Lake Clark National Park: Acoustic Monitoring Report, Coastal Deployments 2018–2023

Betchkal DH . 2026. Lake Clark National Park: Acoustic Monitoring Report, Coastal Deployments 2018–2023. Science Report. NPS/SR—2026/396. National Park Service. Fort Collins, Colorado. https://doi.org/10.36967/2317108

This report documents acoustic conditions at three coastal sites in Lake Clark National Park (LACL) to support development of the LACL Coastal Management Plan and to establish a baseline for future monitoring. The study addresses how increasing motorized access associated with visitor use influences natural soundscapes in areas that concentrate both wildlife activity and visitor experience. Acoustic data were collected during 2018, 2019, and 2023 using standardized National Park Service monitoring protocols and were analyzed to characterize existing ambient sound levels, estimate natural ambient sound levels, and quantify the audibility of human-caused noise sources. Results indicate that natural soundscapes along the LACL coast are shaped primarily by wind, surf, and biological activity, but are periodically fragmented by discrete noise events associated with transportation corridors, particularly aircraft and watercraft. Across three sites, noise was audible for approximately 14–29% of an average day, with aircraft representing the most commonly heard source. Differences between existing and estimated natural ambient sound levels were generally small in magnitude but occurred in patterns that reflect repeated and spatially concentrated access routes rather than diffuse background change. These findings demonstrate that acoustic conditions at coastal portals into the park are closely coupled to transportation patterns and are therefore responsive to shifts in visitation, technology, and access practices. The results also provide a physical description of habitat conditions in areas important to brown bears and other wildlife that rely on auditory cues for foraging, communication, and predator avoidance. Together, these data establish an acoustic reference condition for the southeastern coastal portion of LACL and offer park managers a framework for evaluating how future changes in access may influence both visitor experience and ecological function. The dataset further serves as a permanent record of soundscape conditions during the study period and contributes to long-term documentation of environmental change in the park.

Type
Published Report
Authors
Betchkal, Davyd
Date of Issue
2026-03
Publisher
National Park Service
DOI
10.36967/2317108
Units
LACL , NRSS
Keywords
Acoustic environment, baseline ambient, indicators and standards, management by objectives, monitoring, natural sound, noise, sound level, soundscape, transportation geography, visitor use monitoring
Subjects
Ecological Framework: Biological Integrity | Focal Species or Communities | Marine Communities , Ecological Framework: Human Use | Point-Source Human Effects | Point-Source Human Effects , Ecological Framework: Landscapes | Soundscape | Soundscape , NPS.gov Subject Site: Natural Sounds , NPS.gov Subject Site: Transportation
License
Public Domain

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