Study proves gliding mammals readily use tall wooden poles as conservation stepping-stones

It was the early 90s and across Australia’s east coast new roads and highways were being planned which would cut through bushland, and potentially disrupt wildlife populations. State road agencies responded to concerns from the community and applied various strategies to minimise the barrier effect of roads on wildlife and to prevent roadkill but none catered for gliding mammals.

A new study led by Associate Professor Ross Goldingay and published in Australian Mammology demonstrates that gliding mammals will readily use dedicated tall poles as stepping stones.

Dr Goldingay said the findings were fantastic.

“I first proposed the idea of using power poles without the wires to reconnect habitat for gliding mammals 25 years ago. For some years the idea was dismissed as a thought bubble.”

Although these mammals can glide across gaps between trees, the gaps created by new freeways are often beyond their gliding capability. The strategy involves installing very tall timber poles so animals can use these as stepping stones to cross the road.

“About 15 years ago we started in north Queensland with poles installed in a paddock between two habitat remnants. Then in Brisbane we investigated poles installed on wildlife land-bridges over two roads, and then we investigated a roadside installation,” Dr Goldingay said.

For this study, Dr Goldingay and his colleagues from the University’s School of Environment, Science and Engineering used cameras to monitor two pairs of poles as well as a rope canopy-bridge along the Oxley Highway at Port Macquarie, on the NSW Mid North Coast, over three years (2013 – 2016).

They detected four species of gliding mammal on the poles, including the first ever records of the feathertail glider and the threatened yellow-bellied glider. They also made hundreds of detections of sugar gliders and the threatened squirrel glider. There were few records of any species on the rope-bridge.

“We built up our evidence and also collected detailed gliding data for squirrel gliders and yellow-bellied gliders so we could get our trigonometry correct, which determines pole height and spacing for a given road,” said Dr Goldingay.

“We high-fived when we saw our first photo of a yellow-bellied glider on a pole. This extends the size range of species documented using glide poles.

“The records do not tell us anything about gene flow but they tell us we have a conservation tool with huge potential.”

The NSW Roads and Maritime Service has now installed poles for gliders at more than 20 locations along the Pacific Highway upgrade.