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Providing evidence to improve practice

Individual study: Is part-night lighting an effective measure to limit the impacts of artificial lighting on bats

Published source details

Azam C., Kerbiriou C., Vernet A., Julien J.-F., Bas Y., Plichard L., Maratrat J. & Le Viol I. (2015) Is part-night lighting an effective measure to limit the impacts of artificial lighting on bats. Global Change Biology, 21, 4333-4341


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

Restrict timing of lighting Bat Conservation

A replicated, paired sites study prior to 2015 at 36 paired rural sites in France (Azam et al 2015) found that turning off streetlights for part of the night resulted in higher activity for two bat species, lower activity for one bat species and similar activity for five bat species when compared with leaving streetlights switched on all night. The average number of bat passes/night was higher with part-night lighting than full-night lighting for Plecotus spp. (part-night lighting: 2.3; full-night lighting: 0.6) and common noctules Nyctalus noctula (data not reported), but lower with part than full-night lighting for common pipistrelles Pipistrellus pipistrellus (part-night lighting: 515; full-night lighting: 1,130). Activity was similar under both light treatments for Kuhl’s pipistrelles Pipistrellus kuhlii, Nathusius’ pipistrelles Pipistrellus nathusii, Leisler’s bats Nyctalus leisleri, serotine bats Eptesicus serotinus and Myotis spp. (see the original reference for detailed results) Each of 36 pairs of sites had one site with streetlighting (high pressure sodium lights, 10–99 lux) and one unlit control site within similar habitats. Streetlights were either turned off for part of the night (between midnight and 05:00 h, 24 sites) or were left on for the full night (12 sites). Each of 36 pairs was sampled simultaneously using bat detectors for one full night between May and August (year not reported).

(Summarised by Anna Berthinussen)