Nature’s orchestra: The soundscapes of the wild
Sound is a fundamental and dynamic property of nature, which describes nature’s orchestra – the composition of different biological organisms occurring in a single area. Here in Toronto, you can experience this symphony of “nature’s music” whenever you go on a hike in one of the many ravines during the summer, where you can hear the different calls from a community of birds throughout the urban landscape. This relationship between the sound composition of wildlife and the landscape is formally known as the soundscape. It can consist of three main acoustic sources: (1) the biophony, which is the combination of sounds of all vocalizing animals in an environment, (2) the geophony, which comprises of sounds that originate from the geophysical environment, and includes wind, water, thunder and so forth, and (3) the anthrophony, which arises from stationary and moving man-made objects.
Given the technological advancements of acoustic recording devices, it is now more possible to record and tease apart characteristics of all three soundscape categories than ever before, which has incredible potential for understanding how each category interacts with one another. This is especially important when you consider how the soundscapes of the wild in a given ecosystem might be altered by climate change or land-use change. While naturalists and hobbyists enjoy nature’s orchestra for recreational purposes, the soundscape itself hasn’t been fully appreciated by researchers as a universal measure of human-nature interactions, especially considering how the prevalence of anthropogenic noises might influence the loss of biodiversity or a severe disturbance in wildlife responses.
Dustin Scarpitti
If you were to consider the entire spectrum of the soundscape, the urban environment contains sounds produced by living organisms and abiotic natural sounds. It also includes human-induced sounds that are regarded as unwanted noise by many people and that do not communicate any biological information to living organisms sharing the same environment . As urban landscapes continue to expand, these unwanted sounds become more common as they persist into more rural and remote areas due to a larger network of motorized transportation. As such, the increase of urbanization often results in a decrease in urban biodiversity. Therefore, researchers can take advantage of the vocal sounds of different organisms as an alternative measure of biodiversity for natural resource management and biological conservation. Indeed, a recent study looked at how human impact affects local biodiversity across a variety of landscapes through the comparison of biodiversity and soundscape measures. After a year of monitoring the sound activity of birds and crickets, the results showed that both sound activity and diversity in the strong dawn and dusk chorus peaks diminish with increasing human disturbance on the surrounding landscape.
Western scrub-jay by Alfred Viola, Northeastern University, Bugwood.org
At a smaller scale, it is also crucial to assess how anthropogenic soundscape qualities like traffic, affect individual wildlife species and populations. Anthropogenic noise could influence wildlife behaviour, such as in predator-prey interactions for bird populations. Birds are particularly useful for studying the interaction between noise and wildlife behaviour since they are known to be sensitive to anthropogenic changes, and they are regularly surveyed. Using species with noise responses representative of other avian community members, a group of researchers found that an increase in the amplitude of anthropogenic noise negatively affected the predation rate of the western scrub-jay (Aphelocoma californica), but it increased the nesting success of its prey, the gray flycatcher (Empidonax wrightii). Based on these results, it is clear that predator populations will be altered without noise-reducing walls, and that companies and land managers should work together to minimize the industry’s impact on natural communities and maintain part of the natural soundscape.
In an era with increasing threats to natural environments, society should value the importance of natural soundscapes, as much as it values biodiversity and ecosystems. Soundscapes reflect a symphony of all living organisms, and providing an auditory link to healthy populations of wildlife and vibrant locally biodiverse communities. Therefore, the sounds of the natural environment and its living organisms should not be something that we try to block out, but rather, something that we value and preserve for generations to come.
By Garland Xie
References:
Krause, B. (2008) Anatomy of the soundscape: evolving perspectives. Journal of the Audio Engineering Society, 56, 73–80.
Francis, C.D., Paritsis, J., Ortega, C.P. & Cruz, A. (2011) Landscape patterns of avian habitat use and nest success are affected by chronic gas well compressor noise. Landscape Ecology, 26, 1269–1280.
Gregory, R.D. & Strien, A. van. (2010) Wild Bird Indicators: Using Composite Population Trends of Birds as Measures of Environmental Health. Ornithological Science, 9, 3–22.
McKinney, M.L. (2008) Effects of urbanization on species richness: a review of plants and animals. Urban ecosystems, 11, 161–176.
Pijanowski, B.C., Villanueva-Rivera, L.J., Dumyahn, S.L., Farina, A., Krause, B.L., Napoletano, B.M., Gage, S.H. & Pieretti, N. (2011) Soundscape ecology: the science of sound in the landscape. BioScience, 61, 203–216.
Wrightson, K. (2000) An introduction to acoustic ecology. Soundscape: The journal of acoustic ecology, 1, 10–13.
Please note that opinions expressed are the author’s own. They do not necessarily reflect the views and values of The Blank Page.
