Artificial light at night can have a disruptive effect on bats, but not if the light is red. Switching to red light may therefore limit or prevent habitat loss for rare, light-shy bat species. The latest issue of Proceedings of the Royal Society B publishes results from five years of pioneering research led by the Netherlands Institute of Ecology (NIOO-KNAW).
Artificial light at night can have a disruptive effect on bats, but not if the light is red. Switching to red light may therefore limit or prevent habitat loss for rare, light-shy bat species. The latest issue of Proceedings of the Royal Society B publishes results from five years of pioneering research led by the Netherlands Institute of Ecology (NIOO-KNAW).
It's the first time researchers have succeeded in measuring the effects of light with different spectra on the activity of slow-flying, light-shy bats in their foraging habitat. "We've found these bats to be equally active in red light and in darkness", says principal researcher Kamiel Spoelstra. "White and green light, on the other hand, substantially reduce the bats' level of activity."
The effect of red light on more common bat species such as the pipistrelle is similar. While there's a strong increase in activity of this species in white and green light, activity in red light is comparable to that in darkness. This is caused by the strong attraction of insects to white and green (not red) light. Pipistrelles opportunistically feed on these accumulated insects.
Real-life conditions
“The lack of effect of red light on both the rarer, light-shy species and the more common non-light-shy bats", concludes Spoelstra, "opens up possibilities for limiting the disruption caused by external, artificial lighting in natural areas, in situations where having light is considered desirable."
Read more at Netherlands Institute of Ecology (NIOO-KNAW)
Image: The red light posts are placed in otherwise undisturbed natural areas, to be able to measure the effect of light pollution. And to compare the differences between different colours of light. (Credit: Kamiel Spoelstra / NIOO-KNAW)
