SA hairy-nosed wombats are flourishing in some areas, struggling in others, Adelaide University research finds
Southern Hairy-nosed Wombat lovers have been given some good news with the “discovery” of 500,000 more of the animals.
SA News
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There are half a million more southern hairy-nosed wombats than previously thought, scientists have discovered using high-definition satellite imagery.
Previous surveys, some done as far back as the 1970s and 1980s, mainly in SA, have proven to be wildly inaccurate.
Adelaide University expert Dr Michael Swinbourne said the dramatic increase in estimates had been made possible through high-resolution satellite imagery providing more accurate burrow counts.
“With the advent of easily accessible satellite imagery, we now can survey areas that have been overlooked in the past, and as a result, we have found the population is a lot more widespread,’’ he said.
Most significantly, the vast Nullarbor Plain population has been revised up to about 930,000 animals. It was previously thought to be 476,00 because the area was so hard to access, and counts on the WA side of the border were poor.
In the Gawler Ranges, the population was previously described as “low” but Mr Swinbourne said an accurate count puts the number at around 206,000.
Of concern is the Murraylands population, which is now about 55,000, much lower than the 2012 count of 150,000.
On Eyre Peninsula, there are now estimated to be 50,000, with no previous counts available.
However, publishing in the CSIRO Australian Mammalogy journal this month, Dr Swinbourne warned that animal numbers were prone to fluctuations, and could change dramatically in drought times.
In particular, there are fears for the 700 wombats that remain on Yorke Peninsula and are considered under threat.
It is on the Yorke and Eyre peninsulas that farmers are lobbying hardest for the animals to be destroyed.
In March, an entire colony of 200 animals on Yorke Peninsula was saved from being killed after The Advertiser exposed approval for the plan.
“There is also little doubt that the (overall) population has been experiencing a long-term increase over the past 60 years or so, mainly because of more effective control of rabbits through myxomatosis and calicivirus,’’ Dr Swinbourne said.
“But this is, in many ways, a recovery of numbers and territories that were lost in the past when the rabbits were in plague numbers.”
Dr Swinbourne said following detailed viewing of satellite images, each covering one square kilometre, burrow numbers were multiplied by a factor of 0.43 animals a burrow to come up with totals.
“We really didn’t have a good handle on the numbers of wombats in the past, mainly because accessing all the areas where wombats can be found is problematic,’’ he said. “They are just too isolated and virtually impossible to get to.
“That’s one of the reasons why it is my view that the numbers were underestimated in the past.
“One of the other reasons is that we have largely looked upon the issue as South Australian, and there had never been a concerted effort to check on wombats in WA.”