Koala nose way across
Bridges create a safe passage
KOALAS aren’t usually known for their incredible intellect, but when it comes to figuring out how to cross bridges over roads … the answer is in their nose.
Griffith University Professor Darryl Jones is an expert in urban ecology and wildlife management who is helping Transport and Main Roads (TMR) decide the location of koala bridges and underpasses along the $2.4bn Coomera Connector.
He is also advising the Gold Coast City Council, which has proposed quirky and colourful koala bridges be built over the Gold Coast Hwy as part of the Stage 4 extension of light rail.
“I once got in trouble for saying koalas were not very smart and that they were probably stoned out of their minds on eucalyptus oil, which is probably true,” Prof Jones said.
“But they (koalas) have proved me very wrong.”
He said koalas and other wildlife knew to cross the man-made overpasses because either side of them are exclusion fences with metal strips that effectively force them to keep moving along the guiding fence until they come to an opening, or the start of the wildlife bridge, and then they just walk across it.
Quite simply, they just follow their noses. “Any koala that wanders along the fence will eventually get to the opening where the overpass structure is and simply make their way over the road,” he said.
“Koalas can climb really well so it’s important these fences have strips of metal along them so they can’t get a grip on them and climb over the mesh fence.”
Prof Jones said koala bridges were used in areas where the terrain wasn’t suitable for underpasses, such as swampy or waterlogged areas or if the road was lower than the surrounding land.
“Usually there’s hundreds of underpasses compared to a just a few bridges over roads and these are built in places where there is an abundance of animals and wildlife on either side of the road,” he said.
“In the last couple of weeks I’ve worked with TMR engineers and design people and made suggestions for passes along the Coomera Connector.”
This is a six-lane, 45km arterial road to run from Nerang to Logan expected to take up to 60,000 vehicles off the M1 every day.
Prof Jones said koala bridges ranged from “basic, no thrills designs to those with flowing lines, vegetation and artwork”. One is in Brisbane adorned with artwork from school students giving the community a sense of ownership of the structure.
“But the beauty of these overpasses is that they really work, and we recorded 45 animals using the structures at Compton Rd every single night. Some nights it was hundreds and others it was less.”
Compton Rd is a 1.3km major east-west arterial road cutting through one of the largest areas of remnant bushland in southeast Queensland.
With mating season coming up in September, Prof Jones said he expected an increase in male mates crossing the road in search of love “or nice food”.
“Either way they’ll eventually make their way along the fence until they can make it to the other side.”