The sounds of silence, and the sounds of nature, are under assault on National Park Service properties.
Researchers liken the blanket of sound that can envelope parts of parks to an acoustical fog. Much like the air pollution that encroaches on parks and vanquishes vistas, anthropogenic noise can detract from the visitor's enjoyment of these otherwise pristine places.
Noise negatively impacts the ability of guests to hear and view wildlife, pushing animals to more remote areas. And, for some sound-sensitive species, entire parks can be rendered uninhabitable by background din.
Plus, excessive noise from inside and outside the boundaries can mask a park's natural sound-shed.
The distant rustling of leaves that once stirred the imagination, now lost behind a cacophony of background noise.
The unwanted reminder that you're not quite away from it all, as the backup alarm blares on a distant delivery truck while you labor along a trail.
And the rush of rivers, wind caressing trees, thunder playing in distant canyons, buffered by the sounds of man and his machines.
For visitors to National Park Service properties, sounds -- the natural ones you hear and the man-made ones you don't -- are an integral part of the experience.
And officials at Zion National Park are wisely taking steps to preserve and protect the park's natural acoustic resources.
First, they'll establish baselines. Park service researchers have been inventorying the sounds in the park since 2001 using solar-powered recording devices, eavesdropping on deer and sheep, rock slides and waterfalls.
Next, they'll set standards, establish objectives and, hopefully, adopt a formal soundscape management plan to reach those goals.
If approved, the plan would be a first for a park service property. But, if park officials are wise, it won't be the last.
It's too late to preserve the soundscapes in much of the country. According to a 2003 study, 83 percent of the land in the lower 48 states is within a mile of a road. And those quiet, roadless areas have most certainly shrunk in the intervening years.
But it's not too late to dial down the sound in our national parks, monuments and recreation areas.
Sound management of noise will help maintain the quality of our parks for generations to come.