Listen Up!
When you visit a national park, you enter a world of memorable sights. When you listen to a park, you enter a world of inspirational sounds. Park Soundscapes
Elk bugling in the cool autumn air of Rocky Mt National Park, birds calling in the Everglades, waterfalls thundering into Yosemite Valley, the quiet reverence at the Vietnam Veterans Memorial. These are examples of natural sounds that make a trip to our national parks a unique and unforgettable experience.
Cultural and historic sounds are also important components of the many National Park units. The sound of a cannon shot echoing across a civil war battlefield or the hypnotic drumbeat of a sacred tribal dance provide visitors with insight into historic events or an earlier lifestyle, people, or culture. Cultural and historic soundscapes are treated and managed as a park resource with a truly unique and inherent value, and as an important component of the park experience for visitors.
National Parks were also created in part to allow the public to enjoy and appreciate the unique natural and cultural resources protected within our parks. Therefore, the sounds of people enjoying the parks through a variety of recreational activities are a common element of National Park soundscapes. Careful management will ensure that the sounds that contribute to our park experience are protected for current and future generations.
Definition of Soundscapes:
A soundscape refers to the total acoustic environment of an area. Both natural and human sounds may be desirable and appropriate in a soundscape, depending on the purposes and values of the park. For example, the sound of canon fire and muskets may be appropriate and desirable at Gettysburg National Military Park but not in the wilderness of Yellowstone. Soundscapes often vary in their character from day to night and from season to season and can be affected by changes in numbers of visitors who introduce human-caused sound into the environment. The soundscape of a national park, like water, scenery, or wildlife, is a valuable resource that can easily be degraded or destroyed by inappropriate sounds or sound levels. As a result, soundscapes require careful management if they are to remain unimpaired for future generations. How are Sounds Experienced?
Sound is defined as pressure variations or a wave traveling
through the air that can be detected by humans and other animals.
How we experience sound depends on two important characteristics:
Frequency and Amplitude. The number of pressure variations per
second in the air or the number of peaks and troughs in the
sound wave is called the frequency of the sound and is expressed
in hertz (Hz). Humans are usually able to hear sound with frequencies
ranging from 20 Hz to 20,000 Hz. Amplitude is what we normally
refer to as volume or loudness. As an object vibrates it creates
sound waves and as it vibrates harder, the height of the wave,
or the distance between the peaks and troughs in the wave, increases.
This height (or the distance between the peaks and troughs in
the sound wave) is known as the amplitude and is measured in
decibels (dB). Most sounds contain numerous frequencies and
each frequency can have a different amplitude. This complex combination of frequencies and amplitudes
is how we experience the unique soundscape within a park.
Soundscapes and Science
The symphony of natural sounds within our national parks is
an important natural resource and a critical component of the
ecological communities that parks seek to preserve. Understanding
the role of sound and acoustics in a healthy ecosystem is critical
to their effective management and protection. Birds, insects, mammals,
and amphibians rely on complex communication networks to live
and reproduce. In habitats where wildlife vocalizations signify
mating calls, danger from predators, or territorial claims,
hearing these sounds is important to animal reproduction and
survival. These types of issues are examined through research
in acoustic ecology which is the study of sound in the relationships between organisms
and their environment. Scientist also use bio-acoustics (bio=life, acoustics=sound) to determine the health of natural
habitats. Scientists can discern details about animal populations
and behavior by recording sounds in the wild. Such bio-acoustical
recordings are used in a variety of ways, including bird censuses,
bat echolocation studies, and marine mammal surveys.
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Featured National
Park
Sound Clip
Click on the photo to
hear the sound
This Bison was recorded in Yellowstone National Park on Sept
14, 2005
“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.”
Sigurd Olson
NPS Mission
The national parks were established "to conserve
the scenery, the natural and historic objects and the wild
life therein and to provide for the enjoyment of the same
in such manner and by such means as will leave them unimpaired
for the enjoyment of future generations..."
Part of the National Park Service mission is to protect
soundscapes. Both the sounds of the wild and the sounds meaningful
in historic settings are protected in the National Park System.
In sites where music, language, and history help people understand
our national heritage, park soundscapes may include jazz music,
battlefield sounds, or the songs of indigenous people.
Natural Sounds Program Mission
“The Natural Sounds Program works to protect,
maintain, or restore natural soundscape resources in parks.
We fulfill this mission by working in partnership with parks
and others to increase scientific and public understanding
of the value and character of natural soundscapes and to eliminate
or minimize noise intrusions.”
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