Custodians

Custodians are defined as “a person who has responsibility for taking care of or protecting something”.

During the 65,000 years they have been here the Australian Aboriginal humans have eaten to extinction too many other animals to be described as taking care of or protecting life on this island.

The image shows some that went into their mouths.

See this article

https://www.sci.news/paleontology/humans-extinction-megafauna-04554.html

Humans Caused Extinction of Australia’s Prehistoric Giant Animals: New Evidence

Jan 23, 2017 by News Staff

New evidence indicates the primary cause of megafaunal extinction in Australia 45,000 years ago was likely a result of humans, not climate change. A paper on the subject is published in the journal Nature Communications.

A range of now extinct megafauna that was present when humans first arrived in Australia. Image credit: Peter Trusler, Monash University.

“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,” said University of Colorado Boulder Professor Gifford Miller, lead co-author on the study.

“More than 85% of Australia’s mammals, birds and reptiles weighing over 100 pounds went extinct shortly after the arrival of the first humans.”

“Whether humans were responsible for the demise of the Pleistocene megafauna across Australia has been debated for many years,” said lead co-author Dr. Sander van der Kaars, a researcher at Monash University, Australia.

“Our study found that the demise of the megafauna in southwest Australia took place from 45,000 to 43,100 years ago and was not linked to major changes in climate, vegetation or biomass burning but is consistent with extinction being driven by ‘imperceptible overkill’ by humans.”

The researchers analysed a continuous and precisely dated sediment core collected offshore southwest Australia that captures the last 150,000 years in high resolution.

Environmental proxies preserved in the sediments track environmental change and the abundance of megafauna.

“We used information from a sediment core drilled in the Indian Ocean off the coast of southwest Australia to help reconstruct past climate and ecosystems on the continent,” Prof. Miller explained.

“The sediment 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.”

“The core allowed us to look back in time, in this case more than 150,000 years, spanning Earth’s last full glacial cycle.”

The team found that the major environmental shifts of the last glacial cycle had little impact on the abundance of megafauna, as recorded by Sporormiella, and megafaunal extinction commenced within 2,000 years of humans colonising Australia and took less than 2,000 years to complete.

“We record high levels of the dung fungus Sporormiella, a proxy for herbivore biomass, from 150,000 to 45,000 years ago, then a marked decline indicating megafaunal population collapse, from 45,000 to 43,100 years ago, placing the extinctions within 4,000 years of human dispersal across Australia,” the authors explained.

“These findings rule out climate change, and implicate humans, as the primary extinction cause.”

“The results of this study are of significant interest across the archaeological and earth science communities, and to the general public who remain fascinated by the menagerie of now extinct giant animals that roamed the planet, and the cause of their extinction, as our own species began its persistent colonisation of Earth,” Dr. van der Kaars said.

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Sander van der Kaars et al. 2017. Humans rather than climate the primary cause of Pleistocene megafaunal extinction in Australia. Nature Communications 8, article number: 14142; doi: 10.1038/ncomms14142

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The megafauna of Australia 50,000 years ago included a variety of giant animals, such as:

Kangaroos: Some weighed over 1,000 pounds 

Wombats: Some weighed over 2 tons 

Lizards: Some were over 25 feet long 

Birds: Some were flightless and weighed over 400 pounds 

Marsupial lions: Some weighed over 300 pounds 

Tortoises: Some were the size of a Volkswagen 

Diprotodon: A giant marsupial that resembled a bear 

Genyornis: A huge flightless bird that was a relative of ducks and geese 

Varanus "Megalania": A giant reptile that was related to goannas and the Komodo Dragon