I went for a walk in the woods this weekend at a park near my house. The 48-acre Yost Park is comprised of roughly 1.5 miles of trails and boardwalks that meander up and down a ravine and over a small creek that empties a mile or so farther west into the Puget Sound. Hemmed in by roads on two sides and neighborhoods on the other, Yost is a pocket of verdant respite from the cacophony of urban sights and sounds just beyond its leafy borders. Dressed in its spring best this past Sunday, the second growth forest of red alder, Douglas fir, red cedar, and western hemlock wove an airy canopy, while the understory stitched a dense carpet of ferns, moss, and brambles.
What I noticed most though was the noise. The trills and chirps of songbirds, rustling of leaves and creaking of branches, steady babbling of the creek – these all intermingled into a sort of vibrant music. Cue the FernGully soundtrack. Though the song of the woods was loud – but not enough to drown out the occasional siren and car horn from the urbanity beyond – I couldn’t shake the thought that the music was not as loud as it once was.
Measuring the soundscape
The person I have to thank for this dispiriting realization is musician and naturalist Bernie Krause. As a pioneer of the relatively new (and still obscure) science of soundscape ecology, Krause has been recording the sounds of the natural world since the 1960s. With 15,000 species captured in 5,000 hours of recordings over the past half century, Krause’s collection is one of the community’s largest and oldest, making it immensely valuable in understanding the sonic landscape of earth’s habitats and how they are changing. By analyzing the soundscape of an ecosystem, scientists like Krause are able to measure parameters relating to density (total number of organisms), diversity (number of different species), and richness (number of sound-producing organisms within range of the mic). Crucially, they can compare those metrics over periods of time to measure how the vibrancy and robustness of the soundscape alters from one point to the next.
Building on prior work in the field, Krause breaks the soundscape sources into three different categories: biophony, or the composition of sounds created by organisms; geophony the nonbiological sounds of wind, rain, thunder, and other ambient noises; and anthrophony, or human-produced sounds. Holistically then, soundscape ecology studies all biological and non-biological sounds produced in a given landscape that create unique acoustical patterns across spatial and temporal scales. In this way, the sounds of a landscape – both as individual acoustic events and as interactions between multiple events – can be studied over geography and time periods, providing us with insight into the vitality and diversity of landscapes over time.
A growing silence
A valuable tool for conservation, Krause’s work sheds light on how climate change and environmental degradation have affected wildlife populations. His research spans the globe, documenting the soundscape of such diverse ecosystems as the wilderness of the Arctic National Wildlife Refuge, the rainforest of the Amazon, and the coral reefs off the coast of Fiji. In comparing recordings from these sites over the decades, a common pattern emerges – the soundscape has grown quieter over time.
Lincoln Meadow in California’s Sierra Neveda’s is a prime example of this. Data collected from Krause’s first recordings at the site in the 1980s reveal a rich and diverse biophony, while recordings made after 1988 – when selective logging was introduced to the area – capture a soundscape much altered, made nearly silent from a loss of bird and frog species. Even after returning to the site in the early 2010s, Krause showed that the density and diversity of the biophony had not recovered to pre-logging levels.
Krause’s work, while perhaps not widely known, is gaining traction in the media. He has published books, presented onstage via TED Talks, and collaborated with the likes of the Foundation Cartier on the 2016 The Great Animal Orchestra, an exhibition that immersed visitors in an auditory-visual exploration of the natural world. In discussing the importance of this kind of public artwork, Krause says that “the soundscape hits audiences in the gut in ways that no scientific paper alone can do.” In the same way that hearing a beautifully composed song elicits an affective or aesthetic response in the listener, engaging with the sounds of nature can strike a chord on some deep, emotional level.
Aural aesthetics
Soundscape ecology, while teaching us more about the earth’s natural habitats, reminds us that there are ways outside of seeing to understand, interact with, and appreciate the world around us. In engaging with the natural world through auditory perception, we are able to connect with things in different, sometimes unexpected ways that can enable powerful aesthetic experiences.
So the next time you’re out for a walk or a hike in the park, spend some time observing not only what you can see, but what you can hear. You might even have a full-on FernGully moment. In the meantime, the Acoustic Ecology Institute has compiled a list of recorded soundscapes that can transport you to nearly every corner of the earth. And if you feel like trying your own hand (ear?) at it, resources like the Center for Global Soundscape’s Record the Earth app allow you to record and upload your own soundscapes for all to enjoy.
Happy listening.
