COLORADO

Unseen pollution is drowning out natural areas

CSU and National Parks Services researchers work to understand the impacts of noise pollution

Cassa Niedringhaus
The Coloradoan
A bull elk bugles near the Big Thompson River in Rocky Mountain National Park in this Sept. 17, 2015, file photo.

The rustle of pine needles, the call of songbirds and the bugle of elk are as much part of Rocky Mountain National Park as the mountain vistas — and researchers say that in some protected areas across the United States, those sounds are at risk of being eclipsed by human-created noise.

A coalition of Colorado State University and National Park Service researchers created a model to understand how noise pollution contributes to the din in protected areas across the country.

In about one in five natural areas, they found noise pollution led to a 90 percent reduction in “listening area.”  

Translation: Where once you could hear a bird’s song from 100 feet away, noise pollution may have reduced that distance to just 10 feet.

“We found fairly alarming levels of noise pollution in large portions of protected areas,” CSU postdoctoral research fellow Rachel Buxton said. “We’re starting to realize more and more what a problem noise pollution is. Until now, we didn’t realize really at what scale that problem was happening.”

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In protected areas — including RMNP, Roosevelt National Forest and Lory State Park — human chatter, traffic, air travel and development contribute to noise pollution that's disruptive to both people and animals.

Noise can have negative effects on how animals communicate; it can appear as a threat that scares them away; and it can distract them from foraging or watching for predators.  

“Those three things together can have some pretty serious consequences, not only for individual species but also for entire ecosystems,” Buxton said.

One example she cited is research in New Mexico that found that noisy oil rigs scared away rodents. The rodents were important seed dispensers, so, when they were scared away, the plants in the area suffered, too.

“It can have cascading effects throughout a community or ecosystem,” Buxton said.

Related:Hear the rustle of grass? Not so much now in many US parks

In Colorado, residents benefit because of the large number of city parks, natural areas, and national parks and forests, said Kurt Fristrup, science and technology branch chief at the National Park Service's Natural Sounds and Night Skies Division in Fort Collins.

The parks and natural areas serve as buffers that help insulate the state’s protected areas from the noise pollution levels faced by national parks other states.

“Our county and our state have invested in creating a lot of protected areas, both here in town, or adjacent to town, but also up near the Wyoming border at Soapstone and Red Mountain open spaces,” Fristrup said. “Some of those are protected areas are big enough that just by their size alone they tend to provide a lot of protection from noise.”

Fristrup said that noise and light pollution can be addressed rapidly and relatively inexpensively, unlike chemical pollution or climate change. 

“Noise and light are just energy-based forms of pollution,” Fristrup said. “If you fix the sources of those pollutions — where the energy is coming from — the entire environment is improved automatically, immediately."

More:RMNP paving project to cause delays, closures this summer

In 2013, the Federal Aviation Administration agreed to route westbound air traffic coming into Denver International Airport above Trail Ridge Road in Rocky Mountain National Park. In effect, the FAA created a “noise corridor” to help keep noise pollution concentrated above the already-busy road, rather than spreading it across the park.

Fristrup said the move particularly improved hiker experiences in the Wild Basin and Mummy Range areas.

Strategies like paving roads with porous pavement that absorbs sounds from vehicle engines, instituting "quiet zones" in which visitors are cautioned to reduce their own noise and reducing traffic via shuttle services can help reduce noise pollution in protected areas, Fristrup said.

“I’d say the first thing that people could do is just to give themselves chances to listen really carefully in quiet places, to learn how amazing our hearing is and how rich the natural sound world is,” Fristrup said. “As a community and as a nation, we’ll only protect things that we value. If all you ever experience is the sound you listen to in your earbuds or the conversations you have at home, you won’t know that your ears are capable of this million fold more sensitivity, this capacity to hear very faint sounds at a distance.”

More:RMNP officials seek to ease 'good problem' of too many visitors

What about RMNP?

Rocky Mountain National Park is more insulated from noise pollution than other protected areas around the state and the country. However, its visitation numbers have been steadily rising. In addition to contributing to noise pollution, high visitation contributes to full parking lots, congested roads, busy trails and long lines at entrances

As they did last year, rangers are temporarily restricting traffic on most weekends this summer and fall in three areas: Bear Lake Road corridor, Alpine Visitor Center and Wild Basin area. Park spokeswoman Kyle Patterson recommended visitors carpool or use the park shuttle, hike early or late and plan ahead for visits.

Visitation by the numbers: 

2016: 4.5 million

2015: 4.2 million

2014: 3.4 million

2013: 3 million

2012: 3.2 million

2011: 3.2 million

2010: 3 million

2009: 2.8 million

2008: 2.8 million

2007: 2.9 million

2006: 2.7 million