Publication Date

5-2019

Date of Final Oral Examination (Defense)

3-11-2019

Type of Culminating Activity

Thesis

Degree Title

Master of Science in Biology

Department

Biology

Supervisory Committee Chair

Jesse R. Barber, Ph.D.

Supervisory Committee Member

Julie Heath, Ph.D.

Supervisory Committee Member

Neil Carter, Ph.D.

Abstract

Protected natural areas are not free from noise exposure, both external to and within park boundaries. Natural soundscapes are important in animal life histories, provide positive visitor experiences, and may increase motivation to protect natural areas. To examine the potential coupling of natural and human systems via the soundscape and the use of signs as an effective anthropogenic noise mitigation strategy, we experimentally introduced educational and enforcement signage along a trail and road system in an alternating, weeklong block design within Muir Woods National Monument, CA and Grand Teton National Park, WY, respectively. In Grand Teton National Park, speed limits were reduced from 45 mph to 25 mph during sign present blocks. We continuously recorded background sound levels while conducting bird point counts and visitor-intercept surveys along each experimental corridor to assess possible linkages between the natural and human worlds via the soundscape. Sound levels were significantly lower during sign present weeks in both park units; however, bird count only decreased in response to background sound levels within the trail system. Visitor perception of bird biodiversity was positively influenced in part by mitigation signage (Muir Woods National Monument) and decreasing sound levels (Grand Teton National Park). Soundscape pleasantness rankings increased as sound levels decreased in the trail system alone. In both locations, the majority of sign mitigation strategies presented were preferred by visitors, and these preferences increased when signs were physically present, indicating sign mitigation increased conservation support by visitors. From this work, we demonstrate complete positive feedback loops between human and natural systems via the soundscape in Muir Woods National Monument. In Grand Teton National Park, we provide evidence of a positive feedback loop within the human system. We show that signs increased visitor experiences and conservation support through reduced anthropogenic noise, improved access to natural sounds, and allowed for a greater ‘carrying capacity’ of visitors through reduced human-created noises. Noise can be mitigated through sign use, but desired positive outcomes may depend on the context of the location and type of noise exposure.

DOI

10.18122/td/1533/boisestate

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