Humans wiped out megafauna in Australia

New York, Jan 21 (IANS) The poop of some of the ancient huge and astonishing creatures that once roamed Australia has indicated that the primary cause of their extinction was humans, not climate change.

Led by Monash University in Victoria and the University of Colorado Boulder, a team of researchers used information from a sediment core which had spores from a fungus called Sporormiella that thrived on the dung of plant-eating mammals.

The study, published in journal Nature Communications, was led by Sander van der Kaars of Monash University and professor Gifford Miller from University of Colorado Boulder.

"The sediment core allowed scientists to look back in time, in this case more than 150,000 years, spanning Earth's last full glacial cycle," said Miller.

"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," added Miller.

The ocean sediment core showed the southwest is one of the few regions on the Australian continent that had dense forests both 45,000 years ago and today, making it a hotbed for biodiversity.

"Because of the density of trees and shrubs, it could have been one of their last holdouts some 45,000 years ago. There is no evidence of significant climate change during the time of the megafauna extinction," Miller noted, suggesting that the extinction may have been caused by "imperceptible overkill."

A 2006 study by Australian researchers indicated that even low-intensity hunting of Australian megafauna could have resulted in the extinction of a species in just a few hundred years.

"The results of this study are of significant interest across the archaeological and Earth science communities who are fascinated by now extinct giant animals that roamed the planet -- and the cause of their extinction -- as our own species began its persistent colonization of Earth," said van der Kaars.