Individual study: Experimental evidence of light disturbance along commuting routes of pond bats Myotis dasycneme
Kuijper D.P.J., Schut J., van Dulleman D., Limpens H., Toorman H., Goossens N. & Ouwehand J. (2008) Experimental evidence of light disturbance along commuting routes of pond bats Myotis dasycneme. Lutra, 51, 37-49
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Avoid illumination of bat commuting routes
A replicated, before-and-after study in 2005 at four canals in the Netherlands (Kujper et al. 2008) found that unlit canals and canals illuminated with lamps had similar numbers of pond bats Myotis dasycneme flying along them at all of four sites, but bats were observed avoiding the lights. At all of four sites the number of bats flying along canals did not differ when they were unlit (122–493 bats) or illuminated with lamps (114–413 bats). However, at all of three sites where observations were made, bats changed their flight paths to fly around the light, with more bats doing so when lamps were facing along canals (96% of bats) than across them (28–42% of bats). At each of four sites, the canal was lit with a 1,000 W halogen lamp (1–30 lux with a 10 m range) either along the canal (three sites) or across the canal (one site). In July–August 2005, bats were surveyed during 2–4 unlit nights immediately before and after 1–4 nights with the lamps switched on. Two surveyors/site counted passing bats (at all of four sites) and made observations of behaviour (at three of four sites).
(Summarised by Anna Berthinussen)