Wild spaces are important for many reasons. For us humans, they give us peace and energy, provide places for recreation and connection with nature, and teach us about the life around us. But wild places are not only necessary for humans – for flora and fauna and the land itself, protected areas are reserves where nature can run its course without as much interference from humans. They provide critical places for the earth to heal itself and resume its organic processes; they also give homes to many endangered species. Yet unfortunately, protected areas may not actually be as protected as their names make them sound. A new study from Buxton et al. looked at the degree to which noise pollution has infiltrated protected areas in the United States, finding that anthropogenic noise doubled background noise levels in a majority of protected areas. Scientists and nature-lovers alike fear that this is affecting habitats that many ecosystems rely on.
Protected areas include, but are not limited to National Parks. Get a glimpse of the 59 US National Parks below.
Protected areas in the United States cover 14% of the country’s land mass. To determine how noise pollution is affecting these areas, scientists from Colorado State University and the U.S. National Park Service collaborated to measure human-caused sounds from aircraft, highways, industrial, and residential sources. The team listened to countless hours of sound measurements from 492 sites around the country.
They found that the most noise came from roads, aircraft, human development, and resource extraction. In 63% of U.S. protected areas, anthropogenic noise doubled background sound levels. In 21% there was an even greater impact, causing a 10-fold or more increase in normal background noise. To break that down in more understandable terms, human-caused noise has reduced the area in which natural sounds can be heard by 50-90%. This means that what could be heard at 100 feet away can now only be heard from a distance of 10 to 50 feet.
Such extreme noise levels disrupt our own enjoyment in wild spaces as well as wildlife’s behavior. Noises can distract or scare animals, which ultimately may impact species composition. Fourteen percent of critical habitats for endangered species have elevated noises. This has huge impacts on entire ecosystems.
"Although plants can't hear, many animals that disperse seeds or pollinate flowers can hear, and are known to be affected by noise, resulting in indirect impacts on plants," said Buxton. When species compositions at such basic levels change, in many cases entire ecosystems are thrown out of balance.
Yet it isn’t all bad. The study saw that more strictly regulated areas suffered from less anthropogenic noise, which means that the study’s findings can suggest mitigation methods. Some protected areas have shuttle services to reduce individual transportation; some have quiet zones where visitors are encouraged to take in the nature quietly. Banning extraction in certain noise-sensitive areas can also help wildlife and visitors’ enjoyment, not to mention keeping natural equilibrium in place.
Rachel Buxton, lead author of the study, said: "The noise levels we found can be harmful to visitor experiences in these areas, and can be harmful to human health, and to wildlife. However, we were also encouraged to see that many large wilderness areas have sound levels that are close to natural levels. Protecting these important natural acoustic resources as development and land conversion progresses is critical if we want to preserve the character of protected areas."