant resources, well, they would have taken many species to extinction.
But we need evidence that the population grew to something like a million. Were there ever that many. Once you get a lot of people and start making resources hard to obtain again, the hunter gatherer populations fall. Maybe too late for for some species but then an equilibrium is established.
In North America, the early Indians found resources that were easy to obtain, but the population never increased to really high levels until agriculture came in the Americas. This is where the population booms were. Same story in Europe, the Middle East and Asia. Was Australia different. How many humans were in Australia 45,000 years ago.
No. Population is not the key in megafaunal extinctions. Most top predators are quite specialized in the areas they live, and increase or decrease in numbers according to their main prey or preys numbers. That’s why top predators do not extinct their preys. Man is at the same time top predator and opportunistic omnivore, which is very rare. Cultural developments made man an extremely efficient hunter and success no longer depended on prey abundance. Megafauna was the prey of choice and their rate of reproduction is low. Unless they were very shy and fearful of man, or dense forest dwellers, they were hunted above replacement rate all the way to extinction.
I don’t see why this is such a difficult concept to accept. We haven’t changed. We recently became top predators in many marine ecosystems, with high success rate due to cultural developments and we have driven every large species that we hunt, whales, sharks, tuna, almost to extinction by hunting them above replacement level.
You raise an interesting point. The prevailing arrid conditions in Australia would lock in people as subsistence hunter gatherers, preventing the progress to widespread early agriculture. The megafauna and who knows what else would be doomed.
Javier – I’m not sure why you start with “no” – what you say – which I agree with – does not seem to contradict Bill’s points.
Another factor is sudden arrival of humans. Here is another hypothesis. Africa is where humans – from ancient australopithecines all the way to behaviourally modern, evolved. Yet Africa is the continent with the most, not least, surviving megafauna. An apparent contradiction. Unless you propose that in Africa, megafauna and evolving humans arrived slowly at a synergy of coexistence together. Whereas in places like North America and Australia, they “suddenly” arrive in a boat, fully modern, into an ecosystem where humans are unknown. Carnage and extinctions follow. We acted as a destructive invasive species in these places, but not in Africa.
Quite right
North American large grazers possibly “overkilled”:
Horse, Tapir, Camelops,; browsers: Mastadon, seven genera large ground sloths.
sthwest is WA so the claims of the spores found in oceans?
where?
cos the east coast landing of much at all, would be a lot far fetched to me.
wouldnt finding aboriginal poop and megafauna dna in that be rather better “proof”
This conflicts with popular impression that the first Australians were wise and in perfect harmony with nature. Sort of like the early western perceptions of the Maya, that they were these philosopher kings of the jungle, studying the stars and cosmos. Now it is accepted that Mayans were in frequent wsrs, blood thirsty and extremely political slaving and sacrificing humans, etc. The first settlers of Australia were Paleolithic humans. Emphasis on humsn, with all the instincts and capabilities that implies.
Yuval Noah Harari in his book “Sapiens” tell the same story re America – within 2000 years of sapiens arrival, 34 of 47 genera of large mammals went extinct.
I am not a weatherman, but I am a biologist.
Megafauna . . . super big animals . . . is generally an adaptation to cold. The deer in Saskatchewan are 3 times the size of Texas deer. Greater volume of body yields less relative surface area, greatly reducing heat loss.
A warming climate is the Occam’s Razor for the end of megafauna. There may be another explanation, but it will take more than speculation, or some egg shells, to prove it.
The megafauna of Oz had survived many warmings and coolings of their environments, which temperature changes weren´t extreme in the Pleistocene.
Elephants ? Rhinoceros ?
Further back large dinosaurs….T rex
http://www.livescience.com/29231-cretaceous-period.html
Large creatures doing quite nicely in a warm climate
Some mammals adapted to the cold by becoming larger and hairy but it is not a necessary adaption [huge mice?] and it doen’t mean that large animals aren’t suited to warmer areas
Anyone have the recipe for BBQ eggs? Sounds intriguing.
(Note: It is fun to watch watermelons explode)
The recipe for an egg is a chicken
The recipe for a chicken is an egg
1j8
It’s obvious to every rational person that the first arrival of people and the extinction of megafauna coincided everywhere. In New Zealand, the cooking ovens holding the large bones of the now-extinct moas are found all over. Those big birds were early KFC, people, say yum yum. This is not rocket science.
I recall attending a dinner some 40 years ago at the University of Melbourne at which the guest speaker was Geoffrey Blainey, then Professor of Australian History at the University (this was while I was teaching chemical engineering at the University). During his address he commented that Aborigines had fire which they used for hunting and which they were never known to put out. He commented that James Cook in his journal while travelling up the East coast of Australia in 1769/70 (?) wrote that the land appeared to covered in a pall of smoke. He stated that he considered this hunting technique was responsible for the disappearance of giant marsupials, citing the discoveries of piles of bones at the bottom of cliffs, believing that the animals were driven over the cliffs by deliberately lit brush fires.
Well, is CO2 not the gas of life?
What if the too low CO2 concentration caused the extinction?
If one goes through the ice cores from the NOAA site (ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/vostok) there are these values for CO2 in the CO2.txt file last modified 12/08/1997 12:00:00 AM:
Barnola et al,Nature, 329, 408-414 (1987)
Depth ice Age Gaz age CO2 ppmv mimimum maximum
m years years value value
700.3 42320 38660 207 211 203
748.3 45970 42310 178.5 196.5 173.5
775.2 48000 44350 200 205 190
Just wondering if the very low CO2 values did not cause starvation or low growth for the plants that stood at the basis of the huge fauna?
The 173.5 value is the lowest from the whole sample and it looks like it was just 42 k years ago?
Well, according to fossils recovered from the La Brea Tar Pits, junipers and other plants were suffering from CO2 starvation during the last glaciation: http://www.pnas.org/content/102/3/690.full?sid=5e3bdf35-c2a6-4fe7-b336-eea3917571f2
Excerpt from the abstract:
Here we report on δ13C of Juniperus wood cellulose, and show that glacial and modern trees were operating at similar leaf-intercellular [CO2](c i)/atmospheric [CO2](c a) values. As a result, glacial trees were operating at c i values much closer to the CO2-compensation point for C3 photosynthesis than modern trees, indicating that glacial trees were undergoing carbon starvation.
Thanks for the feedback and the link. Form the abstract it becomes clear:
” By scaling ancient c values to plant growth by using modern relationships, we found evidence that C3 primary productivity was greatly diminished”
Here another post about CO2 starvation which explains why CO2 does not tend to go lower once a certain low limit is reached – massive negative feedback – read plants no more growing
http://people.earth.yale.edu/sites/default/files/files/Pagani/6_2012%20Beerling%20JEcol.pdf
” lower limit of [CO2] a is buffered by a strong negative feedback, ca used by a diminished capacity
of land plants to weather Ca- and Mg-bearing silicates as[CO2]a falls to critically low ‘starvation’ levels (Pagani et al. 2009)”
I remember having read also about megafauna in the Eurasian area and the disappearance of specific plants. I think there is not enough such research and we do not yet understand the constrain of 200 and lower CO2 ppm on whole ecosystems.
Here one about “trees that miss the mammoth” in NA.
http://www.americanforests.org/magazine/article/trees-that-miss-the-mammoths/
What it fails to consider is that trees have a high dependency on CO2 concentration.
Of course humans are again mentioned, and for sure they did their part, but what is missing from the whole picture is the strain put on the whole system by the low CO2 content.
If the basis of the food pyramid is severely constrained that what happens with the whole ecosystem? And of course huge animals are the first to have a problem finding the needed food as they need now to look on a larger area. The energy balance works no more for them.
Megafauna mostly live on C4 plants (like grass). So when C3 trees had a difficult time were actually good times for megafauna.
tty says: January 22, 2017 at 10:22 am
Megafauna mostly live on C4 plants (like grass).
You mean megafauna that survived? Yes, I agree.
Wondering if you can point to any study of what the extinct megafauna was eating?
In one example I gave was a tree “missing” megafauna, so that was not grass, but certain tree fruits.
I remember there was also a study about extinct megafauna in the Eurasian continent, and surprise, surprise, the plants that were at the basis were also gone. I’ll need to try to find it again.
ok found something – forbs not grasses which are classified as C3 plants:
http://www.sussex.ac.uk/broadcast/read/23194
“The study challenges the prevailing view that the Ice Age “mammoth steppe” (which fed the Ice Age megafauna – giant mammals including woolly mammoths, woolly rhinoceros, bison and horse) was grass-dominated.
Instead, the DNA analysis reveals that the dry steppe tundra on which the animals lived and fed was dominated by forbs (herbaceous vascular plants that are not grasses, sedges and rushes), which provided more nutrients to the grazing animals than grasses.
The composition of the mammoth steppe-tundra of course changed over time, but is now effectively extinct. Its components still exist, so it will reemerge during the next glacial cycle. However its largest and most characteristic herbivores are gone. Horses, bison, ibex, saiga antelope and some others still survive, often in modified form.
Its fauna resembled the Serengeti, with mammoths for elephants, woolly rhinos for the black and white rhinos, horses for zebras, bison for wildebeest, saiga for some antelopes, etc.
Gloateus Maximus
January 24, 2017 at 8:09 am
However its largest and most characteristic herbivores are gone. Horses, bison, ibex, saiga antelope and some others still survive, often in modified form.
Exactly. Why horses, bison etc survived and others not?
Was wondering if we do not have the case where herbivores feeding on C4 plants survived, whilst the ones feeding on C3 plants died, as the respective plants got rare/seldom due to CO2 starvation during the ice age.
But Perfesser Flim Flammery told us in his book it was climate change!
So, what was the Aboriginal population of Australia in the 1700s? (about 400 years ago).
If one believes Wikipedia, it was ” between 315,000 and 1.25 million, mostly concentrated in the fertile south east of the continent.”
If this figure is correct, than if one goes back 45,000 to 150,000 years ago the aboriginal population most likely would have been less than cited in Wikipedia.
So basically, the continent of Australia was devoid of humans (land area of Australia is 2.9 million square miles) until the Europeans showed up in large numbers.
Note that the upper estimates for the Native American population in 1492 in what is now the lower 48 US states tops out at about 5 million and the land mass of this area is about 3.12 million square miles; not much larger than that of Australia , but about 4 times the native population of Australia .
When the evil white man showed up in North America in what is now the USA, the land was teeming with wildlife.
The fact is that Australia and even North America, even as late as 1500 , were almost devoid of humans. There are today more folks in Queens and Brooklyn, NYC than lived in all of Australia and North America in 1500.
The idea that humans wiped out the wildlife of Australia 50,000 years ago is laughable.
…………..in the 1700’s……….. I meant to say about 300 years ago.
The environments of Australia and North America 300 years ago were very different. Many American Indians were farmers.
The environment of Australia was also different before the arrival of humans. The earliest Aboriginal population probably ballooned at first, then crashed after killing off the megafauna.
“When the evil white man showed up in North America in what is now the USA, the land was teeming with wildlife.”
It was a lot less teeming in 1500 than in 1700 after disease had virtually wiped out the native population. Have a look at Cahokia next time you’re in St Louis. That wasn’t built by a few wandering hunter-gatherers.
Dear John,
Come and have a look. Check the carrying capacity of most of Australia.
A lot of Australia is needed to support one big animal.
People arrive with pointed sticks. It’s all over for the big things.
Maoris in New Zealand did for the Moa very quickly
Dodos were wiped out very quickly as they weren’t scared of people.
They ended up in Dutch sailors’ cooking pots.
There’s no suggestion that aboriginal people in Australia wiped out the wildlife 50,000 years ago.
There is a suggestion the the aboriginal people wiped out the big stuff…
“Monash University in Victoria, Australia”
OK
” and the University of Colorado Boulder”
What country is that in?
The preference for hunting megafauna over lesser fauna is one of simple economics. The meat of a 1000 kg will feed the tribe a lot longer, and with a lot less work, than the meat of
The preference for hunting megafauna over lesser fauna is one of simple economics. The meat of a 1000 kg will feed the tribe a lot longer, and with a lot less work, than the meat of a 1 kg tree-dwelling mammal or bird.
“New evidence involving the ancient poop of some of the huge and astonishing creatures that once roamed Australia indicates the primary cause of their extinction around 45,000 years ago was likely a result of humans, not climate change.”
Think that was evident for archaeologists since ever.
Remember me doing similarly claim some time ago on “wuwt” labeled ‘laymen may tell what scientists are not allowed.’
Cheers – Hans