Light pollution harm plants and insects

Light pollution is not only interfering with our ability to see the stars, it is affecting the growth and flowering patterns of plants and reducing the numbers of insects that depend on them, a study in the UK shows.

Researchers from the University of Exeter simulated the effects of street lighting on artificial grassland plots containing a community of invertebrates at night, exposing them to two different types of light treatment – white LED light and amber sodium street lamplight.

The amber light was shown to have the most pronounced affect and inhibited flowering in greater bird’s foot trefoil, a wild relative of peas and beans, with a fall in the number of pea aphids that feed on the flowers.

Responses for the “white” light treatment, with a spectral distribution similar to those of modern commercial LED street lighting, were intermediate between the amber and control treatments

The researchers say the experiment showed that light pollution could impact the natural environment in complex ways that may be hard to predict.

“Our results suggest that by lighting up our night time environment we trigger complex effects on natural food webs. While we are all aware that street lights often attract insects at night, we show that they may have more permanent, widespread impacts on wildlife and ecosystems,” said Dr Jonathan Bennie of the university’s Environment and Sustainability Institute.