An integral part of a national park experience is experiencing natural sounds. In Denali National Park and Preserve these can include the howls of wolves, thunder of avalanches, roar of rivers, buzzing of mosquitoes, and the croaking of ravens. Sometimes there are no sounds - it is just completely silent. This is the park’s natural soundscape, where the acoustic properties are those of the land, without sounds caused by humans or human technology.
Denali began its soundscape program in 2000 in order to document baseline levels of motorized sound and monitor these sounds over time. Automated sound stations “listen in” and record samples of the park’s soundscapes from sites representing different habitats, elevations, and levels of motorized use. Digital recordings and sound pressure levels (how loud the sounds are) are collected continuously for a month at each location.
Soundscape staff also sample additional sites each year to document levels of human-caused noise at locations of management interest. These include popular snowmobiling areas (winter) and glacier tour landing sites or areas of frequent aircraft overflights (summer). Park managers use the acoustical analyses to determine whether sound standards set for wilderness by the Denali backcountry management plan are being met and to inform other efforts to achieve desired resource conditions in the park.
A recent New York Times article explores the intrusion of human-caused sound in natural spaces through an experience at Denali this winter. To read the article, click on the link below.