Loosing the silence

The NYtimes reports on how human noise is overwhelming natural sounds in the remotest places and the effort to document the baseline quiet of natural sounds before they are lost in the mechanical cacophony. The quest to map the quiet zones of the planet have been going on for the past decades and there was a recent special edition of Landscape Ecology dedicated to soundscape ecology.

From the NYTime’s article:

[Davyd] Betchkal’s stations capture exactly what we would hear if we could stand invisibly in the wilderness for a month. The recordings can reveal the sonic relationships that play out in our absence — and help us to modify our acoustic footprint. But our understanding of sound will always be limited by our perception of it. We will never experience the ultrasonic cries of insects, lizards or bats without distorting them.

Sounds recordings from Denali

…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. Once, in the course of 24 hours, a single recording station captured the buzzing of 78 low-altitude props — the kind used for sightseeing tours; other areas have logged daily averages as high as one sky- or street-traffic sound every 17 minutes. The loudest stretch of the year is summer, when hundreds of thousands of tourists flock to Denali, embarking on helicopter or fixed-wing rides. Snowmobiles are popular with locals, and noise from the highway, the park road and daily passenger trains can travel for miles. That sort of human din, studies are beginning to suggest, is imperiling habitat — in Denali as well as wilderness areas around the world — as surely as a bulldozer or oil spill.

At the Grand Canyon (which is briefly mentioned in the NYT article), flight restrictions are now in place to preserve a modicum of tranquility without the buzzing of helicopters and planes over the entire canyon.

The magnitude of the problem can be seen by juxtaposing the roadless areas with the flight patterns – which all but cover the entire lower 48. Road Ecology has clearly linked the impacts of vehicle noise with habitat quality.

To illustrate the maritime noise issue:

The One Square Inch of silence in the Hoh Rainforest is reputed to be the quietest place in the lower 48 thanks to the sound absorbing qualities of moss and high humidity.

Wind turbines are a recurring topic at Infrascape Design, so I couldn’t pass up a chart of the noise from a utility-scale turbine.

Other interesting soundscape maps include:

A5 Indexing of the Exchange District in Winnipeg, MB

Philadelphia decibel map

See also


Pijanowski, Soundscape ecology: the science of sound in the landscape, Bioscience 2011

Bryan C. Pijanowski, Almo Farina, Stuart H. Gage, Sarah L. Dumyahn and Bernie L. Krause, ‘What is soundscape ecology? An introduction and overview of an emerging new science’, Landscape Ecology, Volume 26, Number 9, 1213-1232, DOI: 10.1007/s10980-011-9600-8

Bryan C. Pijanowski and Almo Farina, Introduction to the special issue on soundscape ecology, Landscape Ecology, Volume 26, Number 9, 1209-1211, DOI: 10.1007/s10980-011-9655-6

Sarah L. Dumyahn and Bryan C. Pijanowski, Beyond noise mitigation: managing soundscapes as common-pool resources, Landscape Ecology, Volume 26, Number 9, 1311-1326, DOI: 10.1007/s10980-011-9655-6

Luis J. Villanueva-Rivera, Bryan C. Pijanowski, Jarrod Doucette and Burak Pekin, A primer of acoustic analysis for landscape ecologists, Landscape Ecology, Volume 26, Number 9,, 1233-1246, DOI: 10.1007/s10980-011-9655-6




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