A stretch of highway in Australia is a “roadkill hotspot” for koalas with nearly 150 of the endangered marsupials killed in just one year, scientists have warned in a new study.
Koalas are struck and killed by vehicles along a 50km stretch of the Peak Downs Highway that connects Mackay with the Bowen Basin coal mining region.
About 145 healthy koalas were struck and killed along this stretch in 2023 compared to an average of 350 elsewhere in Australia due to road accidents every year, researchers from the Central Queensland University found.
Koalas are critically endangered marsupials native to Australia and only about 100,000 to 250,000 are left now, according to the country’s National Koala Monitoring Programme.
They face threats such as dog attacks, diseases like Chlamydia, wildfires, habitat loss, and fragmentation.
Roadkills are also a major cause of the endangered population’s decline.
The latest analysis found that over 80 per cent of the koalas hit by speeding vehicles on the Peak Downs Highway die as a result.
“We found that the spatial distribution of these accidents fit a random pattern along this stretch of road,” the study, published in the journal Animals, noted.
The relative homogeneity of vegetation across this particular landscape could be causing koalas to not concentrate at specific crossing points, researchers said. “There are horrendous numbers of koalas getting hit and killed by vehicles every year on this relatively short stretch of road, with no reduction in sight,” Rolf Schlagloth, a co-author of the study, said.
They call for the avoidance of high-quality koala habitat for highway infrastructure.
“Unfortunately, these koalas are not receiving enough protection from the Government,” Griffith University researcher Douglas Kerlin said.
“In Queensland, koalas are listed as ‘endangered’ under the Nature Conservation Act, but policies enacted by the State Government are currently focused on populations in South East Queensland, while koalas in places like Central Queensland are largely ignored,” Dr Kerlin said.
In the short term, scientists said retrofitting protective infrastructure such as bridges to separate traffic and wildlife could help reduce roadkill.
“We have monitored three bridges that had been retrofitted with short sections of wildlife exclusion/diversion fencing to encourage koalas (and other wildlife) to pass underneath the road rather than taking the risk of crossing the road properly,” Dr Schlagloth said.
Wildlife exclusion fencing could also assist in keeping koalas away from particular stretches of road, researchers said, but such infrastructure was not found to facilitate koala crossings under the Peak Downs highway.
Improving driver attention and awareness of the potential for koalas to be on specific roads may also reduce deaths.
“Driver visibility is also a contributing factor. We know that the better or greater the visibility a driver has, the less likely it is for a koala vehicle collision to occur,” Dr Schlagloth said.
