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Humans, Not Climate Change, Wiped Out Australian Megafauna (phys.org)
"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," reports Phys.org. schwit1 quotes their report on new analysis of a prehistoric sediment core from the Indian Ocean off the coast of Australia.
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, who participated in the study... 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... "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."
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... "There is no evidence of significant climate change during the time of the megafauna extinction."
The article adds that last year Miller also identified the first direct evidence that humans preyed on Australian megafauna -- burned eggshells from a 400-pound bird.
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... "There is no evidence of significant climate change during the time of the megafauna extinction."
The article adds that last year Miller also identified the first direct evidence that humans preyed on Australian megafauna -- burned eggshells from a 400-pound bird.
We can look to our recent history and see the same extinction process created by man. The passenger pigeon, Tasmanian tiger, the Dodo, Great auk, Quaggas, Carolina parakeet and so on. Even today there are several species who are literally on the brink of going extinct, including the northern white rhino of which the last known male of its species is under 24 hour guard to protect it from poachers. Had it not been for Teddy Roosevelt, the American bison would most likely also be extinct, slaughtered by the literal tens of thousands as short as 130 years ago.
Man-made extinction also occurs in human populations. How many different Native American tribes were exterminated either because of Europeans or their Native American allies? How about those of Central and South America or those in the Far East?
We can see the same extinction process in places like Borneo where the habitat of orangutans is being wiped out due to illegal farming or clear cutting for palm oil trees, and similar processes under way in Madagascar where many animals exist in no other place on the planet, such as the ring-tailed lemur of which only an estimated 2,500 still survive.
Anyone who says man doesn't and can't have an effect on the environment is simply blind to reality.
Yes, yes, humans 45,000 years ago were "bad" for the big animals, who knows, maybe they're the ones that turned the Outback into a desert, too; we're certain that humans desertified the fertile crescent more recently.
However, modern man is so much more capable - we're scraping the oceans clean, and if we stay the course, we can bake the entire planet into the biggest and most thorough extinction event ever. 100 million years from now, the intelligent descendants of cockroaches will study our culture and chitter gleefully about how they have risen above their pesticide spraying overlords of the early 4th billenia.
Tell that to the mammoths and sabretooths.
> It is possible that a short lived disaster could have caused the die off. Something like a nearby super volcano or an asteroid impact.
They found evidence of a constant decrease in populations over thousands of years, without a corresponding climatic change. It is possible, or perhaps likely that a event like that finished them off. But something other than climate change pushed these local populations to the brink first, and it started at the same time as humans showed up.
Humans probably hunted mostly juveniles, not adults. Juveniles are safer targets. And, killing off most of the juveniles easily leads to extinction.
Table-ized A.I.