The relationship between aircraft noise exposure and day-use visitor survey responses in backcountry areas of national parks

Abstract

To evaluate the relationship between aircraft noise exposure and the quality of national park visitor experience, more than 4600 visitor surveys were collected at seven backcountry sites in four U.S. national parks simultaneously with calibrated sound level measurements. Multilevel logistic regression was used to estimate parameters describing the relationship among visitor responses, aircraft noise dose metrics, and mediator variables. For the regression models, survey responses were converted to three dichotomous variables, representing visitors who did or did not experience slightly or more, moderately or more, or very or more annoyance or interference with natural quiet from aircraft noise. Models with the most predictive power included noise dose metrics of sound exposure level, percent time aircraft were audible, and percentage energy due to helicopters and fixed-wing propeller aircraft. These models also included mediator variables: visitor ratings of the "importance of calmness, peace and tranquility," visitor group composition (adults or both adults and children), first visit to the site, previously taken an air tour, and participation in bird-watching or interpretive talks. The results complement and extend previous research conducted in frontcountry areas and will inform evaluations of air tour noise effects on visitors to national parks and remote wilderness sites.

Anthropogenic noise in US national parks – sources and spatial extent

“…The negative effects of noise on a range of animal species, ecological communities, and human visitors in protected areas are well documented (Rapoza et al . ; Shannon et al . ).…”

“…The negative effects of noise on a range of animal species, ecological communities, and human visitors in protected areas are well documented (Rapoza et al 2015;Shannon et al 2016). Noise that overlaps in frequency with important natural signals compromises a primary sensory system for wildlife (Swaddle et al 2015) and people.…”

“…In addition to masking important acoustic information, noise exceedance in this range reduces visitor enjoyment of parks through annoyance and interference with natural quiet and natural sounds (Rapoza et al . ). Moreover, the scholarly literature published over the past two decades demonstrates that noise exceedance in this range affects wildlife species richness, reproductive success, behavior, and physiology (Shannon et al .…”

“…Exceedances of 3 dB and 10 dB correspond to a doubling and tenfold increase, respectively, in acoustic energy, and to a 50% and 90% decrease, respectively, in the spatial extent of acoustic signal detection (ie "listening area"; Barber et al 2010) in many vertebrates (Buxton et al 2017a). In addition to masking important acoustic information, noise exceedance in this range reduces visitor enjoyment of parks through annoyance and interference with natural quiet and natural sounds (Rapoza et al 2015). Moreover, the scholarly literature published over the past two decades demonstrates that noise exceedance in this range affects wildlife species richness, reproductive success, behavior, and physiology (Shannon et al 2016).…”

Modeling anthropogenic noise impacts on animals in natural areas

“…In the second case study, we chose to examine audibility, as it may determine a minimum level of impact (i.e., audible or not). However, audibility will depend on species, individual, and even the degree of attention paid by an individual animal to the noise source (Fay 1988;Rapoza, Sudderth & Lewis 2015). Furthermore, a sound may be audible without necessarily causing any negative effects (Rapoza, Sudderth & Lewis 2015).…”