Different combinations of human hunting and climate change caused Australia’s famed ‘giant’ species to go extinct, and now it turns out that for some species, changing food availability made things worse.
Sophisticated new modelling has uncovered a previously unrecognised process contributing to the disappearance of ancient megafauna communities across south-eastern Australia tens of thousands of years ago — and for the huge herbivores, it comes down to dinner.
Complex ecological network models developed by Australian and international researchers reveal how the big, plant-eating megafauna of the Naracoorte region in the southeast of modern-day South Australia were vulnerable to changes in the plants on which they fed. Changing food supply driven by climatic changes or human land use in the Late Pleistocene era might have facilitated the extinction of the biggest herbivores.
The research was led by scientists at the Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage (CABAH) at Flinders University. The modelling methods and analysis are reported in a paper in the scientific journal Ecography.
The Naracoorte Caves World Heritage area is well-known for its ancient megafauna fossils. However, while we know that animals such as the giant, wombat-like plant eaters Diprotodon roamed Australia and eventually went extinct, the combination of events leading to their extinction varies across the continent. The particular blend of environmental changes and human hunting responsible in any given region is therefore still debated.
To shed some ecological light on the problem, a team of ecologists, computer modellers and palaeontologists from five universities used sophisticated mathematical techniques to build computer-based networks that represented the Naracoorte ecosystem — from plants to invertebrates, plant-eaters, and the carnivores that ate them — to investigate why certain species eventually died off, and others survived.
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Materials provided by Flinders University. Note: Content may be edited for style and length.