Listen: Nature Is Quieter Than Ever Before

We're muffling wild voices—from bird songs to wolf howls to insect footsteps, scientist claims.

The next time you're out in nature, stop, close your eyes, and listen.

That’s what Bernie Krause would like us all to do, before it’s too late to hear the full symphony of the natural world. Founder of the scientific field called "soundscape ecology," Krause has been recording the noises of our wild places, whether it's on land or at sea, since 1968.

He's created an international archive of over 5,000 hours of habitat recordings, featuring at least 15,000 identified organisms. Some regard his library as a national treasure.

Sadly, increasing human interference is muffling nature’s voices—from bird songs to wolf howls to insect footsteps. And many of an ecosystem's sounds, which he calls biophonies, have ceased playing forever.

“The orchestra is losing not just volume but instrumentalists,” says Krause, who published a new book, Voices of the Wild: Animal Songs, Human Din, and the Call to Save Natural Soundscapes.

Krause recently did an email interview with National Geographic about why wild sounds matter.

How did you turn to the language of sound to describe nature?

I began my first professional career as a musician, having introduced the synthesizer to pop music and film with my late music partner, Paul Beaver. In the late 1960s, we composed the first music album on the theme of ecology using natural soundscapes as a component of orchestration.

I switched from art to science so I could continue to enjoy the wonder of working out of doors. During my Ph.D. studies of bioacoustics, I created a new field, soundscape ecology, the study of sounds produced by organisms in a particular landscape.

Can the soundscape tell us something different than the landscape?

Absolutely. One example: A logging company came to the Sierra Nevadas in 1988 [and used] a new method called selective logging. I recorded dawn choruses before and after. Visually, the forest looked untouched after the trees were removed. But the bird song was heavily diminished, and, decades later, the original biophony hasn't returned.

Listen to recordings from Lincoln Meadow, in California's Sierra Nevadas, before logging (1988) and after (1989). 

What types of sounds does nature generate?

The soundscape is divided into three basic sources: The geophony, or the non-biological sources of sound that occur in a wild habitat (e.g., wind in the trees, water in the stream, waves in the ocean); the biophony, the collective sound all signal-generating organisms produce in a given habitat or biome; and anthropophony, or the sounds [“noise”] we humans produce. Most of those are incoherent or chaotic, generated by our technologies. (Listen: Lemur Calls Turned Into Beautiful Beatbox Jams.")

What are some living things that we might not expect generate sound?

Aside from ants, insect larvae, and anemones, I’ve been working to capture the signatures that different species of fish produce [by moving their tails]. I’ve also recorded earthworms plying their way through soil and hippo vocalizations under water. One colleague has recorded organisms as small as a virus. It may be that every living organism on earth produces some kind of sound signature. We’d like to learn how they do it, and record them all.

You’ve recorded thousands of hours of natural soundscapes in more than 1,200 locations. How has habitat alteration changed what you hear?

I’ve been astonished to realize that over half of the places I’ve recorded in five decades no longer support enough living organisms to generate a cohesive biophony. They’re either totally silent, or so compromised by human endeavor that the natural soundscapes are unrecognizable. Where I’ve gone back to re-record, there are clear shifts in density—total numbers of vocal organisms—and diversity, [the] total number of overall vocal species.

In our area, [Sonoma County, California's] Valley of the Moon, there was no birdsong this past spring or summer. Zip. None whatsoever. There were birds, to be sure. And they called a bit. But no singing… the first time in my 77 years I can ever remember not hearing that.

Listen to a clip of sounds recorded between 2004 and 2015 in Sugarloaf State Park, near Glen Ellen, California. Rapid changes to the ecosystem, including an earlier spring, shifts in species compositions, and a drought have all altered the soundscape.

How does the soundscape offer us a unique approach to conservation?

In order to fully comprehend nature’s function and properties, we have to learn about its operation as it performs. That means getting to know a whole system rather than deconstructing it to study component parts, as we tend to do. That’s a bit like trying to understand the magnificence of Mahler’s 8th Symphony by abstracting the sound of a single violin player and hearing just that one part.

Instead, by listening to the whole natural soundscape, we are not only able to discern melody, but also the ways in which sound is organized. I’ve discovered there are acoustic and temporal niches—just like instruments in an orchestra—where each critter establishes its own bandwidth or time to sing so that its voice won’t be impeded by others.

Where could one go today to hear a truly impressive and near-intact soundscape?

The richest soundscapes can be found as one gets closer to the Equator. In the equatorial rain forests, especially, the vocal-creature density and diversity is at its greatest because the habitat is so supportive. As for the loudest soundscape I’ve measured, that would be somewhere in a Sumatran rain forest. The level there reached 117 [decibels. That’s almost as loud as a thunderclap, if it were sustained, or a chainsaw.]

Listen to the Sumatran rain forest clip.

What have you taken away from your work so far?

First, the sounds of nature can be calming and healing; they’re really important to our health and well-being. Plus, they’re absolutely free. (Related: "Why Did Humans Invent Music?")

Second, the natural world responds acoustically to everything we do to it. With improving technology, we can hear these responses more clearly than ever. We have to learn to read and pay attention to their meanings, because they are telling us that our actions can have dire consequences for the health and diversity of life on Earth. We dismiss that opportunity at our peril.

This interview has been edited and condensed.

Follow Jennifer S. Holland on Twitter.


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