Acoustic sensors alert wildlife when cars are near – saving hundreds of animals from getting hit on the road.
On a cool, windy night in a remote corner of Tasmania, Australia, a narrow unlit road cuts through the bush, lined on both sides by chest-high white posts – the only signs of civilisation. Where the road dips, a dark-furred animal, smaller than a fox but bigger than a cat, sniffs the air. A Tasmanian devil, the world’s largest surviving marsupial, is out looking for food. It knows that wallabies and pademelons sometimes cross here to graze in the pasture lands on the other side of the road. What it doesn’t know is that a big, heavy four by four is speeding along the road, obscured by the dip.
This tale might have a sad ending, but it doesn’t. As the vehicle’s headlights fall upon the white post behind the devil, a device inside the post emits a bright light and a shrill sound. Startled, the devil looks up, sees the vehicle hurtling towards it, and scurries into the bush and safety.
This is virtual fence – a device helping to curb animal deaths on the road with nothing but light and sound. As well as Tasmania, the devices are also being trialled in the UK, with a number already installed on a stretch of the A513, in Cannock Chase. It’s there that 27 deer lost their lives in collisions with vehicles between 2015 and 2016. With roadside verges not always well maintained, animals often hid in the thicket, only emerging onto the road when it was too late.
“Since we installed these devices, the number of animal road deaths is down significantly, particularly in the autumn when the male deer cross the road to rut in the open fields on the Shugborough Estate,” says Rob Taylor, a local ranger. Across the UK, nearly 4,000 animals were killed by motorists during 2016 and 2017. Many more animal deaths have likely gone unreported.
In Tasmania, the ‘fences’ sit 25 to 30 metres apart along a six kilometre stretch of the C214 road between the River Arthur and Marrawah settlements, not far from Tasmania’s northwest coast. They’ve been there since 2015 – part of a three-year research project in one of the region’s most notorious roadkill spots. Each device contains optical and acoustic sensors that are triggered by vehicle headlights and approaching sound.
Conservationist Sam Fox from the Tasmanian government’s Save the Tasmanian Devil Programme (STDP) says that these devices could help stop the devil from going extinct in certain parts of the country. “In some areas, numbers are so small that losing just a few breeding females on the road would threaten the entire population,” he says.
But on this stretch of the road, the situation seems to be improving. A STDP report, published earlier this month, recorded 50 per cent fewer animal deaths where the devices had been installed compared to the rest of the C214. That’s Bennett’s wallabies, pademelons, spotted-tailed quolls, as well as devils. “In places where the road dips, animal deaths are down a lot more,” says Dale Crosswell, a ranger with the Tasmanian Department of Primary Industries, Parks, Water and the Environment. “Up to 75 per cent in the most dangerous places, usually where there’s bush on one side of the road and feeding grounds on the other.”
Croswell explains that animal deaths rose dramatically after the C214 was tarmacked in 2012, enabling cars to reach higher speeds than on the old gravel track. “We already tried ripple strips which made a noise when cars went over them, but the animals just got used to them and they made no difference,” he says.
The trials have been so successful that other countries have started expressing an interest. In Austria, where the devices are made by iPTE Traffic Solutions, there are thousands of them on secondary and regional roads. In January, another thousand will be placed along several stretches of highway, national road and railway as part of a new research project being conducted by the Austrian rail, highway authorities and the Ministry for Transport Innovation and Technology.
“Austrian highways are fenced off, so devices will be placed at entrances and exits, or where the fence has been damaged,” says Andreas Schalk from iPTE Traffic Solutions.
Schalk explains that on the highways, where there is a steady flow of traffic, the device will be triggered not by the vehicle but by the animal, through a thermal sensor. “The latest sensors also pick up the speed of the approaching vehicle, making them useable in daylight,” Schalk adds.
The sensors used on the Austrian railways will be louder and have greater range than those used on the roads. All the Austrian devices emit blue and yellow light, colours that deer – the most frequent casualty on European roads – see best.
Fuente de la noticia: https://www.wired.co.uk/article/virtual-fences-tasmanian-devils-uk-deer