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Over increasingly large areas of the United States, spring now comes unheralded by the return of the birds. The early mornings are strangely silent where once they were filled with
the beauty of bird song. – Rachel Carson, Silent Spring

Bernie Krause (theappendix.net)

Have you ever sat quietly in the woods and just listened to the sound of the wind in the trees and the birds calling to one another? Or enjoyed the soothing sounds of waves on the beach? Or perhaps you have purchased a CD of relaxing nature sounds to help you fall asleep at night. If you have ever listened to a recording of nature, you have one person to thank: Bernie Krause.

Bernie Krause was one of the first electronic musicians, and he is credited with introducing the synthesizer and natural soundscapes to pop music and film. But even more important is his contribution to our understanding of ecology. In 1969 he and fellow musician Paul Beaver produced the first album that incorporated natural soundscapes. The album was also the first to be encoded in quadraphonic and surround sound, or sound that creates the sensation that it is coming from all around the listener.

When Beaver passed away, Krause continued to record natural soundscapes and founded a new field of study in the process: soundscape ecology.

Biophonies and geophonies are the signature voices of the natural world, and as we hear them, we’re endowed with a sense of place, the true story of the world we live in. – Bernie Krause

According to Krause, every wild habitat has its own unique auditory signature, and this is made up of three parts:

  • Geophony – non-biological sounds like wind, water, waves, and earth.
  • Biophony – sounds generated by living things in a habitat at a specific time.
  • Anthrophony – sounds created by humans, some controlled but mostly incoherent noise.

What is soundscape ecology?

Over the 45 years that he has been making recordings, Krause has come to the conclusion that sound is much more important than we previously believed. Biophony is not only just the sounds that creatures make, but the process each species takes in creating an acoustic territory. Organisms work to make themselves heard over the sounds of other organisms by establishing their own bandwidth.

The ecological soundscape has dramatically changed as humans have interfered in the natural world through resource extraction, habitat destruction, and noise from our ever-increasing transportation and population. To capture those changes, Krause founded Wild Sanctuary, an audio archive of over 4,500 recordings from his 45 years of efforts, including over 15,000 identifiable life forms in 3,700 habitats. Over 50% of these soundscapes are now from habitats that are completely gone, radically altered, or completely silent.

Trees are sanctuaries. Whoever knows how to speak to them, whoever knows how to listen to them, can learn the truth. They do not preach learning and precepts, they preach undeterred by particulars, the ancient law of life.
– Hermann Hesse, Wandering

The true value of an ecological soundscape recording is that it provides a 360° picture of something that wouldn’t necessarily be visually apparent. Krause demonstrated this by performing an experiment in California’s Lincoln Meadow in the Sierra Nevada.

A logging company was about to selectively log the forest around this meadow, a process that was supposed to have little environmental impact. Krause performed controlled recordings in the meadow before and after the logging, and the difference was dramatic.

The major impact of subtle change

Prior to logging, the birdsong was constant and filled with many different bird species, but afterwards the woods are almost silent. While selective logging created almost no visual difference around the meadow, those key trees had been an important habitat to many of the bird species in the area.

A great silence is spreading over the natural world even as the sound of man is becoming deafening. Little by little the vast orchestra of life, the chorus of the natural world, is in the process of being quietened.

As the world has changed, so has the process of capturing soundscapes. What had once taken 10 hours to get one usable hour of recording now takes hundreds or thousands of hours. Noise pollution is so prevalent that it’s almost impossible in the developed world to take an uninterrupted recording of nature.

The silence is what alarms Krause the most. As noted in his book, The Great Animal Orchestra, “A great silence is spreading over the natural world even as the sound of man is becoming deafening. Little by little the vast orchestra of life, the chorus of the natural world, is in the process of being quietened. There has been a massive decrease in the density and diversity of key vocal creatures, both large and small. The sense of desolation extends beyond mere silence.”

The future of soundscape ecology

While the act of recording the sounds of nature and identifying what’s alive and what isn’t may sound basic, the actual science of soundscape ecology is is much more involved. Each recording is conducted with as much control as possible so that multiple recordings from the same location can be compared over time. This may involve hundreds of microphones suspended throughout a habitat.

These recordings are then converted into spectrograms, visual representations of a sound spectrum that allow researchers to identify and analyze each unique frequency. As Krause hypothesized, organisms tend to stake out their own unique frequency of sound in order to be heard, and these can be recognized and tracked over time. Today sophisticated computers can analyze huge quantities of data quickly, without the need for tedious visual comparison by human eyes.

A spectrogram of an American elk bugle.

A spectrogram of an American elk bugle.

These comparison studies have helped researchers answer questions such as how forest fires change the desert or what fish farming does to neighboring populations. They can also be used for something simpler: gauging how the chatter of hikers in the woods affects communication between species, for example.

Krause has become increasingly concerned with the greater impacts of climate change: “[The soundscapes] speak eloquently to all of the climate issues we are now confronting. Global warming, severe weather shifts, earlier and later warm seasons, shifts in the density and diversity of bird, frog and mammal populations. All of these factors are conveyed.”

Originally designed to entertain us, soundscapes now equip us with the information we need to understand the impact of our actions and make the necessary changes. The trouble is, are we listening?

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