Conservation Evidence strives to be as useful to conservationists as possible. Please take our survey to help the team improve our resource.

Providing evidence to improve practice

Individual study: WC1011: The biodiversity impacts of street lighting. Appendix G: An experimental test of a mitigation strategy to reduce the impacts of lighting on bats

Published source details

Mathews F., Gaston K., Bennie J., Day J., Schofield H. & Baker J. (2015) WC1011: The biodiversity impacts of street lighting. Appendix G: An experimental test of a mitigation strategy to reduce the impacts of lighting on bats. Department for Environment, Food and Rural Affairs (Defra), UK report.


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Use UV filters on lights Bat Conservation

A randomized, replicated, controlled study in 2014 at five hedges in Devon, UK (Mathews et al. 2015) found that hedges lit with ultraviolet (UV) filtered lights had higher activity for one of two bat species than at hedges lit with unfiltered lights or unlit hedges. Soprano pipistrelle Pipistrellus pygmaeus activity was higher at hedges lit with UV filtered lights (average 5 bat passes/night) than at hedges lit with unfiltered lights (3 bat passes/night) or at unlit hedges (4 bat passes/night). Common pipistrelle Pipistrellus pipistrellus activity did not differ significantly between any of the light treatments (data not reported). At each of five hedges, two lights (8W LED flood lamps with additional UV bulbs) were set up 15 m apart and 5 m high. Filtered lights were covered with UV film filters to reduce UV emissions by 40%. Three treatments (UV filtered lights, unfiltered lights, unlit/control) were carried out at each pair of lights in a random order for three nights each between July and October 2014. Two additional unlit locations were also surveyed at each site. During each night, bat activity was recorded using bat detectors placed at the treatment site and at the unlit locations for 3 h from sunset.

(Summarised by Anna Berthinussen)