Soundscape Ecology: Principles, Patterns, Methods and Applications
Abstract
Soundscape Ecology represents a new branch of ecology and it is the result of the integration of different disciplines like Landscape ecology, Bioacoustics, Acoustic ecology, Biosemiotics, etc. The soundscape that is the object of this discipline, is defined as the acoustic context resulting from natural and human originated sounds and it is considered a relevant environmental proxy for animal and human life. With Soundscape Ecology Almo Farina means to offer a new cultural tool to investigate a partially explored component of the environmental complexity. For this he intends to set the principles of this new discipline, to delineate the epistemic domain in which to develop new ideas and theories and to describe the necessary integration with all the other ecological/environmental disciplines. The book is organized in ten chapters. The first two chapters delineate principles and theory of soundscape ecology. Chapters three and four describe the bioacoustic and communication theories. Chapter five is devoted to the human dimension of soundscape. Chapters six to eight regard the major sonic patterns like noise, choruses and vibrations. Chapter nine is devoted to the methods in soundscape ecology and finally chapter ten describes the application of the soundscape analysis. © Springer Science+Business Media Dordrecht 2014. All rights are reserved.
Chapters (10)
The soundscape is defined as the entire sonic energy produced by a landscape and is the result of the overlap of three distinct sonic sources: geophonies, biophonies, and anthrophonies.
The geophonies are the result of sonic energy produced by nonbiological natural agents such as winds, volcanoes, and sea waves.
The biophonies are the results of animal vocalizations (song, contact and alarm calls, voices).
The anthrophonies are the result of all the sounds produced by technical devices (engines, wheel revolutions, industries, etc.).
The spatial overlap of geophonic, biophonic, and anthrophonic patterns creates the sonotopes. Each sonotope for the effect of behavioral constraints can be further subdivided into soundtopes. In the zone of contact between different soundtopes, a tension zone of acoustic uncertainty/overlap is called a sonotone.
The sonic environment, which is important for most organisms that perceive, in a species-specific way, the acoustic information coming from different components of the ecosystems, represents a promising field of ecological research: “soundscape ecology.” This new ecological discipline was first presented to a landscape ecology congress in 2009 with a symposium titled “Soundscape Ecology: Merging Bioacoustics and Landscapes,” where a primary role was recognized for different components such as acoustic ecology, landscape ecology, bioacoustics, urban and environmental acoustics, behavioral ecology, and biosemiotics.
Soundscape ecology finds important applications in the assessment of the environmental quality of parks and protected areas, in urban planning and design, in ethology and in anthropology, and finally in long-term monitoring.
The sonic characters of the landscape are important to better understand animal communication in a perspective of biodiversity conservation and to guide sustainable actions to achieve the well-being of humanity.
Weather conditions and climatic context in general have a great influence on the sonic environment, affecting the sound activity of vocal species. Wind depresses biophonies but on the other hand is a source of important information on atmospheric turbulence.
Most of the vocal species experience direct effects from changes in climatic and weather conditions, confirming the importance of the sonic ambience as an indicator of ecosystem modifications.
The structure of vegetation and its density are important drivers of sonic propagation. Vegetation interferes with sonic energy for effects of reverberation, absorption, and scattering.
In a forested landscape, sound propagation is strongly affected by ground effect, by the scattering from tree trunks and branches, and by absorption by leaves.
Wind-generated noise and animal-borne sounds are differently distributed when core and edge areas are compared.
The sonic characters of the landscape are important for better understanding of animal communication in a perspective of biodiversity conservation and to guide sustainable actions to achieve the well-being of humanity.
Weather conditions and climatic context in general have a great influence on the sonic environment, affecting the sound activity of vocal species. Wind depresses biophonies but on the other hand is a source of important information on atmospheric turbulence.
Most vocal species experience direct effects by changes in climatic and weather conditions, confirming the importance of the sonic ambience as an indicator of ecosystem modifications.
The structure of vegetation and its density are important drivers of sonic propagation. Vegetation interferes with sonic energy by effects of reverberation, absorption, and scattering.
In a forested landscape, sound propagation is strongly affected by ground effect, by scattering from tree trunks and branches and by absorption by leaves.
Wind-generated noise and animal-borne sounds are differently distributed when core and edge areas are compared.
The jungle environment represents a more spectacular example of sonic environment at the highest acoustic diversity. The dense vegetation, the complexity of the vertical layers of vegetation, high humidity, and the lack of wind create a unique system to which vocalizing species have been adapted for a long time.
Four major hypotheses are considered relevant in the perceiving and communicating processes common to all animal species: the morphological adaptation hypothesis (MAH), acoustic adaptation hypothesis (AAH), acoustic niche hypothesis (ANH), and species recognition hypothesis (SRH).
The morphological adaptation hypothesis (MAH) refers to the role of body size as a biological constraint of the vocalization organs and their acoustic performances, confirming an inverse relationship between acoustic frequencies and body size.
The acoustic adaptation hypothesis (AAH) states that the environment is an important cause of modification and alteration of the acoustic signals. Dominant frequencies and other long-distance calls are the result of an interaction between the animals and the environment to maximize the efficiency of the emitted sounds. Frequency and structure of the acoustic repertoire are plastic traits that can be modified according to the environmental constraint.
The acoustic niche hypothesis (ANH) states that every species has a unique acoustic space in which to structure the sonic species-specific signature to reduce interspecific competition and to optimize intraspecific communication mechanisms.
The species recognition hypothesis (SRH) supposes that species living in sympatry try to reduce the risk of utilizing similar sonic traits that could confound species in reproduction and create the risk of hybridizations. This set of hypotheses has epistemic relationships to form a meta-bioacoustic theory.
A central principle in the communication theory states that biological signals are honest, which means, for an acoustic signal such as a song, that the complexity of the repertoire and all the secondary characters associated are an expression of natural selection.
In communication, a sender and a receiver are connected by an informative signal. A third subject is the eavesdropper or the involuntary receiver that utilizes the information which circulates between the two. Eavesdropping represents an important evolutionary phenomenon. Communication is costly in term of energy budget allocated by vocal individuals, and a well-designed communicative framework should be the result of selective pressure.
Communication is an important component of animal life contributing to reproduction and to survival life traits. Acoustic signals are used in several groups of species, humans included, to find resources, to avoid predators, and to find or adapt locations for reproduction.
To improve the efficacy of a signal, it is important to reduce the loss of energy on one hand and on the other to optimize the information contained in the signal. The efficiency of a signal largely depends on the internal design and on the capacity of an emitter to separate the signal from the background noise.
Analysis of the complexity of acoustic communication codes and specifically the acoustic codes represents an interesting perspective.
The sonic ambience associated with visual aesthetics is important to human well-being, and the search for a quiet area becomes a priority strategy in human societies surrounded by growing anthropogenic noise. The study of the soundscape from the human perspective requires a psychological approach that allows a synthesis between visual and acoustic stimuli.
The quality of the sonic ambience increases the acoustic capacity in human hearing and alters the relationship between acoustic cues and their cultural and social interpretation.
Noise sensitivity is defined as an attitude to rating sound according to an individual-based criterion and represents a major antecedent of individual noise annoyance. Sensitivity is independent of the predisposition to perceive a sound event more intensely or the capacity to better discriminate sounds.
Direct and indirect effects of noise exposure on human health produce hearing impairment, reduction of speech communication, cardiovascular risk, sleep disturbance, psychological and performance reduction effects, and a subjective feeling of annoyance. Exposure to outdoor noise represents the highest risk to human health. Insomnia is one of the most common effects, but in the long term ischemic heart disease and rising blood pressure have to be considered equally probable.
Noise can be defined as a sound with a poor information or simply an unwanted sound that can mask other sounds. Accordingly, the source of noise may be of natural (geophonies, biophonies) or manmade (anthrophonies) origin. The noise produced by human activities has grown quite rapidly in the past century, over the larger part of the Earth. Noise reduces the distance from the sender at which a signal can be detected by a receiver. This distance is called active space and represents an important parameter in communication.
Choruses are the result of contemporary vocalization of several individuals and species at a precise time of the day (dawn or dusk).
Several hypotheses have been presented in recent years. First, the beginning of the chorus activity is species specific, and this can be explained with body size and eye size.
Intrinsic factors, environmental factors, and social factors can concur in the chorus performance.
Among the several hypotheses to explain this phenomenon, the acoustic transmission hypothesis has received much credit. This hypothesis claims a more favorable condition of acoustic transmission at dawn and at dusk for a quieter atmosphere and the lowest background noise. Reduced foraging efficiency at dawn and at dusk and an excess of food storage the day before are further good arguments.
In amphibians choruses are very common, energetically costly, and occur especially during the short reproductive period. In frogs, a cooperative hypothesis according to which a chorus produces benefits in the entire population is opposed to a competitive hypothesis in which a leading caller is preferred in sexual selection.
In birds there is considerable evidence that choruses can be explained by at least two major hypotheses: an energetic hypothesis and a behavioral hypothesis. According to the first hypothesis, the choruses are performed in coincidence with a food surplus or fat reserves. The second hypothesis considers the choruses as an interactive communication between concurrent males that seem a reaction to the previous day’s vocal interactions between males.
Soil is a medium rich in acoustic information. Most of the sounds present in the soil are originated by stridulating animals or are the result of the digging activity of fossorial organisms. Acoustic information from the soil is an important tool for monitoring soil biodiversity in a nondestructive way.
In some reptiles, vibrations produced by prey are used for hunting. Vegetation vibration has been proved to orient fossorial moles toward vegetation clumps rich in insect food. Soil percussion is also a common mechanism used by elephants to communicate at a great distance.
In insects and arthropods, vibrations are used extensively to communicate or to escape predators. Well documented is the case of Diplocardia mississippiensis, an earthworm that emerges from the soil after a vibration is produced in the soil using a “grunting device.” This behavior is explained as a strategy utilized by worms to escape mole hunting.
It is disputed if ants have hearing systems or body vibrational sensing, but their capacity to react to soil vibration is surprisingly rapid. Substrate-borne vibrations are extensively used by animals to locate mates, prey, and predators, as in the well-documented case of antlion larvae.
Despite the scarcity of studies, soil monitoring appears a promising field of research.
Sound is a complex phenomenon that copies the environmental characteristics of the context in which is generated. For this reason, many descriptors are required to approach the behavior of sound and its effects on physical and biological objects. Frequency, pitch, period, wavelength, sound speed, wavenumber, amplitude, sound pressure, sound power, sound intensity, and loudness are some of the distinctive parameters used to describe a sound.
A sound pressure measurement and a spectral-frequency analysis are the two distinct approaches adopted today to collect information on the sonic environment.
Field recording now offers a great variety of recording devices that can sample at different rates and in different types of digital memories. Single microphones, sets of adjacent microphones, and regular arrays of microphones are some possibilities for collecting sound data from the environment.
Spectral analysis, which is central in bioacoustics research, offers some metrics to evaluate the complexity of the sonic environment: acoustic entropy index, median of amplitude envelope, acoustic richness, acoustic dissimilarity index, acoustic complexity index. These metrics capture the emerging patterns of a sonic environment and allow characterizing the soundscape in delimited areas of interest.
The popularity of automated digital field recording devices allows storing a great amount of data that urgently requires an easy browsing approach to consolidate sound computing.
Soundscape ecology finds several important applications in the field of valuing and assessment of natural and protected areas and of urban spaces as well.
Noise intrusion appears a growing threat to the maintenance of a high level of biological and ecological complexity. In particular, noise of anthropogenic origin masks or degrades the acoustic signals between individuals and species. Habitat loss and isolation, land use transformation, chemical pollution, hunting activity, and tourism intrusion are concurrent factors responsible for dramatic modification of the sonic environment.
Acoustic communication is the most powerful semiotic process with which organisms exchange information. Every phenomenon that reduces acoustic communication can have severe consequences on the survival of many vocal species.
Acoustics coupled with other data can produce a very efficient tool to try to respond to questions pertaining to the effects of global warming, the changes in land use, and the effect of agriculture practices on natural systems or on pest spread.
Long-term monitoring of the sonic environment appears a new and promising approach to understand the dynamics of natural and human-modified systems and represents an important tool to create efficient practices to protect and preserve valuable areas.
... Introduction 1 1 Introduction 2 Segregation of niche space by sympatric species in order to reduce competition is a fundamental 3 concept in ecology [22]. An ecological niche can generally be thought of as a hypervolume in In that sense, "acoustic space" -just like more traditional ecological factors -represents a scarce 11 resource that organisms compete for [17,18,21,32], especially in crowded, dark habitats with dense 12 vegetation, wherein optical cues become less reliable. If the acoustic partitioning hypothesis were 13 true, we would expect to see a nonrandom segregation of signal frequency (and/or other signal 14 properties such as trill rate) among co-occurring species. ...
... Such segregation could manifest itself as an 15 effective repulsive force between signal frequencies of neighboring neighbouring species, resulting in 16 a distribution of signal spacings that is more even than would be expected under the null hypothesis. 17 Results of published studies have been mixed, [13,24,[33][34][35]38], perhaps in part due to the 18 existence of alternative strategies for alleviating acoustic interference, such as temporal avoidance 19 (on short or long scales), spatial avoidance (horizontally or vertically), or tuning recognition space [9]. 20 Attempts to detect acoustic partitioning can also be undermined by study design choices [38], such as 21 relatively small sample sizes (< 30 species), using microphones with a low signal-to-noise ratio [15,16], 22 or sampling on an excessively large spatial scale. ...
... Additionally, we argue that physiological and 23 ecological constraints play an important role and must be accounted for when investigating the 24 acoustic niche hypothesis. In particular, vocalization frequency scales with body mass [17,19,32], 25 which induces a bias in the distribution of vocalization frequencies, an effect largely ignored in 26 the literature. For instance, a meta-analysis study on frog communities failed to account for this 27 bias, generating data under the null hypothesis by sampling uniformly between the minimum and 28 maximum frequencies of each dataset [13]. ...
The acoustic niche hypothesis suggests that vocal signals of sympatric animal species are structured so as to minimize acoustic interference and facilitate communication. Accordingly, each species attempts to establish its own acoustic bandwidth so that intra-species signals are not masked. Detecting a non-random partitioning of the frequency spectrum among sympatric species could constitute evidence for the existence of acoustic avoidance behaviour. However, results from previous studies have been mixed or inconclusive, possibly as a consequence of overlooking the importance of physiological and ecological constraints. Here we introduce an improved test that incorporates prior information on body mass to account for the allometric correlation between mass (size) and vocalization frequency. By correcting for the bias induced by this correlation, the new test uncovers evidence of acoustic niche partitioning as a function of frequency in several tropical bird communities that would not be detected under a more standard test. Separately, we introduce a spatial version of the acoustic partitioning test which, in theory, could prove effective when data are collected from multiple sites located in close spatial proximity.
... The soundscape is all the sounds existing in our environment and is composed of three types of sounds produced by three different sources: Anthropogenic, Biological and geophysical (Krause, 2008;Farina, 2014). For instance, sounds produced by anthropogenic sources, such as cars, airplanes, and factories, are called anthropophony (McGregor et al., 2013). ...
... Our results are consistent with observations that a lower level of anthropogenic noise intensity is favorable for population survival (Farina, 2014;Pijanowski et al., 2011a;Slabbekoorn et al., 2018;Kunc et al., 2016;Kight and Swaddle, 2011;De Vincenzi et al., 2021;Goldbogen et al., 2013;Hildebrand, 2009). Likewise, although the Lombard effect is known to be beneficial in that important acoustic signals are not masked by noise, when noise exceeds the permissible limit, a limit up to which noise has no effect on the population, observations indicate that the use of higher intensity acoustic signals increases energetic, behavioral, and predation costs, which could result in lower ecological fitness, influencing animal survival rates in noisy environments (Brackenbury, 1979;Calder III, 1990;Oberweger and Goller, 2001;Warren et al., 2006;Barber et al., 2010;Read et al., 2014;Brown et al., 2021;Swaddle et al., 2015;Farina and Gage, 2017;Zollinger and Brumm, 2015;Brumm and Todt, 2002;Brumm, 2004;Luczkovich et al., 2016;Sementili-Cardoso and Donatelli, 2021). ...
Noise is a form of pollution resulting from the undeniable increase in industrialization worldwide. Consequently, it is becoming increasingly important to understand the underlying mechanisms and potential effects of noise on ecosystems. In this study, we propose a deterministic mathematical model that uses a system of nonlinear, non-autonomous differential equations to describe the population dynamics of a single species exposed to noise. The Lombard effect is a phenomenon that involves increasing the intensity of acoustic signals in response to noise, which can mask and degrade acoustic signals and prevent them from being recognized or discriminated by their target receivers. However, when the anthropogenic noise is chronic and critical (i.e., that by its long duration and high intensity positively affects the mortality rate), the increase in the intensity of acoustic signals (due to the Lombard effect) only increases the chronic critical anthropogenic noise and also increase energetic, behavioral and predation costs. Therefore, the critical noise generated by the use of higher intensity acoustic signals (due to the Lombard effect) together with the chronic critical anthropogenic noise, negatively affect population survival. We analyzed the persistence of the population and found that our results are consistent with the observed ecological data as they suggest that, the maximum intensity level of critical chronic anthropogenic noise, consequently, by the Lombard effect, the maximum intensity of self generated acoustic signals, must decrease to ensure population persistence. However, when the maximum intensity level of critical chronic anthropogenic noise is uncontrollable, it is sufficient to reduce its mean intensity level to ensure persistence in the population mean. Furthermore, decreasing the degree to which noise affects the population favors the survival of the species. Finally, to validate our results, we performed numerical simulations.
... Propusieron la distinción tipológica de las fuentes de sonido (geofonías, biofonías y antropofonías) (Pijanowski et al., 2011;Truax & Barret, 2011). Asimismo, realizaron aportaciones al procedimiento metodológico, tales como las hipótesis de adaptación morfológica, de adaptación acústica, del nicho acústico y del reconocimiento de especies (Pijanowski et al., 2011;Farina, 2014). ...
... FIGURA 2. Esquema tipológico de las fuentes de sonido de acuerdo con Pijanowski y colaboradores (2011) y patrones espaciales en la ecología del paisaje sonoro de acuerdo con Farina (2014) FUENTE: elaboración propia. ...
En este trabajo realizamos un análisis descriptivo del desarrollo histórico conceptual del paisaje sonoro. El objetivo es identificar la manera en que se ha construido un campo de estudio alrededor de dicha propuesta. Se desarrolló una búsqueda selectiva de literatura que tuvo como punto de partida textos clave de Murray Schafer y del World Soundscape Project, a partir de los cuales se rastreó su influencia en distintas partes del mundo. Se identificó un periodo de expansión durante la década de 1980, en el cual se conformaron sus dos enfoques principales: el ecológico y el perceptual-cultural. Así mismo, se hizo énfasis en la manera en que fue abordado dicho término desde enfoques culturalistas en geografía y se identificó que a partir de las discusiones hechas surgieron como propuesta las geografías auditivas y del sonido. Finalmente, se realizó una revisión sistemática en índices y buscadores de literatura académica y se encontró un interés latente, durante los últimos tres lustros, por incorporar el sonido como objetivo de estudio a partir de alguna de las posturas mencionadas (paisaje sonoro, geografías auditivas y geografías del sonido), sin embargo, es un tema que continúa en proceso de consolidación.
... Increasing traffic noise and sounds from wind reduce the acoustic space available for animal communication. This may force animals to change song characteristics, temporal singing patterns, vigilance, feeding behaviour, or in some cases to abandon the habitat (Derryberry et al., 2020;Evans et al., 2019;Farina, 2014;Francis, 2015;Ghadiri Khanaposhtani et al., 2019;Le et al., 2019;Slabbekoorn et al., 2018;Ware et al., 2015). Hence, land-use intensity and landscape structure could indirectly and directly affect the local soundscape. ...
... We showed that changes in local land-use and landscape structure influence the composition and dynamics of acoustic communities on different temporal scales, a finding that has been predicted by ecoacoustic models (Farina, 2014;Farina and James, 2016;Krause and Farina, 2016;Krause, 1987). Orthopteran species richness, orthopteran composition and bird composition were important drivers for acoustic composition. ...
Understanding drivers and monitoring changes of biodiversity forms the basis for evidence-based management and policy recommendations that aim to reduce biodiversity loss and to ensure the delivery of ecosystem services on which we rely. Ecoacoustic monitoring can be applied across large spatial and temporal scales, offering the potential for less resource-intensive ecosystem monitoring. Indices of acoustic diversity have been shown to correlate with species richness of various taxa, as well as vegetation and landscape structure. In order to apply ecoacoustic monitoring at large scales we need to improve our understanding of the effects of local and regional land-use on acoustic patterns, and assess how temporal aspects of acoustic patterns can be integrated in these analyses. We hypothesized that land-use intensity and landscape structure affect species richness and composition of birds and orthopteran, and therefore indirectly affect acoustic diversity and composition. To test this, we set up autonomous recording systems in grassland plots along land-use intensity gradients in three regions in Germany. We applied structural equation modelling to analyze the direct and indirect drivers of acoustic diversity and composition, including mowing and grazing intensities, landscape diversity, distance to the nearest road, vascular plant species richness as well as bird and orthopteran species richness and composition. Single indices of acoustic diversity did not reflect changes in bird or orthopteran species richness, making them poor predictors for local land-use related changes in species richness in grassland plots. Acoustic composition (non-metric multidimensional scaling combination of mean monthly acoustic indices at different day phases), however, did relate to differences in landscape structure, land-use intensity, vocalizing species composition and orthopteran species richness. We propose the developed acoustic composition metric as suitable proxy to detect ecosystem changes in grasslands.
... More categories of labels can increase training difficulty because categories become similar, making it difficult for the algorithm to discriminate between them. Additionally, biophony is now classified according to their soundtope (Farina, 2014). Soundtopes are the collective sounds produced by biophony at the same time. ...
... Potential explanations include that SERF has a more complex soundscape, or more likely that the increase may be attributed to the lack of wind at SERF relative to Bowra, resulting in more minutes with signal and less noise. Although soundscapes are known to vary between different environments, major soundtopes (Farina, 2014) were still expected to be found in both ecosystems (e.g., dawn and dusk choruses). Daily cycles were evident across the month at SERF, although variation could still be detected. ...
High rates of biodiversity loss caused by human-induced changes in the environment require new methods for large scale fauna monitoring and data analysis. While ecoacoustic monitoring is increasingly being used and shows promise, analysis and interpretation of the big data produced remains a challenge. Computer-generated acoustic indices potentially provide a biologically meaningful summary of sound, however, temporal autocorrelation, difficulties in statistical analysis of multi-index data and lack of consistency or transferability in different terrestrial environments have hindered the application of those indices in different contexts. To address these issues we investigate the use of time-series motif discovery and random forest classification of multi-indices through two case studies. We use a semi-automated workflow combining time-series motif discovery and random forest classification of multi-index (acoustic complexity, temporal entropy, and events per second) data to categorize sounds in unfiltered recordings according to the main source of sound present (birds, insects, geophony). Our approach showed more than 70% accuracy in label assignment in both datasets. The categories assigned were broad, but we believe this is a great improvement on traditional single index analysis of environmental recordings as we can now give ecological meaning to recordings in a semi-automated way that does not require expert knowledge and manual validation is only necessary for a small subset of the data. Furthermore, temporal autocorrelation, which is largely ignored by researchers, has been effectively eliminated through the time-series motif discovery technique applied here for the first time to ecoacoustic data. We expect that our approach will greatly assist researchers in the future as it will allow large datasets to be rapidly processed and labeled, enabling the screening of recordings for undesired sounds, such as wind, or target biophony (insects and birds) for biodiversity monitoring or bioacoustics research.
... Sometimes, these sounds are subjectively deemed noise by a listener [25]. Biophony includes the sounds produced by non-human living organisms such as insects, amphibians, frogs, birds, and other animals [36][37][38] and geophony is related to weather changes and climatic conditions such as waves, earthquakes, lightning, rain, and wind [39]. The phonic identity is considered a significant part of urban areas [11] that depends on the characteristics of the sonic environment furnishing, material, space, and shape. ...
The goals of a good soundscape are to create a sense of place, provide comfort to the users, and encourage intractability in a public space. At the same time, many public areas in cities are having problems due to the weakness in creating the opportunity for people to attend. Therefore, knowing the importance of the subject, this study has measured the aspects of the sonic environment and investigated its effect on the attendance of 15 Khordad Street, District 12, Tehran. The results of this study showed that attendance in urban spaces based on the aspects of the sonic environment focuses on the quality of the surrounding environment as a source of sound. By assessing the perceptual and sensory aspects of sounds in the environment, it is possible to understand the effects of sound on the behaviors, activities, and overall pleasantness of the space for the users. Based on the three statistical communities related to the study, among the key findings, we show that the majority of attendance to the case area was for the purpose of studying, shopping, and work, and despite the fact that this case study is a historic area, people are less willing to attend it. This street, part of which is designed as a pedestrian area, encourages individualism, and not bringing friends and family along is reinforced by unpleasant psychological effects. Since nowadays the problems of the sonic environment are expanding in cities, and noise pollution in some parts of Tehran is considered a major environmental problem, the findings of this study have taken a step to increase urban sustainability and try to improve the main criteria and results, which were to rationally evaluate the existing situation of attendance in urban spaces affected by the qualities of the sonic environment, to promote the policy and strategic city planning for city managers.
... The main principles of soundscape are common to the principle of landscape with natural and human systems cooperating to form spatial-temporal modelling of sound in landscapes, as figure 1 shows the conceptual framework of soundscape , how the landscape structure provided by the human influences the distribution of the surrounding elements by many motion patterns as wind and water (arrow 1-2), how the climate influences the geophonic and the antrophony sounds (arrow 3), and how the sounds produced by the human activities (anthrophony) and the natural components of geophony and biophony integrate together to create the soundscape patterns (arrow [4][5]. What happens in soundscape can come back to natural processes (arrow 6); and soundscapes can effect human well-being (arrow 7). ...
The auditory perception of urban spaces has the same effect of the visual perception as it enhances the people‟s subjective impression of space but unfortunately, most of the designers neglect the auditory perception of urban spaces. In this paper, we will study Mansoura zoological historical garden; the second old zoological garden in Egypt after the famous Giza zoological garden. Although the park has a great historical value, it has been abandoned by the public owing to neglect, lack of maintenance and lack of attractive elements which the park suffers from. In this research, we aim at using soundscape as a tool to restore and revive Mansoura zoological historical garden by gathering data through field observations, questionnaire surveys and acoustic measurement, then determine the focal points to analysis and develop according to the main principles of soundscape; the biophony “animals‟ sound”, the geophony “wind and rain sound” and the anthrophony “the human sound”. The changes which will be made in the design are; landscape elements will be altered and new sound sources will be added. All these factors will be studied and analyzed in relation to the soundscape. At the end of this paper, we could reach a development proposal and its theoretical analysis.
... The sound components of the landscape (such as noise and species richness) are directly related to landscape elements (topography, vegetation patterns, animal distribution). They are involved in sound production and dissemination [8] . Bird activity in the Prambanan Temple tourist park is supported by a river providing resources for fish-eating specialist birds. ...
Sleman Regency has the most temple cultural heritage in Yogyakarta, supported by Green Open Space (GOS). The area is a habitat for urban birds and can be used as an indicator of environmental quality. This study aims to analyze the environmental quality based on the soundscape and character of the bird community in the GOS of Prambanan Temple and Ratu Boko Temple. Sound recordings were taken with a smartphone, and the recording time was set using the Arbimon touch in the morning, afternoon, and evening. The sound recordings are used to calculate acoustic indexes. The sound recordings and spectrograms are processed to identify bird species and calculate the Bird Community Index. The number of bird species was higher in the Ratu Boko area. According to the NDSI value, the sound of biophony at Ratu Boko Temple is more dominant than anthrophony and geophony. The environmental quality in the Prambanan Temple area is in the low category than in the Ratu Boko Temple area, which is classified as a medium category. The area's topography, the arrangement of vegetation, and the noise of vehicles due to the proximity to the highway affect the environment quality in temple areas.
... This was similar to previous studies conducted in urban green areas [48,49]. We also found that LAeq and L10 displayed overlapping intervals, since there were fewer sources of mechanical noise in urban forests and animals did not need to raise their volume to communicate [50]. As our observation sites were in areas with some tourist activity, the maximum LAeq was higher ...
Natural soundscape is considered a dominant type of hearing in forested areas and contributes to health and recovery effects from exposure to the biophilic outdoor environment. This study focuses on the different forest structures, and aims to explore the relationship between perceived soundscape and acoustical parameters, observe physiological indicators, and model the physiological restorative role of soundscape. Questionnaires and measuring equipment were used to gather psychophysical and physiological information at 20 observation sites in urban forested areas. Back-propagation neural network techniques were conducted to determine the forecasting model from psychophysical to physiological parameters. Our results suggested that LAeq and L10 are important factors that influence questionnaire responses. Our findings also showed that electromyogram (EMG) signals were the most obvious and sensitive in physiological parameters. Additionally, we found that L10–90 played the most important role among all physical parameters in the physiological restorativeness soundscape model. This can facilitate the understanding of the physiological restorative role of soundscape in different forest structures when proposing suitable forest-based health care strategies.
... By definition, communication is a process between a signaler and a receiver in which information in the form of temporally modulated energy is transmitted between the two sides. 27 At the level of whole organisms, vibration and chemicals are assumed to be the oldest modes of communication and both probably evolved from the original cell−cell mechanical and chemical interactions within early metazoans. 28 Even small microorganisms vibrate in response to their metabolic activity and nanoscale vibrations is a signature of life. ...
The extracellular matrix (ECM) is a fibrous network supporting biological cells and provides them a medium for interaction. Cells modify the ECM by applying traction forces, and these forces can propagate to long ranges and establish a mechanism of mechanical communication between neighboring cells. Previous studies have mainly focused on analysis of static force transmission across the ECM. In this study, we explore the plausibility of dynamic mechanical interaction, expressed as vibrations or abrupt fluctuations, giving rise to elastic waves propagating along ECM fibers. We use a numerical mass-spring model to simulate the longitudinal and transversal waves propagating along a single ECM fiber and across a 2D random fiber network. The elastic waves are induced by an active contracting cell (signaler) and received by a passive neighboring cell (receiver). We show that dynamic wave propagation may amplify the signal at the receiver end and support up to an order of magnitude stronger mechanical cues and longer-ranged communication relative to static transmission. Also, we report an optimal impulse duration corresponding to the most effective transmission, as well as extreme fast impulses, in which the waves are encaged around the active cell and do not reach the neighboring cell, possibly due to the Anderson localization effect. Finally, we also demonstrate that extracellular fluid viscosity reduces, but still allows, dynamic propagation along embedded ECM fibers. Our results motivate future biological experiments in mechanobiology to investigate, on the one hand, the mechanosensitivity of cells to dynamic forces traveling and guided by the ECM and, on the other hand, the impact of ECM architecture and remodeling on dynamic force transmission and its spectral filtering, dispersion, and decay.
... Furthermore, soundscapes have been classified as geophonic sounds (relating to naturally occurring non-biological sources, e.g. wind and water sounds), antrophonic sounds (referring to all humanly produced sounds including mechanical sounds) and biophonic sounds (produced by animals) (Krause, 2008;Farina, 2013;Devos, 2016). ...
Eighty percent of our cities outdoor public spaces are streets. Apart from the infrastructural function, urban streets are a place for social interactions – a place for a daily talk or a coffee break. Based on the example of Berlin's Maaßenstraße – a novel street model based on the shared space idea – this thesis sets out to discover the potential of specific urban design on urban soundscapes and to improve understanding of the relationship between activity and sound perception. The lack of knowledge on the actual use of urban design tools for soundscape issues resulted in the development of a methodology that combined activity maps and soundscape assessment. The results showed that the number of people who are sitting in cafes, contribute a positive influence on the perception of human sounds. Furthermore, the quantitative and the qualitative analyses of the assessment of the soundscape showed that human sounds decrease the perception of loudness, and increase acoustic quality. Considering human sounds as a consequence of activity a framework is proposed which links activity to the physical setting and built environment. To point out the practical use of the framework, the arrangement of some (non-acoustic) elements are proposed to improve the sonic quality of the street. The proposed framework can be used as a tool for urban planners to design future urban spaces with an adequate sound environment and consequently improve public health.
... The soundscape is an acoustic composition resulting from a combination of natural and/or urban sounds, 1,2 where its creation is mainly based on a mixture of different sounds, such as biophony, geophony, and anthrophony. [3][4][5][6] It is considered a relatively complex and multidisciplinary approach for the evaluation of the sound environments of architectural and urban spaces. 7 In urban environments, soundscape represents an important environmental reference for the quality of life of city inhabitants, 8 that can preserve their health, 9 and their well-being. ...
This paper aimed to examine the impact of the COVID-19 lockdown in Algeria on the soundscapes’ components throughout the cafe terraces in coastal cities. The methodology is based on a laboratory qualitative approach established and divided into two stages. And the monitoring of sound recordings through twenty-one cafe terraces inside the coastal city of Azzaba in Algeria was conducted before and after the lockdown of whole the country due to the COVID-19 pandemic. Using the McNemar’s test on the first stage, results suggest that the lockdown measures in Algeria affect the soundscape components of the cafe terraces, specifically the predominance of the anthrophonical sounds over the natural sound components. The predominance of traffic sounds on the soundscapes after the lockdown period does not reflect an increase in noise level, whereas the soundscapes through the cafe terraces during the two periods were similar, and showed as less noisy by the semantic difference analysis evaluation, of the second stage. The factors of the principal component analysis suggest that the soundscapes of the cafe terraces reflect the main patterns of the acoustics design in the public spaces, such as functions (relaxation and communication), space-time for the two factors of the soundscapes of the period before the lockdown, and by relaxation, space and time for the three factors of those of the period after lockdown. Otherwise, the Marginal Homogeneity Test shows that there are significant differences in the assessment of the soundscapes of the cafe terraces during the two periods, which were only associated to the functions. Findings suggest that additional long-term research is needed to preserve and improve the cultural soundscapes among the urban spaces to ensure the acoustic comfort of the occupants and preserve their health.
... Although soniferous species produce sounds ranging from infrasound to ultrasound, we recommend constraining the upperfrequency limit to 22,050 Hz, which is approximately the maximal frequency audible to humans (Farina, 2013). Most wildlife sounds can be found in this frequency range (Farina & James, 2016), so the evolutionary mechanisms structuring acoustic assemblages are likely strongest in this range. ...
Soundscape studies are increasingly used to capture landscape‐scale ecological patterns. Yet, several aspects of soundscape diversity remain unexplored. Although some processes influencing acoustic niche usage may operate in the 24‐hour temporal domain, most acoustic indices only capture the diversity of sounds co‐occurring in sound files at a specific time of day. Moreover, many indices do not consider the relationship between the spectral and temporal traits of sounds simultaneously. To provide novel insights into landscape‐scale patterns of acoustic niche usage at broader temporal scales, we present a workflow to quantify soundscape diversity through the lens of trait‐based ecology. Our workflow quantifies the diversity of sound in the 24‐hour acoustic trait space. We introduce the Operational Sound Unit (OSU), a unit of diversity measurement that groups sounds by their shared acoustic properties. Using OSUs and building on the framework of Hill numbers, we propose three metrics that capture different aspects of acoustic trait space usage: (i) soundscape richness; (ii) soundscape diversity; and (iii) soundscape evenness. We demonstrate the use of these metrics by (a) simulating soundscapes to assess if the indices possess a set of desirable behaviours; and (b) quantifying soundscape richness and evenness along a gradient in species richness. We demonstrate that (a) the indices outlined herein have desirable behaviours; and (b) the soundscape richness and evenness are positively correlated with the richness of sound‐producing species. This suggests that more acoustic niche space is occupied when the species richness is higher. Additionally, species‐poor acoustic communities have a higher proportion of rare sounds and use the acoustic space less evenly. Our workflow generates novel insights into acoustic niche usage at a landscape scale and provides a useful tool for biodiversity monitoring. Moreover, Hill numbers can also be used to measure the taxonomic, functional, and phylogenetic diversity. Using a common framework for diversity measurement gives metrics a common behaviour, interpretation, and standardised unit, thus ensuring comparisons between soundscape diversity and other metrics represent real‐world ecological patterns rather than mathematical artefacts stemming from different formulae.
... PAM was even combined with color perception for representation of urban soundscape quality [11]. With the help of PAM, there is growing interest in soundscape ecology: a recently developed research field that focuses on the study of the temporal and spatial distribution of sound through a landscape, reflecting important ecosystem processes and human activities [12][13][14][15]; soundscape changes can affect animal population and community status [16]. Soundscape ecology uses the acoustic index, a statistic metric summarizing some aspects of the distribution of acoustic energy and information in a recording [17], to rapidly quantify the typical complexity of the biotic songs of a soundscape despite the presence of various noise [18]. ...
Passive acoustic sensor-based soundscape analysis has become an increasingly important ecological method for evaluation of ecosystem conditions using acoustic indices. Understanding the soundscape composition and correlations between acoustic indices and species richness of birds, the most important sound source in the ecosystem, are of great importance for measuring biodiversity and the level of anthropogenic disturbance. In this study, based on yearlong sound data obtained from five acoustic sensors deployed in Dalongtan, Shennongjia National Park, we analyzed the soundscape composition by comparing the distributions of the soundscape power in different frequency ranges, and examined the correlations between acoustic indices and bird species richness by means of the Spearman rank correlation coefficient method. The diurnal dynamic characteristics of acoustic indices in different seasons were also described. Results showed that the majority of sounds were in the frequency of 2-8 kHz, in which over 50% sounds were in 2-6 kHz, commonly considered the bioacoustic frequency range. The Acoustics Complexity Index, Bioacoustic Index, and Normalized Difference Soundscape Index were significantly correlated with bird species richness, suggesting that these indices can be used for evaluation of bird species richness; Apparent diurnal dynamic patterns of bird acoustic activities were observed in spring, summer, and autumn; however, the intensity and duration of bird acoustic activities in summer is larger/longer than in spring and autumn.
... Soundscape ecology is an area of research that bridges several disciplines: acoustics, animal behaviour and landscape ecology (Pijanowski et al., 2011;Farina, 2014). Soundscapes are characterized by three different sources of sound -biological ones such as bird song (biophony), abiotic ones such as wind or running water (geophony) and human ones such as traffic (anthrophony) (Fig. 11.2). ...
In this chapter, I introduce experiments in landscapes that are somewhat “novel”. Research in riverscapes, seascapes and soundscapes requires different tools and techniques than what researchers working in terrestrial landscapes use. I illustrate how landscape ecologists can learn from collaborations with marine biologists, aquatic, behavioural and acoustic ecologists to develop experimental approaches that address questions about space use in these novel environments. Some experimental approaches, such as those focused on patch pattern on the seafloor, are very similar to terrestrial experiments. Others, like measuring connectivity in a dendritic riverscape, require entirely new approaches. I close the chapter with a discussion of two other novel landscapes. Micro-landscapes are artificially constructed landscapes, which share similarities with mesocosms and microcosms but occur in a controlled lab setting. Finally, I show how medical researchers have realized insights by applying a landscape ecology lens to our own bodies, and I suggest that considering experiments on cells and tissues may offer new opportunities for our discipline.
... To avoid these costs, we expect that animals should employ strategies that reduce acoustic competition 5-7 . This idea has been formalised in the acoustic niche hypothesis, in which acoustic space can be viewed as a niche axis that can be partitioned to avoid negative impacts of co-occurring signals 8,9 . However, clear support that acoustic niche paritioning occurs in nature remains elusive. ...
The acoustic niche hypothesis proposes that to avoid interference with breeding signals, vocal species should evolve to partition acoustic space, minimising similarity with co-occurring signals. Tests of the acoustic niche hypothesis are typically conducted using a single assemblage, with mixed outcomes, but if the process is evolutionarily important, a pattern of reduced acoustic competition should emerge, on average, over many communities. Using a continental-scale dataset derived from audio recordings collected by citizen scientists, we show that frogs do partition acoustic space. Differences in calls were predominately caused by differences in spectral, rather than temporal, features. Specifically, the 90% frequency bandwidths of observed frog assemblages overlapped less than expected, and there was greater distance between dominant frequencies than expected. To our knowledge, this study is the first to use null models to test for acoustic niche partitioning over a large geographic scale.
... If we understand acoustic indices as an integrative measure of biodiversity that reflects the soundscape composition and particularly the acoustic communities as a whole in response to human activity and ecological gradients (Pijanowski et al., 2011;Farina, 2014;Farina and Gage, 2017) we also have to understand that a single acoustic index will rarely correspond only to a single vocalizing animal group (Retamosa Izaguirre et al., 2021). This is probably especially true in the tropics as different vocalizing animal groups often vocalize at the same time (Eldridge et al., 2018) and could explain why in our study the temporal patterns of the chosen acoustic indices did not match the patterns of a single vocalizing animal group perfectly well. ...
In this ecoacoustic study we used the setting of a tropical tree diversity planted forest to analyze temporal patterns in the composition of soundscapes and to test the effects of tree species richness on associated biodiversity measured as acoustic diversity. The analysis of soundscapes offers easy, rapid and sustainable methods when assessing biodiversity. During the last years the quantification of regional or global acoustic variability in sounds and the analysis of different soundscapes has been evolving into an important tool for biodiversity conservation, especially since case studies confirmed a relationship between land-use management, forest structure and acoustic diversity. Here we analyzed soundscapes from two seasons (dry and rainy season) and aurally inspected a subset of audio recordings to describe temporal patterns in soundscape composition. Several acoustic indices were calculated and we performed a correlation analysis and a non-metric multidimensional scaling analysis to identify acoustic indices that: (i) were complementary to each other and such represented different aspects of the local soundscapes and (ii) related most strongly to differences in acoustic composition among tree species richness, season and day phase. Thus, we chose “High Frequency Cover,” “Bioacoustic Index,” and “Events Per Second” to test the hypothesis that acoustic diversity increases with increasing tree species richness. Monocultures differed significantly from polycultures during night recordings, with respect to High Frequency Cover. This index covers sounds above 8 kHz and thus represents part of the orthopteran community. We conclude that increasing tree species richness in a young tropical forest plantation had positive effects on the vocalizing communities. The strongest effects were found for acoustic activity of the orthopteran community. In contrast to birds, orthopterans have smaller home ranges, and are therefore important indicator species for small scale environmental conditions.
... Much like what was observed of coastal soundscapes in British Columbia, Canada (Ritts et al., 2016), lowfrequency geophony presented the most dominant acoustic component in the overall coastal EW soundscape in Aialik Bay. However, soundscape power was not homogenous between sample sites suggesting the presence of distinct sonotopes (Farina, 2014). ...
I recorded the ambient sounds at three locations in the wilderness of Aialik Bay in Kenai Fjords National Park, Alaska between 25 June and 21 September 2019. My aim was to capture an ecoacoustic snapshot of the coastal soundscape to provide a comparable baseline for evaluating wilderness characteristics defined by the Wilderness Act of 1964. I visually and empirically characterized the Aialik Bay wilderness soundscape using the acoustic metrics of soundscape power (normalized watts/kHz) and Normalized Difference Soundscape Index (NDSI) from 5373 five-minute recordings, combined with visual and aural spectral examination of 4386 recordings. Soundscape power exhibited similar patterns across frequency intervals with sound sources primarily occurring in the low-frequency (1–2 kHz) and mid-frequency (2–5 kHz) intervals. Significant differences within frequency intervals between sites suggested the presence of distinct sonotopes. Low-frequency sounds were dominant across all three sites with peak soundscape power values across study days and 24 h timeframes attributed to wind and occasional periods of technophony emitted from commercial tour boats and private boating activities. Low-frequency geophony from wave action was ever present. Technophony exhibited some predictable patterns consistent with the timing of sightseeing boat tours. Peak values of soundscape power at mid-frequencies were attributed to the geophony of rain. Although biophonies were less common than geophonies, the choruses of songbirds were prevalent in July and promptly occurred daily between 0300 and 0600. Biophonies generally declined over the course of the day. All sites displayed negative NDSI values over most study days and consistently negative values over 24 h time frames, indicating a soundscape primarily influenced by low-frequency geophony and periods of technophony. However, NDSI values showed patterns and peaks similar to biophonies at mid-frequency intervals indicating biophony was still a notable contribution to this geophony-dominant soundscape. Despite the acoustic footprint of motorboat noise detected at all sample sites, the soundscape of the Aialik Bay wilderness was dominated by the natural sounds of geophony, biophony, and occasional periods of natural quiet indicative of a wilderness only partially impacted by technophony.
... Long-distance avoidance of meteorological events by birds might also be explained by their ability to detect, and respond navigationally, to infrasound (e.g., Streby et al., 2015). While soundscape ecology has become a well-established field (Farina, 2014), the idea of infrasound use for navigation remains controversial (e.g., Wallraff, 2014;Lisovski et al., 2018), as little is known about infrasound detection mechanisms in birds (Zeyl et al., 2020), and what information infrasound would provide as a navigational cue. ...
Seabirds are amongst the most mobile of all animal species and spend large amounts of their lives at sea. They cross vast areas of ocean that appear superficially featureless, and our understanding of the mechanisms that they use for navigation remains incomplete, especially in terms of available cues. In particular, several large-scale navigational tasks, such as homing across thousands of kilometers to breeding sites, are not fully explained by visual, olfactory or magnetic stimuli. Low-frequency inaudible sound, i.e., infrasound, is ubiquitous in the marine environment. The spatio-temporal consistency of some components of the infrasonic wavefield, and the sensitivity of certain bird species to infrasonic stimuli, suggests that infrasound may provide additional cues for seabirds to navigate, but this remains untested. Here, we propose a framework to explore the importance of infrasound for navigation. We present key concepts regarding the physics of infrasound and review the physiological mechanisms through which infrasound may be detected and used. Next, we propose three hypotheses detailing how seabirds could use information provided by different infrasound sources for navigation as an acoustic beacon, landmark, or gradient. Finally, we reflect on strengths and limitations of our proposed hypotheses, and discuss several directions for future work. In particular, we suggest that hypotheses may be best tested by combining conceptual models of navigation with empirical data on seabird movements and in-situ infrasound measurements.
... En manglares y estuarios, las geofonías como el viento, la lluvia y el oleaje, constituyen una fuente acústica con intensidades variables que dependen de las condiciones del cuerpo de agua (Wenz, 1962;Hildebrand, 2009 antropofonías (Hildebrand, 2009) que posiblemente enmascaran las biofonías, causando efectos negativos en la comunicación de los organismos (Parris & Schneider 2008;Barber et al. 2010;Farina, 2014). ...
En los ecosistemas costeros, las geofonías forman parte fundamental del entorno acústico y el impacto del oleaje sobre su geomorfología es un ejemplo de ello. Se colocó una grabadora Audiomoth en cuatro sitios de Punta Morales, Puntarenas, Costa Rica, del 22 de noviembre al 18 de diciembre, 2020. Se programaron para registrar 60 segundos cada 10 minutos durante 24 horas con el objetivo de caracterizar el paisaje acústico asociado al ciclo de mareas de la localidad. De las grabaciones obtenidas, se analizaron: el Índice de Diferencia Normalizada del Paisaje Sonoro (NDSI), las Tecnofonías, la Entropía Acústica (TE) y el Nivel de Presión Sonora (SPL). Estos valores se contrastaron entre sitios mediante un análisis de medias recortadas unidireccionales; se realizó una correlación entre el SPL y el nivel de marea en cada lugar y, por último, se compararon los valores en un mismo punto de muestreo entre pleamar y bajamar. Se encontraron diferencias en todas las comparaciones realizadas; además, en dos sitios se identificó una correlación positiva y se observaron diferencias de SPL entre pleamar y bajamar. El sustrato y la vegetación de cada lugar pudieron influir en estas diferencias. Asimismo, el oleaje modifica la dinámica acústica de algunos sectores significativamente, por lo que pudo haber afectado el paisaje sonoro de esta zona costera.
... Soundscapes comprise the complex variety of biological, anthropogenic, and environmental sounds of a given habitat (Krause, 2008;Pijanowski et al., 2011). They provide a unique perspective into a given ecosystem, whether terrestrial or marine, due to the integrative approach of studying all sounds of an environment together (e.g., Farina, 2013). However, recent capacity increases in long-term acoustic data collection are challenging scientists to develop new and creative ways to analyze these complex data (e.g., Gibb et al., 2019). ...
Soundscape analyses provide an integrative approach to studying the presence and complexity of sounds within long-term acoustic data sets. Acoustic metrics (AMs) have been used extensively to describe terrestrial habitats but have had mixed success in the marine environment. Novel approaches are needed to be able to deal with the added noise and complexity of these underwater systems. Here we further develop a promising approach that applies AM with supervised machine learning to understanding the presence and species richness (SR) of baleen whales at two sites, on the shelf and the slope edge, in the western North Atlantic Ocean. SR at both sites was low with only rare instances of more than two species (out of six species acoustically detected at the shelf and five at the slope) vocally detected at any given time. Random forest classification models were trained on 1-min clips across both data sets. Model outputs had high accuracy (>0.85) for detecting all species’ absence in both sites and determining species presence for fin and humpback whales on the shelf site (>0.80) and fin and right whales on the slope site (>0.85). The metrics that contributed the most to species classification were those that summarized acoustic activity (intensity) and complexity in different frequency bands. Lastly, the trained model was run on a full 12 months of acoustic data from on the shelf site and compared with our standard acoustic detection software and manual verification outputs. Although the model performed poorly at the 1-min clip resolution for some species, it performed well compared to our standard detection software approaches when presence was evaluated at the daily level, suggesting that it does well at a coarser level (daily and monthly). The model provided a promising complement to current methodologies by demonstrating a good prediction of species absence in multiple habitats, species presence for certain species/habitat combinations, and provides higher resolution presence information for most species/habitat combinations compared to that of our standard detection software.
We have performed a detailed analysis of the soundscape inside an urban park (located in the city of Milan) based on simultaneous sound recordings at 16 locations within the park. The sound sensors were deployed over a regular grid covering an area of about 22 hectares, surrounded by a variety of anthropophonic sources. The recordings span 3.5 h each over a period of four consecutive days. We aimed at determining a soundscape ranking index (SRI) evaluated at each site in the grid by introducing 4 unknown parameters. To this end, a careful aural survey from a single day was performed in order to identify the presence of 19 predefined sound categories within a minute, every 3 minutes of recording. It is found that all SRI values fluctuate considerably within the 70 time intervals considered. The corresponding histograms were used to define a dissimilarity function for each pair of sites. Dissimilarity was found to increase significantly with the inter-site distance in space. Optimal values of the 4 parameters were obtained by minimizing the standard deviation of the data, consistent with a fifth parameter describing the variation of dissimilarity with distance. As a result, we classify the sites into three main categories: “poor”, “medium” and “good” environmental sound quality. This study can be useful to assess the quality of a soundscape in general situations.
In the context of rapid urbanization, urban foresters are actively seeking management monitoring programs that address the challenges of urban biodiversity loss. Passive acoustic monitoring (PAM) has attracted attention because it allows for the collection of data passively, objectively, and continuously across large areas and for extended periods. However, it continues to be a difficult subject due to the massive amount of information that audio recordings contain. Most existing automated analysis methods have limitations in their application in urban areas, with unclear ecological relevance and efficacy. To better support urban forest biodiversity monitoring, we present a novel methodology for automatically extracting bird vocalizations from spectrograms of field audio recordings, integrating object-based classification. We applied this approach to acoustic data from an urban forest in Beijing and achieved an accuracy of 93.55% (±4.78%) in vocalization recognition while requiring less than ⅛ of the time needed for traditional inspection. The difference in efficiency would become more significant as the data size increases because object-based classification allows for batch processing of spectrograms. Using the extracted vocalizations, a series of acoustic and morphological features of bird-vocalization syllables (syllable feature metrics, SFMs) could be calculated to better quantify acoustic events and describe the soundscape. A significant correlation between the SFMs and biodiversity indices was found, with 57% of the variance in species richness, 41% in Shannon’s diversity index and 38% in Simpson’s diversity index being explained by SFMs. Therefore, our proposed method provides an effective complementary tool to existing automated methods for long-term urban forest biodiversity monitoring and conservation.
This study incorporates a relational approach to investigating the dynamics and complexity of how tourists interact with diverse sounds as they are mobile while visiting nature-based destinations. Using a mixed-methods approach, this study combined in-situ photos and videos, real-time portable sound sensing, GPS tracking, wristband wearing, and in-depth interviews among 34 participants during their one-day trip to Mount Huangshan, China. The study argues that tourists’ experience of sounds in nature are dynamic and contextual. Sound influences tourist experiences not as intrinsic properties but through ongoing interrelationships among individual tourists, sounds, and their surroundings. Natural sounds of silence are experienced only when human voices and visual stimuli are absent and when certain natural sounds are assembled in particular situations. This study contributes theoretically and methodologically to the literature by understanding the mobile and relational process of how various sounds influence tourist experiences at nature-based destinations. The mechanisms of why tourists experience sounds differently can be explained by the contingency, temporality, and heterogeneity of the interrelationships among tourists, sounds, and the contexts. This study also provides practical implications for nature-based destination planners and managers through re-connecting tourists with diverse natural sounds in various contexts to enhance tourist experience.
Sound in the landscape is an element of the multisensory experience of the environment. In areas that are naturally valuable and additionally used for tourism, the quality of this element is much more important than in urban areas. The aim of the study was to assess the soundscape diversity of mountain trails included in the Crown of the Polish Beskids (Korona Beskidów Polskich). Two methods were used in the study: The first was sound intensity measurement using a sonometer, which provided information on the physical aspect of the landscape. The second method involved recording all sounds divided into two basic categories: anthropogenic and natural. These results made it possible to propose a new method for assessing the naturalness of the soundscape by plotting naturalness curves. In contrast to frequently used survey-based methods, in this method we minimise subjectivity, which is mainly due to the different perceptions of sounds by the assessors. Given how many psychophysical aspects can affect the reception and perception of sounds, the method of naturalness curves allows for a universal assessment of landscape quality. On all the mountain trails surveyed, the average sound intensity values exceeded 40 dB, which the authors considered to be borderline for areas of natural value and recreational use. In the study area, the influence of anthropopression on soundscape formation was found to be diverse and dependent on many factors. However, there was no clear evidence that tourism was the main negative influence. The plotted naturalness curves showed a large variation between trails, but not all trails showed a correlation between this parameter and the number of tourists on the trail.
Özet
Bu çalışmanın amacı, Türkiye’deki bir şehir turizmi destinasyonu olan Eskişehir’in iki rekreasyon alanına ait ses atmosferinin turistlerin duygu durumuna etkisini demografik özellikler çerçevesinde incelemektir. Bu amaçla Eskişehir’de bulunan ve turistler tarafından mutlaka ziyaret edilen Sazova Bilim, Kültür ve Sanat Parkı ve Adalar mevkii çalışma alanı olarak seçilmiştir. Buralardaki toplam 794 turiste 2021 yılı haziran ve temmuz aylarında yüz yüze anket uygulanmıştır. Anket aracılığıyla ses atmosferinin turistlerin duygu durumuna etkisinin ortaya koyulması ve sesleri algılamalarında turistlerin demografik özelliklerinin etkisinin tespit edilmesi amaçlanmıştır. Anket formunda turistlerin duygu durumunu ölçmeye yönelik kullanılan Pozitif ve Negatif Duygu Ölçeği (PNDÖ) ve demografik özelliklerinin belirlenmesi amacıyla hazırlanmış sorular bulunmaktadır. Elde edilen verilerden, çalışma alanlarındaki ses atmosferinin turistlerde daha çok pozitif duyguları ortaya çıkardığı anlaşılmaktadır. Sazova Bilim, Kültür ve Sanat Parkı’ndaki turistlerin ses atmosferi kaynaklı pozitif duygu durumunun yaşa, eğitim durumuna ve ikamet yerine göre; negatif duygu durumunun ise cinsiyete göre farklılaştığı belirlenmiştir. Buradaki erkek turistlerin negatif duygu durumu ortalamalarının kadınlara göre yüksek olduğu da elde edilen sonuçlar arasındadır. Adalar bölgesindeki turistlerin ses atmosferi kaynaklı pozitif duygu durumunun eğitim durumuna göre farklılaştığı belirlenmiştir. Buradan hareketle, buraya gelen turistlerden ilkokul mezunu olanların pozitif duygu durumu, ortaokul mezunu olanların ise negatif duygu durumu ortalamalarının yüksek olduğu sonucuna ulaşılmıştır.
Abstract
The aim of this study is to examine the effect of the soundscape of the two recreation areas of Eskişehir, which is a city tourism destination in Turkey, on the mood of the tourists within the framework of demographic characteristics. For this purpose, Sazova Science, Culture and Art Park and the Adalar locality, which are in Eskişehir and are definitely visited by tourists, were chosen as the study area. A face-to-face survey was applied to a total of 794 tourists visiting these areas in June and July 2021. It is aimed to reveal the effect of the soundscape on the mood of the tourists and to determine the effect of the demographic characteristics of the tourists on the perception of the sounds through the questionnaire. The questionnaire form includes the Positive and Negative Affect Schedule (PANAS), which is utilized to measure the moods of tourists, and questions prepared to determine their demographic features. From the data obtained, it is understood that the soundscape in both study areas reveals more positive emotions in tourists. It was determined that the positive mood differed according to the age, education level, and place of residence of the tourists in Sazova Science, Culture and Art Park; it was determined that the negative mood differed according to gender. It is also among the results obtained that the average of the negative mood of the male tourists in this place is higher than that of the females. It has been determined that the positive mood of the tourists in the Adalar locality due to the soundscape differs according to their education level. From this point of view, it has been concluded that the average of positive mood of the tourists who are primary school graduates, and the average of negative mood of those who are secondary school graduates are high.
The local diversity and global richness of coral reef fishes, along with the diversity manifested in their morphology, behaviour and ecology, provides fascinating and diverse opportunities for study. Reflecting the very latest research in a broad and ever-growing field, this comprehensive guide is a must-read for anyone interested in the ecology of fishes on coral reefs. Featuring contributions from leaders in the field, the 36 chapters cover the full spectrum of current research. They are presented in five parts, considering coral reef fishes in the context of ecology; patterns and processes; human intervention and impacts; conservation; and past and current debates. Beautifully illustrated in full-colour, this book is designed to summarise and help build upon current knowledge and to facilitate further research. It is an ideal resource for those new to the field as well as for experienced researchers.
The local diversity and global richness of coral reef fishes, along with the diversity manifested in their morphology, behaviour and ecology, provides fascinating and diverse opportunities for study. Reflecting the very latest research in a broad and ever-growing field, this comprehensive guide is a must-read for anyone interested in the ecology of fishes on coral reefs. Featuring contributions from leaders in the field, the 36 chapters cover the full spectrum of current research. They are presented in five parts, considering coral reef fishes in the context of ecology; patterns and processes; human intervention and impacts; conservation; and past and current debates. Beautifully illustrated in full-colour, this book is designed to summarise and help build upon current knowledge and to facilitate further research. It is an ideal resource for those new to the field as well as for experienced researchers.
The local diversity and global richness of coral reef fishes, along with the diversity manifested in their morphology, behaviour and ecology, provides fascinating and diverse opportunities for study. Reflecting the very latest research in a broad and ever-growing field, this comprehensive guide is a must-read for anyone interested in the ecology of fishes on coral reefs. Featuring contributions from leaders in the field, the 36 chapters cover the full spectrum of current research. They are presented in five parts, considering coral reef fishes in the context of ecology; patterns and processes; human intervention and impacts; conservation; and past and current debates. Beautifully illustrated in full-colour, this book is designed to summarise and help build upon current knowledge and to facilitate further research. It is an ideal resource for those new to the field as well as for experienced researchers.
Over the last 100 years, there has been an explosion of research in the field of animal bioacoustics. These changes have been facilitated by technological advances, decrease in size and cost of recording equipment, increased battery life and data storage capabilities, the transition from analog-to-digital recorders, and the development of sound analysis software. Acousticians can now study the airborne and underwater sounds from vocal species across the globe at temporal and spatial scales that were not previously feasible and often in the absence of human observers. Many advances in the field of bioacoustics were enabled by equipment initially developed for the military, professional musicians, and radio, TV, and film industries. This chapter reviews the history of the development of sound recorders, transducers (i.e., microphones and hydrophones), and signal processing hardware and software used in animal bioacoustics research. Microphones and hydrophones can be used as a single sensor or as an array of elements facilitating the localization of sound sources. Analog recorders, which relied on magnetic tape, have been replaced with digital recorders; acoustic data was initially stored on tapes, but is now stored on optical discs, hard drives, and/or solid-state memories. Recently, tablets and smartphones have become popular recording and analysis devices. With these advances, it has never been easier, or more cost-efficient, to study the sounds of the world.
Climate change is increasing aridity in grassland and desert habitats across the southwestern United States, reducing available resources and drastically changing the breeding habitat of many bird species. Increases in aridity reduce sound propagation distances, potentially impacting habitat soundscapes, and could lead to a breakdown of the avian soundscapes in the form of loss of vocal culture, reduced mating opportunities, and local population extinctions. We developed an agent-based model to examine how changes in aridity will affect both sound propagation and the ability of territorial birds to audibly contact their neighbors. We simulated vocal signal attenuation under a variety of environmental scenarios for the south, central semi-arid prairies of the United States, ranging from contemporary weather conditions to predicted droughts under climate change. We also simulated how changes in physiological conditions, mainly evaporative water loss (EWL), would affect singing behavior. Under contemporary and climate change-induced drought conditions, we found that significantly fewer individuals successfully contacted all adjacent neighbors than did individuals in either the contemporary or predicted climate change conditions. We also found that at higher sound frequencies and higher EWL, fewer individuals were able to successfully contact all their neighbors, particularly in drought and climate change drought conditions. These results indicate that climate change-mediated aridification may alter the avian soundscape, such that vocal communication no longer effectively functions for mate attraction or territorial defense. As climate change progresses, increased aridity in current grasslands may favor shifts toward low-frequency songs, colonial resource use, and altered songbird community compositions.
Anthropogenic noise is a growing threat to marine life due to the incrementation of human activity in the marine environment. In Europe, the Directive 2008/56/EC of the European Parliament and of the Council was published with the aim of establishing a framework for community action in the field of marine environmental policy. The directive introduces underwater acoustic energy, as detailed in Descriptor 11, and stipulates that the member states should set the threshold levels at which a good environmental status can be achieved by means of long-term monitoring campaigns. This research presents the results of a long-term underwater noise monitoring campaign with a duration of three years in the port of Cartagena located on the south-eastern coast of Spain, focusing on the monthly and annual variation patterns of low-frequency continuous noise. The acquired data are classified according to the source of the acoustic noise into shipping, other anthropogenic, and natural noise measurements. These three groups of measurements are processed in order to obtain one-third octave band levels centered at 63 and 125 Hz, as well as the overall bandwidth of unweighted Sound Pressure Level (SPL). The analysis of the measurements shows an increase in the annual average overall band of 4 and 3 dB of the natural and shipping noise, respectively, from 2013 to 2015. This monitoring campaign provides accurate acoustic values to establish threshold levels to achieve good environmental status and recommendations to conduct monitoring programs and regulations to control underwater noise pollution.
Passive acoustic monitoring (PAM) is a promising method for biodiversity assessment, which allows for longer and less intrusive sampling when compared to traditional methods ( e.g ., collecting specimens), by using sound recordings as the primary data source. Insects have great potential as models for the study and monitoring of acoustic assemblages due to their sensitivity to environmental changes. Nevertheless, ecoacoustic studies focused on insects are still scarce when compared to more charismatic groups. Insects’ acoustic activity patterns respond to environmental factors, like temperature, moonlight, and precipitation, but community acoustic perspectives have been barely explored. Here, we provide an example of the usefulness of PAM to track temporal patterns of acoustic activity for a nocturnal assemblage of insects (Orthoptera). We integrate satellite remote sensing and astronomically measured environmental factors at a local scale in an Andean Forest of Colombia and evaluate the acoustic response of orthopterans through automated model detections of their songs for nine weeks (March and April of 2020). We describe the acoustic frequency range and diel period for the calling song of each representative species. Three species overlapped in frequency and diel acoustics but inhabit different strata: canopy, understory, and ground surface level. Based on the acoustic frequency and activity, we identified three trends: (i) both sampled cricket species call at lower frequency for shorter periods of time (dusk); (ii) all sampled katydid species call at higher frequency for longer time periods, including later hours at night; and (iii) the diel acoustic activity span window seems to increase proportionally with dominant acoustic frequency, but further research is required. We also identified a dusk chorus in which all the species sing at the same time. To quantify the acoustic response to environmental factors, we calculated a beta regression with the singing activity as a response variable and moon phase, surface temperature and daily precipitation as explanatory variables. The response to the moon phase was significant for the katydids but not for the crickets, possibly due to differences in diel activity periods. Crickets are active during dusk, thus the effects of moonlight on acoustic activity are negligible. The response to precipitation was significant for the two crickets and not for the katydids, possibly because of higher likelihood of rain interrupting crickets’ shorter diel activity period. Our study shows how the local survey of orthopteran acoustic assemblages, with a species taxonomic resolution coupled with remote-sensing environmental measurements can reveal responses to environmental factors. In addition, we demonstrate how satellite data might prove to be a useful alternative source of environmental data for community studies with geographical, financial, or other constraints.
As biodiversity decreases worldwide, the development of effective techniques to track changes in ecological communities becomes an urgent challenge. Together with other emerging methods in ecology, acoustic indices are increasingly being used as novel tools for rapid biodiversity assessment. These indices are based on mathematical formulae that summarise the acoustic features of audio samples, with the aim of extracting meaningful ecological information from soundscapes. However, the application of this automated method has revealed conflicting results across the literature, with conceptual and empirical controversies regarding its primary assumption: a correlation between acoustic and biological diversity. After more than a decade of research, we still lack a statistically informed synthesis of the power of acoustic indices that elucidates whether they effectively function as proxies for biological diversity. Here, we reviewed studies testing the relationship between diversity metrics (species abundance, species richness, species diversity, abundance of sounds, and diversity of sounds) and the 11 most commonly used acoustic indices. From 34 studies, we extracted 364 effect sizes that quantified the magnitude of the direct link between acoustic and biological estimates and conducted a meta‐analysis. Overall, acoustic indices had a moderate positive relationship with the diversity metrics (r = 0.33, CI [0.23, 0.43]), and showed an inconsistent performance, with highly variable effect sizes both within and among studies. Over time, studies have been increasingly disregarding the validation of the acoustic estimates and those examining this link have been progressively reporting smaller effect sizes. Some of the studied indices [acoustic entropy index (H), normalised difference soundscape index (NDSI), and acoustic complexity index (ACI)] performed better in retrieving biological information, with abundance of sounds (number of sounds from identified or unidentified species) being the best estimated diversity facet of local communities. We found no effect of the type of monitored environment (terrestrial versus aquatic) and the procedure for extracting biological information (acoustic versus non‐acoustic) on the performance of acoustic indices, suggesting certain potential to generalise their application across research contexts. We also identified common statistical issues and knowledge gaps that remain to be addressed in future research, such as a high rate of pseudoreplication and multiple unexplored combinations of metrics, taxa, and regions. Our findings confirm the limitations of acoustic indices to efficiently quantify alpha biodiversity and highlight that caution is necessary when using them as surrogates of diversity metrics, especially if employed as single predictors. Although these tools are able partially to capture changes in diversity metrics, endorsing to some extent the rationale behind acoustic indices and suggesting them as promising bases for future developments, they are far from being direct proxies for biodiversity. To guide more efficient use and future research, we review their principal theoretical and practical shortcomings, as well as prospects and challenges of acoustic indices in biodiversity assessment. Altogether, we provide the first comprehensive and statistically based overview on the relation between acoustic indices and biodiversity and pave the way for a more standardised and informed application for biodiversity monitoring.
Landscape ecology has a long history in scientific research and humanities with an epistemology rich in different interpretations and meanings that often produces not coincident syntheses. A landscape can be considered a domain, a system, or a unit. Apparently heterogeneous and fragmented, the land mosaic literally connects not only environmental patches of different composition, morphology, and functions but reunifies distant disciplines and theoretical perspectives.
Recurrent landscape patterns occur around the world. Some of these are particularly important because they are strictly connected with human life and habits (e.g., urban landscapes, farming landscapes, cultural landscapes, etc.). Urban landscapes concentrate the majority of benefits that human culture and technology have achieved along with the history of human civilization. Energy, trends, threats, and level of sustainability are some of the fundamentals considered in the urban landscape. The farming landscape is the food source for the entire human population and in particular for the urban dwellers. The farming activity can be distinct in an industrialized regime that produces food for a great mass of (urban) people and a low-intensity activity still connected to old farming uses and practices. Japanese Satoyama and Montado of Iberian peninsula are selected examples of traditional land use in cultural landscape. Tropical agroforestry systems for the production of cacao and coffee contrast with industrialized systems like palm oil plantations and extensive deforestation for cattle ranching. Landscape ecology helps to sustain traditional farming systems and to guide urban development with the goal to maintain biodiversity and healthy human conditions, integrating information from freshwater landscapes, mining and energy landscapes, hybrid landscapes, and therapeutic landscapes.
Environmental fundamentals like time, senses, and signs originate as many ecoscapes (timing-scapes, sensory-scapes, semio-scapes) species specific. Timing-scape is represented by a mosaic of patches shaped by phenomena that occur at a geological, biological, ecological, cultural, and semiotic time.
This paper aimed to develop a multisensory approach in a university campus, based on quantitative and qualitative approaches, investigating sense walk experiences (thermo-visual sound walk) under interactions of luminous, thermal, and auditory environments. The study was conducted in October 2021, in Chetma university campus in Biskra city, southern Algeria, which remains a famous oasis settlement of arid regions over the country. A comparative and correlation analysis was performed between the physical dimensions collected through a walking experience in three campus routes (outdoor, semi-outdoor and indoor). In addition, a multisensory survey of the walking experience on perceptual dimensions was evaluated in parallel to the empirical contribution. The paper shows that walkers’ thermal levels were balanced between neural and slightly hot in different spatial aspects. The glare was almost unperceived regarding the luminous conditions in the study site. The auditory experience reveals that the conducted points were generally quiet and well placed for educational requirements. Findings also show a strong relationship between the physical dimensions of the luminous and auditory environment. Furthermore, the findings suggest that the thermal and luminous environments are more perceptible than the auditory environment for the walkers of the outdoor and indoor routes. In contrast, the semi-outdoor route is often perceptible by the perceptual dimensions of the luminous and auditory environments. The findings on sensorial thresholds and spatial adaption are essential for the educational practices’ architectural and urban strategies for the Saharan cities and oasis settlements.
Artificial creativity is often applied in the production of artefacts and ideas for
a human audience. However, as a creative force that is not bound to human
experiences, it can act as a way of approaching nonhuman creative forces from
a new perspective. This paper develops a concept of endemic machines to
describe a process of engaging the creativity of an ecosystem through a
machine that adapts with that ecosystem. A case study detailing the design and
testing of an endemic machine called the Rowdy Krause helps to ground the
concept of endemic machines in practice.
The acoustic complexity indices represent a family of metrics formulated to extract information from sonic matrices. These indices are based on the differences of acoustic energy measured along a temporal interval of a sonic matrix across all the spectral lines (ACIft) and along each individual spectral line (ACItf) obtaining respectively a temporal and a frequential sonic signature. The distribution of information in time and in frequency returns respectively an ACIft evenness and an ACItf evenness that, when combined in a ternary code with ACIft, compose the codes of Ecoacoustic Events (EE). The Ecoacoustic Events are defined as an emergent aggregation of sonic information that assumes a sense for a species or for an ecological process. In order to obtain realistic data, every sonic matrix must be cleaned from low energetic elements, mainly artifacts, by applying adapt energy filters that are also used to delimit near and far acoustic fields contributing to better understand the relationships between sounds and the environment. A clumping procedure can aggregate original data before the application of ACI metrics. The Sonic Signature Dissimilarity (SSD) is used to assess the distance in ACItf between two sonic matrices. The application of the Shannon theory returns the value of entropy of ecoacoustic events. The application of different temporal scales to the ACI computation allows to overpass the uncertainty in the selection of the more adapt temporal resolution obtaining a fractal dimension of ecoacoustic events and of sonic dissimilarity.
Ecoacoustics is a new discipline that aims to investigate the ecological role of sounds of geological, biophonic, and anthropogenic origin. Its development has been favored by new robust theoretical principles associated to efficient metrics for data processing and by the availability of autonomous acoustic recorders to collect a great number of acoustic files at different temporal and geographical scale.The double role of sound as a semiotic tool to communicate and as ecological proxy of environmental conditions to select habitats and to navigate represents the ideal condition for a rapid development of this discipline. The transformation of latent vibrations as generators of any typology of sound, a clear semiosis that recognizes a sonoscape as the component of the original vibroscape sensed by organisms, and a soundscape as the portion of sonoscape interpreted by individual species are three components of the sonic domain. Sonotope and soundtope, respectively, are sensed and interpreted patches with which soniferous species and acoustic communities interact in a spatial sonic mosaic.The Morphological Adaptation Hypothesis, the Acoustic Adaptation Hypothesis, the Acoustic Niche Hypothesis, the Acoustic Community Hypothesis, and the Acoustic Habitat Hypothesis represent the theoretical fundaments of ecoacoustics.An acoustic community is defined as the collection of soniferous species acoustically active in space and time. Such aggregation of soniferous species determines a sonic environment variable in space and time and represented by sonic matrices (on which to apply ecoacoustics metrics) after a process of migration from a temporal domain to a frequential domain via a Fourier Transform. A large portion of ecoacoustic investigations focuses on the role of noise (especially of anthropogenic origin) on behavioral and ecological processes in terrestrial and in aquatic ecosystems.To describe the complex sonic domain where an originator vibroscape evolves into several distinct objects obtained after a latent, sensed, and interpreted semiosis requires the development of a dedicated narrative. Sonoscape is the result of a sensed vibroscape, and a soundscape is obtained from an interpreted sonoscape. Sonotopes represent the “geographical” elements composing a sonoscape, and their detection is obtained by the deployment of sound recorders according to a configuration that enhances the spatial heterogeneity. Sonotopes are the spatial unit of a sonic information system and represent the link with the geographical character of a landscape. Every sonotope is characterized by species-specific sonic and acoustic signatures. The former (species-specific sonic signature) is the result of a sensed vibroscape and the latter (species-specific acoustic signature) of the interpretation of sonic signals.Ecoacoustic events obtained by coding three metrics (ACIft, ACIft evenness, and ACItf evenness) are an attempt to discretize acoustic signals into functional or statistical distinct units.KeywordsEcoacousticsVibroscapeSonoscapeSonotopeSoundscapeSoundtopeMorphological adaptation hypothesisAcoustic adaptation hypothesisAcoustic niche hypothesisAcoustic habitat hypothesisAcoustic community hypothesis
Several human activities in the urban environment pose as a source of pollution including environmental noise. The increasing human population movement towards urban areas has brought a series of environmental pressures that affect the quality of life and the quality of the overall environment. A response towards the problems caused by noise is the creation of quiet areas in agglomerations. The quiet areas of an urban complex, as defined in the Directive 2002/49 / EC, are a societal response in order to deal with environmental noise. However, the concepts of noise and quietness are multidimensional and vague. So far, two approaches have been applied in order to find quiet areas. The first recognizes noise as a sound of increased intensity and the rational that "less" is better than "more", urges the creation of noise maps in order to highlight areas with lower levels of intensity. An important remark about this particular tactic is the homogenization of all sounds in the light of their intensity. However, the emergence of noise as an urban disease and the promotion of quietness as a panacea, offers short-term and one-dimensional benefits. The second way concerns the general conclusion that the quality of the acoustic environment is responsible for declaring an area as quiet and not the intensity of the sounds it contains. This soundscape approach inevitably leads to the search for the concept of the aforementioned quality and its connection with the concept of quietness. The potential risk of using this tactic, which has now been applied in several European countries, is left to the human instrumental rationality towards the environment, the grouping of opinions in order to highlight the preferred one and the practical application of the dominant opinion in a public space without investing in ecological co-benefits. The goals of this dissertation was to create a flexible protocol for urban quiet areas identification, the efforts of ecological connection of quiet areas, the redefining of the concept of urban quietness and the creation of the new Composite Urban Quietness Index (CUQI) that quantifies the state of urban quiet areas, so that possible changes in the quality of the urban environment are observed in a timely manner. The main research tools were noise level measurements and sound recordings. The collected data were used in such a way as to extract noise maps and sound maps that strengthened the efforts of quiet area identification, with the study area being the city of Mytilene. At the same time, altered fixed tactics of evaluating soundscapes such as the soundwalk were used in order to highlight the perception of the acoustic environment. Then, using a special sampling protocol, the Composite Urban Quietness Index was formed. In conclusion, noise emerged as an immaterial barrier to ecological connectivity in an urban environment. Finally, the dysfunctionality of the so far evaluation metrics which concern exclusively to intensity or preference emerged. The introduction of additional aspects of sound in the analysis of urban acoustic environments regarding frequency and acoustic complexity is considered necessary.
Context
One mainstay of soundscape ecology is to understand acoustic pattern changes, in particular the relative balance between biophony (biotic sounds), geophony (abiotic sounds), and anthropophony (human-related sounds). However, little research has been pursued to automatically track these three components.
Objectives
Here, we introduce a 15-year program that aims at estimating soundscape dynamics in relation to possible land use and climate change. We address the relative prevalence patterns of these components during the first year of recording.
Methods
Using four recorders, we monitored the soundscape of a large coniferous Alpine forest at the France-Switzerland border. We trained an artificial neural network (ANN) with mel frequency cepstral coefficients to systematically detect the occurrence of silence and sounds coming from birds, mammals, insects (biophony), rain (geophony), wind (geophony), and aircraft (anthropophony).
Results
The ANN satisfyingly classified each sound type. The soundscape was dominated by anthropophony (75% of all files), followed by geophony (57%), biophony (43%), and silence (14%). The classification revealed expected phenologies for biophony and geophony and a co-occurrence of biophony and anthropophony. Silence was rare and mostly limited to night time.
Conclusions
It was possible to track the main soundscape components in order to empirically estimate their relative prevalence across seasons. This analysis reveals that anthropogenic noise is a major component of the soundscape of protected habitats, which can dramatically impact local animal behavior and ecology.
In 2011, the Coffee Cultural Landscape of Colombia (CCLC) was inscribed in the UNESCO World Heritage List. Several studies have been undertaken to increase its knowledge and promote its conservation and sustainable development; however, there still exists a gap between the knowledge of the visible features of this landscape and the audible ones, which are associated to anthropophonic, geophonic, and, mainly, to biophonic sound-emitting sources. The perception or recording of the audible features in a place has been recently termed as soundscape and is studied by a relatively novel discipline known as ecoacoustics. This chapter is, therefore, aimed to discuss the potential opportunities and challenges of applying ecoacoustic methods—particularly non-negative matrix factorization and acoustic indices—to enrich the study of the CCLC. Essential concepts for both the CCLC and ecoacoustics are also briefly explained, along with an outline of future work directions in short- and long-term perspectives.
Humans categorize unwanted sounds in the environment as noise. Consequently, noise is associated with negative human and ecological values, especially when it is derived from an anthropogenic source. Although evidence confirms that many machine-generated anthropogenic sounds have negative impacts on animal behavior and communication, natural sources of non-biological sound, such as wind, rain, running water, and sea waves (geophonies) have also been categorized as noise and are frequently dismissed or mischaracterized in acoustic studies as an outside factor of acoustic habitats rather than an integrated sonic component of ecological processes and species adaptations. While the proliferation of machine-generated sound in the Biosphere has become an intrusive phenomenon in recent history, geophony has shaped the Earth’s sonic landscapes for billions of years. Therefore, geophonies have very important sonic implications to the evolution and adaptation of soniferous species, forming essential ecological and semiotical relationships. This creates a need to distinguish geophonies from machine-generated sounds and how species respond to each accordingly, especially given their acoustic similarities in the frequency spectrum. Here, we introduce concepts and terminology that address these differences in the context of ecoacoustics. We also discuss how Acoustic Complexity Indices (ACIs) can offer new possibilities to quantifiably evaluate geophony in relation to their sonic contest.
Sound pressure levels expressed in variations of decibel (dB) formulations are a common approach to describe the urban acoustic environment (AE) in regard to noise and health exposure. However, as noise descriptors mainly focus on sound pressure level, further concepts are needed to analyze the effects of the AE on human health. In recent years, different approaches to describe the AE have gained traction, like the soundscape ecology approach that focuses on sound in the natural environment. To determine the feasibility of applying this approach to cities, a comprehensive dataset of high-quality sound recordings with high spatial and temporal resolution is essential.
The acoustic quality and health in urban environments (SALVE) project aims to establish a spatially and temporally high-resolution dataset of the urban AE to connect it to human health as well as to the built environment. Since 2019, we have assessed the AE at selected places in the densely populated city of Bochum, Germany. For a high temporal resolution, we used automatic devices at 52 locations that recorded every 26 min for three minutes. For a high spatial resolution, we used manual devices to perform a five-minute recording four times a year at 730 selected locations. So far, we sampled 1,500,493 min of sound recordings. Comprehensive health data used were already available from the ongoing epidemiological Heinz Nixdorf Recall Study, in the Ruhr Area, Germany.
The aim here is to outline our sampling design, methods used, and applied quality procedures in order to achieve a well-defined and high-quality dataset. To the best of our knowledge, our study provides one of the most extensive datasets currently available. This will allow for the next steps, analyzing in-depth associations between the urban AE, urban fabric and human health.
Soundscape ecology has gained prominence in the monitoring of marine ecosystems due to its non-invasive characteristics and spatiotemporal efficiency. However, the development of ecoacoustic indices is a recent field that needs to address many challenges to fulfill its great potential, especially in the context of marine ecology. Here, we reviewed the most recent studies that used ecoacoustic indices in marine ecosystems. The literature search was conducted in the Scopus (Elsevier) database and used the chain referral sampling in the list of references of each publication. In total, we identified publications that used ecoacoustic indices in marine environments such as coral reefs, rocky shores, coastal regions, and offshore regions. A total of four major limitations were identified and addressed, including: the challenge to find adequate acoustic bioindicators; the lack of a universal index or standardized protocol; the issue that most acoustic indices applied to marine environments have been developed to be used in terrestrial environments; and the lack of studies that have tested ecoacoustic indices under different environmental conditions. Once these challenges are addressed, the analysis of marine sound based on the interpretation of ecoacoustic indices has a great potential to become one of the most cost-effective tools for monitoring environments.
Acoustic emissions of animals serve communicative purposes and most often contain species-specific and individual information exploitable to listeners, rendering bioacoustics predestined for biodiversity monitoring in visually inaccessible habitats. The physics of sound define the corner stones of this communicative framework, which is employed by animal groups from insects to mammals, of which examples of vocalisations are presented. Recording bioacoustic signals allows reproducible identification and documentation of species’ occurrences, but it requires technical prerequisites and behavioral precautions that are summarized. The storing, visualizing and analysing of sound recordings is illustrated and major software tools are shortly outlined. Finally, different approaches to bioacoustic monitoring are described, tips for setting up an acoustic inventory are compiled and a key for procedural advancement and a checklist to successful recording are given. Extensive literature and reference to a collection of web resources (http://www.bioacoustics.myspecies.info) complete the text.
An analysis of visitor survey responses and concurrent noise exposure was performed using data from ten sites in four scenic U. S. National Parks. Data collection was structured to learn the effects of air-tour aircraft noise and high-altitude jet noise on the experience of park visitors at scenic overlooks and on short hikes. The analysis utilized multilevel logistic regression and resulted in six doseresponse relations: two responses (annoyance and interference with natural quiet), paired with three response dichotomizations (slightly or more, moderately or more, and very or more). Each of those six relations retained the same set of regression predictors. Individual-visitor Leq from all aircraft (averaged over the visitor duration at the site) proved to be the most reliable/accurate predictor of all noise dose metrics tested. The relation with visitor Leq was significantly strengthened by inclusion of three additional dose-related predictors: the energy-percentage due to tour helicopters for each visitor, the same due to fixed-wing tour aircraft, and the interaction of these two percentages. In addition, the relation was also strengthened by inclusion of the following context variables: Scenic overlook or short hike, natural quiet very important (or not) to that visitor, visitor group includes only adults (or not), and first-time visit at that site (or not). For a given noise exposure, visitors expressed more negative response regarding interference with natural quiet than regarding annoyance. In addition, visitor response to a given dose of air-tour noise was less severe when there were low-to-moderate levels of high-altitude jet noise present.
measurements of underwater pile driving noise recorded during the construction of the duplicate Houghton Highway bridge in western Moreton Bay, Queensland. Moreton Bay is a protected marine park, a World Heritage Site and a Ramsar Wetland, providing habitat for turtles, dugong, sharks, dolphins and whales, some species of which are listed as vulnerable to endangered. Pile driving noise was measured for small and large piles at various locations and ranges. Using an acoustic propagation model, a sound map was computed for Bramble Bay. Sound levels were compared to currently available information on impact thresholds. Ranges greater than those corresponding to impact thresholds were scanned for the absence of dolphins before and during pile driving in line with a monitoring and response plan.
Pupae of several insect species are known to generate air-borne sounds and/or substrate-borne vibrations, but the functions of the sounds/vibrations are not well understood. Here, we present the first evidence of vibratory communication between pupae and larvae of a group-living Japanese rhinoceros beetle Trypoxylus dichotoma which inhabits humus soil. The last-instar larvae of this beetle construct their own pupal cells to ensure normal pupation and eclosion. These cells are fragile and subject to damage from burrowing larvae because pupae and larvae co-inhabit the same patches of humus. In laboratory experiments, we demonstrated that pupal cells harboring live pupae were less likely to be broken by larvae than those harboring dead pupae. It was also demonstrated that pupae produced vibrations in response to larvae approaching the pupal cells. High-speed video and vibration analyses showed that pupae emitted 3–7 pulses at 1.3-s intervals by beating their pronotum against the inner wall of the pupal cell. The pupal vibration was of low frequency with a maximum energy at ≈ 100 Hz. The drumming behavior was more frequently observed in the presence of an approaching larva than in its absence. When pupal vibrations were played back near to vacant artificial pupal cells, these cells were rarely disturbed by the larvae. These results provide evidence that pupae generate vibrations to deter conspecific larvae, thereby preventing damage to the cells. This larval response to pupal vibrations may have evolved through preexisting anti-predator and/or sib-killing-avoidance behavior.
Aircraft overflight noise from helicopter tours is frequently encountered in such national parks as Grand Canyon, Hawaii Volcanoes, Haleakala, and Bryce Canyon. Noise is an environmental stressor and is associated with a variety of physiological and psychological effects, some of which are long-lasting. Psychologically, attributing a stressor to a nonhostile origin (e.g., a helicopter rescue mission) could mitigate stress effects. In this study, 200 undergraduates rated National Park scenes while exposed to either natural sounds (birds, brooks, wind), helicopter noise attributed to tourist overflights, helicopter noise attributed to backcountry maintenance operations, or helicopter noise attributed to the rescue of a back country hiker. Regardless of the source, 60 decibel (dB(A)) helicopter noise resulted in lower ratings of scenic beauty, solitude, tranquility, freedom, naturalness, and preference, and higher ratings of annoyance. These effects occurred across all types of scenery. Results suggest that park management-related overflight noise is just as disturbing as tourist aircraft noise, and that the impact of this noise is substantial across demographic variables and across types of vistas.
Aims To test the responses of Robins to conspecific playbacks between Wales and Ireland and between day and night.Methods We measured the responses of Robins to conspecific playbacks during daylight, and at night on territories illuminated by streetlights, and compared Robins in Wales and in Ireland.Results Most Welsh Robins responded to playbacks at night, whereas Irish Robins rarely responded. Both populations responded equally during daylight.Conclusion We show for the first time that different populations with similar daytime behaviours may differ in nocturnal behaviour. Such population differences in communication behaviour should be taken into account, for example when using acoustic playback to census populations.
Measurements obtained at three British woodlands for the frequency‐dependent attenuation of broadband sound with distance under neutral atmospheric conditions are compared with the predictions of a model obtained by summing the separate contributions of the ground, the trunks and branches, and the foliage. The two latter contributions are predicted by an empirically modified multiple scattering approach. The principal features of the measured spectra, viz., the low‐frequency peak in excess attenuation below 500 Hz and a gradual increase of attenuation with frequency above 1 kHz, are predicted in a tolerable fashion by the composite model, as are the observed differences in acoustic propagation in the three different woodland areas.
Introduction, Interactions between individuals make up a significant part of life in social animals. They form a crucial behavioural mechanism establishing and maintaining particular spacing patterns among individuals and groups of individuals and are inherent in the regulation of social relations. Animals interact with each other in a broad range of contexts, such as during intersexual competition, mate choice, or parent–offspring communication, but still many of the underlying principles share common ground (Hauser, 1996; Bradbury & Vehrencamp, 1998). It is well documented that the performance of individuals in interactions has profound implications for the resolution of conflicts over resources, such as mates, food or space. Interactions may consist of complex behavioural displays or may be based exclusively on signals in either one or several signalling modalities. Vocal interactions are among the most conspicuous forms of interactions and have been well studied in several taxonomic groups, such as insects, anurans and birds (Bradbury & Vehrencamp, 1998). In birds, vocal interactions are most evident in parent-offspring communication (Kilner & Johnstone, 1997; Ch. 9), calling and singing in group-living species (Farabaugh & Dooling, 1996; Zann, 1996), duetting in tropical songbirds (von Helversen, 1980; Farabaugh, 1982) and in singing interactions between male territorial songbirds (Todt & Naguib, 2000). In this review, I will focus on singing interactions in male territorial songbirds. Their vocal interactions are among the most striking examples of bird vocal communication and are an established model for studies on territoriality and communication networks (McGregor, 1993; McGregor & Dabelsteen, 1996; Todt & Naguib, 2000).
One calendar year of Automatic Identification System (AIS) ship-traffic data was paired with hydrophone recordings to assess ambient noise in northern Admiralty Inlet, Puget Sound, WA (USA) and to quantify the contribution of vessel traffic. The study region included inland waters of the Salish Sea within a 20 km radius of the hydrophone deployment site. Spectra and hourly, daily, and monthly ambient noise statistics for unweighted broadband (0.02-30 kHz) and marine mammal, or M-weighted, sound pressure levels showed variability driven largely by vessel traffic. Over the calendar year, 1363 unique AIS transmitting vessels were recorded, with at least one AIS transmitting vessel present in the study area 90% of the time. A vessel noise budget was calculated for all vessels equipped with AIS transponders. Cargo ships were the largest contributor to the vessel noise budget, followed by tugs and passenger vessels. A simple model to predict received levels at the site based on an incoherent summation of noise from different vessels resulted in a cumulative probability density function of broadband sound pressure levels that shows good agreement with 85% of the temporal data.
The description of the landscape is based on the visualization of geographic features and the representation of their attributes. Although sound is a major component of any environment, its cartographic representation is limited mainly on noise mapping and in urban or sub-urban areas. Soundscape is a term that describes the acoustic relation between the environment and the individual in a landscape context, considering all kinds of interactions between space, sound and humans. The representation of the soundscape at a spatial level would support many applications such as geographic analysis, ecosystem evaluation, environmental education, landscape management, urban or rural planning and protection of sonic particularities. This paper proposes a methodology for the mapping of both quantitative and qualitative attributes of a rural soundscape, which is described through the study of the acoustic environment around a protected wetland in Greece.
Chorus counts are widely used to assess population abundance in breeding anurans. It is however unclear how such counts translate into true population sizes. We monitored chorus activity in two populations of the European tree frog (Hyla arborea) over three years, while simultaneously conducting a capture-mark-recapture (CMR) study on breeding males. Three to four capture sessions were made each year, spread across the acme of the breeding season. Individual recognition was ensured by photographs of the linea marginalis. We used Pollock's robust design to test several biological hypotheses and estimate demographic parameters. Male survival was estimated as mean ±SE = 0.297 ± 0.154. Population trends deduced from chorus counts (maximum or mean) and modelled male population sizes were not concordant. We showed that there is no simple relationship between maximum or mean chorus size and modelled male population sizes estimated from CMR study and that population trends inferred from chorus counts are likely to be biased to an unknown extent. Even though CMR methods need significant time and personnel investments in order to produce reliable results, we advocate their use in the study of pond breeding amphibians' demography, as it provides unbiased and more precise estimates.
In territorial songbirds, duets between mates represent one of the best-known examples of communal display, with the main function being the defence of joint resources. In this study, we found evidence of a coordinated choral display performed by neighbouring heterospecific songbirds. In such choruses, most of the participating species perform a deliberate temporal overlap of songs, thus suggesting agonistic behaviour. However, they then utilize a complex form of behaviour to avoid signal jamming, making the aggressive purpose unlikely. We define these displays as “coordinated interspecific choruses”. We recorded dusk choruses of songbirds living in a mixed turkey oak wood in central Italy, and then carried out a niche overlap analysis using null models that were intended for investigations of concurrent emissions of songs, finding that species tend to sing concurrently instead of using the refractory period of another species. Among the species singing concurrently, about half used the same frequency range, but instead of finding considerable spectral overlap between their vocalizations, the number of real spectral overlaps was lower than would be expected by chance. We propose a tentative explanation for this, where such choruses are the expression of the existence of a neighbourhood of different species that has evolved a communal signal that is similar to that used by mates in a pair, i.e. coordinated vocalizations. As coordination requires experience of each other’s songs, we propose that evolution has selected individuals that are more skilled at learning heterospecific songs.
Sonic aspects relevant to landscape architects and planners are examined in order to show that soundscapes can be acknowledged and developed as an aesthetic resource for sustainable development. This auditory approach aims at an inter-sensory understanding of human perception and its significance for the design of physical environments. Two settings—a pasture landscape and a city garden—were studied by skilled listeners on site. They contributed to a preliminary terminology for the design of sonic environments, sonotopes. Clarity emerged as one cardinal principle for auditory refuges, and it was found to be related to the balance of particular sonic features and their background sounds. A figure/ground model described these proportions. The distances to sonic events and the tempo of sonotopes defined refuges. Sonic events mirrored the land use and constituted acoustic space according to the distribution of sound sources. Distant sources were suggested as a practical pointer and design tool for overall conditions together with tempo, which is described as the pace of interplay of figures that fade in and out of a background.
Several species of frogs of the subgenusRana (Paa) and one species of bird of the genusPhylloscopus, which are calling in or near torrents in the Himalayas, show striking similarities in their vocal signals: 1) The calls are composed of short sequences of notes separated by periods of silence; 2) the notes are pure, short, and have a narrow frequency band; 3) within each sequence, the notes are rhythmically emitted. We suggest that these characteristics may be adaptive, the convergence being caused by the selective pressure of the acoustic constraints of the biotope.Mehrere Frosch-Arten der UntergattungRana (Paa) und ein Laubsnger der GattungPhylloscopus, die in oder in unmittelbarer Nhe von Gebirgsflssen des Himalayas leben, weisen in ihren akustischen Signalen bemerkenswerte hnlichkeiten auf. 1) Die Rufe bzw. Gesnge setzen sich aus kurzen Folgen von Elementen zusammen, die durch lange Pausen getrennt sind. 2) Die Elemente sind rein und kurz; ihre Frequenzbnder sind schmal. 3) Innerhalb jeder Ruffolge werden die einzelnen Elemente rhythmisch geuert. Wir vermuten, da diese Eigenschaften adaptiv sind. Derart hnliche Rufe bei nur weitlufig verwandten Tiergruppen wrden somit auf Konvergenz beruhen, hervorgerufen durch den Selektionsdruck der akustischen Eigenschaften des Biotops.
Frogs and toads commonly form large choruses around suitable breeding habitat during the mating season. Although often regarded
as a constraint on the acoustic behavior of signalers and receivers, the sounds of a chorus could also serve as an acoustic
beacon that allows some frogs to locate the breeding aggregation. Attraction to chorus sounds might be particularly important
for explosively breeding frogs. In these species, which often mate just one or a few days during the year, the timing and
location of breeding aggregations can be unpredictable because their formation often depends on local climatic factors, such
as rainfall or a change in temperature. I used laboratory playback experiments to test the hypothesis that male wood frogs
(Rana sylvatica), an explosively breeding frog, exhibit positive phonotaxis toward the sound of a conspecific chorus. Males were released
at the center of a rectangular arena with a speaker positioned in each corner facing toward the release point. In a single-stimulus
experiment, more males approached a speaker broadcasting a conspecific chorus than the three silent speakers in the arena.
In a two-stimulus experiment, more males approached a speaker broadcasting a conspecific chorus compared to the two silent
speakers or a fourth speaker simultaneously broadcasting the spectrally overlapping sound of a heterospecific (R. septentrionalis) chorus. These results are consistent with the hypothesis that male wood frogs could use the sound of a chorus as a beacon
to locate a short-lived breeding aggregation.
The acoustic properties of the environment influence sound propagation. Many previous studies examined whether various species of anurans, birds and mammals adjust usage and/or structure of their vocal signals to limit degradation during propagation in this environment (“acoustic adaptation hypothesis”). The present review examines how widespread such adaptations actually are across taxa. First, evidence for environment-related adjustments in usage of vocal signals is collected from studies in birds and other vertebrates (i.e., anurans and mammals). Second, a meta-analysis conducted by Boncoraglio & Saino (2007) on the influences of the environment on the acoustic structure of avian vocalisations is taken as a reference, and results from additional studies in birds are reviewed and compared to its conclusions. Finally, evidence from similar studies conducted in anurans and mammals is collected and discussed. Concerning the usage of vocal signals, evidence of environment-related adaptations in the few studies found was more widespread in anurans and mammals than in birds. Regarding structure of vocal signals, evidence from additional studies in birds did not completely confirm results of the meta-analysis of Boncoraglio & Saino (2007). Pooling all bird studies together presented minimum frequency, frequency modulations and frequency range as acoustic variables most often adjusted to the environment, in contrast to temporal features, repetition rate and maximum frequency. The few studies conducted in anurans and mammals did not allow the identification of specific acoustic variables that typically show environment-related variations. Overall, evidence for the acoustic adaptation hypothesis was not as widespread as expected across taxa. The different aspects of vocal behaviour adapted to environmental conditions varied according to the species and local habitats. Environment-related adjustments in structure of vocal signals seem to be constrained by call function in anurans and mammals. This effect was not examined in birds, but vocal learning does not appear to be a pre-requisite to environment-related adjustment in this group.
The divergence of signals along ecological gradients may lead to speciation. The current research tests the hypothesis that variation in sound absorption selects for divergence in acoustic signals along climatic gradients, which has implications for understanding not only diversification, but also how organisms may respond to climate change. Because sound absorption varies with temperature, humidity, and the frequency of sound, individuals or species may vary signal structure with changes in climate over space or time. In particular, signals of lower frequency, narrower bandwidth, and longer duration should be more detectable in environments with high sound absorption. Using both North American wood warblers (Parulidae) and bats of the American Southwest, this work found evidence of associations between signal structure and sound absorption. Warbler species with higher mean absorption across their range were more likely to have narrow bandwidth songs. Bat species found in higher absorption habitats were more likely to have lower frequency echolocation calls. In addition, bat species changed echolocation call structure across seasons, using longer duration, lower frequency calls in the higher absorption rainy season. These results suggest that signals may diverge along climatic gradients due to variation in sound absorption, although the effects of absorption are modest.
Auditory displays are becoming more and more common, but there are still no general guidelines for mapping data dimensions (e.g., temperature) onto display dimensions (e.g., pitch). This paper presents experimental research on different mappings and metaphors, in a generic process-control task environment, with reaction time and accuracy as dependent measures. It is hoped that this area of investigation will lead to the development of mapping guidelines applicable to auditory displays in a wide range of task domains.
Acoustic signals play a fundamental role in avian territory defence and mate attraction. Several studies have now shown that spectral properties of bird song differ between urban and rural environments. Previously this has been attributed to competition for acoustic space as a result of low-frequency noise present in cities. However, the physical structure of urban areas may have a contributory effect. Here we investigate the sound degradation properties of woodland and city environments using both urban and rural great tit song. We show that although urban surroundings caused significantly less degradation to both songs, the transmission efficiency of rural song compared to urban song was significantly lower in the city. While differences between the two songs in woodland were generally minimal, some measures of the transmission efficiency of rural song were significantly lower than those of urban song, suggesting additional benefits to singing rural songs in this setting. In an attempt to create artificial urban song, we mimicked the increase in minimum frequency found several times previously in urban song. However, this did not replicate the same transmission properties as true urban song, suggesting changes in other song characteristics, such as temporal adjustments, are needed to further increase transmission of an avian signal in the city. We suggest that the structure of the acoustic environment, in addition to the background noise, plays an important role in signal adaptation.
The study of the Weinstein Noise Sensitivity Index, a method for determining noise sensitivity, is discussed. It was found that the people who were noise sensitive (NS) were friendly, generous and sociable and very much aware of their environment. It is suggested that the noise management should include an effort to inform the NS population before they move into a noisy neighborhood. It is also suggested that using the Weinstein Noise Sensitivity Scale, emphasizing the positive side of being NS persons and avoiding mention of the statistical association with neuroticism, it will be possible to educate NS persons.
The acoustic adaptation hypothesis (AAH) predicts that vocalizations intended for unambiguous long range communication should possess amplitude modulation (AM) characteristics such that the temporal patterning of amplitude degrades less than alternative patterns during transmission through native habitat. The specific predictions are that open habitat signals should be structured as rapid AM trills, whereas closed habitat signals should be structured as low-rate AM tonal whistles. To investigate the benefit of trill- and whistle-structured signals in open and closed habitats, respectively, a high and low carrier frequency set of four synthetic signals which ranged from rapid AM trills to low rate AM whistles were transmitted 3 hours after sunrise through five different habitat types ranging from closed mature forest to open grassland. Results indicate that, on average, whistles degrade less than trills in both habitats. Trills benefit in open habitats through their tendency to be received with a more consistent quality than whistles. Such differences in transmission consistency among AM patterns are not found in closed habitats. While not degrading less on average, lower frequency signals are received with a more consistent quality than are higher frequency signals of the same AM structure, in both open and closed habitats.
Introduction All communication occurs in a network environment with the exception of a subset of systems that unequivocally meet both of the following criteria: (a) a signal can never be received by more than one receiver; (b) a receiver can never receive more than one signal simultaneously. In other words, all communication networks have at least one of two defining properties: (a) signals can be, at least potentially, received by several receivers; and (b) receivers can, at least potentially, receive signals from several signallers at any one time. Consequently, in moving from a dyadic consideration of communication to a network view, signallers and receivers both take on a range of costs and benefits, which are the theme of this book. In this chapter, I will consider the implications of a particular type of receiving behaviour that becomes possible in a network, namely eavesdropping. I will begin by reviewing different definitions of eavesdropping that are found in the literature and the evidence for different types of eavesdropping, distinguishing between eavesdropping on signals and eavesdropping on signal interactions. I will then examine the costs, benefits and implications of eavesdropping on interactions, as recognition of this phenomenon emerged from considerations of qualitative differences between dyadic and network views of communication (McGregor, 1993; McGregor & Dabelsteen, 1996).
The acoustic adaptation hypothesis (AAH) predicts that vocalizations intended for unambiguous long range communication should possess amplitude modulation (AM) characteristics such that the temporal patterning of amplitude is minimally degraded (due to atmospheric turbulence and reverberation) during transmission through native habitat. Specifically, signals should possess rapid AM (trills) in open habitats and low rate AM (whistles) in closed habitats. To determine which of these amplitude patterns incurs less degradation from its two main components, reverberation and irregular amplitude fluctuations (IAFs), we constructed two synthetic 'source' signals, a rapid AM 'trill' and a low rate AM 'whistle', from pure tone frequency sweeps. We applied the degradation components independently, thus avoiding their complex interactions typical of field recordings. Signals were degraded by various echo treatments (modeling closed habitat reverberation) or by various amplitude decrease treatments (modeling open habitat IAFs). Results revealed that the difference in performance between signal types lies not so much in their average transmission quality, as in the variability of that quality. In closed habitats, whistled signals transmit with more consistent quality than trilled signals over biologically realistic echo delays. In open habitats, trilled signals transmit with far lower variability of quality than do whistled signals. The inherent redundancy of trills transmits information more effectively than whistles in open habitats. Our results show strong support for the AAH predictions regarding what type of signal structure is best suited for open or closed habitats. However, this support is based on variability in performance of signal types in different habitats rather than average transmission quality.
Geographic variation in alarm calls of Gunnison's prairie dogs (Cynomys gunnisoni) was analyzed at regional and local scales. Alarm calls in response to a common stimulus (the same human) were recorded at four colonies near Flagstaff, Arizona, and at six sites throughout the southwestern United States. The acoustic structure of calls was analyzed for seven call variables. Regional differences fit the prediction of greater differences with increased geographical separation. Differences between colonies at a local scale were not related to geographical distance, suggesting that local dialects exist within a region. Differences in the level of predation by humans between colonies or habitat effects on sound propagation may explain variation in calls at the local level.
In this article, the author will argue that the act of listening through public soundwalks and other formal and informal exercises builds environmental and social awareness and promotes changes in social and cultural practices. By examining the act of listening as an alternative pathway and comparing the research, writings, and creative work of leaders of the acoustic ecology movement (i.e., R. Murray Schafer, Hildegard Westerkamp, and Bernie Krause), the author hopes to shed light on these potentials. For purposes of comparison, projects that explore the sonification and audification of inaudible signals will be examined, including the work of Christina Kubisch. The process of audification and sonification of these signals will be examined in comparison to soundscape experiences in order to develop a theory of data sonification based on the soundscape. In order to build a community around the urban soundscape, in 2003, the author co-founded the New York Society of Acoustic Ecology. Through this endeavor, she co-created the ongoing NYSoundmap and Sound Seeker projects, which provide some practical research for this article. Thus, by comparing and contrasting theoretical writings with leading listening exercises, public soundwalks, soundscape-related brainstorming sessions, and presenting field recordings in various settings, new methodologies will be documented.
Sound in public urban spaces is often considered in negative terms as both intrusive and undesirable – its referred to as noise! However, this issue is multi-facetted and goes much deeper than simply reducing levels. There are many positive aspects of a soundscape.In an attempt to progress thinking on positive soundscapes and move towards more practical planning approaches and decision making tools for soundscape assessment, this paper proposes an approach traditionally used in product development and manufacturing quality – The Kano Model. The approach is captured in the form of a broader framework which covers: the composition of a soundscape in objective terms; the factors affecting whether it might be perceived as positive; and how the Kano model for product development can be used as a means of understanding the range of applicability of approaches to create positive soundscapes (including several novel approaches which are the subject of other papers in this issue). It can be considered to be complementary with previous frameworks, some of which have concentrated on sound sources, others on the factors affecting perception or even as a model for understanding individual evaluation. In this case the motivation behind the framework is to help assess the likely impact of practical interventions on the positive aspects of a soundscape.The framework proposes that the meaning of “positive” for a public space is quite different for three types of people, each with a different level of direct engagement with the soundscape: planners; serious listeners; users of the space. The first two are influenced by the soundscape itself, either in meeting legislation and reducing nuisance, or as an artistic or creative opportunity. However the third, arguably most important group of people, users of the space, are more concerned with the space itself and have their perception of it influenced by the soundscape, which is an inconvenient and highly complex intermediate step. This influence is largely determined by their activity e.g. reading, holding a conversation, shopping or sightseeing.The paper discusses the further implementation of the framework, and how barriers to the wider application of the concept of positive soundscapes might be overcome. It shows how adapting an approach previously used in automotive sound quality can be adapted for urban soundscapes. It concludes with recommendations for taking the framework forward as a practical approach.
Describing resources and their relationships with organisms seems to be a useful approach to a ‘unified ecology’, contributing
to fill the gap between natural and human oriented processes, and opening new perspectives in dealing with biological complexity.
This Resource Criterion defines the main properties of resources, describes the mechanisms that link them to individual species,
and gives a particular emphasis to the biosemiotic approach that allows resources to be identified inside a heterogeneous
ecological medium adopting the eco-field model. In particular, this Criterion allows to couple matter, structured energy and
information composing the ecological systems to the biosemiotic and cognitive mechanisms adopted by individual species to
track resources, transforming neutral surroundings into meaningful species-specific Umwelten. The expansion of the human semiotic niche that is a relevant evolutionary process of the present time, assigns the role
of powerful and efficient agency to the Resources Criterion to evaluate the effect of human intrusion into the natural systems
with habits of key stone species, under the challenge of a growing use of alloctonous, immaterial and symbolic resources of
the actual globalized societal models. The Resource Criterion interprets the ecological dynamics contributing to complete
the epistemology of the ecology, to open a bridge toward economy and other societal sciences, and to contribute to formulate
a General Theory of Resources.
Marine sound, natural or anthropogenic,has long fascinated scientists, mariners, andthe general public. The haunting songs ofhumpback whales and the pings of antisubmarinesonar, among other sounds from theoceans, convey allure and suspense.
Ambient noise was measured once a month in the Salton Sea, California, from January to August 1970 with a calibrated recording system. The nighttime spectrum level at 1000 Hz increased nearly 50 dB from January to May. The change in level resulted entirely from a chorus of sounds produced by a single species of fish—the orangemouth corvina, Cynoscion xanthulus. The seasonal peak of sound production coincided with their breeding season. This increase in ambient noise level is the greatest sustained effect ever reported from underwater natural causes.
Transmission of random noise through dense corn, a dense hemlock plantation, an open pine stand, dense hardwood brush, and over cultivated soil was measured. The relation between attenuation and frequency in these diverse cases suggested models that permit the prediction of attenuation in any configuration of vegetation and soil. The corn crop had an excess attenuation of 6 dB/100 ft for each doubling of frequency between 500 and 4000 Hz. On the other hand, the stems of the hemlock, pine, and brush all reduced noise by only about 5 dB/100 ft at 4000 Hz. Bare ground attenuates frequencies of 200–1000 Hz, and the frequency of maximum attenuation depends on the soil permeability to air. Thus, tilling the soil reduced the frequency of peak attenuation from 700 to 350 Hz and increased maximum attenuation at 52 m from the source by nearly 80%. Furthermore, earlier conflicting reports of noise attenuation by vegetation appear reconciled if ground attenuation is taken into account. Scattering and ground attenuation are the principal factors in sound attenuation by vegetation. Both factors attenuate relatively less sound as distance from the sound source increases. Hence measurements far from the source can underestimate the effect of a narrow band of vegetation or soil.