Smoking gun found for megafauna extinction

February 12, 2014

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A new study revealed that a change in vegetation caused by climate change wiped out the megafauna species of the last Ice Age.

The paper which was just published in Nature, was led by Professor Eske Willersley from the University of Copenhagen and involved more than 40 academic institutions including Murdoch University.

For decades, scientists have debated the reasons behind the megafauna extinctions, which caused the loss of a third of the large mammal species in Eurasia and two thirds of the species in North America.

Dr James Haile from Murdoch University said the team managed to reconstruct the last 50,000 years of Arctic vegetation using little more than a few grams of permafrost soil, plus a lot of state-of-the-art techniques.

Additionally, they were able to discover what mammoth, woolly rhino and other megafauna were eating, from extremely scarce gut and faeces remains of these animals.

“Knowledge about the way in which the arctic environment responded in the past to climate fluctuations will help us to predict the effects of any future changes,” Dr Haile said.

Professor Willersley said results showed the landscape was far more diverse and stable than today, and big animals like woolly rhino and mammoth fed on grasses and particularly on protein-rich forbs.

But at the Last Glacial Maximum 25,000 – 15,000 years ago, at a time when the climate was at its coldest and driest, a major loss of plant diversity took place. The animals barely survived.

Results show that plant diversity did not return after the Ice Age ended about 10,000 years ago, with a new kind of vegetation dominating the landscape.

The protein rich forbs, which had been one of the key food sources of the large mammals did not fully recover to their former abundance.

This likely proved fatal for species like woolly rhino, mammoth, and horse in Asia and North America.

Professor Willersley said: “We knew from our previous work that climate was driving fluctuations of the megafauna populations, but not how. Now we know that the loss of protein-rich forbs was likely a key player in the loss of the ice age megafauna.

“Interestingly one can also see our results in the perspective of the present climate changes. Maybe we get a hold on the greenhouse gases in the future. But don’t expect the good old well-known vegetation to come back when it becomes cooler again after the global warming. It is not a given that the ‘old’ ecosystems will re-establish themselves to the same extent as before the warming. It’s not only climate that drives vegetation changes, but also the history of the vegetation itself and the mammals consuming it.”

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