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Synthesis of Studies on the Effects of Noise

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1978-2018, with 2019 update

Project Summary

The Natural Resource Stewardship and Science Directorate (NRSS) develops, utilizes, and distributes the tools of natural and social science to help the National Park Service (NPS) fulfill its core mission: the protection of park resources and values. For scientific topics experiencing rapid growth in knowledge, producing a balanced summary of this knowledge is challenging, especially because the most recent articles may contain crucial, relevant information for management of resources and visitor experience. This project addresses the challenge of realizing balanced coverage through a stringent application of a systematic, comprehensive queries of the scientific literature.

Noise arising from expansion of human population and infrastructure, transportation networks, and resource extraction alter conditions in public lands and protected areas, including national parks (Figure 1)1. A comprehensive query that captures the relevant literature on noise impacts to wildlife and park visitors was developed by experts who conducted original research in this area and published an authoritative synthesis of the literature2. That published synthesis offered an important, peer-reviewed summary of the state of knowledge at the time of submission. However, its relevance diminishes with time when the literature expands and evolves rapidly. To offer relevant updates, this resource report represents the first of a series of summaries of the results from our systematic query of the literature, providing park managers with an accessible perspective of the size and scope of the relevant scientific knowledge regarding the effects of noise on wildlife and park visitors.

We emphasize the distinction between our approach and the results from an ad hoc query using Google Scholar or a related tool. Our query was developed and tested - by experts in the field - to ensure that the results encompassed all the relevant literature. This query was reviewed and improved in an iterative process. Though no query can guaranty it will capture every relevant paper, our current query delivers results that are far more comprehensive than our initial searches, even though those initial searches were performed by experts in the field. In the context of offering a comprehensive, balanced assessment of the literature of noise effects on humans and wildlife, we are confident that our present query is the best tool to identify the pertinent papers.

This resource brief represents our first attempt to concisely render knowledge of noise effects on wildlife and people in an accessible format. The focus here is on the size of the literature, the kinds of noise sources that were studied, and the breadth of effects that have been documented. We believe the value of this brief to NPS managers is to raise awareness of the extent of scientific support for park planning and management, and identification of distinct subsets of this literature that may be of special relevance for specific locations or management actions. The authors will assist parks and regions with more detailed and specific analyses of this literature upon request.

four images: a heard of elk, a bus driving toward a caribou, a train traveling along a lake, a boat on a lake
Figure 1. Within national parks, aircraft (a) and vehicle noise (b) are most frequently heard whereas train (c) and watercraft (d) are the loudest noise sources. Analysis is based on acoustic recordings collected and analyzed at 247 sites in 64 national parks across the United States3

Finding Relevant Studies

We conducted a peer-reviewed literature search using Thompson's ISI Web of Science (WOS). The search included papers published after 1977 to ensure all relevant literature was captured. The search was optimized to capture a known list of relevant studies. Ninety percent of the studies were captured using our search criteria. We feel that enlarging the query beyond its present scope is likely to add very few relevant papers, at the expense of adding many more irrelevant papers.

The final search for papers published between 1978-2018 resulted in 2,474 studies. These papers were reviewed by a subject matter expert so only studies focused on documenting the effects of anthropogenic noise were included in the final data set (N = 1,409). Papers that were not relevant included that those that just summarized noise levels without documenting a response and studies that occurred inside hospitals and vehicles (indoor learning spaces were included, due to their relevance for park interpretation). For the papers deemed relevant, the subject matter expert labeled each paper with a noise source category (e.g. transportation) and effect category (e.g. human, wildlife). Additionally, studies were automatically labeled using key words that appeared in the title of the publication (e.g. sleep, annoyance, birds).

Number of Studies

Over the past few decades there has been a growth in studies documenting the effects of noise on humans and wildlife (Figure 2). Literature on humans remained relatively constant with about 10 publications per year until about 2004 when number of publications in a year nearly doubled. For wildlife, studies did not really appear until early 2000s and saw a large increase in yearly publications after 2010. An increase in review papers on both human and wildlife response occurred in 2010, with highest number of publications in 2018.

The number of peer-reviewed studies published each year (1978-2018)
Figure 2. The number of peer-reviewed studies published each year (1978-2018) documenting the effects of noise based on our WOS search criteria and manual verification. Note: this graphic excludes studies using laboratory animals. For an alternative way to read this data, see the table at the bottom of this page.

Source of Anthropogenic Noise

All relevant papers were labeled by a subject matter expert with a single category of noise source: noise from built environment (all sources together), recreation, transportation, resource extraction (which included industrial sources), or military. We did not find any studies where multiple sources were investigated. Most of the human studies are focused on transportation noise, while the majority of wildlife studies are focused on noise from urban or built environment.

Two pie charts show the proportion of studies in different noise source categories. Human Studies: Generic/Built; Recreation; Resources extraction; Transportation. Wildlife Studies: Generic/Built, Military, Resource extraction, Transportation.
Figure 3. Proportion of studies within different noise source categories. Human studies N = 791 ; Wildlife studies N = 489. These graphics exclude studies using laboratory animals. Data for figure 3 is included in the text below.

Effects on Humans

In the 791 studies on human response to noise, there were:

  • 327 on traffic
  • 218 annoyance
  • 158 on aircraft noise
  • 117 sleep
  • 49 on wind farm noise
  • 39 on industrial noise sources
  • 30 on hypertension
  • 15 on speech
  • 9 studies in park setting

Effects on Wildlife

In the 489 studies on wildlife response to noise, there were:

  • 68 on traffic noise
  • 27 on underwater sonar
  • 12 on chronic noise
  • 7 on aircraft noise
  • 7 studies in a park or protected areas
A word cloud showing the most used words in the abstracts and titles from the studies on the effects of noise on humans A total of 918 papers were included. Largest words, corresponding to the most common, are traffic, exposure, and annoyance.
A word cloud of most used words in abstracts on human studies, 1978-2019 (918 papers. The largest words correspond to the most common.The largest words are traffic, exposure, and annoyance.

Trends in topics, 1978-2019

To examine different topics discussed in the literature, we generated word clouds for wildlife and human studies from the titles and abstracts for all publications (1978-2019), publications before 2000, publications between 2000-2009, and publications between 2011-2019.

Wildlife studies: Early wildlife publications focused on dolphins and birds, while later studies included more diverse taxa (fish) and noise sources (e.g. urban, sonar, road).

Human studies: Early studies focused on annoyance from aircraft, and later studies included sleep and health effects of multiple noise sources (wind energy, traffic).

Suggested Reading

Where to Find More Information

A searchable spreadsheet of all the relevant studies is available upon request (see contact information below) or on our website. The spreadsheet will be updated quarterly, and an annual briefing document will be prepared and appended to this summary. The results will be shared with the NPS community and archived on our website. In most cases, NSNSD staff has access to the full text of the publications and can share a link, email a pdf, or assist in finding the reference.

Project Contacts

Megan McKenna, PhD; Sharolyn Anderson, PhD, Kurt Fristrup, PhD
Natural Resource Stewardship and Science Directorate, Natural Sounds and Night Skies Division

2019 Update

The search for publications in 2019 resulted in 319 papers; 147 were found to be relevant by a subject matter expert. 59 new studies on wildlife (5 reviews; 83 new studies on humans (5 reviews).

In the 59 studies on wildlife response to noise, there were:

  • 10 on traffic noise
  • 3 on underwater sonar
  • 1 on chronic noise
  • 0 on aircraft noise
  • 0 studies in park or protected areas

In the 82 studies on human response to noise, there were:

  • 26 on traffic
  • 19 on aircraft noise
  • 18 on annoyance
  • 11 on wind farm noise
  • 9 on sleep
  • 6 on industrial noise
  • 1 on hypertension
  • 1 on speech
  • 0 studies in park setting
A graph that details the number of peer reviewed studies published each year, 1978-2018
Figure 4. The number of peer-reviewed studies published each year (1978-2019) documenting the effects of noise based on our WOS search criteria and manual verification. Note: this graphic excludes studies using laboratory animals. For an alternative way to read this data, see the table at the bottom of this page.

Suggested Reading


1 Buxton et al. Noise pollution is pervasive in US protected areas. Science 356.6337 (2017): 531-533.

2 Shannon et al. A synthesis of two decades of research documenting the effects ofnoise on wildlife. Biological Reviews 91(2016): 982-1005.

3 Buxton et al. Anthropogenic noise in US national parks-sources and spatial extent. Frontiers in Ecology and the Environment 17.10 (2019): 559-564.

Alternative text for Figure 1:

(clockwise from top left) Photographs showing different noise sources heard in National Parks. a) helicopter and a herd of bison, b) bus and caribou crossing road, c) train next to a river, d) tour vessel and bears on a nearby beach.

Alternative text for Figures 2 and 4:

The bar graph displays the number of peer-reviewed studies published each year from 1978 to 2018. Five bars are displayed for each year: studies on human response, review papers on human response, review papers on wildlife response and papers on wildlife response. The graph reads:

  • 1978: 9 human response studies;
  • 1979: 9 human response studies;
  • 1980: 8 human response studies;
  • 1981: 8 human response studies;
  • 1982: 5 human response studies;
  • 1983: 12 human response studies; 1 wildlife response study;
  • 1984: 4 human response studies;
  • 1985: 5 human response studies;
  • 1986: 2 human response studies;
  • 1987: 7 human response studies;
  • 1988: 7 human response studies;
  • 1989: 4 human response studies;
  • 1990: 5 human response studies; 1 wildlife response study;
  • 1991: 8 human response studies; 1 review-human study;
  • 1992: 2 human response studies;
  • 1993: 6 human response studies; 1 wildlife response study;
  • 1994: 10 human response studies;
  • 1995: 6 human response studies; 1 wildlife response study;
  • 1996: 15 human response studies; 2 wildlife response studies;
  • 1997: 13 human response studies; 1 review-human study;
  • 1998: 8 human response studies; 1 wildlife response study;
  • 1999: 14 human response studies; 2 wildlife response studies;
  • 2000: 11 human response studies;
  • 2001: 10 human response studies; 1 review-human study;
  • 2002: 11 human response studies; 1 review-human study; 3 wildlife response studies;
  • 2003: 13 human response studies; 1 review-wildlife study; 7 wildlife response studies;
  • 2004: 21 human response studies; 7 wildlife studies;
  • 2005: 17 human response studies; 5 wildlife studies;
  • 2006: 18 human response studies; 2 review-wildlife; 11 wildlife studies;
  • 2007: 21 human response studies; 3 review-human studies; 13 wildlife studies;
  • 2008: 23 human response studies; 1 review-wildlife studies; 6 wildlife studies;
  • 2009: 34 human response studies; 21 wildlife studies;
  • 2010: 39 human response studies; 1 review-wildlife studies; 14 wildlife studies;
  • 2011: 35 human response studies; 11 review-human studies; 2 review-wildlife studies ; 34 wildlife studies;
  • 2012: 36 human response studies; 3 review-human studies; 57 wildlife studies;
  • 2013: 45 human response studies; 1 review-human studies; 42 wildlife studies;
  • 2014: 43 human response studies; 2 review-human studies; 1 review-wildlife studies; 37 wildlife studies;
  • 2015: 55 human response studies; 3 review-human studies; 1 review-wildlife studies; 43 wildlife studies;
  • 2016: 74 human response studies; 6 review-human studies; 67 wildlife studies;
  • 2017: 59 human response studies; 5 review-human studies; 4 review-wildlife studies; 57 wildlife studies;
  • 2018: 59 human response studies; 13 review-human studies; 2 review-wildlife studies; 56 wildlife studies;
  • 2019: 78 human response studies; 5 review-human studies; 5 review-wildlife studies; 54 wildlife studies

Data for Figures 2 and 4:

The number of peer-reviewed studies published each year (1978-2018) documenting the effects of noise based on our WOS search criteria and manual verification.

Effects of Noise Papers
YearHumanReview-humanReview-wildlifeWildlife
Download This Dataset

Last updated: August 24, 2020