Conservation and Biodiversity
Hear the Planet on World Listening Day
July 18, 2025
This World Listening Day, we’re tuning in to the world around us to learn how to respect the sounds of our planet and what they tell us about the health of our ecosystems.
One of the most powerful parts of the natural world is the soundscape. Originally coined by Michael Southworth in 1969, it describes the relationship between the sonic environment and humans. Put more simply it describes how we relate to the sounds around us in their natural world and the environment. It was subsequently popularized by composer Murray Schafer in 1977 who focused on how environments are structured acoustically. Today, the definition remains a little vague, but is generally defined as the acoustic space we can study through the frame of ecology.
Building on this, bioacoustics, reflects on the sounds produced by animals themselves. This includes mammals, marine animals, insects and birds–everything from the smallest beetle to the blue whale. These sounds and recordings can help us understand species biodiversity better, and provide essential insight on how to combat climate change.
Unfortunately, our soundscape has slowly suffered as hundreds of species go extinct, and we lose the sonic diversity of the natural world. Notably, ‘noise’, described as “unwanted sound” by David Heskell, is on the rise as human beings take over.
But there is hope. Unwanted noise, unlike pollution, has no lasting effects which means as soon as it stops the environment starts to heal. During the “Anthropause”–a period defined by the halt of human activities during COVID–scientists found multiple species began to recover with bright chirps replacing the drone of humming cars.
So this World Listening Day let’s celebrate nature’s symphony, to learn how to appreciate its harmony.
Coral Calling/Fizz, Crackle, Pop
You may have held a seashell to your ear in hopes of smelling the salty air or hearing the crash of an ocean wave. But you may be surprised that deep beneath the deep blue sea, a crackling sound echoes throughout the sand. Brightly colored coral emerges in a spectacular underwater rainbow, providing habitat to 25% of marine life worldwide.
In 2022, researchers were able to train a computer program with hundreds of sound recordings to track the health of a coral reef of islands in central Indonesia by listening to it. While unhealthy reefs reportedly sound “desolate”, healthy coral reefs emit a crackling similar to a campfire. Using the loudness and frequency of sounds in the recordings, the AI system can detect whether a reef is healthy or not about 92 percent of the time.
And preserving these reefs is essential, now more than ever. Between 2009 and 2018, roughly 14% of the world’s coral reefs were lost. According to the Global Coral Reef Monitoring Network that’s 2.5 times the area of the Grand Canyon National Park! Luckily, the team has no plans of stopping, with hopes to collect from the Virgin Islands, Mexico and Australia. In the future, scientists also hope these recordings will help rebuild reefs globally.
Underground Heroes: Wriggling their Way to Victory
Nestled under the bright green grass of your lawn is one of nature’s most riveting features–dirt. Soil is essential for most terrestrial ecosystems, but is being degraded at extreme rates. From intense agriculture to corrosive chemicals from unsustainable human activities, our soil has seen extensive degradation over the last couple of decades. In fact, 2021 to 2030 has been declared the Decade on Ecosystem Restoration by the United Nations, highlighting the urgency of restoring these ecosystems.
Fortunately, scientists have found that listening to the bioacoustics of the smallest ant to the wriggliest worm, can determine if an ecosystem is healthy. Researchers at Flinder University in Adelaide, Australia set up six locations throughout Mount Bold Reserve. Over the five days they were there, the team made 240 recordings lasting nine minutes each.
Research revealed that sites not kept solely as grasslands have more soil invertebrate species, and an overall higher number of specimens than the cleared plots. Soil from regrown vegetation sites in particular have a 21% higher index score compared to sites that are cleared. The score is based on the premise that biological actions, like ants marching underground, have characteristic sound patterns. This way, the number of sounds helps scientists determine how many organisms are present. And the more organisms, the better the ecosystem.
Tree Talk
As a gentle breeze makes its way through the park, rustling leaves can be heard among the chirp of the songbirds. As you walk amidst a canopy of oak, ash and birch, more of nature’s sound secrets lie just beneath the bark of our trees.
Scientists have discovered that trees make a variety of sounds, from creaks to tunes, that tell us about the environment. In fact, according to biologist David Haskell, who has spent years fascinated by trees, they are powerful communicators. He notes that tree species have different sonic signatures that change according to the seasons.
Even more, trees have multiple ways to show they are stressed, or in drought. When connected to an ultrasonic detector, branches emit a kind of crackling sound. Some sound like a Morse Code tapping, while others emit a pulsing akin to blood running through human veins when water flows over the branches.
Leaves are also indicators of stress, although like humans there’s a range. Far from simply if the leaves are green, anything from how reflective the leaf is to where the color of the green leaf falls on the electromagnetic spectrum is an indicator of stress.
Musically, aside from their wood being valuable in the creation of many musical instruments, when converted into piano notes fatter twigs made higher sounds while thinner ones made lower. It’s safe to say trees have a lot to tell us, and we’re ready to listen.
Our soundscape and sonic diversity are in danger. But, from the high tops of trees to the deepest depths of the oceans, nature provides us with a symphony of hope.
In February, we released the article The Hills Are Alive, With the Soundscapes of Nature, highlighting the different sounds of our world and the importance of preserving them. Now, it’s time to turn that listening into action for the planet.
If the Earth calls, let’s be ready to answer. If you want to help make the sound of trees stronger, donate to our Canopy Project and help us plant more trees globally.
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