September 19, 2012
Biology Notes Help Recreate Sound Of Times Past
Brett Smith for redOrbit.com - Your Universe Online
For urban and suburban dwellers, the cutting drone of a jet engine or the swoosh of a passing car is more familiar than any bird´s song or chipmunk´s chatter. The wheels of progress have slowly changed modern man´s soundscape, for better or worse, as the industrial revolution forges ahead.To recreate the aural experience of an earlier time, two ecologists have turned to the 70-year-old notes of biodiversity pioneer Aldo Leopold. Leopold, a biologist at the University of Wisconsin-Madison, took countless notes that described the sounds of his Depression-era Sauk County home. The conservationist made up for the lack of an audio recorder with his detailed documentation of the early dawn song of a robin or the mid-day buzz of cicadas.
"Leopold took amazing field notes," said Stan Temple, a senior fellow of the Aldo Leopold Foundation and University of Wisconsin-Madison professor of wildlife ecology. "He recorded his observations of nature in great detail."
Temple and his colleague Christopher Bocast, a UW-Madison graduate student, scoured these notes in an attempt to create a composite of sounds that could replicate the world that Leopold heard just outside his door.
To establish a foundation of background sounds, Temple and Bocast worked hard to find a location free of the manmade noises that would have been absent in Leopold´s time and place. Temple noted that any setting in the contiguous United States is 21 miles or less from the nearest road.
"It is increasingly difficult to study natural soundscapes that represent normality," said Temple.
The ecologist also noted that other factors have affected local sounds in places like the rain forests of Hawaii. The encroachment of a Puerto Rican tree frog is having many different effects on the ecosystem of the archipelago´s forests.
“They sound more like the rain forests of Puerto Rico because the calls of an introduced, invasive tree frog are becoming pervasive,” Temple said.
After establishing their aural foundation, the team layered sounds drawn from Leopold´s notes across five minutes of compressed audio. Using the comprehensive sound catalog at the Cornell Lab of Ornithology's Macaulay Library, Temple and Bocast were able to add bird songs to their composition, which is currently being hosted online by the university.
Their finished product is as much an art instillation as it is a science experiment and was likely influenced by the internal preferences of the ℠composers´. Although sounds can appear in nature in both patterns and as random events–it seems unlikely that innate human hearing bias did not play a role in constructing the sound collage.
Regardless of its degree of accuracy, the recording made by the two ecologists is the first historical soundscape ever constructed and continues Leopold´s efforts to raise awareness surrounding everything that nature provides, including some aspects that often go unnoticed.
"We shall never achieve harmony with land, any more than we shall achieve absolute justice or liberty for people,” Leopold wrote in his essay entitled, 'A Taste for Country' from his 1949 book A Sand County Almanac. “In these higher aspirations the important thing is not to achieve, but to strive."