It’s harder now than it ever has been to enjoy the unspoiled quiet of natural places, according to a recent study. Noise pollution created by vehicles and industry has doubled sound levels in over half of all protected areas in the U.S., and some places are now 10 times louder than they once were.
This increase in noise isn’t just stressful for people looking for a quiet escape–it’s also detrimental to animals and their habitats. As residential and industrial areas continue to expand and get closer to protected places, researchers are looking for ways to limit the spread of noise.
Researchers from Colorado State University teamed up with the National Park Service to examine how far noise pollution has spread into natural areas around the United States. The study was co-authored by Rachel Buxton and George Wittemyer, conservation biologists at CSU. The group’s findings were published in Science, in May 2017.
The research team measured noise levels at close to 500 locations in protected areas, ranging from small neighborhood parks, to large, remote swaths of wilderness–and they found human-made noise nearly everywhere they looked. After collecting the sound data and adding in other information such as elevation and distance from roads, they created a formula which they fed into a computer to map out noise levels in thousands of protected areas. The results showed that noise is “pervasive” in natural areas across the U.S.
The computer model revealed that noise pollution has doubled sound levels in 63 percent of protected areas and created a 10-fold increase in 21 percent of these areas. More isolated or restricted areas, such as natural parks and wildlife preserves, were quieter, but these areas still had increased noise levels. Open spaces and parks managed by local governments, often bordering cities, were the loudest. State and federal lands which permit logging, mining, and oil and gas extraction were also found to have disruptive noise levels.
“We were surprised we found such high levels of noise pollution in such high amounts of protected areas,” said Buxton. “Twenty-one percent of protected areas experienced levels 10 decibels above background (sound levels), and that’s a very significant increase.”
People visit natural areas to escape the noise and hubbub of cities, so hearing these excessive sounds can be stressful and annoying for park visitors, and may even undo the benefits of spending time in nature such as improved mood and concentration. But the effects of noise pollution are even more deeply felt in the plant and animal kingdoms, where the ruckus can disturb entire ecosystems. For example, certain plants need rodents to disperse their seeds–rodents which may be scared away by the noise of engines. Human-made noise also stifles the songs of birds, makes it harder for predators to hear their prey, and for prey to hear predators.
These findings may be discouraging, but there was some good news as well. The researchers discovered that the natural soundscape was still largely undisturbed in many areas, primarily national parks and large wilderness preserves. According to Wittemyer, “We still have some incredibly natural soundscapes across the United States.”
He also noted, though, that our level of activity is increasing and keeping these areas sonically pristine will require some effort.
So what about the natural places that are closer to urban areas and have begun to be inundated with noise? Many–but not all–of these protected places already make use of noise-reducing strategies, including using shuttles to reduce traffic or concentrating flight paths and highways into “noise corridors”. Buxton hopes that her team’s findings and noise map will guide land managers in deciding where to implement more protective measures such as these so that they have the greatest benefit.
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