Park natural soundscape resources encompass all the natural sounds that occur in parks, including the physical capacity for transmitting those natural sounds and the interrelationships among park natural sounds of diff erent frequencies and volumes. Natural sounds occur within and beyond the range of sounds that humans can perceive, and they can be transmitted through air, water, or solid materials. The National Park Service will preserve, to the greatest extent possible, the natural soundscapes of parks.
Some natural sounds in the natural soundscape are also part of the biological or other physical resource components of the park. Examples of such natural sounds include:
- sounds produced by birds, frogs, or katydids to define territories or aid in attracting mates
- sounds produced by bats or porpoises to locate prey or navigate
- sounds received by mice or deer to detect and avoid predators or other danger
- sounds produced by physical processes, such as wind in the trees, claps of thunder, or falling water.
Using appropriate management planning, superintendents will identify what levels and types of unnatural sound constitute acceptable impacts on park natural soundscapes. The frequencies, magnitudes, and durations of acceptable levels of unnatural sound will vary throughout a park, being generally greater in developed areas. In and adjacent to parks, the Service will monitor human activities that generate noise that adversely aff ects park soundscapes, including noise caused by mechanical or electronic devices.
The Service will take action to prevent or minimize all noise that through frequency, magnitude, or duration adversely aff ects the natural soundscape or other park resources or values, or that exceeds levels that have been identifi ed through monitoring as being acceptable to or appropriate for visitor uses at the sites being monitored.
(See General 4.1; Cultural Soundscape Management 188.8.131.52; Recreational Activities 8.2.2; Use of Motorized Equipment 8.2.3; Overfl ights and Aviation Uses 8.4. Also see 36 CFR 2.12: Audio Disturbances)