Wildlife on the move
How did the endangered gliding possum cross the road? With the help of Kylie Soanes, of course.
Known as a squirrel glider, this native mammal gets around by air. It has a web of furry skin between its wrist and ankle which forms a sail as it glides from tree to tree. Sometimes it has a baby in its pouch or on its back. “They’re amazing little aeronauts,” says Soanes, who has been studying the gliders since 2007.
And they are little; adults weigh under 300g, so Soanes holds one in the palm of her hand as she fits it with a radio tracker.
Squirrel gliders (Petaurus norfolcensis) are endangered in Victoria, partly because they can’t cross busy highways. They don’t like to move on foot and if a highway is more than 50m wide they can’t glide across it. That’s why Soanes sometimes finds them dead by the side of the road.
In an attempt to help gliders survive, some rope bridges were strung up over busy highways, and “glider poles” – similar to telegraph poles – built on median strips as a mid-way landing pad. But no one knew if the gliders were using these devices.
That’s where Soanes came in. She joined a University of Melbourne project to research whether gliders were using the rope bridges. “It was a great idea, but whether or not it worked, that was something we hadn’t figured out yet,” she said of the rope bridges. “Some people were sceptical.”
Her work won her a Young Scientist Research Prize from the Royal Society of Victoria
Seven years on and Soanes, a wildlife ecologist, has turned her research into a PhD, which she finished in late 2014. Her work won her a Young Scientist Research Prize from the Royal Society of Victoria. And she uncovered some surprising results along the way.
The project looked at rope bridges on the Hume Freeway, the main road between Melbourne and Sydney, at a point near Benalla in northern Victoria. For Soanes that meant going back to her home town. She visited the structures to download images from solar-powered cameras, and caught gliders (a mixture of peanut butter, honey and oats lures them in) to fit them with radio trackers. She stuck it out despite watching hand-sized huntsman spiders colonise the bridges and cockatoos dismantle her equipment.
Her team, from the Australian Research Centre for Urban Ecology, which is a joint project between the University and Melbourne’s Royal Botanic Gardens, found that gliders do use the bridges. It took them about a year to start using them, but there were 2000 crossings recorded in the four years after that.
The team also found the bridges weren’t needed to save glider lives because animals mostly didn’t even try to cross the highway if there was no rope bridge. What the bridges did do was allow gliders to move around to find food, nests and a mate. Soanes’ research found one of the bridges was used nearly every night by a father, mother and daughter glider, enabling genetic exchange.
The next step for Soanes is to analyse the effect of the bridges on the long-term survival of glider populations. “There are so many more parts of the story that I’d like to look into,” she says. “There are so many species that we see dead on our roads.”
Bridges and poles are now being built in Queensland, NSW and Western Australia to help squirrel gliders and other species cross highways. Overseas, bridges and underpasses are used for everything from bears and elephants to turtles and porcupines. But Soanes says there aren’t many rigorous studies that measure the effect on species survival.
Soanes says a problem is the structures are being built only on new roads in Australia, not older roads. And without protecting animals’ habitat, bridges won’t save these species.
She has no regrets about her work on squirrel gliders. “A lot of people fall out of love with their project and their PhD and I haven’t yet,” she says with a laugh.
You can check out her blog here
CLICK TO DOWNLOAD