Soundscape ecology is a growing field of research that uses sound to track how ecosystems change over time. Bryan Pijanowski and Matt Harris work with a team of researchers to collect hours of sound at locations from the Alaskan tundra to a rainforest in Borneo. By analyzing the recordings they can reveal changes in each ecosystem that we might not otherwise be able to see.
Posted: April 2, 2015
Narrator: You've heard of landscapes. This is a soundscape. And like landscapes, soundscapes capture a single moment in time by recording what’s making all that noise. Scientists can use these “sound snapshots” to monitor how the environment changes. It's called soundscape ecology.
Bryan Pijanowski: So sound is actually a much more powerful variable for us in the science community because we can’t see everything.
Narrator: Bryan Pijanowski is a soundscape ecologist. He and his research assistant, Matt Harris, base their operations at Purdue University in Indiana, but their team uses microphones set up in ecosystems all over the world.
Pijanowski: Fundamentally what we're very interested in is how do sounds reflect their ecosystem: their function, the dynamics, and the ways in which humans impact those ecosystems?
Narrator: Every sound in an ecosystem falls into one of three categories. First there's the geophysical: that’s the wind, or thunder, or the sound of water running in a stream. Then, there's the biological: the birds, or frogs, or crickets.
Pijanowski: The third layer that we’re very interested in is the one that just happened right now, the sounds produced by humans, the sounds of sirens, church bells, road noise.
Narrator: The combination of sounds in a given location produce a sort of signature for that ecosystem, which can be visualized in something called a spectrogram. Pijanowski’s research show that in really diverse ecosystems the spectrogram holds many different frequencies.
On the other hand, areas disturbed by humans have less active and less diverse soundscapes. Why? Well, let’s say a highway gets built through this rainforest. The sound of cars might drown out certain animals' mating calls. Other animals will have lost habitat or resources due to the construction. While some animals will adapt, say, by changing the frequency of their calls, others won’t be so lucky. Their frequencies will drop out of the soundscape altogether. Just observing the environment might not immediately reveal these subtle changes. But listening to how the soundscape changes over time can tell you who’s thriving, who’s struggling, and who’s simply gone.
Matt Harris: In the past people might have gone out into the wilderness and and recorded their observations and their notes. What soundscape ecology allows us to do is we can go out and deploy sensors in many different locations. Then we have that crystallized forever, and we can go back to it, and really dig in depth into the problem that we’re studying.
Narrator: The problems are about as varied as the ecosystems. In Arizona they’re wondering if they can hear ecosystem recovery after a wildfire. And in Costa Rica, how is climate change affecting water flow? But changes to the sound of an environment don’t just influence wildlife. Pijanowski says it has an effect on humans, too.
Pijanowski: Are we becoming so removed from nature that we don’t realize that the noise that is all around us is truly a problem? It forces us to almost to turn off our ears.
- Produced, Animated and Narrated by
- Elizabeth Gillis
- Editorial help from
- Anna Rothschild
- Original Footage
- © WGBH Educational Foundation 2015
- Additional Video and Images
- Courtesy Bryan Pijanowski and Matt Harris
- Dvorak - Serenade for Strings Op22 in E Major larghetto
- © Advent Chamber Orchestra (CC BY_SA 3.0 US)
- © Podington Bear (CC BY-NC 3.0)
- Field cricket Gryllus pennsylvanicus.ogg
- Wikimedia Commons/Thatcher
- Grain Waves
- Freesound/Cheeseheadburger (CC BY 3.0)
- Freesound/Bassmonkey91 (CC BY 3.0)
- Freesound/acclivity (CC BY-NC 3.0)
- (main image: illustration of meadow)
- © WGBH Educational Foundation 2015