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Artificial light at night can disrupt everything from astronomers' views of the stars to the path-finding abilities of migrating animals. The impacts of artificial light on wildlife was the focus of a symposium at the 24th annual International Congress for Conservation Biology, held 37 July in Edmonton, Alberta.
Lights at night have long been known to confuse migrating birds, which are drawn mothlike to the beams. Some crash into brilliantly lit skyscrapers, lighthouses or offshore oilrigs. Many others are lured off course by the glow of cities on the horizon.
Sea-turtle hatchlings, too, are dazzled by bright light. Normally, they move away from the dark shadows of dune vegetation and towards moonlight or starlight reflected on the sea. In the presence of bright artificial light, they end up wandering in the wrong direction on the beach.
Research
Researchers presenting their work at Edmonton added further examples of species affected by brightness in various ways. Some, like the turtles and migrating birds, become visually bewildered, whereas others, such as voles, can have their circadian or seasonal rhythms disrupted by artificially lengthened days, leading to rising levels of stress hormones.
Not all lights have the same effects. Astronomers and conservationists are looking closely at the increasing popularity of LED lights, for instance. LEDs are more energy efficient than many alternatives, which carries environmental benefits. But LEDs that include light from all
wavelengths are also closer to sunlight than traditional bulbs and are therefore more disruptive to many species.
Always full moon
Longcore works with the International Dark-Sky Association, based in Tucson, Arizona, to encourage dark-sky preserving policies in cities, parks and elsewhere. The association was founded by two Arizona astronomers, says spokeswoman Johanna Duffek, and initially attracted only astronomers as members. In the last decade, however, it has also embraced the conservation agenda.
"It helped our cause," she says. "[Before] we had people saying, 'I am not an astronomer, so what do I care if you can't see the stars?'"
The Starlight Initiative, based in La Palma in the Canary Islands, mentions the effects of night light on wildlife in its 2007 Declaration in Defence of the Night Sky and the Right to Starlight, which asserts that "an unpolluted night sky that allows the enjoyment and contemplation of the firmament should be considered an inalienable right of humankind equivalent to all other environmental, social, and cultural rights, due to its impact on the development of all peoples and on the conservation of biodiversity".
Longcore himself, living in lit-up Los Angeles, has to wait for special events like the observatory party to get a good look at the heavens. But like people all over the world, he once spent hours gazing at the night sky in wonder.
"I grew up in Maine," he says. "We had the northern lights. I could go outside in the backyard and lie in the grass and have that universal human experience."
