No evidence that bat bridges work

Bat bridges erected across many highways to reduce roadkill are not working, according to this article in the Independent. During an interview with this newspaper, John Altringham, Professor of Ecology and Conservation at Leeds University said that bat bridges are a “waste of money because bats don’t like to use them”. He also noted that these bridges have been installed to help bats safely cross new highways despite evidence that they do not work.

The Highways Agency says there are no official counts of bats dying because of traffic, since any carcasses would be too small, too easily carried away from the scene by the vehicles that kill them, or too quickly predated on to leave a record. However, it has been estimated that between 15,000 and 340,000 bats are killed on British roads each year.

Bat bridge
Bat bridge over the A590 dual carriageway.
Bat bridge over the A590(T) road was used a mitigation measure to replace a hedgerow which was used as a commuting and foraging corridor.

Professor Altringham has 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.

All 16 bat species in the UK are protected under the 1981 Wildlife and Countryside Act, which requires that any projects that would disturb the bats or their roosting habitats have a minimal impact.

Professor Altringham will give a talk entitled “The effects of major roads on bat activity and diversity, and the effectiveness of current mitigation” at the forthcoming Bat Conservation Trust ‘Wildlife and Transport Infrastructure Symposium’.

For further information please see the following links:-

Also see this following paper.  This study was one of the first to show that roads have a major negative impact on bat foraging activity and diversity. It highlighted the requirement for roads to be made more permeable to bats through the use of effective crossings, such as underpasses and overpasses, and that habitat is improved within 1 km of major roads. It also noted that due to the fact that the effectiveness of current mitigation measures is unknown, well-designed monitoring of mitigation is essential.

Also if you have any queries regarding bat surveys or mitigation please do not hesitate to contact us.

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