Effects Of Anthropogenic Noise Research Articles

The effects of anthropogenic noise on frogs housed on exhibit at a public aquarium.

Anuran behavior and reproduction are dominated by vocalizations, rendering them vulnerable to the effects of signal masking. For anurans on display in zoos and aquaria, a major source of ambient noise is visitors, which pose a unique source of potential anthropogenic signal masking. Call characteristics (total call duration, and minimum and maximum call frequencies) of three populations of dendrobatids (Dendrobates leucomelas, Epipedobates tricolor, and Ranitomeya imitator) on public display were investigated at time periods of increasing visitor-related noise (closed, off-peak, and peak aquarium visiting hours) to determine if there were changes in call characteristics that correlated with changes in visitor noise levels. The data revealed that call length increased with more visitor noise for D. leucomelas and E. tricolor, with their longest calls during peak hours, and all three species had their shortest calls during closed hours. Both minimum and maximum call frequencies increased with more visitor noise for E. tricolor and R. imitator, with their highest frequencies during peak hours, and lowest frequencies during closed hours. This study found evidence that anurans on public display adjust their vocalizations in the presence of visitor noise. These findings support expanded monitoring of ambient noise for animals on public display to determine if noise poses significant effects that might influence well-being or reproduction.

Difference in acoustic responses to urbanisation in two African passerines

Modification of ecosystems as a consequence of urbanisation alters natural habitat structures and soundscapes, creating constraints for vocal communication in animals. Birds are able to adjust their vocalisation to the prevailing acoustic features of their habitat. As such, their sounds have been shown to reflect the level of anthropogenic disturbances across landscapes. While the effect of a single anthropogenic disturbance like ambient noise on birds’ vocal communication is widely investigated, the combined effects of various disturbances remain less explored. We tested single and combined effects of anthropogenic noise and urban physical structures on the vocalisations of two African passerines, the Common Bulbul Pycnonotus barbatus and Northern Grey-headed Sparrow Passer griseus. We predicted that (i) both species would increase the minimum frequency of their vocalisation to avoid masking by ambient noise, (ii) both species would decrease their maximum frequency to evade distortion by physical structures, (iii) the two urban components would have a significant combined effect on the vocalisations, and (iv) the change in minimum or maximum frequency will lead to a corresponding change in the vocalisation bandwidth. For the Common Bulbul, the minimum frequency increased significantly as the ambient noise level increased, but the maximum frequency did not change in response to urban physical structures. For the Northern Grey-headed Sparrow, the minimum frequency did not show a response to ambient noise, but the maximum frequency decreased significantly as physical structures and ambient noise increased. We did not find any evidence for a combined effect of urban physical structures and ambient noise on the vocal adjustment of either species. A change in either the minimum or maximum frequency resulted in a corresponding change in the vocalisation bandwidth of each species. Our findings highlight how the same vocalisation traits of different songbird species can be affected differently by novel selective pressures in acoustic communication that arise in urban environments.

Characterization of anthropogenic noise and oyster toadfish (Opsanus tau) calling behavior in urban and small-town coastal soundscapesa).

The oyster toadfish (Opsanus tau) is an ideal model to examine the effects of anthropogenic noise on behavior because they rely on acoustic signals for mate attraction and social interactions. We predict that oyster toadfish have acclimated to living in noise-rich environments because they are common in waterways of urban areas, like New York City (NYC). We used passive acoustic monitoring at two locations to see if calling behavior patterns are altered in areas of typically high boat traffic versus low boat traffic (Pier 40, NYC, NY, and Eel Pond, Woods Hole, MA, respectively). We hypothesized that toadfish in NYC would adjust their circadian calling behavior in response to daily anthropogenic noise patterns. We quantified toadfish calls and ship noise over three 24-h periods in the summer reproductive period at both locations. We observed an inverse relationship between the duration of noise and the number of toadfish calls at Pier 40 in comparison to Eel Pond. Additionally, toadfish at Pier 40 showed significant differences in peak calling behavior compared to Eel Pond. Therefore, oyster toadfish may have acclimated to living in an urban environment by potentially altering their communication behavior in the presence of boat noise.

The effects of anthropogenic noise and urban habitats on song structure in a vocal mimic; the gray catbird (Dumetella carolinensis) sings higher frequencies in noisier habitats

In urban and human-modified landscapes, animals face novel selection pressures resulting from differences in habitat structure and increased anthropogenic noise. Urban noise pollution can negatively impact songbirds because low-frequency noise often masks portions of birds’ mating signals and reduces signal transmission. Previous research has demonstrated that the songs of birds in more urban habitats have structural differences that can enhance signal transmission when noise is present. The majority of these studies have focused on species that deliver short, stereotyped songs and have limited repertoires. Gray catbirds (Dumetella carolinensis, family: Mimidae) sing long bouts containing imitated, improvised, and invented song elements, and therefore may have an increased ability to vary songs in response to noise. We hypothesized that aspects of developed habitats including loud anthropogenic noise and changes to land cover would impact catbirds’ song structural parameters, including song minimum, peak, and maximum frequency, frequency bandwidth, and entropy. We recorded and processed songs from 42 male catbirds and analyzed over 18,000 song elements from sites along an urban gradient from western Virginia to the Washington, DC metropolitan region. We quantified the urban intensity at each site-centroid based on percent canopy cover, percent impervious surface, and noise level. Song features such as minimum, maximum, and peak frequency increased significantly as noise levels increased, demonstrating that catbirds in noisier areas sing higher frequency songs compared to individuals in quieter habitats. Land cover variables also significantly predicted certain song features such as maximum frequency (impervious surface) or entropy (canopy cover). These structural differences in catbird song can limit the negative effects of environmental noise-masking, even for their long song bouts, and suggest that vocal mimics respond to anthropogenic noise. Future studies could investigate repertoire size and composition along an urban gradient and if these structural differences lead to functional consequences for the songs of vocal mimics.

Stay here, but keep quiet: the effects of anthropogenic noise on Guiana dolphins (Sotalia guianensis) in southeastern Brazil

Stay here, but keep quiet: the effects of anthropogenic noise on Guiana dolphins (Sotalia guianensis) in southeastern Brazil

Cognition mediates response to anthropogenic noise in wild Western Australian magpies (Gmynorhina tibicen dorsalis).

Anthropogenic noise is a pollutant of growing concern, with wide-ranging effects on taxa across ecosystems. Until recently, studies investigating the effects of anthropogenic noise on animals focused primarily on population-level consequences, rather than individual-level impacts. Individual variation in response to anthropogenic noise may result from extrinsic or intrinsic factors. One such intrinsic factor, cognitive performance, varies between individuals and is hypothesised to aid behavioural response to novel stressors. Here, we combine cognitive testing, behavioural focals and playback experiments to investigate how anthropogenic noise affects the behaviour and anti-predator response of Western Australian magpies (Gymnorhina tibicen dorsalis), and to determine whether this response is linked to cognitive performance. We found a significant population-level effect of anthropogenic noise on the foraging effort, foraging efficiency, vigilance, vocalisation rate and anti-predator response of magpies, with birds decreasing their foraging, vocalisation behaviours and anti-predator response, and increasing vigilance when loud anthropogenic noise was present. We also found that individuals varied in their response to playbacks depending on their cognitive performance, with individuals that performed better in an associative learning task maintaining their anti-predator response when an alarm call was played in anthropogenic noise. Our results add to the growing body of literature documenting the adverse effects of anthropogenic noise on wildlife and provide the first evidence for an association between individual cognitive performance and behavioural responses to anthropogenic noise.

Finite-element modeling on noise impacts and hearing in marine fauna

Despite increasing interest in the effects of anthropogenic noise on marine fauna, relevant research is limited, particularly in those inaccessible species. Unfortunately, some of these inaccessible species are endangered, such as the little penguins (Eudyptula minor) and Australian sealions (Neophoca cinerea). In this study, we collected freshly deceased bight redfish (Centroberyx gerrardi), little penguins, and Australian sealion for medical computed tomography (CT)/microCT scans. Ear structures were reconstructed based on high-resolution imaging data for the three species. Moreover, 3D finite-element models were built to simulate the sound reception processes and ear responses to the incident planar waves from various directions toward the heads. The received sound pressure levels and motion (e.g., displacement and acceleration) of the internal ear related structures were computed. The data was used to predict the absolute hearing curves of the little penguins and Australian sealions. Our results also indicate that the motion difference plus the geometry of the otoliths plays an important role in the fish otoliths' response to incident sounds from different directions, resulting in different levels of damage to the hair cells. This study may potentially aid researchers in investigating the hearing of some other marine animals.

From ocean ambient noise to soundscape ecology

Ambient noise in the ocean has been studied for more than 80 years but recently there has been a tendency to use the word “soundscape” for what appears to be the same phenomenon. Ambient noise is usually defined as the background noise from all sources, excluding sounds from individual identifiable sources and is an important limitation on sonar performance and the use of sound by marine animals. The term “soundscape” has been used for decades outside of underwater acoustics with varying definitions depending on the application. Probably the most relevant is “soundscape ecology,” which comes from terrestrial ecology and includes the acoustic interaction between animals and between animals and their environment. A soundscape, therefore, includes all sounds in an environment, not just the background or ambient noise. Sounds from individual identifiable sources may have particular interest to marine animals especially if they are from conspecifics, predators, or prey. This paper discusses the value of applying the broader concepts of soundscapes and soundscape ecology to the underwater environment, the advantages of recognizing the distinction between soundscapes and ambient noise and the importance of soundscape ecology in understanding animal acoustic behavior and the effects of anthropogenic noise.

The silent assumption of the masking hypothesis: avian auditory processing and implications for behavioral responses to anthropogenic noise

Anthropogenic noise and its impact on wildlife has recently received considerable attention. Research interest began to increase at the turn of the century and the number of publications investigating the effects of anthropogenic noise has been growing steadily ever since. Songbirds have been a major focus in the study of anthropogenic noise effects, with a significant portion of the literature focusing on the changes in singing behavior in noise. Many of these studies have found increases in the amplitude or frequency of song, or changes in the temporal patterning of song production, putatively due to the masking effects of noise. Implicit in the masking hypothesis is the assumption that all species process sounds in noise similarly and will therefore be subject to similar masking effects. However, the emerging comparative literature on auditory processing in birds suggests that there may be significant differences in how different species process sound, both in quiet and in noise. In this paper we will (1) briefly review the literature on anthropogenic noise and birds, (2) provide a mechanistic overview of how noise impacts auditory processing, (3) review what is known about the comparative avian auditory processing in noise, and (4) discuss the implications of species level differences in auditory processing for behavioral and physiological responses to anthropogenic noise.

Effects of anthropogenic noise and natural soundscape on larval fish behavior in four estuarine species.

The larval and post-larval forms of many marine organisms, such as oysters, crabs, lobster, coral, and fish, utilize ambient acoustic cues to orient, settle, or metamorphose. In this study, the effect of anthropogenic and ambient sounds on the orientation behavior of four larval estuarine fishes was examined in a controlled, laboratory experiment. Pre-settlement size red drum Sciaenops ocellatus, southern flounder Paralichthys lethostigma, spotted seatrout Cynoscion nebulosus, and Florida blenny Chasmodes saburrae larvae were exposed to four sound treatments-control, estuarine soundscape, seismic airguns, and large-ship passage-in a linear acoustic chamber. Initial significant (p < 0.05) avoidance of airguns was observed in three of the four species (all but the Florida blenny), but habituation to this sound occurred as the experiment progressed. All species avoided ship passage sounds; however, the avoidance behavior was not significant. Interestingly, none of the species studied were significantly attracted to the acoustic cues alone of the estuarine soundscape; in fact, three of the four species spent less time near the speaker when it was broadcast. These results suggest that larval fish can potentially habituate to anthropogenic noise relatively quickly (<10 min). Understanding how sounds affect larval behavior is necessary because successful recruitment ultimately affects a population's success.

The effect of anthropogenic noise on foraging and vigilance in zoo housed pied tamarins

The phenomenon of human-induced rapid environmental change (HIREC) is a great challenge in the modern world that presents a threat to all species. Research on the effect of anthropogenic noise on free-living wildlife is increasing but the effect of anthropogenic noise on the behaviour and welfare of captive wildlife has received limited attention, even though captive settings are full of human activity and a wide range of sounds. Moreover, studies in captivity tend to classify noise subjectively by volume according to human hearing and as part of the overall ‘visitor effect’ rather than a stressor in its own right. Research on free-living wildlife suggests that anthropogenic noise can negatively impact foraging behaviour; similar impacts in captive species could have a detrimental effect on their health and welfare if animals cannot perform functional feeding behaviours and access adequate nutrition. In the current study, we designed a forage box experiment for captive pied tamarins, a Critically Endangered callitrichid primate species that is prone to poor physical health and breeding success in captivity. Ten pairs of tamarins housed at Jersey Zoo were provided with a forage box containing cryptic (hidden) prey items (waxworms). Using a within-subjects design, tamarins were provided access to the forage box in noise and non-noise conditions of anthropogenic noise (machinery used for gardening in the zoo). Both active (foraging with the hands) and observational (looking into the forage box) foraging were significantly less frequent in the presence of anthropogenic noise; however, there was no difference in the duration of these behaviours or in foraging success. Furthermore, the presence of anthropogenic noise did not significantly affect vigilance behaviour. We found no sex differences in the effect of noise, and our results suggest that the anthropogenic noise we tested was only a minimal distractor for tamarins. However, large individual differences in foraging suggest that other factors may have a larger impact on foraging than the anthropogenic noise used in this experiment. More research into how captive animals may respond to the presence of anthropogenic noise is needed.

A Quieter Ocean: Experimentally Derived Differences in Attentive Responses of Tursiops truncatus to Anthropogenic Noise Playbacks before and during the COVID-19-Related Anthropause

The effects of anthropogenic noise continue to threaten marine fauna, yet the impacts of human-produced sound on the broad aspects of cognition in marine mammals remain relatively understudied. The shutdown of non-essential activities due to the COVID-19-related anthropause created an opportunity to determine if reducing levels of oceanic anthropogenic noise on cetaceans affected processes of sensitization and habituation for common human-made sounds in an experimental setting. Dolphins at Dolphin Quest Bermuda were presented with three noises related to human activities (cruise ship, personal watercraft, and Navy low-frequency active sonar) both in 2018 and again during the anthropause in 2021 via an underwater speaker. We found that decreased anthropogenic noise levels altered dolphin responses to noise playbacks. The dolphins spent significantly more time looking towards the playback source, but less time producing burst pulse and echolocation bouts in 2021. The dolphins looked towards the cruise ship sound source significantly more in 2021 than 2018. These data highlight that different sounds may incur different habituation and sensitization profiles and suggest that pauses in anthropogenic noise production may affect future responses to noise stimuli as dolphins dishabituate to sounds over time.

Assessing the influence of rocket launch and landing noise on threatened and endangered species at Vandenberg Space Force Base

Understanding how species of concern respond to anthropogenic activities is becoming increasingly important. While the ways in which anthropogenic activities affect species are many, our understanding the effects of anthropogenic noise on species is still developing. Vandenberg Space Force Base (VSFB) along the California Central Coast presents a unique opportunity to study the effects of anthropogenic noise on species of concern as (1) the rate of rocket launches/landings is predicted to significantly increase in the coming years compared to the last three decades and (2) there are multiple threatened and endangered species at VSFB that may be impacted by the increased launch cadence. Our interdisciplinary research team composed of wildlife biologists and acousticians will be studying the short and long-term behaviors of threatened and endangered shorebirds that nest relatively close to active VSFB launch complexes. Using previously collected and current bird counts and acoustic data from VSFB, models will be created that describe behavioral changes in species of concern. We will discuss the scope and overview of this project.

A legacy of excellence: SAY’s contributions to bioacoustics research at the Navy Marine Mammal Program

The dolphin SAY is considered a jack-of-all-trades in marine mammal science. This comes as no surprise as her mother was one of the five dolphins deployed to Cam Ranh Bay, Vietnam as part of the Navy’s first deployable marine mammal system. SAY was born in 1979 and began participating in research from birth; she was the first dolphin to have her caloric intake and weight tracked as a calf into adulthood, and while carrying her own calf in 1991. In her early years, she participated in cutting-edge studies using high-speed video endoscopy to better understand dolphin click production. She later participated in echolocation vigilance tasks that spearheaded our understanding of dolphin cognitive abilities focusing on duration and the effects of anthropogenic noise. During this same time, she diligently contributed to projects that revolutionized our understanding of dolphin biosonar and its relation to perception and auditory system neurophysiology. SAY will be remembered by her charismatic personality and her 38 years of service to science and the United States Navy. Her daughter continues to carry out her legacy working for the Navy’s fleet mine-hunting system.

Temporary threshold shifts in Boris the bottlenose dolphin (Tursiops truncatus), varying noise duration and intensity

There is much concern regarding increasing noise levels in the ocean and how it may affect marine mammals. Early on, there was little information regarding how sound affects marine mammals and no empirical data on the relationship between noise intensity and exposure duration. Working with Boris the bottlenose dolphin, Tursiops truncatus, we explored the effects of octave-band noise, and sonar signals on odontocete hearing and noise-induced temporary hearing threshold shifts (TTS). Sound pressure levels (SPLs) and exposure durations were varied to measure the effects of exposure duration and amplitude. Hearing thresholds were initially measured behaviorally, and later using auditory evoked potentials before and after sound exposure to track TTS and recovery. These efforts showed that threshold shifts were not linear but rather shorter sounds required greater sound exposure levels to induce TTS; a contrast to some early published literature. Further, sound exposure levels of sonar signals required to induce TTS were high, supporting the notion that relatively short sounds must be of relatively high intensity to induce threshold shifts. From these data and this remarkable animal, a novel algorithm was written that predicts the physiological effects of anthropogenic noise if the intensity and duration of exposure are known.

Acoustic monitoring to evaluate the effect of anthropogenic noise within a park

The aim of this paper is to propose the use of passive acoustic monitoring (PAM) as a non-invasive method to investigate the state of communities and ecosystems. PAM operates through the study and characterization of the soundscape of an area. One of the three components of the soundscape (beside geophony and biophony) is anthrophony, which is the collection of sounds produced by human activities. This kind of sounds can have effects on natural envi-ronments and natural population. In this study, recording instruments and sampling tech-niques have been used to acquire and collect sound data for long periods (two weeks) in a nat-ural terrestrial ecosystem (Ticino Park) which is affected by road and rail traffic noise. The analysis conducted studied the trends of the eco-acoustic indices belonging to three measure-ment sites to detect the presence of characteristic trends and to evaluate the influence of the two anthropogenic noise sources at different distances.

The effects of anthropogenic noise on nest predation with respect to predator species across different habitats and seasons

Noise pollution is a major component of sensory pollution that can disrupt the well-being and functioning of living organisms, affect a variety of life history traits in animals, and reduce their reproductive success. In this study, we used artificial nest experiments with noise manipulation to investigate the influence of anthropogenic noise on nest predation during the breeding and non-breeding seasons and in different forest habitats. We found that the noise treatment did not alter the predation rates or survival probabilities of birds in artificial nests. However, the diversity and species composition of nest predators in artificial pine forests varied between breeding and non-breeding seasons, which may be explained by season-specific adaption of nest predators to bird nests or the unstable ecosystems of artificial forests. The diversity and species composition of nest predators differed between the different forests, probably because of differences in habitat heterogeneity. Predation time varied with treatment, season, and habitat, although most predators were nocturnal mammals. Niche segregation or changes in optimal foraging time may explain this phenomenon.

Effects of anthropogenic noise on cognition, bill color, and growth in the zebra finch (Taeniopygia guttata)

Effects of anthropogenic noise on cognition, bill color, and growth in the zebra finch (Taeniopygia guttata)

Differential effects of anthropogenic noise and vegetation cover on the breeding phenology and success of two urban passerines

The urban environment is associated with a multitude of challenges and stressors for populations of wild species from the surrounding natural environment. Among those, habitat fragmentation and noise pollution are suspected to have negative effects on the behavior and physiology of free-living birds in urban areas. Exposure in early life and chronic exposure to anthropogenic noise could be particularly deleterious, with short-and long-term consequences. In this study, we investigated if noise levels in city parks affect the distribution and reproductive success of two common bird species in the urban environment, the great tit (Parus major) and the blue tit (Cyanistes caeruleus) and if vegetation cover could mitigate those effects. We predicted that high noise levels might correlate with a decreased nest-box occupancy rate, a delayed laying date or a decreased clutch size, hatching, and fledging success. On the contrary, vegetation cover was expected to correlate positively with nest occupancy rate, advanced laying date, increased clutch size, hatching, and fledging success. We used data from population monitoring collected between 2012 and 2019 in parks and green public spaces in the city center and suburbs of Paris, France, and did not find any correlation between nest occupancy rates and noise levels or vegetation cover for both species. Laying date was not significantly related to anthropogenic noise in any species but was delayed with increasing vegetation cover in the great tit, while we did not find any association with clutch size. Hatching success in blue tits negatively correlated with increasing noise levels, and positively with increasing vegetation coverage. Finally, we did not find any correlation between anthropogenic noise or vegetation cover and the clutch size or fledging success in both species. In this study, two closely related species that share a common environment show a different sensibility to environmental parameters during reproduction, a key period for population maintenance. It also highlights the importance of considering multiple parameters when studying wild populations living in the urban environment.

Context-dependent effects of anthropogenic noise on nest defence in a singing toadfish

Noise pollution has been steadily increasing in the ocean, negatively affecting aquatic ecosystems by causing both behavioural and physiological deficits for many marine animals, including fishes. To date, most research investigating the effects of noise on fishes has been conducted in controlled laboratory settings; however, these experimental conditions often lack ecological validity, and it is largely unknown whether the effects observed in aquaria are representative of real-world responses for animals experiencing noise in the wild. In this study, we used a combination of laboratory and field playback experiments to assess the effects of noise on nest defence and parental care behaviours in an intertidal-breeding toadfish, the plainfin midshipman, Porichthys notatus . Nest-guarding males without eggs in the laboratory exhibited a nearly four-fold increase in defensive behaviours under boat noise playbacks compared to under ambient conditions. However, in the field, no significant changes were detected in the defensive or parental behaviours by guarding males with eggs under exposure to noise. Our study demonstrates that anthropogenic noise can impact nest defence behaviour in plainfin midshipman males, but also that its impact depends on contextual cues such as testing environment, presence of eggs and the noise stimulus used. Our results highlight the urgent need for more field studies and for studies that pair and compare laboratory versus field results to quantify and mitigate the potential harm caused by noise pollution to organisms and populations in coastal environments. • We tested whether noise affects defence or parental care in plainfin midshipman. • Nest-guarding males in the laboratory were more defensive during boat noise. • Egg-guarding males in the field did not alter nest defence or parental care. • Males in the field were more defensive than nest-guarding males in tanks. • The effects of anthropogenic noise depend on context.