Bats just don't seem to be able to catch a break.
The nocturnal creatures are facing all sorts of potentially lethal threats, from climate change and habitat loss to white nose syndrome to the spinning blades of wind turbines. And an alarming new study shines a light on another threat to bats--the light pollution in our cities.
The study, published online on June 5 in the journal Global Change Biology, shows that bats tend not to move freely in brightly lit areas. Why does that matter, you ask?
"The ability to freely move around is key to individual bat fitness and resilience of the broader bat population," James Hale, a research associate in the school of geography at the University of Birmingham in England and the study's lead author, said in a written statement.
The availability of cheap, energy-efficient lighting could "prove a real problem for bats as they move around a city," he added.
Why bats matter. Even if you're not a big fan of bats, that could spell trouble on a number of fronts. Bats play a key role in global ecology, pollinating plants and providing the guano that acts as a fertilizer, as well as eating bugs that decimate our crops and suck our blood.
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Distribution map of P. pipistrellus.
Watching bats. For the study, Hale and a group of colleagues that included scientists from Lancaster University conducted field observations of bats in England's West Midlands region. The scientists observed bats as they left their roosts at night and "commuted" along lines of trees to reach areas where they could find plenty of bugs to eat.
The observations showed that while the bats would traverse narrow gaps between trees even in the presence of strong lighting, they would not cross bigger gaps even with low levels of light.
"Even bats that are broadly tolerant of urbanization are still disturbed by lighting," Hale told The Huffington Post in an email.
And while the scientists focused their efforts on a common species of bat known as Pipistrellus pipistrellus, Hale said in the email that other species, including some in North America, would likely have a similar response to light.
Good news? If the finding is a bit of a bummer for bat lovers and conservation-minded people, it could also bring new efforts to help urban bats.
As Gemma Davies, a Lancaster University scientist involved in the research, explained in the statement, "The logical next step... would be to feed these findings into the town and city planning process, by identifying areas where bat populations are low and strategically dimming or shielding street lamps and narrowing gaps" between trees.
"Adding shields, switching off lamps, or dimming them at certain times are all practical ways to save energy, reduce glare, and broader lighting nuisance and to create a more natural environment for local wildlife," Hale said in the email. "Special care needs to be taken near to habitat corridors that can act as highways for nocturnal wildlife."
Bully for you, bats!