Scientists Explore Potential Impact of LED Street Lighting on Wildlife

Scientists from the University of Exeter are looking into the potential impact of light-emitting diodes (LED) street lighting on the environment and wildlife.

Their research, described in a paper published in the journal Global Change Biology, showed that LED lighting used in streets at night could attract predatory spiders and beetles. However, the researchers observed that the number of species affected was reduced when the LED lighting was dimmed by 50 percent and switched off between midnight and four in the morning.

"The growth of LED lighting is an issue of global concern, and the number of documented impacts on the environment is growing rapidly," said Dr Thomas Davies, of the Environment and Sustainability Institute at the University of Exeter's Penryn Campus, in a press release. "Our research shows that local authorities might be able to manage LED lighting in a way that reduces its environmental impacts. We now need to establish whether this is the case for a greater variety of species."

For the study, the researchers conducted a three-year field experiment. In these experiments, the researchers simulated different lighting strategies used by local authorities to cut down expenses and CO2 emissions. These strategies include changing the spectrum of colors produced by the light, dimming the light and switching the light off from midnight until 4 a.m.

The researchers observed that predatory spiders and beetles were attracted to grassland patches lit by LED lighting at night, increasing their total abundance and changing their assemblage composition. When the LED lights were dimmed by 50 percent or changed to a different spectrum, the number of commoner species affected went from seven to four. The combination of dimming the lights by 50 percent and switching it off between midnight and 4 a.m. showed most promise in reducing the ecological costs of LEDs. However, the abundance of two common species were still affected by the light.

Due to this, the researchers showed that the use of LED and nighttime lights should be avoided in order to totally avoid potential impacts of these lights on the environment and wildlife.