Climate change

Naracoorte’s megafauna has succumbed to both humans and climate change, research finds


A team of scientists, computer modelers and paleontologists have discovered the reasons why megafauna have disappeared from southeastern South Australia.

Led by researchers at Flinders University, the team built computer networks to recreate the Naracoorte ecosystem and investigate the extinction of prehistoric megafauna.

The region is home to the Naracoorte Caves World Heritage Area, which is a treasure trove of ancient megafauna fossils.

While other continents had animals such as mammoths, Australia had giant marsupials such as Diprotodon – a wombat-like animal that weighed between 2 and 3 tons, marsupial lions and giant kangaroos.

Researchers now believe that the megafauna of the Naracoorte region were more vulnerable to changes in the food supply than the surviving species, which could have led to their extinction.

An artist’s impression of a Palorchestes megafauna.(Provided: Eleanor Pease)

Evolutionary ecologist and senior author from Flinders University John Llewelyn said the study took a more holistic approach and was not limited to looking at species that became extinct.

He said the team reconstructed a synthetic version of the community with all species and interactions, and then tested the vulnerability of those species.

Climate change a factor

Dr Llewelyn said changes in the food supply were most likely affected by climate change and human intervention at the end of the Pleistocene (between 11,700 and 129,000 years ago).

Previous research concluded that it was more likely to be climate change or humans.

“There are people who say it was the arrival of humans, potentially hunting by humans that led them to extinction or human use of the land and fire stick agriculture, which burned the earth by changing the vegetation and having a flow effect causing extinction, “said Dr Llewelyn. .

“Other people suggest that non-anthropogenic climate change has affected species influencing plants or directly influencing megafauna.

Dr Llewelyn said other factors could have led to the extinction of large herbivores.

“The megafauna had far fewer predators than the surviving species and therefore the naivety of the predators may also have made the megafauna particularly vulnerable to the arrival of a new predator like humans,” he said.

Map of the ancient Sahul continent and the Naracoorte Coastal Plains Bioregion.
A map showing the ancient Sahul continent and the Naracoorte Coastal Plains Bioregion.(Provided: Dr John Llewelyn)

Dr Llewelyn said the Naracoorte Caves are an amazing World Heritage Site.

“The caves opened to the surface at different times and the animals fell into the caves like a trap [then] were kept in the sediment at the bottom, ”he said.

Dr Llewelyn said network modeling has positive future implications.

“Network modeling is an emerging field. It has been used a lot in marine systems, but very little in paleo systems,” he said.

“One obvious threat that we talk about a lot right now is the impact of climate change.”

So far, Dr Llewelyn said much of the research on climate change has focused only on the direct effects of climate change.

“So it’s going to get a lot hotter, or a lot drier, using network models, we can also get indirect effects, which could be very important,” he said.

“By looking at these old extinctions, we can better understand what is going to happen in the future.”