Kangaroo Island: a megafauna haven?

ki-fossilsFlinders palaeontologist Dr Gavin Prideaux and PhD student, Matthew McDowell, have just returned from a preliminary survey of Kangaroo Island’s south-west with the beginnings of a potentially rich fossil bounty – courtesy of cavers, tourists and owls.

“The Kelly Hill Caves have attracted adventure cavers and tourists over decades. But this very large system of caves also has acted as a pitfall trap for unwary animals, and has been used as a den by owls and other animals over possibly tens of thousands of years,” Dr Prideaux said.

“And as owls don’t digest all the bones of their prey, such as small mammals and lizards, they cough up ‘pellets’ of bones. After years of nesting in an area, you get a little mountain of bones building under the owls’ nests,” he said.

“In addition, over the years, as the human visitors have been walking and crawling through the sediment, they’ve kicked up bones and kindly put them in neat piles. While not ideal in one sense – because the fossils are now out of their original context – this has effectively flagged several sites within the caves worthy of excavating.”

The researchers returned with well-preserved bones of short-faced kangaroos and some other important finds.

“We came across bones of the Kangaroo Island emu, which is about one quarter the size of a mainland emu; and native rodents that do not appear in the historical fauna records of KI. They may have disappeared soon after European settlement or beforehand – we just don’t know,” Dr Prideaux said.

Over the next six months or so, the researchers will collect bones from the Kelly Hill Caves and Rocky River in Flinders Chase National Park, the site of earlier fossil digs by Flinders palaeontology doyen Dr Rod Wells that uncovered many megafauna fossils.

“We want to establish what fauna and types of plants were dominant on KI before European settlement,” Dr Prideaux said.

“We also want to study how climate change and the island’s connection and disconnection to and from the mainland over thousands of years affected the island’s fauna.”

Dr Prideaux is optimistic that KI may have some important stories to tell about the demise of Australia’s megafauna.

“In different parts of the world, megafauna tended to stick it out longer on islands than on mainland areas because it often took longer for people to colonise them.”

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