This week’s facts come from an interesting piece in the NY Times Magazine section that talks about researchers and ecologists catching sound in Alaska’s Denali Park. Worry that the constant hum of modern human life is negatively affecting natural habitats has led to several efforts to gather recordings of what nature sounds like without humans or any of their noisy inventions. “To restore ecosystems to acoustic health, researchers must determine, to the last raindrop, what compositions nature would play without us.” The article has links to the sound of an avalanche, birds, insects, and flowing streams that can be accessed here, but here are a few sobering reminders of the amount of human-made noise, even in places thought to be remote.
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An undeveloped swath of land nearly the size of Vermont, Denali should be a haven for natural sound. Yet since 2006, when scientists at Denali began a decade-long effort to collect a month’s worth of acoustic data from more than 60 sites across the park — including a 14,000-foot-high spot on Mount McKinley — Betchkal and his colleagues have recorded only 36 complete days in which the sounds of an internal combustion engine of some sort were absent. Planes are the most common source.
Noise can mask mating calls, cause stress, and prevent animals from hearing alarms, the stirrings of prey and other useful survival cues. There’s no way animals can alter their ability to listen — for their very survival — if human noise conceals, for example, the twig-snap of a prowler or the skittering of prey.
When Woodrow Wilson created the National Park Service in 1916, it was to “conserve the scenery”; not until 2000 did a Park Service director issue systemwide instructions for addressing “soundscape preservation.”
In Yosemite, planes were heard 30 to 60 percent of the day. In the Haleakala volcano crater in Maui, 8 to 10 helicopters passed overhead per hour.
In the United States, more than 80 percent of land is within two-thirds of a mile of a road.
