Skip to main content
Move the World.
Sifting Through Sound: Using Soundscapes to Understand Ecosystem Health

What is the sound of a recovering ecosystem? Abe Borker knows.

As a seabird biologist at the University of California, Santa Cruz, Borker once counted the calls of individual nesting seabirds. Now he listens to soundscapes — the totality of the sounds of nature — and hears beyond the cacophony of white noise.

Ecologists Matthew McKown and Ahiga Snyder install sound recording devices in their surrogate wetland habitats on a farm near Santa Cruz, CA. Ecoacoustics is an emerging field of research that aims to measure the health through sound. Photo courtesy of Greg Golet.
Ecologists Matthew McKown and Ahiga Snyder install sound recording devices in their surrogate wetland habitats on a farm near Santa Cruz, CA. Ecoacoustics is an emerging field of research that aims to measure the health through sound. Photo courtesy of Greg Golet.

Sifting Through the Noise

"Ecoacoustics" is an emerging field of research. It is like bioacoustics, which focuses on the sounds made by or impacting individual organisms, but more holistic. Instead of chasing down isolated animal sounds, researchers put a recording device in the middle of an ecosystem, such as a forest, and pick up sounds made by animals, insects, weather, and even humans. They are using all of the acoustic properties of a location to answer ecological questions.

Ecoacoustic researchers put a recording device in the middle of an ecosystem, such as a forest, and pick up sounds made by animals, insects, weather, and even humans.

"A lot of bioacoustics has been focused on individual signals in a vacuum. I think ecoacoustics recognizes that none of these things exist by themselves. That whale is communicating against the backdrop of noise from ships and noise from fish and all sorts of stuff," Borker says.

Borker wanted to know if he could use soundscapes to measure ecosystem health. He listened to recordings of islands in the Bearing Sea to find out if the noise could predict the outcomes of local landscape restoration efforts. In a study published in September in Restoration Ecology, he found that, indeed, the soundscapes indicated that the islands were recovering.

Because of climate change, over half of the habitats from Krause's 5000 hours of recordings can no longer be heard in their original form.

The Aleutians are a chain of islands that jut off the tip of Alaska. In the 1800s, fur trappers introduced foxes to the westernmost islands, which caused a decline in the number of seabirds. When the islands became a federal wildlife refuge, the government began removing foxes to restore the seabird populations. Now, there are islands with foxes, islands without, and some that never had them at all.

It's a little like trying to understand the magnificence of Beethoven's 5th Symphony by extracting the sound of a single violin player, out of the context of the orchestra, and hearing just that one part.

Bernie Krause, soundscape ecologist

Listening to the soundscapes, Borker compared seabird colonies that had no time to recover, to colonies that had as much as 34 years to recover. He looked at variations in acoustic energy over time and within different frequencies. He found islands that had longer recovery times sounded like islands that foxes never invaded.

"This suggests that we don't necessarily have to (count individual bird calls) to get a really coarse and rapid assessment of how those islands are recovering," he says. "We can use indices of acoustic complexity and look at a more holistic measurement of how complex and how rich the soundscape is."

The Birth of a Field

Bernie Krause, a soundscape ecologist and founder of Wild Sanctuary, says that "people need to listen to the natural world." He is concerned that people are drawing too far from nature, and that climate change will soon get the better of us.

Krause has an archive of 5,000 hours of natural soundscapes recorded since 1968. He says that, because of climate change, over half of the habitats from those recordings can no longer be heard in their original form.

"I turned on that recorder, and I heard the sound of the entire habitat. It completely changed my mind. I thought to myself, ‘My God, this is where the information is.’ Not in a collection of individual sounds."

Bernie Krause, soundscape ecologist

"Think about that," he says. "We're not talking about individual animals now, we're talking about habitats."

Borker considers Krause a pioneer in the field of ecoacoustics, and some would argue that he is the founder. For Krause, who is also a trained composer, it all began in 1968 when he was recording sounds for an album called In A Wild Sanctuary. With a recorder in hand, Krause ventured into the forest.

"I turned on that recorder, and I heard the sound of the entire habitat. It completely changed my mind. I thought to myself, 'My God, this is where the information is.' Not in a collection of individual sounds."

It was Krause who first described the "acoustic niche" hypothesis. Animals in an ecosystem compete for resources, like food, water, and space, to survive. Their vocalizations are also crucial to their survival. They need to be heard and not masked by other sounds. So, the organisms also compete for space in the soundscape. They all settle into their own bandwidth — insects, birds, mammals, reptiles, each having their own niche in which to vocalize.

To Krause, it no longer makes sense to take an animal sound out of the ecosystem context when trying to understand their relationship to the habitat.

"It's a little like trying to understand the magnificence of Beethoven's 5th Symphony by extracting the sound of a single violin player, out of the context of the orchestra, and hearing just that one part," he says.

Hearing Hope in a Soundscape

Ecologist Matthew McKown, founder of Conservation Metrics, says that conservation efforts are already strapped for cash. There is little left for measuring how successful they are. Ecoacoustics could be a solution.

McKown launched Conservation Metrics to provide cost-effective ways to measure the outcomes of conservation efforts. In a collaborative project with the Nature Conservancy, McKown used ecoacoustics to measure the effectiveness of restoring shorebird habitat with manufactured wetlands.

Shorebirds are declining in numbers. Greg Golet, an ecologist at the Nature Conservancy, noticed that during their fall and spring migrations, suitable habitat is sparse. There are only about 70,000 acres of managed wetlands in California. But there are seven times as much farmland, most of which lies fallow during the shoulder seasons. So Golet recruited local farmers to flood their fields and create surrogate wetland habitats. He hopes this effort will bolster the shorebird population.

That's where McKown comes in. Instead of traditional, time-consuming, costly surveys — where researchers sit near the fields with their binoculars, tallying the number of birds they see — McKown deploys recording devices and analyzes the soundscape.

"They are complementary approaches. The acoustics is like a window into a new world that we haven't thought about much," Golet says. "I was excited. It made all kinds of sense to me. Given how the animals communicate, we're listening to their world instead of just looking in on it."

The field of ecoacoustics is growing. The International Society of Ecoacoustics is now in its third year, with several hundred participants at the annual meeting. As it evolves, both Borker and McKown expect to see more automation and computer learning applied to analyze the soundscapes.

But, even a computer can't replace the trained musician's ear. Have a listen — as Krause says, ecosystems really are like orchestras. There are flutes, violins, and woodwinds, all playing a complementary tune.

And if instruments drop out, as species diversity is lost to climate change, you'll still have a song, but it isn't quite as beautiful.

Explore More Stories

The Sound of Science
This Musician Transforms Scientific Data Into Elaborate Melodies
This Musician Transforms Scientific Data Into Elaborate Melodies
The Sound of Science
This Musician Transforms Scientific Data Into Elaborate Melodies
When we convert complex data into sound and listen to it, quite often what emerges is something we can understand through sound, even though we could never understand it visually.
By Teresa Carey

If you think staring at rows of numbers and graphs seems humdrum, these musicians agree. They are on a mission to expose new scientific information through sound, by turning flat datasets into musical scores --- creating the soundtrack for science: Listen to Mark Ballora’s sonification of singularity with flutes and electronics: Jenni Evans first met Mark Ballora at a Penn State social gathering. Both were professors at...

Fossil Finds
What Dinosaur Poop Tells Us About Ancient Life
Coprolites and dinosaur poop
Fossil Finds
What Dinosaur Poop Tells Us About Ancient Life
Coprolite, aka dinosaur poop, is giving scientists a surprising glimpse into the world of the dinosaurs. Learn what industry leader Karen Chin has been learning from dino dung.
By Tien Nguyen

Coprolite, aka dinosaur poop, is giving scientists a surprising glimpse into the world of the dinosaurs. Learn what industry leader Karen Chin has been learning from dino dung.

Innovation
How the Technology Behind Deepfakes Can Help Us Create a Better World
How the Technology Behind Deepfakes Can Help Us Create a Better World
Innovation
How the Technology Behind Deepfakes Can Help Us Create a Better World
Deepfakes have ignited fierce media criticism and call into question the public’s ability to discern fact from...
By Jackie Snow

Deepfakes have ignited fierce media criticism and call into question the public’s ability to discern fact from fiction. But the technology behind Deepfakes, called GANs, has enormous potential to drive innovation beyond fake social media videos. Read more to find out some of the amazing things being done with this technology.

Technology
Is This the End of Language Barriers?
Is This the End of Language Barriers?
Watch Now
Technology
Is This the End of Language Barriers?
What if you could travel anywhere in the world and there was no language barrier?
Watch Now

Real-time translation seeks to break down all language barriers in the world. Several tech companies believe they are on the verge of making this a reality through new devices such as Google's Pixel Bud headphones, which can translate up to 40 languages in one to two seconds. While the technology is still a work in progress, Google and others hope it might not be long before such technologies can help connect the world...

DIY
Can Coding Prevent Overdoses?
Can Coding Prevent Overdoses?
Watch Now
DIY
Can Coding Prevent Overdoses?
A group of teenagers in Baltimore have created an app that can notify the public about heroin overdoses and save countless lives
Watch Now

In Baltimore, sometimes referred to as the heroin capital of the U.S., a group of teenagers have developed an app that can track bad batches of drugs and alert nearby users. The so-called Bad Batch Boys believe that giving the information to the people that need it most has the potential to save countless lives.

Superhuman
3-D Printing Prosthetics for Kids
3-D Printing Prosthetics for Kids
Watch Now
Superhuman
3-D Printing Prosthetics for Kids
The incredible movement of shared designs and tech that’s making prosthetics better and cheaper for everyone.
Watch Now

Powered by 3D printer technology, people are making prosthetics at a fraction of the cost. Watch this episode of “Superhuman” for the story of how e-NABLE, an online network of volunteers, has created 3,000 bionic hands for people in need (mostly kids) across 90 countries.

Coded
The People’s NSA
The People’s NSA
Watch Now
Coded
The People’s NSA
Hackers and journalists team up to expose crime and corruption around the world
Watch Now

At an undisclosed location in Sarajevo, a group of hackers are working with journalists to expose organized crime and corruption. But those engaged in illicit activity respond with cyber attacks and other intimidation tactics. Can the group fight off the attacks and help journalists bring the truth to light?

The New Space Race
Why the U.S. Government Treated Satellites and Machine Guns as the Same for 15 Years
Why the U.S. Government Treated Satellites and Machine Guns as the Same for 15 Years
The New Space Race
Why the U.S. Government Treated Satellites and Machine Guns as the Same for 15 Years
Regulations forced companies that planned to sell satellites to other countries to register, in effect, as arms...
By Jeff Foust

Regulations forced companies that planned to sell satellites to other countries to register, in effect, as arms dealers.

Superhuman
The Real Bionic Man
The Real Bionic Man
Watch Now
Superhuman
The Real Bionic Man
After losing part of his arm to cancer, Johnny now has one of the world's most advanced prosthetics.
Watch Now

After losing part of his arm to cancer, doctors outfit Johnny, a self-described “hillbilly” from West Virginia, with one of the world’s most advanced robotic arms. Johnny is able to control his new arm with his mind, giving him a level of motor control impossible until now.