During the last Ice Age, Australia, Tasmania and New Guinea formed a single landmass. It was a strange and often hostile place populated by a bizarre cast of giant animals – massive kangaroos and others claimed in a global mass extinction 30,000 years ago.
Researchers argue what caused it, but a Vanderbilt study released in June used fossil teeth to compare the diet of a variety of Australian megafaunal herbivores from when they were plentiful to when they were almost gone. The analysis suggests that climate change had a significant impact on their diets and may well have been a primary factor in their extinction.
“We have found evidence that, as the climate was changing and getting drier, animal diets were shifting dramatically,” said Larisa DeSantis, assistant professor of earth and environmental studies at Vanderbilt University, who directed the study. “If climate change was a primary or contributing factor in their demise, as it appears, we need to pay more attention to how current levels of climate change are affecting animals today.”
The results of the study were described in a paper published on Jan. 25 by the journalPaleobiology.
The teeth that were analyzed came from the Cuddie Springs site in southeastern Australia. During the megafaunal heyday around 500,000 years ago, the dental analysis revealed that the climate was semi-arid. In addition, the animals’ diets were highly variable, implying that there were a number of ecological niches available to them.
That contrasts markedly with the period from 30,000 to 40,000 years ago. Here, the analysis indicates that the climate was substantially drier and the diet of the giant herbivores was considerably more restricted.
“It appears that long-term aridification may have reduced the ability of megafauna to consume certain types of plants, including salt-bush. Eating salt-rich plants requires drinking additional water that was less available and likely increased competition for similar plant resources,” said DeSantis. “These data clarify the impacts of climatic change on marsupial megafauna and suggest that the long-term drying out of Australia, identified here and in other records, likely played a key role in the decline and disappearance of this unique suite of animals.”
Source : Vanderbilt University