In southwestern Idaho, biologists are purposefully making a racket this summer to study the value of natural quiet. A Boise State University research team is testing how wildlife and humans respond to noise pollution.
The findings could someday guide solutions to lessen our noisy footprint in the world.
The experiment started with an invisible road in 2012.
"The 'phantom road' was the first landscape-scale noise playback experiment that we conducted,” Boise State University Professor Jesse Barber said.
A half kilometer long string of outdoor speakers in the Boise National Forest mimicked the sounds of passing cars. Barber said the two year experiment demonstrated road noise alone causes migratory birds to flee and fail to gain weight.
Now comes the "phantom natural gas field."
"This study is replicating compressor station noise from natural gas extraction fields on a much larger scale than the phantom road,” Barber explained. “We have six noise sites and six control sites."
At full volume, the sound is irritating. But it’s a reality in oil and gas basins throughout the Mountain West.
The value and cost of quiet
Thirty minutes south of Boise the simulation by stadium loudspeaker blares virtually 24/7. The purpose is to examine an interactive cascade of effects from noise pollution. Not just on birds now, but also insects, bats, plants and people.
"We are testing the idea that these things are coupled; that as the soundscape gets louder, wildlife suffers,” Barber explained. “But that also feeds back on to how much people get out of that experience, how much they value it, and thus how willing they are to protect that same place."
It’s a negative feedback loop of sorts. The research team recruited amateur birdwatchers as study subjects. Graduate student Mitch Levenhagen measured how much the artificial noise impaired the volunteer listeners' ability to identify recorded bird songs.
Three at a time, the volunteers stood facing a secondary array of speakers hidden behind sagebrush plants, which played back bird songs at Levenhagen's command. The volunteers recorded when they heard an avian sound and when they could recognize the species. The bird sounds were hard to pick out until they got quite loud. Repeating the experiment without the background noise came as a relief to the participants.
The study volunteers found the simulated compressor more disruptive than anticipated. They said it makes them value quiet moments more.
"The whole thing has been ear-opening, shall we say,” said Jim Lyons of Boise. “To be part of this is very stimulating, very interesting. I am going to think about it from now on."
For fellow volunteer Janice Engle, the natural soundscape matters a lot.
"I moved out of the city to a little place in the country where I wanted it to be quiet,” she said. “I greatly value that. It is hard to find those places more and more."
Engle moved to rural Marsing, Idaho.
"There are lots of ways to mitigate sound,” she added. “But it is tradeoff. There is always a cost. It comes down to people's values. What we value more?”
Is quieter pavement a solution?
One proven solution to cut noise pollution is to build sound walls or berms beside the road. But those can block views or animal migration. Lowering the speed limit can dramatically reduce sound levels too, but requires drivers to buy in. Generators can be muffled, but at extra cost.
The National Park Service is funding some of the science in this field and exploring other options. Those include road resurfacing treatments. Also, establishing quiet zones where signs direct park visitors to silence cell phones and behave like they're in a library or church.
"Visitor sound level dropped as though half as many visitors were there," said NPS senior scientist Kurt Fristrup describing the effects at the first permanent quiet zone established in the park system at Cathedral Grove in Muir Woods National Monument. Fristrup is the branch chief for science and technology in the Natural Sounds and Night Skies Division of the park service.
He said Glacier National Park in Montana and Crater Lake National Park in Oregon are among the parks investigating "quieter pavement." Another strategy getting traction at some park units is to shift visitors from private cars onto shuttle buses during peak season. Congestion relief is main impetus behind that, but it has additional benefits.
Fristrup said acoustic monitoring at Utah’s Zion National Park found the shuttles certainly leave a noise footprint, but their use reduced vehicle traffic so much that natural quiet noticeably increased.
And there is more. A new partnership between the park service and a nonprofit called Powering Imagination -- headed by aviator Charles Lindbergh's grandson Erik Lindbergh of Bainbridge Island, Washington -- aims to develop quiet, electric aircraft that could greatly reduce the noise from air tours someday.
Further research needed
As the second and final field season at the "phantom gas field" winds down in southwestern Idaho, Barber and his research team avoid anointing any favorite solution. "There is a lot of basic (science) work yet to be done," Barber said. "There is definitely not an overt management objective behind these projects."
Next year, Levenhagen and Barber will temporarily relocate to Northern California to survey visitors at Muir Woods National Monument and other parks about how they perceive noise.
Funding for the research into interactive effects of noise on natural and human systems comes from a four year, $600,000 grant awarded by the National Science Foundation last year. Barber's lab also received support from the National Park Service.
Co-investigators include Clinton Francis and Crow White at California Polytechnic State University who bring expertise on wildlife and statistical modeling. Social science expertise comes from Peter Newman and Derek Taff at Penn State. Chris Monz of Utah State University is also collaborating on the studies.
