A study of the effectiveness of wildlife corridors at a $1.6 billion bypass in south-east Queensland finds feral cats, wild dogs, and foxes were the biggest users.
Researchers from University of Southern Queensland (USQ) spotted only one koala and a handful of native animals using the crossings under the recently opened Toowoomba bypass throughout a 12-month study using camera traps to monitor animal movements.
Meanwhile, seven koalas and possums were recorded as roadkill on the bypass in the same period.
"Humans just do a pretty bad job looking after animals in general, and as the world rolls forward there's less and less space for animals and more for humans."
About 75 per cent of wildlife using the underpasses, viaducts, and culverts were invasive species.
"How does anyone make a fence or tunnel or structure to help a possum but not a cat?" Dr Allen said.
'No koala friendly road'
The report will be given to the Department of Transport and Main Roads and recommends ongoing monitoring.
It suggests investment in fences and underpasses are, in many cases, not that good at reducing actual risks to native fauna.
The only caveat is time, and Dr Allen said native animals took a while to get used to new wildlife corridors and more monitoring was needed.
The report also proposes refocusing investment on meaningful biodiversity offsets to mitigate the negative effects of major road construction.
That could include the creation of "feral-free" wildlife reserves or more effective control of feral animals in fragmented wildlife areas disturbed by human infrastructure.
The Australian Koala Foundation is staunchly opposed to offsets and questions the efficacy of wildlife corridors.
"Ultimately, [wildlife corridors] don't work, and I suppose I could live with the fact they don't work when they're building the road, but I think there's a lot of public relations and idealism about what can happen."
Planning future roads
Dr Allen said some exciting technological opportunities on the horizon could increase the effectiveness of nature corridors.
"You can stick up a little camera, it will visualise that animal, it will tell you what it is, and it will open and close a gate, for example," he said.
As the development of south-east Queensland gains momentum, Dr Allen said studies of this kind could help inform future planning and make wildlife corridors more effective.
"We're only likely to see more and more roads getting put up in and around these [native wildlife] habitats, so any of this type of information is really helpful to planners to try and figure out how to accommodate the needs of humans without hacking off the wildlife too much," Dr Allen said.
Queensland Conservation Council's Andrew Picone said more research on the effectiveness of wildlife crossings was needed to better inform assessments of wildlife impacts on future roads.
"It's good to know what works and what doesn't work," he said.
