While images of cities seen at night from the air are beautiful, the use of artificial light at night is of concern to conservationists hoping to protect an internationally endangered species: bats. Bats are nocturnal animals, using darkness to protect them from predators, and artificial light at night can interfere with their natural hunting patterns.
Researchers at the Netherlands Institute of Ecology (NIOO-KNAW) and the Wageningen University recently published a report in the Proceedings of the Royal Society. The culmination of five years of research, the report establishes which types of lights affect bats, and how they are impacted.
The researchers partnered with Philips Lighting, who provided the LEDs for the study, to evaluate how light can protect bats. In addition, the study looked at the development of road lighting that won’t disturb light-shy bats from foraging.
“The report is the culmination of five years of research which has highlighted how light can protect bats which are an endangered species group globally. In conjunction with NIOO-KNAW, our next step is to build on this research, and to assess how much of the bats’ habitat is being lost when damaging light is used and how Philips ClearField light can mitigate this,” says Maurice Donners, Senior Scientist at Philips Lighting.
The study used eight sites across The Netherlands to determine how bats respond to three different experimental light spectra in an otherwise dark and undisturbed natural habitat. Philips LED light poles were installed emitting red, green and white light using Philips ClearField technology for red LED light and Philips ClearSky technology for the emission of green light. Each study site consisted of four rows of streetlights in a single colour, and a control row of unlit streetlights.
The results showed that white and green lights are detrimental to bat activity, dramatically reducing foraging at night. Red light, on the other hand, proved to have no impact at all.
According to the researchers, this is the first time measuring the effects of light with different spectra on the activity of slow-flying, light-shy bats in their foraging habitat has been successfully done. “By working together with Philips Lighting we are taking a crucial next step in researching LED lighting technology that doesn’t impact bat species and preserving wildlife and the environment,” says Dr. Kamiel Spoelstra, Researcher at the Netherlands Institute of Ecology
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