Saving the dunnnat and eradicating feral cats intersecting needs after South Australia's fires on Kangaroo Island
A rescued dunnat and another falling victim to a feral cat, in the aftermath of bushires on South Australia's Kangaroo Island.
Image by Pat Hodgens, Terrain Ecology
Saving the endangered dunnarts became two of the nature challenges for Kangaroo Island after its 2020 black summer bushfires.
The small and shy dunnats lost 98% of their habitat in the island fires and a combined study found that feral cats were taking their toll on the survivors. A study of the stomach contents of cats trapped on the island in the months after the fires found 263 different prey, including an endangered southern brown bandicoot. It also found the remains of eight dunnarts from the 86 cats sampled.
The study lead author Pat Hodgens, a fauna ecologist with Terrain Ecology, said this confirmed the suspicion that cats were attacking dunnats. Hodgens moved in soon after the bushfires to try to capture and remove as many feral cats as possible from the only known dunnart habitats at the western end of the island that became a “battleground" between the theatrened species and feral cats trying to survive.
As well as removing cats, Hodgens worked with local private landholders, the Australian Wildlife Conservancy, and the Kangaroo Island Land for Wildlife to build a cat-exclusion enclosure over some remaining dunnart habitat after the fires. The Western River Refuge enclosure was a 369-hectare "predator-free refuge".
A co author of the study, Louis Lignereux from Adelaide University, thought previous estimates of cats are on the island, from about 1,000 up to about 5,000, were low, going on the numbers captured after the bushfires: “The number of cats we've been trapping has been staggering and they're in really good health as well.”
In 2016, the federal government introduced a plan to eradicate all feral cats from the island within 15 years. James Smith, project leader for feral cat eradication with the Kangaroo Island landscape board, saw it as a longer-term possibility.
By 2022, Smith's operation removed cats from about 65% of the Dudley Peninsula in the island's east, and were on track to clear the entire 384 square-kilometre peninsula by 2025. Given that success, and with the fire having killed many cats, he said it made sense to push for total eradication.
Advances in cat monitoring and trapping technology meant cat eradication was a lot less labour intensive. Cameras at traps could send an image straight to a mobile device as soon as a cat walked in front of the sensor.
Smith said the eradication project mostly needed funding with 99% of the poulation in favour of getting rid of feral cats. The cats were not only bad for native wildlife but they spread sarcocystis and toxoplasmosis to sheep.
If eradication did succeed, Kangaroo Island would be the largest in the world to have ever been cleared of cats.