Bridge to nowhere: Bat bridges are failing to prevent deaths, says ecologist

IAN JOHNSTON

Sunday 15 March 2015

Bat bridges erected across many major British roads to reduce roadkill are a waste of money because bats don’t like to use them, one of the UK’s leading experts has warned.

The bridges, which can cost hundreds of thousands of pounds, have been installed to help bats safely cross new highways despite evidence that they do not work, according to John Altringham, an ecologist at Leeds University.bats

“I’ve no idea who came up with this strange idea, nobody seems to admit to it now,” he told The Independent. “It seemed to me even before we did the science that no self-respecting bat was going to look at these strange things.”

Professor Altringham, who will this week submit a report to the Government on the issue, estimates that between 15,000 and 340,000 bats are killed on our roads every year.

He said road builders were continuing to use bat bridges – essentially poles on either side of the road with some wires strung between them – as a box-ticking exercise, even though they have proved ineffective. He said a “big industry” had grown up about the legal requirements designed to safeguard bats from traffic.

“When you want to build a road, you have to do bat surveys and spend money on these mitigation features. A significant amount of money is spent on it, but then nobody bothers to do any serious or accurate monitoring,” professor Altringham said.

Continued ...

Bat Bridges Don't Work

ScienceDaily (June 13, 2012) — Wire bridges built to guide bats safely across busy roads simply do not work, University of Leeds researchers have confirmed.

In a study published June 13, 2012 in PLoS ONE, a team from the University's Faculty of Biological Sciences monitored four wire bridges spanning major roads in the north of England. All had been built over the last nine years to replace hedgerows -- the bats' established commuting routes -- when these routes were severed by new roads.

Roads act as barriers to bats, cutting colonies off from established feeding sites and reducing their ability to feed themselves and their young. Most species of bat fly relatively close to the ground or close to trees and hedges, for protection against the weather and potential predators. Those that do cross roads typically do so at traffic height, with a high risk of collision -- so the wire bridges are a common conservation measure aimed at encouraging bats to cross above the traffic.

Continued:  http://www.sciencedaily.com/releases/2012/06/120613184009.htm