Rocky Mountain National Park in Colorado is famous for its majestic mountains, lush forests, and crystal clean air. The late John Denver even sang about the “Rocky Mountain High” he felt within this beautiful setting. When scientific recordings are made there and at the majority of other US protected areas, however, a major problem becomes evident: noise pollution.
Accompanying nearly every bird song and peaceful brook babble in even the most seemingly pristine spots is the unmistakable din of roaring airplane engines, accelerating cars, booming radio music, industrial clatter, and other loud, persistent human-produced noises often ranging from 3 to 10 decibels and up.
“These levels can directly interfere with communication — we call this masking,” said Rachel Buxton, a postdoctoral research fellow at Colorado State University. “For example, if a predator is listening for prey, noise can mask this sound, reducing the hunting efficacy.”
Her colleague George Wittemyer of the Global Biodiversity Center and an assistant professor at the university added that noise pollution can also distract and lead to additional behavioral changes in animals, such as when they spend more time being vigilant versus foraging. Very loud sounds can also cause direct physical damage to wildlife, as evidenced by sonar impacts on marine mammals. Even plants may become victims of noise pollution, since entire ecosystems can change when seed dispersers and pollinators avoid noisy areas.
“Personally, I have been struck by the pervasiveness of noise of jet traffic in extremely remote areas,” Wittemyer continued. “You can be miles from anything and still have loud jets overpass, which changes the experience of remoteness.”