Increased noise may keep birds from finding mates and locating prey, and it interferes with other complex communications networks important for the birds’ survival. ©Eric Rock

When trying to measure the impact we humans have made on the natural world, we often concentrate on the number of animal species that have been lost or the plants that are disappearing. In today’s predominantly visual world, it’s not often that we think about the sounds that are now gone for good. That’s why a recent project from the University of Wisconsin (UW) is capturing attention.

In the 1940s, well-known ecologist, author, forester and UW professor Aldo Leopold was working on his hypothesis that birds sing in response to daylight; that each species begins to vocalize when the light reaches a particular brightness. Although he had no tape recorder, he was a meticulous note-taker and recorded the time and brightness (gauged with a light meter) of when each type of bird started its morning songs. Using his notes, UW researchers have been able to recreate the world of sound that Leopold heard more than 70 years ago.

“Soundscape ecology” is a relatively new field of study that is starting to be taken seriously by conservationists. But can hearing the world as it once was truly be a tool for helping to create stronger environmental protections, or is it just an exercise in nostalgia? 

The word “soundscape” refers to the total acoustic environment of an area. ©Henry H. Holdsworth

The sound of silence

Aldo Leopold’s journal notes were so detailed that the UW researchers were able to take digital recordings of birdsong from the Cornell Lab of Ornithology to recreate the sounds that would have been heard at “Leopold’s Shack” on the Wisconsin River on the morning of June 1, 1940. Each of the species of birds sings in the order that Leopold recorded.

The area around the Leopold Shack is much different today than it was seven decades ago. Now, there are fewer farms in the area, and a busy interstate runs nearby. As a result, there is a lot more human-generated noise and the bird populations are different.

Although the fact seems shocking, in the Lower 48 today there is no place more than 22 miles from the nearest road. The most remote, landlocked spot is deemed to be in the Teton Wilderness off Yellowstone National Park’s southeast corner in a valley known as Thorofare. While it takes a round-trip hike of more than 70 miles to reach the point, it is only 22 miles as the crow flies from the nearest road. Tuning out the hum of human activity today—even in places designated as wilderness—is almost impossible. So to get background sound that was free of the roar of cars and trucks for the Aldo Leopold project, wind and water sounds were recorded at a rural property that one of the lead researchers owns.

Soundscape ecologists say that projects such as the Leopold study are important for understanding the role of sound and acoustics in a healthy ecosystem. They believe that sound is critical to effective management and protection of natural environments. It has been demonstrated that increased noise may disrupt wildlife behavior, particularly in mating, locating prey and other complex communications networks important for survival. In addition, 72 percent of visitors to national parks say that one of the most important reasons they come is to experience natural peace and the sounds of nature.

The National Park Service is a big proponent of soundscape ecology. Under the National Park Service Organic Act of 1916, a premier part of the agency’s mission is to preserve or restore the natural resources of the parks. It logically follows, then, that along with protecting and conserving the wildlife, water, air quality and geologic features that sound should also be included. In the Grand Canyon National Park Enlargement Act of 1975, for example, it’s stated that natural quiet is “a value or resource in its own right, to be protected from significant adverse impact.” The National Parks Overflight Act of 1987 requires the park service to report on the nature and scope of overflight problems in parks, as well as on the injurious effects of air tours—including noise—on natural, historic and cultural resources, impairment of visitor enjoyment and impacts of noise on safety of park users.”

Sigurd Olson believed that “hearing the singing wilderness” is akin to catching its real meaning. ©Eric Rock

The song of wilderness

Some say, however, that when compared to the imminent extinction of animals and plants, soundscape ecology is a “small issue.” Since preserving the natural sounds of a place may be just as challenging as conserving the mosaic of plants and animals that keep an ecosystem intact, precious conservation dollars should be spent first on conserving that mosaic. Maintaining the natural soundscape is secondary to making sure the biota is still there.

Others point out that soundscape ecology is just another reiteration of acoustic ecology, a discipline that has been around since the 1960s. The new term is just a way to bring buzz to an older field of study. And since we’ve had acoustic ecology studies for 50 years now, it’s unlikely renaming such research under a new umbrella will have any meaningful impact on conservation policies and measures.

Sigurd Olson, author, environmentalist and advocate for wilderness, once wrote, Far more important than the places I have seen or what I have done or thought about is the possibility of hearing the singing wilderness and catching, perhaps, its real meaning.”

Do you think that soundscape ecology research will impress policymakers, especially given our visually oriented culture? Is restoring natural soundscapes even possible in our modern world?

Here’s to finding your true places and natural habitats,

Candy