A new study suggests that humans may have had a role in the disappearance of the Australian megafauna. A former climate change was the previous most likely culprit.
The Australian continent was once the home of megafauna. This latter is a term used to describe massively large animals. Flightless birds weighing 400 pounds are one such example. Another are huge kangaroos. They believed to have been 1,000 tons.
Marsupial lions, car-sized tortoises, and lizards 25-feet-long could have also roamed the continent. But what happened to such creatures? Some 45,000 they reportedly started disappearing.
Previous studies tied their extinction to climate changes. Over 70,000 years ago, scientists found traces of an important such change. Formerly, the landscape was believed to be covered in eucalyptus trees. After the event, it reportedly turned into an arid landscape. And it had little vegetation left.
Now, a new study introduces a new factor. It adds humans to the mix that led to the megafauna’s disappearance. Research showed that some 50,000 years ago, human communities had already been established in Australia.
These humans could have hunted the megafauna. And perhaps unknowingly led to its extinction.
The new research was a collaboration. Monash University and University of Colorado, Boulder scientists were part of the team. Their research was released earlier this week. It was published in the Nature Communications. The paper was released on January 20. Research was led by Sander van der Kaars.
Reports indicate the following. About 85 percent of the megafauna was wiped out. And quite shortly after humans settled on the continent.
The scientists base their theory on sediments. These were drilled off the Australian Southwest coast. Estimates show that they are 150,000 to 45,000 years old.
Sediment layers are considered as being time-capsules. They can offer precious information about our planet and its history. The said sediments contained several elements. Ash and dust fragments were amongst them. Also a fungus.
This latter is called Sporormiella. Scientists know that it thrived it the excrements of mammals. More exactly, omnivorous ones. An analysis revealed the fungus’s abundance in the sediment layers.
This also points out another fact. The omnivorous megafauna mammals were once very widespread. But this stopped some 45,000 years ago. Gifford Miller went to offer details. He is a University of Colorado, Boulder Department of Geological Sciences Professor.
According to him, over just a few thousands of years, their numbers dropped dramatically. Humans are known to have started populating the continent some 50,000 years ago. And it coincides with the disappearance of the megafauna.
Miller also pointed out another fact. No traces of a significant climate change were found. Research investigated the potential ecosystem from some 45,000 years ago. And it would have offered a lush vegetation. It would have also included dense forests.
As such, the megafauna should have had a proper habitat. But instead, it started disappearing. As the climate was normal, and no significant changes were registered, the scientists reached the following conclusion.
Humans must have inadvertently led to their extinction. Intensive hunting is believed on of their most common activities at the time. But this may not have been the case.
Even a low-intensity hunting could have hurt the species. Humans could have lived amongst the megafauna for quite some years. Their presence in the habitat did not necessarily lead to a rapid extinction.
Still, their hunting practices could. According to research, killing just one megafauna juvenile is enough. Because of the annual killing, humans could have limited the reproduction. This could have led to a gradual decline. Still, the final effect is the same. And it is extinction.
Miller described the process as an “imperceptible overkill”. The current research results could be a great cause of interest in the domain.
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