When it comes to sounds in national parks and other protected areas in the United States, the things that come to mind are birds chirping, trees rustling or streams flowing. However, noise pollution has become an increasingly pervasive problem, a new study finds, and it’s doing more harm than just disrupting the peace and quiet.
Noise generated by human activity, such as traffic, activities involving machinery and so on, are a threat to the survival of plants and animals, Nature.com reports.
Rachel Buxton, an acoustic ecologist at Colorado State University in Fort Collins, and a team of researchers examined data gathered by the US National Park Service that shows sound levels across the nation. The information covered over 1.5 million hours in 492 protected sites in the USA, including city parks and remote places.
Buxton and the team then created a background noise model that removed all potential sounds made by human activities. Then they compared this model with the information gathered from the NPS maps, in order to determine the levels of noise humans contributed in protected areas.
The results showed that 63% of these parks and protected areas were two time louder than they should be. Buxton said,
So if you used to be able to hear a bird song at 100 feet [30 meters], now you could only hear it at 50 feet.
In 21% of the areas surveyed, the noise levels were 10 times more than background levels. Buxton said that in those places, “you can only hear that bird at about 10 feet.”
Many of these areas are habitats for endangered species, affecting plants and animals. For example, higher noise levels could change the behavior of plant pollinators, plant-eating animals, or species that distribute seeds.
On the bright side, around one-third of the protected areas the team analyzed still had undisturbed environments, which is good for plants, animals and humans alike. In addition, the most protected places, called “wilderness areas,” were the quietest.
The study was published in the journal Science.