London, Mar 25 (ANI): Giant vertebrates living in Australia were hunted into extinction by humans around 40,000 years ago, says a new research.
The reason behind the widespread extinction has provoked much debate, with climate change being one theory.
However, scientists studied dung samples from 130,000 and 41,000 years ago, when humans arrived, and concluded hunting and fire were the cause.
The extinction in turn caused major ecological changes to the landscape.
The scientists looked at pollen and charcoal from Lynch's Crater, a sediment-filled volcanic crater in Queensland that was surrounded by tropical rainforest until European settlement, the BBC reported.
They found Sporormiella spores, which grow in herbivore dung, virtually disappeared around 41,000 years ago, a time when no known climate transformation was taking place.
At the same time, the incidence of fire increased, as shown by a steep rise in charcoal fragments.
It appears that humans, who arrived in Australia around this time, hunted the megafauna to extinction, the scientists said.
The megafauna included three-metre tall giant kangaroos and marsupial lions, as well as giant birds and reptiles.
Lead research author Chris Johnson, from the School of Zoology at the University of Tasmania, said the research raised further questions about the ecological impact of the extinction.
"Big animals have big impacts on plants. It follows that removing big animals should produce significant changes in vegetation," he said.
The removal of large herbivores altered the structure and composition of vegetation, making it more dense and uniform, he added.
"Getting a better understanding of how environments across Australia changed as a result of megafaunal extinction is a big and interesting challenge, and will help us to understand the dynamics of contemporary Australian ecosystems," he said.
The research was published in the journal Science. (ANI)
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