Light pollution causes massive harm to wildlife
In Germany, 40 percent of people under 30 have never seen the Milky Way. The same is likely true for Switzerland. And artificial light not only outshines the night sky — it also harms nocturnal animals.
Moths, fireflies, bats, martens and their kin depend on dark nights, as the organisation Pro Natura reports in its magazine this Monday. Light pollution has doubled over the past thirty years.
This puts nocturnal animals — and night-flying moths in particular — in mortal danger. 95 percent of the 3,668 butterfly and moth species known in Switzerland are nocturnal. Moths navigate by scent and can detect a female from kilometres away.
Bats hunt exclusively at night using echolocation. Migratory birds navigate by the starry sky on their journeys. At night, insects hatch from their larvae at the water’s edge. All of them depend on darkness. The night also provides vital protection for many animals.
Blinded moths
When searching for nectar and carrying out pollination, moths do not compete with bees and other daytime pollinators. They can see up to 2,000 times better than day-flying butterflies and are particularly drawn to white and yellow flowers. Yet these are precisely the colours emitted by artificial light, meaning moths can no longer find and pollinate the flowers.
Added to this, the light spectrum of artificial lighting attracts moths, and they exhaust themselves circling street lamps endlessly. Every summer night, around 150 insects perish at each street lamp. The insects also become easy prey for bats, birds and cats. As a result, they are lost both as pollinators and for reproduction.
Fireflies outshone
Female fireflies send their gentle light signals to the males. But when the surroundings are too bright, the males can no longer see them — and reproduction fails. Lights along waterways draw insects in swarms, but the creatures perish and are then absent as a food source for fish, birds and bats.
The University of Bern showed that the marsh thistle, for example, produced 13 percent fewer fruits and was visited by 62 percent fewer pollinating nocturnal insects when it was exposed to artificial light rather than darkness.
Simple solution: Turn off the lights
The solution would be simple, writes Pro Natura: turn off the lights. Hope comes in the form of LED street lighting, which has been installed in some places. It disturbs nocturnal animals less, especially when it has a high orange-red component.
Nocturnal animals are further protected by dimming the lights, switching them off via motion detectors or radar when no one needs illumination, or turning them off completely during certain nighttime hours. In addition, municipalities save electricity and therefore money through modern lighting.
