杏吧原创

A warning system that lets wildlife know when cars are approaching has saved hundreds of animals from becoming roadkill in an Australian trial.

Collisions between cars and wildlife are common around the world. An estimated in the US and in the UK, for example, are hit and killed by vehicles each year. In addition to endangering animals, these accidents cause over in the US alone.

The state of Tasmania in Australia has one of the highest roadkill rates in the world, with one survey finding one squashed animal for . Among these casualties are Tasmanian devils, which are already under dire threat from devil facial tumour disease.

To prevent these accidents, the Tasmanian government recently trialled a 鈥渧irtual fence鈥澛爏ystem that was developed in Austria to prevent car collisions with deer. They installed it along a 5-kilometre stretch of highway near the state鈥檚 north-west coast, which is a known roadkill hotspot.

The virtual fence is a network of alarm units mounted on posts at 25-metre intervals along the side of the road. As cars approach, their headlights trigger the devices to emit loud sounds and flashing lights to warn animals to get off the road. 鈥淭he alarms go off in a wave ahead of the car as it travels,鈥� says Samantha Fox, who led the project.

Over the 3-year trial, the system almost halved the roadkill rate. About 0.7 animals were killed per kilometre along the fenced road, compared to 1.2 animals per kilometre along unfenced stretches of road at either end. This equated to saving the lives of about 200 animals, including bandicoots, wallabies, possums, pademelons, quolls and wombats.

A promising finding was that only 5 Tasmanian devils were run over and killed in the fenced area, compared to 14 in the unfenced area, says Fox.

The devices do not distract drivers because the sound and light they release are directed towards the side of the road, says Fox. Moreover, they are only loud and bright enough to disturb wildlife near the road, she says.

The devices cost about A$150 each, making them cheaper to install than overpasses and tunnels that are sometimes built to let animals cross roads safely.

The Tasmanian government is now planning to install virtual fences at other roadkill hotspots, and other parts of Australia are considering following suit, says Fox.