Dark night skies are a precious natural resource – a source of awe, and, for astronomers, a prerequisite for probing the mysteries of the cosmos. They’re vanishing rapidly – on average, cities are growing 10 percent brighter each year. Not everyone is going gently into that starless night. Around the world, advocates are fighting to preserve dark skies, as a vital asset for humankind.
But there’s also new research showing the importance of dark skies for nonhuman creatures. And our region is a hub for that research.
Stephen Hummel is the McDonald Observatory’s dark skies coordinator.
“Astronomers are kind of the canaries in the coal mine,” he said. “We were the first to notice the increase in artificial light in the environment on a global scale. But increasingly, the biological impacts of light pollution are rising to the forefront of the conversation.”
The Davis Mountains observatory has had challenges and successes in recent years. Since 2007, when oilfield activity began surging west of the Pecos River, light pollution here has increased by almost 700 percent. Yet the observatory’s advocacy also led to the creation, in 2022, of the Greater Big Bend International Dark Sky Reserve. It’s the world’s largest such reserve, spanning 15,000 square miles, and it testifies to a local commitment to dark skies.
Eighty-five years after its founding, the McDonald Observatory remains a center for cutting-edge astronomy, and Far West Texas still boasts some of the darkest night skies in the U.S.
Big Bend residents have long appreciated the value of that. Biologists have been a little late to the game. It’s understandable. As daytime creatures, we have a “diurnal bias,” Hummel said. And, of course, it’s hard to conduct research in the dark.
But the impacts of light pollution on wildlife have become impossible to ignore. There are striking images of sea turtle hatchlings thrown of course in their seaward sprints by man-made lights.
Migratory birds rely on moonlight and starlight; millions die each year because of artificial light.
Indeed, all types of creatures, from amphibians to mammals, have evolved with the patterns of sun, moon and stars.
“There are very few things that are static in the evolution of life over millions of years,” Hummel said, “and it's only in the last a hundred years that that's no longer a reliable cue. The introduction of artificial light can wreak havoc on these natural cycles, these natural rhythms, and confuse animals, sometimes with deadly consequences.”
LED lights are particularly disruptive, Hummel said. Most LEDs emit a significant amount of blue light, which mimics the sun, and disorients wildlife.
Now, the observatory has partnered on research into light pollution here. In one project, UTEP scientists are studying the impacts on Chihuahuan Desert insects. They hope to develop lighting that will attract fewer insects.
A second collaboration, with scientists at the Xerces Society, focuses on the Sky Island firefly. This unlikely desert creature is known only in the Davis Mountains. Lightning bugs are enchanting, but their flashes are also a matter of survival. Amidst light pollution, fireflies can’t communicate, and therefore can’t protect themselves from predators, or find mates.
Fortunately, the same measures that benefit astronomers and stargazers – shielding household lights, choosing dark-sky-responsible LEDs – also benefit wildlife. Unlike some challenges, the solution to light pollution is fairly straightforward, Hummel said.
“So unlike a lot of other environmental problems, light pollution is easy to fix and it's immediate,” he said. “Light doesn't persist in the environment, like air or water pollutants often do. You flip the switch it, it's immediately gone.”
Next time you savor the starry West Texas night, know that other creatures savor it too.
This story was made possible by generous donations from supporters like you. Please consider showing your support with a contribution today.
