In Cumbria, UK – an area with excellent nighttime sky quality – ecologists charted the effects of varying levels of light pollution by tracking the singing behaviour of robins. Over a three-month period, samples of birdsong were taken in paired sites consisting of one light and one dark site.
The study’s findings indicated that artificial lighting, especially uncontrolled or unshielded lighting fixtures, caused earlier singing and calling in robins and other songbird species. Both song repertoire and UV light are used by animals for mate selection and if mating strategies are changed by light levels, females run the risk of choosing lesser fit males.
According to Jack Ellerby, project officer for Cumbria Dark Skies, fieldwork tracing the impact of light pollution and wildlife tends to fall under the radar, because the effects on animals are more incremental than that of other pollution, such as sewage, oil spills or plastic litter.
While light pollution can’t be blamed for the entirety of wildlife behavioural change, Stephanie Holt, a bat expert at the UK’s Natural History Museum, believes it may be a “tipping point”. She notes that some of the most important impacts of lighting on invertebrates are still largely unknown. “[A]s the cornerstone of all of our ecosystems, we should be targeting research and conservation in that direction,” she says.
However, lighting legislation, at least in the UK, is slow to get off the ground. As few ecologists are employed at the planning authority level, artificial lighting schemes are often swept to the back of the pile of government priorities, Holt says.
Elsewhere in the world, strides are being taken to protect wildlife at night. In the Netherlands, LED street light schemes in towns and cities are supporting rare bats species, while France has adopted one of the most progressive light pollution policies to date. Enshrined in the 2018 law are technical requirements for the design and operation of outdoor lighting installations used in both public and private property.
UK campaigners are hoping that 2020’s first meeting of the All Party Parliamentary Group for Dark Skies, which resulted in a 10-point policy plan for improving provisions for dark skies, could be the country’s gateway into artificial lighting control.
In the meantime, the baton is held by individuals, who can lobby local politicians and authorities, create nocturnal corridors for wildlife, and ensure that their own homes and offices do not contribute to additional sources of light pollution, says Holt.
