Impact of lighting on bats in tunnels

Across the UK many disused railway tunnels are being redeveloped for use as cycle and footpaths (see https://www.bbc.co.uk/news/uk-wales-46291959). Such developments require substantial works to tunnels to facilitate human use and comply with safety standards. Works include resurfacing, roof and wall stabilization and artificial lighting (AL) of the inside and entrance of tunnels.

Disused tunnels make good habitat for bats which use them for roosting, commuting, foraging and swarming. The presence of bats often creates conflicts between humans and bats for completing use of tunnels.

Despite increased understanding of the impact of lighting on bats, there is a lack of understanding of how and why bats use tunnels, and the relative importance of tunnels to bat populations and therefore conservation. The impact of lighting on bats using tunnels has not been tested and there is no guidance on effective tunnel lighting strategies to minimise impacts on bats. The lack of evidence and research often prevents or at best delays the opening of tunnels and their public use. This lack of research limits the ability of communities and local economies to benefit from the opportunities provided by opening up tunnels.

Opening tunnels could bring substantial benefits for both communities and bats alike by providing opportunities for economic growth, connecting communities with nature, improving community wellbeing, opportunities for environmental public engagement and creation of wildlife habitats.

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Funded by and in partnership with TRT Lighting and Greenways and Cycleroutes, PhD student Chiara is assessing the importance of tunnels for bat populations and investigating the impact of lighting in tunnels on bats.