Guest essay by Eric Worrall
Just like the USA, Australian Megafauna disappeared from Australia soon after humans arrived, but scientists claim the evidence suggests climate change was responsible.
Giant kangaroo victim of climate change
Robyn Wuth
MAY 18 2020 – 12:11PMGiant kangaroos and enormous crocodiles that lived 40,000 years ago in tropical northern Australia died out because of climate change, a study has found.
As the rest of the world was running from giant man-eating carnivores, Australia was home to a kangaroo that stood 2.5 metres tall and weighed a massive 274kg.
It fought for its place in the food chain alongside a marsupial “lion” and the world’s largest wombats.
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“The megafauna at South Walker Creek were uniquely tropical, dominated by huge reptilian carnivores and mega-herbivores that went extinct around 40,000 years ago, well after humans arrived on to mainland Australia,” said palaeontologist Scott Hocknull.
“Their extinction is coincident with major climatic and environmental deterioration both locally and regionally, including increased fire, reduction in grasslands and loss of fresh water.
“Together, these sustained changes were simply too much for the largest of Australia’s animals to cope with.”
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Read more: https://www.canberratimes.com.au/story/6760372/giant-kangaroo-victim-of-climate-change/
The abstract of the study;
Extinction of eastern Sahul megafauna coincides with sustained environmental deterioration
Scott A. Hocknull, Richard Lewis, Lee J. Arnold, Tim Pietsch, Renaud Joannes-Boyau, Gilbert J. Price, Patrick Moss, Rachel Wood, Anthony Dosseto, Julien Louys, Jon Olley & Rochelle A. Lawrence
Explanations for the Upper Pleistocene extinction of megafauna from Sahul (Australia and New Guinea) remain unresolved. Extinction hypotheses have advanced climate or human-driven scenarios, in spite of over three quarters of Sahul lacking reliable biogeographic or chronologic data. Here we present new megafauna from north-eastern Australia that suffered extinction sometime after 40,100 (±1700) years ago. Megafauna fossils preserved alongside leaves, seeds, pollen and insects, indicate a sclerophyllous forest with heathy understorey that was home to aquatic and terrestrial carnivorous reptiles and megaherbivores, including the world’s largest kangaroo. Megafauna species diversity is greater compared to southern sites of similar age, which is contrary to expectations if extinctions followed proposed migration routes for people across Sahul. Our results do not support rapid or synchronous human-mediated continental-wide extinction, or the proposed timing of peak extinction events. Instead, megafauna extinctions coincide with regionally staggered spatio-temporal deterioration in hydroclimate coupled with sustained environmental change.
Read more: https://www.nature.com/articles/s41467-020-15785-w
The issue of the possible role of Aboriginals in megafauna extinction is as sensitive in Australia as elsewhere. From the study;
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The ODP820 charcoal record illustrates an increased fire frequency starting ~44 ka, intensifies from ~40 ka, and peaking ~28 ka23,27,43(Fig. 3g). While anthropogenic landscape burning has been attributed to these increases over the last 50,000 years27,43, this has been challenged and a more likely explanation involves the complex relationship between climate and vegetation with fire frequency47. Importantly, the increased and sustained burning from ~44 ka indicates a fundamental shift toward environmental deterioration and instability that would have impacted the survival of megafauna.
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A role for people in the extinction of Sahul megafauna through their direct extirpation has been previously proposed. However, with no evidence of butchery or kill sites, it has been proposed that extinction occurred rapidly across Sahul shortly after human arrival12,13,14,22,52,53,54,55. In the absence of evidence for direct extirpation, indirect human-mediated factors such as landscape burning have been proposed but are difficult to differentiate from non-human factors15,16,21,56,57.
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Read more: Same link as above
I suspect humans at least contributed to Australian megafauna extinction, despite the delay between human arrival and extinction. The theory that humans had very little to do with megafauna extinction requires accepting the hypothesis that the abrupt extinction of megafauna which had likely survived for millions of years, and the arrival of humans at roughly the same time, was all just a big coincidence.
It is not necessary to believe that humans ate all the megafauna, for humans to have played a role in their extinction. A 2013 study suggested land clearance in Australia can cut local rainfall in half. Fire wielding humans can clear a lot of land, deliberately or otherwise, though as the study suggests, it would be difficult to differentiate human started fires from natural fires.
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Has Tim Flannery changed his mind on this subject I wonder? Before he became a climate activist he wrote “The Future Eaters”.
There is no doubt that increased fire and reduction in grassland were a direct consequence of the arrival of man in Australia. I don’t know about the loss of fresh water.
The Australian aborigines have a long history of regular small burn offs going back circa 50ky. It was the abandonment of this practice which has led to the recent periodic years of severe bush fires in Australia.
More like 40-45 ky. Have a look at this profile from Lynch’s Crater in Queensland. It’s not very hard to see that something drastic happened to fire frequency at that time:
Note that “MIS 6” in the diagram is the previous ice age. Nothing even remotely similar happened then. What was different this time around?
And by the way, notice that Poaceae = grasses increased strongly with increased fire, so no, it wasn’t “reduction in grassland” that killed Cock Robin.
The aboriginals still burn off in central and remote areas of Australia. Our early farmers were taught this method by the indigenous people and it worked well for them too till the leftist/greens put a stop to it. These days you can be fined for removing trees that are a danger to your home if you don’t go through the lengthy process of obtaining permission.
And I agree with you Eric, this has led to the more severe bushfires that we experience here in Australia today.
However the severe bushfires are mostly due to the dominance of eucalypts and other fire-prone vegetation.
This was not so in previous interglacials. See the diagram in the link above. Today’s Australian bush is a direct result of 40,000 years of firestick farming. It is really no more a natural vegetation than is Central Park.
Unfortunately there is probably no way to get back to natural much less fire-prone forests dominated by gymnosperms. There is no way to prevent eucalypts from burning long enough to allow other trees to take over.
“Unfortunately there is no way back”
Says it all really doesn’t it tty.
Retrospect, and all that. Trouble is, looking back, we were different people then. Who knew where our actions would lead us. Who knows where our actions will take us. Blame is futile when the future is changed forever.
Had another thought tty, we’ve sent eucalyptus trees right the way round the world. Trouble with humans, renewable energy as an example, we just don’t think things through. Cane toads were supposed to control beetles I think, they’re killing off our native species. Rabbits cause massive land degradation, feral horses, camels, goats and wild boar and deer were all introduced and compete for food with our other introduced animals, cattle and sheep. Not to mention dogs and cats. We can’t turn back the clock, and animal activists will insist we harm no creature.
Can’t burn off overgrown scrub to prevent bushfires, yet it’s fine to strip the forests for biomass.
I have no answers for the stupidity of mankind. In regard to mankind being responsible for the changing nature of the Australian landscape, I’m sure they largely contributed, but nothing is and has ever been static. Weather events, volcanic activity, colliding tectonic plates, tsunamis and asteroids have all made dramatic changes to the world past and present.
We think that we are so important, that we have the ability to control the climate. Yet in the scheme of things we have only been here for a nanosecond, we are a very small part of earths history, and likely it will continue long after we’re gone.
Everyone always forgets to take into account the one great law of biology:
“Under normal circumstances – when there is enough to eat – every group of animals expands in size until the group is to big, the food is not enough and famine breaks out.”
Animals eat themselves into famine through population growth – and so did humans until the 1960s, when population growth came to a halt in the Western World.
In prehistoric times that meant that humans had the choice between war with each other and hunting more dangerous prey.
There is not now and never was a balance in nature.
Humans never lived in harmony with nature.
Humans were hungry and over time found ways to kill and eat even the most dangerous animals.
Fun fact about Roos is they are one of the ultimate boom/bust drought survivors.
Roos have the ability to ‘stasis’ a pregnancy, so when a Mummy and a Daddy Roo love each other very much they can do the deed, and then the mother can wait until there is excess food around before giving birth.
Once born, the baby roo is about the size of a peanut and makes it way into the pouch and onto a nipple, where it remains until it is grown larger. While this is happening the mother is able to get pregnant again and also feed a larger joey. Hence three generations of roo are on the go at the same time and from this ability as long as there is water and grass, roos can breed like an Imperial College pandemic prediction.
Now back pre 1788 this worked out fine for roos. In droughts the population slimmed down to what the limited water and grass could support and once the rains came the population could explode again. And… die off again in the next drought.
Post 1788 those pesky Europeans started building dams as they spread their farms across the land. This meant for roos there was now a more reliable water supply, their population said ‘thank you very much’ and kept growing.
It has been argued that there are now significantly more roos in Australia then there were pre 1788 and that this is directly linked to European settlers changing the water dynamics.
So there you go. They may look cute and fluffy, but we also cull them for a reason.
(also if cooked correctly they taste great 😀 Australia, the country that openly eats it’s coat of arms. )
I’m with you Craig, kangaroo meat is yum! It’s also very lean and is high in iron, steaks are best cooked medium rare with a little salt and pepper, and the mince makes an excellent spaghetti bolognese.
Perhaps not so much dams as water bores tapping the Great Artesian aquifer. But it is almost certainly true that there is many more ´roos now than in 1788. In some areas e. g. in Pilbarra the density is almost absurd. I remember trying to drive from the coast to Tom Price one night. After an hour we gave up, stopped and put up our tents. It was impossible to drive faster than about 10 mph since ´roos kept jumping onto the road every few seconds.
On the other hand most small marsupials (and indigenous rodents) have been wiped out by foxes and cats.
tty
And introduced rodents?
And there’s many more white-tail deer, at least in the US now — hunting has been ostracized for the last few generations (just one of the reasons). Hello, chewed up landscaping, Lyme’s disease, and bloody carnage on the roads.
beng135
I spent my youth running around the forest in northern Illinois with my dog. Never once did I ever come across a deer, nor did I ever see tracks in mud or snow. Now the place is filthy with them, and I’ve seen white tail deer tracks larger than mule deer.
Two kinds of roos. One small and fast, the other big and slow. Who you gonna go after first?
Wow, we’re off the hook. I feel so much better….. (Humming the tune to Tie me kangaroo down, sport…..)
“Mega_fauna” — the so-called mega-roo was 8 feet tall, standing on its hind legs? That may be big for a kangaroo, but that doesn’t add up to mega-fauna to me.
Male American Grizzly Bears are about that size and weight — and we call them “big” but not mega-fauna.
Yes, I saw that article a few days ago. I was astounded to see those paleontologists claim “climate change” killed the large animals, just when people arrived. It’s not like it’s an unopened topic — this debate has been going on a long time and has been definitively won by those who acknowledge that the world-wide evidence that where people went they killed off the large animals, applies in Australia just the same.
I would like to add a contribution, though. There was a carnivore in those days, a particularly disgusting-looking type of hyena, which was undoubtedly a hostile threat. It disappeared at the start of human occupation, whereas other megafauna survived for another 20k years — this earlier die-out is considered a mystery. It’s pretty clear though, if you give it some thought, that wherever the aborigines went throughout Australia, the first order of business would have been to wipe out those hyenas. It probably explains a lot of the huge forest burnouts of the earliest time, as the people burned out forests just to get rid of the hyenas living in there. So no mystery why those hyenas died out first if you imagine yourself as one of those first people.
Another very annoying of those dumb-as paleontologists who cry “climate change” as wiping out large animals (which by the way had been surviving just fine for tens of millions of years) is that they’re purposely stirring up present-day unfounded fears about climate change. Clearly, scientists can be as dumb as anyone else — competence is a scarce commodity in every field, including science.
Willy
The whole issue of extinctions from dinosaurs to more recent megafauna is characterized by “What about ____?” No one hypothesis seems to adequately explain what became extinct and when. Perhaps that is because there were multiple reasons.
I concur with the view that early humans had little or nothing to do with the Australian extinctions. And even if humans had something to do with later extinction around 10,000 BP, the burden of proof, I must see first before I decide on this issue. I think that the extinction event must have been sudden, perhaps in the realm of being full scale catastrophe, something that the Giant Kangaroo was not able to avoid. Because of its very large size, the Giant Kangaroo was unable to hop, so avoidance of a cataclysmic event would have been next to impossible. I suggest, only speculating here is that some sort of cosmic event may have been responsible. We know only too well that comets and asteroids are capable of such an event. But, this long ago, there may well have been a not too distant star that went supernova. There are some tantalizing clues from various ice cores as in Antarctica particularly of sudden beryllium 10 increases, a possible sign of such an event. Thank-you Rod Chilton