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Abstract

Emerging evidence indicates that anthropogenic noise has highly detrimental impacts on natural communities; however, the effects of noise on acoustically specialized predators has received less attention. We demonstrate experimentally that natural gas compressor station noise impairs the hunting behavior of northern saw-whet owls (Aegolius acadius). We presented 31 wild-caught owls with prey inside a field-placed flight tent under acoustic conditions found 50–800 m (46–73 dBA) from a compressor station. To assess how noise affected hunting, we postulated two hypotheses. First, hunting deficits might increase with increasing noise—the dose–response hypothesis. Secondly, the noise levels used in this experiment might equally impair hunting, or produce no impact—the threshold hypothesis. Using a model selection framework, we tested these hypotheses for multiple dependent variables—including overall hunting success and each step in the attack sequence (prey detection, strike, and capture). The dose–response hypothesis was supported for overall hunting success, prey detection, and strike behavior. For each decibel increase in noise, the odds of hunting success decreased by 8% (CI 4.5%–11.0%). The odds of prey detection and strike behavior also decreased with increasing noise, falling 11% (CI 7%–16%) and 5% (CI 5%–6%), respectively. These results suggest that unmitigated noise has the potential to decrease habitat suitability for acoustically specialized predators, impacts that can reverberate through ecosystems.

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... Recent experiments using playbacks of anthropogenic noise revealed that increasing industrial noise levels negatively affect the hunting success of northern saw-whet owls, Aegolius acadicus (Mason et al. 2016), and traffic noise reduces the foraging efficiency of long-eared owls, Asio otus, and short-eared owls, Asio flammeus (Senzaki et al. 2016). There is other evidence to suggest that owls may be sensitive to noise; spotted owls (Strix occidentalis), for example will flush from nests more frequently with increased proximity to a temporary noise stimulus (Delaney et al. 1999). ...
... When hunting at night, owls also use acoustic cues made by prey, such as rustling leaves, to aid in prey capture (Payne 1971, Martin 1990). Increasing industrial noise levels negatively affect the hunting success of northern saw-whet owls, Aegolius acadicus (Mason et al. 2016), and reduce the foraging efficiency of long-eared owls, Asio otus, and short-eared owls, Asio flammeus (Senzaki et al. 2016). However, a study on the nocturnal space use of western burrowing owls, Athene cunicularia hypugaea, found they did not avoid areas affected by anthropogenic noise (Scobie et al. 2016). ...
... Two recent studies have estimated hunting success and hunting efficiency of owls in the presence of anthropogenic noise (Mason et al. 2016, Senzaki et al. 2016). The conclusions of both these studies were that noise levels corresponding to 120 m from a road and 200 m from a compressor station results in reduced detection of prey (Senzaki et al. 2016) and lower capture success of prey (Mason et al. 2016). ...
Thesis
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Anthropogenic disturbance is known to have negative population consequences and alter animal behaviour, and a growing body of research on the effects of anthropogenic noise is finding similar negative impacts on wildlife. Noise in natural environments can mask important acoustic signals used for animal communication. Owls use vocal communication to attract mates and defend territories, and rely on acoustic cues to locate their prey. Industrial noise has been shown to negatively affect owl hunting success and reduce foraging efficiency by affecting their ability to detect prey, but whether this results in reduced habitat suitability for owls in areas near industrial noise sources is largely unknown. It is also not known if the abundance of small mammals, the primary prey of owls, is affected by industrial noise. Communication between small mammals is unlikely to be directly affected by noise because they primarily communicate using olfactory rather than vocal signals, but small mammals could be indirectly affected through altered predation dynamics. I sought to determine if owls avoid the areas surrounding chronic industrial noise sources, if prey availability is affected by chronic industrial noise, and the relative importance of noise compared to other types of disturbance resulting from industrial development on owl habitat use. I used autonomous recording units and automated recognizers to survey for owls and scan recordings for owl vocalizations, to assess the impacts of disturbance from industrial development on owls in northeastern Alberta, a region that has seen increased development in the oil and gas industries in recent years. I found that barred owls (Strix varia), great horned owls (Bubo virginianus), and boreal owls (Aegolius funereus) were equally likely to occupy noisy sites compared to sites with no noise, indicating that site-level occupancy (representing a home range scale) was unaffected by the presence of noise sources on the landscape. I found no difference in abundance or activity of red-backed voles (Myodes gapperi) iii and deer mice (Peromyscus maniculatus), indicating that these important prey species are not strongly affected by noise. Finally, I found each owl species responded differently to the different disturbance types. Barred owls were less likely to be present in areas with greater proportions of human footprint and roads, whereas great horned owls were more tolerant to disturbance and were more likely to be present in areas with greater proportions of soft linear features (e.g. seismic lines, pipelines), though they did avoid areas with large industrial facilities. Boreal owl presence was more strongly affected by forest composition than disturbance; they prefer more coniferous forests, and it was less clear if they were sensitive or relatively tolerant to disturbance. Assessing the relative impacts of multiple types of disturbance and how the accumulation of disturbances can impact wildlife is important in understanding species declines and can help focus conservation efforts. My thesis contributes to research on the impacts of anthropogenic disturbance and suggests the effect of noise on barred owls, great horned owls, and boreal owls is minimal at the spatial scales I looked at. Similarly, the effect of noise on abundance and activity of red-backed voles and deer mice was weak, suggesting similar prey availability for owls. For the owl species I studied, forest composition and other types of disturbance on the landscape are more likely to influence their habitat use.
... Apart from limiting intra-specific communication, noise disrupts predator-prey interactions, which are largely dependent on acoustic signals used to locate both prey and predator. Noise could reduce hunting efficiency of listening predators (Francis et al. 2012b;Mason et al. 2016;Senzaki et al. 2016;Agha et al. 2017) and impair the anti-predatory behaviors of listening prey (Shannon et al. 2016;Petrelli et al. 2017). This could force predators to change foraging techniques (Mason et al. 2016) and/or avoid habitats under high noise levels Ciach 2017, 2018). ...
... Noise could reduce hunting efficiency of listening predators (Francis et al. 2012b;Mason et al. 2016;Senzaki et al. 2016;Agha et al. 2017) and impair the anti-predatory behaviors of listening prey (Shannon et al. 2016;Petrelli et al. 2017). This could force predators to change foraging techniques (Mason et al. 2016) and/or avoid habitats under high noise levels Ciach 2017, 2018). Noise also leads to an increase in vigilance of potential prey (Shannon et al. 2016;Petrelli et al. 2017) and has an impact on prey mortality (Francis et al. 2012b). ...
... Most owls are acoustic predators (Mikkola 1983); thus, noise limits their foraging efficiency (Mason et al. 2016;Senzaki et al. 2016) and may influence nest site selection of some species (Fröhlich and Ciach 2017). Development of road networks, which are considered as a main source of anthropogenic noise, could force owls to abandon seemingly suitable habitats (Hindmarch et al. 2012), which can lead to a decrease in their population density (Silva et al. 2012). ...
Article
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Habitat loss and fragmentation are listed among the most significant effects of urbanization, which is regarded as an important threat to wildlife. Owls are the top predators in most terrestrial habitats, and their presence is a reliable indicator of ecosystem quality and complexity. However, influence of urbanization on owl communities, anthropogenic noise in particular, has not been investigated so far. The aim of this study was to identify the role of noise and landcover heterogeneity in the species richness of owl assemblage in the urban ecosystem. Owls were surveyed in the city of Kraków (southern Poland) on 65 randomly selected sample plots (1 km²). The area of main landcover types, landcover diversity index, mean size of landcover patch, and nocturnal noise level were defined within the sample plots and correlated with owl species richness. Five owl species were recorded in the study area with forests as the dominant landcover type for Tawny and Ural owls, grasslands for Long-eared and Barn owls, and gardens for Little owls. In total, 52% of sample plots were occupied by at least one species (1–3 species per plot). The number of owl species was positively correlated with landcover diversity index and negatively correlated with nocturnal noise emission. This study demonstrates that species richness of owls in urban areas may be shaped by landcover heterogeneity and limited by noise intensity. This indicates that noise changes top predator assemblage, which in consequence may disturb predator-prey interactions within human-transformed habitats.
... Despite recognition that human-weighting of sound pressure levels is understood to be potentially unsuitable for wildlife [16,27], we found that most terrestrial studies nonetheless evaluated responses to A-weighted sound pressure levels. In addition to thresholds for people [28,29], the final suite of terrestrial species (or genus) contrasted against in-air received levels were: marbled murrelet [30], owls [31][32][33], harlequin duck (Histrionicus histriónicas) [34], and caribou (Rangifer tarandus) [35]. Marine species selected for contrast with underwater received levels were: killer whales [36], common murre [37], harbor porpoise (Phocoena phocoena) [38], herring (Clupea harengus) [39], and California sea lion (Zalophus californianus) [40]. ...
... The remaining 70 events were Growlers, with a maximum of two aircraft observed at any one time; 13 events of Growlers taking off were also audible but not visible. [31], 50% chance of nest flushing [32], and 50% reduction in the probability of prey detection and hunting strikes [33]; humans, 67 dBA = 50% probability of awakening at night [29] and increases in nighttime blood pressure [28]; harlequin duck, 80 dBA = reduced courtship and increased vigilance and agonism [34]; marbled murrelet, 92 dBA = risk of disturbance in nesting marbled murrelets [30]; caribou, 98 ASEL (A-weighted sound exposure level) = interrupted resting bouts and increased activity [35]. (Note: The threshold for caribou was reported in ASEL which likely overestimates RL (dBA).) ...
... The distribution of received levels (RL) for (a) 23 in-air overflight events and (b) 10 flight events recorded under water relative to thresholds known to cause behavioral and physiological responses in humans and representative suites of terrestrial and marine wildlife. In-air: owls, 60 dBA = physiological stress responses [31], 50% chance of nest flushing [32], and 50% reduction in the probability of prey detection and hunting strikes [33]; humans, 67 dBA = 50% probability of awakening at night [29] and increases in nighttime blood pressure [28]; harlequin duck, 80 dBA = reduced courtship and increased vigilance and agonism [34]; marbled murrelet, 92 dBA = risk of disturbance in nesting marbled murrelets [30]; caribou, 98 ASEL (A-weighted sound exposure level) = interrupted resting bouts and increased activity [35]. (Note: The threshold for caribou was reported in ASEL which likely overestimates RL (dBA).) ...
Article
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Military operations may result in noise impacts on surrounding communities and wildlife. A recent transition to more powerful military aircraft and a national consolidation of training operations to Whidbey Island, WA, USA, provided a unique opportunity to measure and assess both in-air and underwater noise associated with military aircraft. In-air noise levels (110 ± 4 dB re 20 µPa rms and 107 ± 5 dBA) exceeded known thresholds of behavioral and physiological impacts for humans, as well as terrestrial birds and mammals. Importantly, we demonstrate that the number and cumulative duration of daily overflights exceed those in a majority of studies that have evaluated impacts of noise from military aircraft worldwide. Using a hydrophone deployed near one runway, we also detected sound signatures of aircraft at a depth of 30 m below the sea surface, with noise levels (134 ± 3 dB re 1 µPa rms) exceeding thresholds known to trigger behavioral changes in fish, seabirds, and marine mammals, including Endangered Southern Resident killer whales. Our study highlights challenges and problems in evaluating the implications of increased noise pollution from military operations, and knowledge gaps that should be prioritized with respect to understanding impacts on people and sensitive wildlife.
... Hearing sensitivities among predators of rodents are likely reflected by this general range (~1-8 kHz). Many predators target rodents using acoustic cues for prey detection (reviewed in Barber et al., 2010) and interference from the soundscape is known to result in declines in prey detection and hunting success (Mason et al., 2016;Senzaki et al., 2016). Lower prey capture success could lead to predators avoiding louder areas, which could then have direct effects on rodent populations and/or decrease rodents' perceived predation risk, changing their behavior. ...
... For instance, moonlight can increase perceived predation risk by small rodents (Fanson, 2010;Johnson & De León, 2015) likely due to improved hunting success by predators (Clarke, 1983;Penteriani et al., 2013). Just as moonlight can influence behavior relevant to predator-prey interactions through relative changes in visibility, variation in natural sounds that can influence an animal's abilities to detect threats or find prey through audition is also highly relevant to animal behavior and distributions (Mason et al., 2016;Römer & Holderied, 2020;Siemers & Schaub, 2011). ...
... The five groups we defined were mesocarnivores, Cricetid rodents, kangaroo rats, ground foraging birds, and insectivorous birds. Because there is evidence of decreased hunting success for predators in noise (Mason et al., 2016;Senzaki et al., 2016;Siemers & Schaub, 2011;Tuttle et al., 1982) we expected that impaired hunting success would cause mesocarnivores to avoid natural sound treated areas. Thus, we predicted that both detection (p) and occupancy (Ψ) probabilities of mesocarnivores would be lower in phantom, shifted, and real ocean conditions relative to control, with the lowest probabilities in shifted conditions due to the shifted treatment's higher frequency overlapping more strongly with mesocarnivores' hearing range and the rustling sounds these predators use to locate prey (Goerlitz & Siemers, 2007;Goerlitz et al., 2008;Heffner, 1983;Neff & Hind, 1955). ...
Article
A growing body of research focuses on how background sounds shape and alter critical elements of animals’ lives, such as foraging behavior, habitat use, and ecological interactions (Bradbury & Vehrencamp, 2011; Barber et al., 2010; Kight & Swaddle, 2011; Shannon et al., 2016). Much of this research has centered on the effects of anthropogenic noise (Dominoni et al., 2020; Francis & Barber, 2013; Ortega, 2012; Swaddle et al., 2015), but recent studies have also revealed that natural sound sources can influence animal behavior (Davidson et al., 2017; Le et al., 2019). Natural sounds, such as crashing surf, can create conditions where signaling and listening are difficult, but how this influences different species’ ecological interactions are unknown. To study the effects of crashing surf sound we experimentally introduced landscape-level acoustic playbacks where surf sound was not naturally present to create a “phantom ocean”. Phantom ocean treatment sites were employed alongside higher frequency “shifted” treatment sites to test for frequency-dependent effects, “real ocean” sites where surf sound was endemic, and ambient control sites. The phantom and shifted treatments were played continuously during the spring and summer of 2017-2019. Within this acoustic experimental landscape we conducted multiple studies to test the effects of crashing surf sound on animal behavior, habitat use, and ecological interactions. Through an artificial caterpillar predation experiment modeled after Roslin et al. (2017), we found that when exposed to natural sound treatments the foraging activity of rodents and arthropods increased, while that of birds declined. A potential explanation for this pattern includes taxon-specific responses reflecting different perceived risk-reward trade-offs in natural sound conditions. To follow this up we performed occupancy modeling on data collected by camera traps set within our system. We observed different responses among groups of species with different functional roles in the community for both detection (p) and occupancy (Ψ) probabilities. Our combined results indicate different species and functional groups have unique foraging behavior and patch use responses to natural sounds, likely based on their ecological interactions. Specifically, Cricetid rodents are likely more active in areas exposed to natural sounds, possibly due to lower perceived predation risk because mesocarnivores are less active. Insectivorous birds are also likely less active under natural sounds conditions, although the frequency of the sound, and the body size and diet of the bird appear influential. Together these findings suggest that natural sounds shape not only individual behavioral adjustments, but also multi-trophic, community level interactions. Our results show that natural sounds are an important driver of ecological interactions, but much remains to be uncovered. The mechanisms by which natural sounds influence individuals, populations, and many other aspects of ecology remain unexplored and provide fertile ground for future inquiry.
... loafing-site location may also play a role (Francis 2015, Mason et al. 2016. Boundary or sound reflection effects can increase the attenuation of low-frequency sounds within a few meters from the ground (e.g., Wiley & Richards 1978); thus, birds that forage or loaf on or near the ground may experience lower sound levels in noisy environments than birds that forage at more considerable distances above the ground. ...
... For species of conservation concern in landscapes impacted by anthropogenic noise, there is still much work to be done to explore the potential for behavioral avoidance of noisy habitat and how the acoustic dimension of the environment potentially regulates habitat use. We suggest that next steps should include experiments designed to explore the role of noise in obscuring social cues that might influence conspecific assessment of habitat quality (Patricelli et al. 2013), how noise alters vigilance-foraging tradeoffs (Ware et al. 2015, Mason et al. 2016, and how noise interferes with various stages of the breeding process (Kleist et al. 2017(Kleist et al. , 2018 such as pairing success or incubation and nestling provisioning rates and rhythms (Ng et al. 2019). ...
Article
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Over the last century, increasing human populations and conversion of grassland to agriculture have had severe consequences for numbers of Greater Prairie-Chicken (Tympanuchus cupido). Understanding Greater Prairie-Chicken response to human disturbance, including the effects of anthropogenic noise and landscape modification, is vital for conserving remaining populations because these disturbances are becoming more common in grassland systems. Here, we evaluate the effect of low-frequency noise emitted from a wind energy facility on habitat selection. We used the Normalized Difference Soundscape Index, a ratio of human-generated and biological acoustic components, to determine the impact of the dominant acoustic characteristics of habitat relative to physical landscape features known to influence within–home range habitat selection. Female Greater Prairie-Chickens avoided wooded areas and row crops but showed no selection or avoidance of wind turbines based on the availability of these features across their home range. Although the acoustic environment near the wind energy facility was dominated by anthropogenic noise, our results show that acoustic habitat selection is not evident for this species. In contrast, our work highlights the need to reduce the presence of trees, which have been historically absent from the region, as well as decrease the conversion of grassland to row-crop agriculture. Our findings suggest physical landscape changes surpass altered acoustic environments in mediating Greater Prairie-Chicken habitat selection.
... Birds rely on acoustic signals and cues to successfully communicate with conspecifics and to detect predators and prey (e.g., Montgomerie and Weatherhead 1997;Mennill et al. 2002;Templeton et al. 2005). As such, they are often used as a model taxon for examining the effects of acoustic masking, showing a reduced ability to detect (discern a signal from irrelevant sound [i.e., noise]; Luther and Gentry 2013; e.g., Lucass et al. 2016), discriminate (differentiate one signal from another, e.g., intruder song from neighbor song; Luther and Gentry 2013; e.g., Pohl et al. 2012), and localize signals (identify the location of the signal source; Senzaki et al. 2018; e.g., Mason et al. 2016) within noise-polluted environments. Recent evidence indicates that avian signalers respond to both anthropogenic and natural noise exposure by adjusting song performance (Davidson et al. 2017) and vocal activity ) under more intense ambient conditions. ...
... Irrelevant stimuli can cause a signal receiver to involuntarily divert its limited attention away from responding to relevant signals and cues (Chan et al. 2010), such as a conspecific intruder. Attributing a specific mechanism -namely acoustic masking or distraction -to behavioral responses is not always delineable from experimental results (e.g., Grade and Sieving 2016;Mason et al. 2016;Senzaki et al. 2016). However, chronic exposure to our treatment playbacks throughout the breeding season (and the water-generated noise naturally present in the unmanipulated, ambient soundscape) may have reduced the mechanistic effect of treatment-related distraction as our focal birds likely became habituated to its presence (Rankin et al. 2009). ...
Article
Recent research suggests that anthropogenic noise can substantially alter animal behavior. Although there are many sources of natural background noise, the relative influence of these sounds on behavior has received much less attention. Using landscape-scale playbacks of rushing rivers and crashing ocean surf, we investigated how habitat appropriate natural noise alters territorial defense behaviors in lazuli buntings (Passerina amoena) occupying riparian areas and spotted towhees (Pipilo maculatus) in riparian and coastal areas when exposed to simulated intruder song. We also incorporated naturally occurring cicada noise as an acoustic source influencing lazuli bunting behavior. Both songbird species possess songs that share substantial spectral overlap with low-frequency, water-generated noise, and lazuli bunting song shares an additional high-frequency overlap with cicada calls. Thus, there is potential for background acoustic conditions to mask conspecific signals. We found that detection and discrimination of conspecific playback occurred more slowly for both species as background sound levels increased. Lazuli buntings also exhibited complex flight behavior in noise, suggesting they respond differently depending on the amplitude and type of background noise (with versus without cicada calls). Our results suggest natural noise can impair territorial defense behaviors in songbirds, highlighting natural soundscapes as an under-appreciated axis of the environment.
... In fact, three of the four top models developed for both seasons (Table 3) included the variable background noise, and the parameter estimate for noise in each was of similar magnitude (-0.1--0.09). We are currently learning more about how birds, including owls, respond to noisy environments (Francis et al. 2009, Francis and Barber 2013, McClure et al. 2013, Ware et al. 2015, Mason et al. 2016. For instance, northern saw-whet owls Aegolius acadicus are unwilling to hunt Mus musculus under high noise [61 dB(A)] treatments in controlled experiments (Mason et al. 2016). ...
... We are currently learning more about how birds, including owls, respond to noisy environments (Francis et al. 2009, Francis and Barber 2013, McClure et al. 2013, Ware et al. 2015, Mason et al. 2016. For instance, northern saw-whet owls Aegolius acadicus are unwilling to hunt Mus musculus under high noise [61 dB(A)] treatments in controlled experiments (Mason et al. 2016). Coincidently, this sound intensity level of 61 dB(A) overlaps that level where barn owl occupancy dropped to zero in our study (Fig. 3). ...
Article
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Owing to habitat loss, changes in farming practices, urbanization, and high mortality through vehicle collisions, barn owls Tyto alba are a species of conservation concern in portions of their range. This species can be secretive and difficult to survey, particularly away from breeding sites, so factors related to barn owl occurrence often remain unknown. We conducted nighttime broadcast surveys for barn owls during the early- and post-breeding seasons and used an occupancy modeling framework to understand how factors related to landcover, landscape features, and human development related to occupancy in southern Idaho, USA. We also assessed the effectiveness of using broadcasts of conspecific vocalizations to improve owl detection. Barn owls were detected during 52 of 666 point counts and at 37 of 222 locations in the early-breeding season and 50 of 198 point counts and 31 of 66 locations in the post-breeding season. The probability of detecting barn owls was 0.32 ± 0.06 (SE) and 0.45 ± 0.07 (SE) during the early- and post-breeding seasons, respectively. Based on analysis within 1-km buffers surrounding point-count locations, occupancy in the early-breeding season increased with percentage of crop coverage and presence of trees and decreased with background noise. Post-breeding season occupancy increased with stream length and decreased with area of development and distance from the Snake River, a major geologic feature that likely provided roost sites in its canyon walls and riparian woodlands and a dispersal corridor for juveniles. Broadcast of barn owl vocalizations increased detection probability as much as nine times. Thus, incorporating call broadcast into future barn owl surveys should help investigators reduce false conclusions of absence. Ultimately, understanding factors influencing occupancy of barn owls will facilitate effective conservation, especially in light of population pressures related to factors such as roadway mortality and loss of nesting sites with increased urbanization.
... Species that use passive acoustics for hunting are likely to be more disturbed by anthropogenic noise [5]. Northern saw-whet owls (Aegolius acadius) exposed to compressor noise playback showed odds of hunting success reduced by 8 % per decibel increase [31]. No mice were captured at noise levels above 61 dB(A). ...
Conference Paper
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Since the beginning of the 1980s a large body of scientific and technical literature regarding the effects of anthropogenic noise on terrestrial wildlife has developed. These effects are mostly documented for birds and anurans. They range from behavioral modifications like signalling louder, increasing the signalling rate or redundancy, signalling at a higher pitch, signalling outside noisy periods, but also to alterations of intraspecific or interspecific interactions. Moreover it is now proven that man-made noise may lead to reduced reproductive success, reduced species richness or reduced density. This paper reviews the published literature on the topic since the beginning of the 2010s. The careful design of experiments helps avoid methodological biases some more ancient studies in this field may suffer from. The paper highlights the progress of knowledge among the different taxa including invertebrates and also on the effects of anthropogenic noise relating to the operation of an ecosystem.
... However, this finding does not necessarily suggest the likelihood of increased mortality to predation in noisy habitats, because predators' perceptual abilities also might be affected by noise. For example, hunting ability of northern saw-whet owls (Aegolius acadius) can be impaired by anthropogenic noise (Mason, McClure, & Barber, 2016). Future studies that experimentally manipulate anthropogenic disturbance are needed to infer causality more strongly. ...
Article
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Traffic noise likely reaches a wide range of species and populations throughout the world, but we still know relatively little about how it affects anti‐predator behavior of populations. We tested for possible effects of traffic noise on responses to predator acoustic cues in Carolina chickadees (Poecile carolinensis), tufted titmice (Baeolophus bicolor), and white‐breasted nuthatches (Sitta carolinensis) near 14 independent feeding stations in eastern Tennessee. We compared anti‐predator calling and seed‐taking behavior in response to playbacks of predator stimuli (screech owl calls) at sites naturally exposed to traffic noise and at sites that faced relatively little traffic noise. The screech owl call playback was designed to simulate the approach of this dangerous predator to a feeder being used by these small songbirds. We found that chickadees responded consistently to the owl stimuli across different levels of traffic noise. However, titmice, and nuthatches exhibited different behavioral responses to the predator stimulus, suggesting that traffic noise masked these low‐frequency predator calls. Overall, chickadees and nuthatches showed the broadest anti‐predator behavioral responses in comparison to titmice, corroborating earlier published work with an Indiana population. Finally, populations exposed to traffic noise overall seemed less able to detect predator cues potentially masked by that noise, and future work will need to assess likely seasonal variation in these responses as well as species‐level variation in anti‐predator responses in mixed‐species groups.
... The limited available data do not suggest owls employing a sit-and-wait hunting strategy preferentially glide rather than flap. Mason et al. (2016) presented prey to Northern Saw-whet Owls Nevertheless, based on these data, gliding during attacks appears to be the exception, not the rule. The sounds of flapping are likely a ubiquitous component of owl hunting. ...
Article
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Synopsis We raise and explore possible answers to three questions about the evolution and ecology of silent flight of owls: (1) do owls fly silently for stealth, or is it to reduce self-masking? Current evidence slightly favors the self-masking hypothesis, but this question remains unsettled. (2) Two of the derived wing features that apparently evolved to suppress flight sound are the vane fringes and dorsal velvet of owl wing feathers. Do these two features suppress aerodynamic noise (sounds generated by airflow), or do they instead reduce structural noise, such as frictional sounds of feathers rubbing during flight? The aerodynamic noise hypothesis lacks empirical support. Several lines of evidence instead support the hypothesis that the velvet and fringe reduce frictional sound, including: the anatomical location of the fringe and velvet, which is best developed in wing and tail regions prone to rubbing, rather than in areas exposed to airflow; the acoustic signature of rubbing, which is broadband and includes ultrasound, is present in the flight of other birds but not owls; and the apparent relationship between the velvet and friction barbules found on the remiges of other birds. (3) Have other animals also evolved silent flight? Wing features in nightbirds (nocturnal members of Caprimulgiformes) suggest that they may have independently evolved to fly in relative silence, as have more than one diurnal hawk (Accipitriformes). We hypothesize that bird flight is noisy because wing feathers are intrinsically predisposed to rub and make frictional noise. This hypothesis suggests a new perspective: rather than regarding owls as silent, perhaps it is bird flight that is loud. This implies that bats may be an overlooked model for silent flight. Owl flight may not be the best (and certainly, not the only) model for “bio-inspiration” of silent flight.
... Our results add to a growing body of literature that emphasizes the importance of the acoustic environment to wild organisms and species interactions (reviewed in [1,33]). Just as female frog navigation and orientation towards calling males is impaired by traffic noise [36], and many acoustic predators, such as owls and bats, have difficulty hunting prey in noisy environments [11,12,37], our results suggest that elevated background noise levels impair phonotaxis of specialized acoustic parasitoids when seeking hosts, potentially indicating a benefit to cricket hosts in noisy areas. Additionally, our findings contribute to a relatively small body of the literature documenting responses to altered noise regimes among insects (e.g. ...
Article
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The soundscape serves as a backdrop for acoustic signals dispatched within and among species, spanning mate attraction to parasite host detection. Elevated background sound levels from human-made and natural sources may interfere with the reception of acoustic signals and alter species interactions and whole ecological communities. We investigated whether background noise influences the ability of the obligate parasitoid Ormia ochracea to locate its host, the variable field cricket (Gryllus lineaticeps). As O. ochracea use auditory cues to locate their hosts, we hypothesized that higher background noise levels would mask or distract flies from cricket calls and result in a decreased ability to detect and navigate to hosts. We used a field manipulation where fly traps baited with playback of male cricket advertisement calls were exposed to a gradient of experimental traffic and ocean surf noise. We found that increases in noise amplitude caused a significant decline in O. ochracea caught, suggesting that background noise can influence parasitoid-host interactions and potentially benefit hosts. As human-caused sensory pollution increases globally, soundscapes may influence the evolution of tightly co-evolved host-parasitoid relationships. Future work should investigate whether female cricket phonotaxis towards males is similarly affected by noise levels.
... The fact that we found stronger behavioural differences in noise trials than the other novelty presentations is consistent with prior work in both birds (Rheindt, 2003;Bayne et al., 2008) and anurans (Eigenbrod et al., 2008), which show that species richness is higher on transects further from noisy traffic ways, indicating that many species tend to avoid anthropogenic noises, though these studies were not testing novelty or response to other stimuli. Moreover, anthropogenic noise negatively impacts animal hunting efficiency in mammals (Siemers & Schaub, 2011;Luo et al., 2015) and birds (Mason et al., 2016), body condition (Schroeder et al., 2012) and pairing success in songbirds (Bayne et al., 2008), foraging success in mammals (Brown et al., 2012;Shannon et al., 2014) and fish (Purser & Radford, 2011), and mating success in birds (Reijnen & Foppen, 1994;Habib et al., 2007;Gross et al., 2010). ...
Article
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Human-inhabited or -disturbed areas pose many unique challenges for wildlife, including reacting to novel environmental stimuli like car traffic, buildings and anthropogenic noise. Animals inhabiting these environments must adapt to such changes by overcoming such novelty (i.e., neotolerance, neophilia), and either exploiting new resources or avoiding danger. Although many studies have tested animal responses to individual forms of novelty (e.g., human objects, food, urban noise), to our knowledge no study has comprehensively assessed behavioural reactions of urban and rural populations to numerous novel environmental stimuli, including noise. We tested exploratory behaviour of urban, suburban, and rural house finches ( Haemorhous mexicanus ) in response to four different types of novelty (novel structural environment, novel object, novel noise, and novel food) in separate captive experiments, while also recording each bird for 30 min before exposure to determine baseline activity level. Although we found few population-level differences in behavioural responses to novel objects, environment, and food, we found significant differences in how finches from different sites responded to novel noises. When played a novel sound (whale call or ship horn), urban and suburban house finches approached their food source more quickly and spent more time on it than rural birds, and urban and suburban birds were more active during the ship-noise presentation. These results indicate that, in comparison with other types of novel stimuli, anthropogenic noise may be a key driver of urban adaptation in birds and its influence may vary depending on the type of sound.
... Small mammals near roads could experience release from predation if predator populations are susceptible to road effects (e.g., from road mortality, habitat destruction, or road avoidance). The predator release hypothesis could also influence the population dynamics of small mammals around compressor stations if it provides a refuge from disturbance-sensitive predators (e.g., Francis et al. 2009) or if the noise negatively affects the foraging efficiency of acoustic predators (Siemers and Schaub 2011;Bunkley and Barber 2015;Mason et al. 2016). Alternatively, small mammals could be more vulnerable to predation in disturbed areas if their attention is compromised by distraction from the noise (Chan et al. 2010;Chan and Blumstein 2011), if the sound of approaching predators is masked by the noise, or if the artificial light makes them more detectable to nocturnal predators (Kotler et al. 1991). ...
Article
Anthropogenic disturbance can negatively impact animal populations and alter the behaviour of individuals. Disturbance associated with the energy sector has been increasing in the boreal forest of northern Alberta. Disturbances associated with the oil and gas industry vary in the infrastructure present and sensory stimuli generated. Two common types are compressor stations and roads. It is important to assess population consequences of disturbance on small mammals because they serve as prey, predators, and seed/spore dispersers in the terrestrial ecosystems they inhabit. To test the effects of disturbance from the energy sector on small mammal abundance and activity, we used mark-recapture methods and live-trapped in forested areas with one side adjacent to a clearing with industrial infrastructure present (road or compressor station) or absent (control sites). We found no difference in abundance or activity of deer mice (Peromyscus maniculatus (Wagner, 1845)) and southern red-backed voles (Myodes gapperi (Vigors, 1830)) between sites, and did not detect an edge effect on abundance within sites, regardless of the presence of industrial infrastructure. Our results suggest minimal effects of industrial disturbance on the abundance and activity of these species, and the infrastructure and sensory stimuli generated are unlikely to be key drivers of their population dynamics or behaviour.
... We found that Brewer's sparrow decreased 15% per 9 decibels under the narrowband playback and 17% per 9 decibels under the broadband playback. Our noise sites did not recreate some of the highest sound level compressor stations that exist in extraction fields(Bunkley et al., 2015;Mason, McClure, & Barber, 2016). We can, therefore, predict that these intense noise sources will have a more detrimental effect on bird populations. ...
Article
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1.Altered animal distributions are a consequence of human expansion and development. Anthropogenic noise can be an important predictor of abundance declines near human infrastructure, yet more information is needed to understand noise impacts at the spatial and temporal scales necessary to alter populations. 2.Energy development and associated anthropogenic noise are globally pervasive, and expanding. For example, 600,000 new natural gas wells have been drilled across central North America in less than twenty years. 3.We experimentally broadcast energy sector noise (recordings of compressor engines) in Southwest Idaho (USA). We placed arrays of speakers creating a “phantom natural gas field” in a large‐scale experiment and tested the effects of noise alone on breeding songbird abundance. To examine variation in human‐caused noise, we broadcast two types of compressor noise, one with a slightly higher sound intensity and greater bandwidth than the other. 4.Our phantom natural gas field encompassed approximately 100 km2. We broadcast noise over three continuous months, for each of two seasons, and quantified over 20,000 hours of background sound levels. 5.Brewer's sparrows (Spizella breweri) were affected by our narrowband playback, declining 30% 50 m from the speaker arrays. During our broadband playback, all species combined and Brewer's sparrows decreased 20% and 33% respectively at the scale of our sites (~0.5 km2; up to 400 m from speaker arrays). 6.Synthesis and applications. Our results show the importance of incorporating the acoustic structure of noise when estimating the cost of noise exposure for populations. We suggest an urgent need for noise mitigation, such as quieting compressor stations, in energy extraction fields and other sources in natural areas broadly. This article is protected by copyright. All rights reserved.
... The results of our study indicate that there was a lower intensity of noise in the areas colonized by roe deer, although this was not a key factor in the population distribution model. Noise, the main source of which in urban areas is road traffic, interferes with the propagation of sound waves and seriously affects the distribution of animal populations in which individuals communicate vocally with one another (Nemeth et al. 2013;Ciach and Fröhlich 2017) and foraging (Siemers and Schaub 2011;Mason et al. 2016) relies on acoustic signals. However, the results of studies conducted on small mammals indicate that traffic noise is not considered a factor leading to avoidance of roads (McGregor and Bender 2008). ...
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Although large and medium-sized herbivorous mammals avoid urbanized areas, they have recently begun to colonize towns and cities. In general, ungulates continue to avoid the centres of urban areas, and utilize mainly their thinly built-up outskirts. While extension of urban development is preventing ungulates from penetrating the urban landscape, the influence of noise and light pollution on the occurrence of mammalian herbivores is still poorly understood. Hence, we investigated the hypothesis that habitat availability shapes the distribution of roe deer Capreolus capreolus and artificial lightening discourages them from penetrating the urban landscape. Roe deer was recorded on 37% of randomly selected sample plots (N = 60) located within the city of Kraków (S Poland). The occupied plots contained significantly more open habitats, woodland patches were larger in them, but proximity to rivers, and noise and light pollution were significantly lower. The logistic regression model revealed that an increasing area of open habitats was positively correlated with the probability of roe deer occurring. However, the artificial lighting at night was negatively correlated with the probability of the species occurring: the negative effect of light pollution was mitigated by the greater area of open habitats. Our study highlights the very considerable potential of light pollution as a predictor of the occurrence of large mammals in the urban landscape. We argue that urbanization and the related artificial lighting at night may be a factor preventing ungulates from penetrating potentially suitable habitats in urban areas.
... The absence of an effect of repetition rate on ABR size and latency within the 21 and 51 s À1 range may represent enhanced temporal resolution and decreased susceptibility to neural fatigue within the auditory system in species that display such a pattern (Corwin et al., 1982;Picton, 2011). In general, owls are known for their auditory capabilities, as many species rely on their hearing to detect and localize prey items in conditions of low light (Mason et al., 2016;Norberg, 1977). However, Northern saw-whet owls have a variety of auditory adaptations that make them unique even among owl species. ...
Article
Monitoring auditory brainstem responses (ABRs) is a common method of assessing auditory processing in non-model species. Although ABRs are widely used to compare auditory abilities across taxa, the extent to which different features of acoustic stimuli affect the ABR is largely unknown in most non-mammalian species. The authors investigated the effects of varying presentation rate and onset time to determine how different features of acoustic stimuli influence the ABR in Northern saw-whet owls (Aegolius acadicus), a species known for their unique auditory adaptations and hunting abilities. At presentation rates ranging from 21.1 to 51.1 s⁻¹, there were no differences in the size or synchrony of ABRs, suggesting that stimuli can be presented at a relatively rapid rate to maximize the number of observations recorded for analysis. While increasing onset time was associated with a decrement in response size and synchrony, tonebursts with 1 ms onset times produced overgeneralized neural responses as a result of spectral splatter. This suggests that 2 to 3 ms onset times may balance the trade-off between response synchrony and frequency specificity when comparing relative neural recruitment across frequencies. These findings highlight the importance of considering stimulus parameters when interpreting ABR data.
... Recent studies on nocturnal birds suggest that anthropogenic noise can have little impact on their habitat occupation (Shonfield and Bayne 2017), while others have shown negative impacts on their foraging efficiency (Mason et al. 2016;Senzaki et al. 2016), decreases of habitat occupation Ciach 2017, 2018), and reduction of their species richness in urban settings (Fröhlich and Ciach 2019). Albeit several species can take advantage of ALAN (e.g., diurnal raptors and waders that can increase their foraging efficiency in light polluted sites; Debrot 2014), it is unclear how ALAN may shape the distribution of nocturnal raptors, as well as its influence on nighttime vocal activity (Gorenzel and Salmon 1995;Longcore and Rich 2004;Canário et al. 2012;Gaston and Bennie 2014;Scobie et al. 2016). ...
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Background: Cities differ from non-urban environments by the intensity, scale, and extent of anthropogenic pressures, which can drive the occurrence, physiology, and behavior of the organisms thriving in these settings. Traits as green cover often predict the occurrence patterns of bird species in urban areas. Yet, anthropogenic noise and artificial light at night (ALAN) could also limit the presence and disrupt the behavior of birds. However, there is still a dearth of knowledge about the influence of urbanization through noise and light pollution on nocturnal bird species ecology. In this study, we assessed the role of green cover, noise, and light pollution on the occurrence and vocal activity of the Mottled Owl (Ciccaba virgata) in the city of Xalapa (Mexico). Methods: We obtained soundscape recordings in 61 independent sites scattered across the city of Xalapa using autonomous recording units. We performed a semi-automated acoustic analysis of the recordings, corroborating all Mottled Owl vocalizations. We calculated two measures of anthropogenic noise at each study site: daily noise (during 24 h) and masking noise (mean noise amplitude at night per site that could mask the owl's vocalizations). We further performed generalized linear models to relate green cover, ALAN, daily noise, and masking noise in relation to the owl's occurrence (i.e., detected, undetected). We also ran linear models to assess relationships among the beginning and ending of vocal activity with ALAN, and with the anthropogenic and masking noise levels at the moment of which vocalizations were emitted. Finally, we explored variations of the vocal activity of the Mottled Owl measured as vocalization rate across time. Results: The presence of Mottled Owls increased with the size of green cover and decreased with increases in both artificial light at night and noise levels. At the temporal scale, green cover was positively related with the ending of the owl's vocal activity, while daily noise and ALAN levels were not related to the timing and vocal output (i.e., number of vocalizations). Furthermore, the Mottled Owl showed a marked peak of vocal activity before dawn than after dusk. Although anthropogenic noise levels varied significantly across the assessed time, we did not find an association between high vocal output during time periods with lower noise levels. Conclusions: Spatially, green cover area was positively related with the presence of the Mottled Owl in Xalapa, while high noise and light pollution were related to its absence. At a temporal scale, daily noise and ALAN levels were not related with the timing and vocal output. This suggests that instead of environmental factors, behavioral contexts such as territoriality and mate interactions could drive the vocal activity of the Mottled Owl. Further studies need to incorporate a wider seasonal scale in order to explore the variation of different vocalizations of this species in relation to environmental and biological factors. Keywords: Anthropogenic noise, Acoustic monitoring, Nighttime ecology, Urban ecology, Urbanization, Vocal activity
... It spans several types of ecosystems including terrestrial [18], aquatic [17] and coastal ecosystems [33]. Many types of sounds produced by human activities would seem to be a form of noise pollution affecting biodiversity, including traffic [20], ships [38], aircraft [4] and industrial activities [23]. Noise pollution can also act in synergy with other disturbances, for example light pollution [26]. ...
Article
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For decades, biodiversity has suffered massive losses worldwide. Urbanization is one of the major drivers of extinction because it leads to the physical fragmentation and loss of natural habitats and it is associated with related effects, e.g. pollution and in particular noise pollution given that many man-made sounds are generated in cities (e.g. industrial and traffic noise, etc.). However, all human activities generate sounds, even far from any human habitation (e.g. motor boats on lakes, aircraft in the air, etc.). Ecological research now deals increasingly with the effects of noise pollution on biodiversity. Many studies have shown the impacts of anthropogenic noise and concluded that it is potentially a threat to life on Earth. The present work describes a protocol to systematically map evidence of the environmental impact of noise pollution on biodiversity. The resulting map will inform on the species most studied and on the demonstrated impacts. This will be useful for further primary research by identifying knowledge gaps and in view of further analysis, such as systematic reviews. Searches will include peer-reviewed and grey literature published in English and French. Two online databases will be searched using English terms and search consistency will be assessed with a test list. No geographical restrictions will be applied. The subject population will include all species. Exposures will include all types of man-made sounds (industrial, traffic, etc.) in all types of environments (or media) (terrestrial, aerial, aquatic), including all contexts and sound origins (spontaneous or recorded sounds, in situ or laboratory studies, etc.). All relevant outcomes will be considered (space use, reproduction, communication, abundance, etc.). An open-access database will be produced with all relevant studies selected during the three screening stages. For each study, the database will contain metadata on key variables of interest (species, types of sound, outcomes, etc.). This database will be available in conjunction with a map report describing the mapping process and the evidence base with summary figures and tables of the study characteristics.
... Energy development and motorized recreation are noise sources of particular concern, as they are widespread and can substantially increase sound levels in natural areas (e.g., Harrison et al., 1980;Ramirez and Mosley, 2015). Noise from natural gas extraction has been shown to reduce species' abundance in large areas of habitat (Bayne, Habib, & Boutin, 2008), change patterns of habitat selection (Kleist, Guralnick, Cruz, & Francis, 2017), interfere with species' hunting behavior (Mason, McClure, & Barber, 2016), alter species' physiology (Blickley et al., 2012), and influence trophic interactions (Francis et al., 2011). ...
Article
Noise is a globally pervasive pollutant that can be detrimental to a range of animal species, with cascading effects on ecosystem functioning. As a result, concern about the impacts and expanding footprint of anthropogenic noise is increasing along with interest in approaches for how to mitigate its negative effects. A variety of modeling tools have been developed to quantify the spatial distribution and intensity of noise across landscapes, but these tools are under-utilized in landscape planning and noise mitigation. Here, we apply the Sound Mapping Tools toolbox to evaluate mitigation approaches to reduce the anthropogenic noise footprint of gas development, summer all-terrain vehicle recreation, and winter snowmobile use. Sound Mapping Tools uses models of the physics of noise propagation to convert measured source levels to landscape predictions of relevant sound levels. We found that relatively minor changes to the location of noise-producing activities could dramatically reduce the extent and intensity of noise in focal areas, indicating that site planning can be a cost-effective approach to noise mitigation. In addition, our snowmobile results, which focus on a specific frequency band important to the focal species, are consistent with previous research demonstrating that source noise level reductions are an effective means to reduce noise footprints. We recommend the use of quantitative, spatially-explicit maps of expected noise levels that include alternative options for noise source placement. These maps can be used to guide management decisions, allow for species-specific insights, and to reduce noise impacts on animals and ecosystems.
... Ambient noise can interfere with the detection and processing of important signals and cues and thereby affect an individual's ability to survive and reproduce (Brumm and Slabbekoorn 2005;Halfwerk and Slabbekoorn 2015). Ambient noise can, for example, mask the acoustic cues of potential prey, an approaching predator, or the alarm calls of surrounding songbirds that have detected a nearby hawk (Mason et al. 2016;Templeton et al. 2016). Ambient noise may also reduce song detection by neighbors and thereby reduce a male's ability to defend his territory. ...
Chapter
Vocalizing birds are ubiquitous and often prominent in areas that are reached by noisy human activities. Birds have therefore been studied for the effects of man-made sound on song production and perception, physiological stress, distribution range, breeding density, and reproductive success. There are examples of birds that sing louder, higher, and longer when ambient-noise levels are elevated due to human activities. This may lead to perceptual advantages through masking release, although song modifications may also lead to a functional compromise. Fitness benefits of noise-dependent modifications have not been proven yet. Masking effects are reported for outdoor and indoor studies, but data on physiological consequences are not widespread yet. There are also still only few experimental studies on more long-term consequences of man-made sound on development, maturation, and fitness. Observational data on species distributions and densities show that there are birds that persist at noisy sites but also that artificially elevated noise levels can have detrimental consequences for particular species. Birds in noisy localities may move away or stay and fare less well. Furthermore, the effects of noise pollution can go beyond single species because all species may be more or less negatively affected, but the effect on one species may also positively or negatively affect another. The variety in sensitivity among species and the diversity in impact and counterstrategies have made birds both cases of concern and popular model species for fundamental and applied research.
... A second possibility is that individuals may experience reduced performance in response to predator attacks in noisy environments (Chan et al., 2010;Simpson et al., 2016) and many animals certainly behave as though they are at greater risk of predation through changes in vigilance in noisy envi- , which may also explain stress-hormone dysfunction due to noise (Kleist, Guralnick, Cruz, Lowry, & Francis, 2018). However, it is important to recognize that predators also avoid noisy areas (Francis et al., 2009) and experience reductions in hunting success due to noise (Mason, McClure, & Barber, 2016;Senzaki et al., 2016). Whether due to predation risk or mortality from vehicles, it may be possible that the documented response is due to cross-generational heritability. ...
Article
1.Anthropogenic noise is widespread, and growing evidence suggests that it can negatively affect animals through many different mechanisms including masking of cues and signals, distraction, and aversion to noise. 2.Acoustic masking has received the most attention from researchers and recent evidence suggests that masking effects can be mitigated by alteration of signal frequencies or amplitudes by signalers. Additionally, alteration can be a learned response via prior experience with noise exposure. However, it remains unclear whether distraction or aversive effects due to noise can be mitigated by prior experience with noise, especially among signal receivers. 3.Here, we addressed this gap by separating mechanisms of noise disturbances on female phonotaxis towards male advertisement calls in anurans. To do this, we experimentally examined phonotaxis of gravid females that differ in their prior experience with noise under three acoustic manipulations: spectrally overlapping and non‐overlapping noise that either mask or do not mask male advertisement calls respectively, plus a silent control. 4.We confirm two experience‐dependent responses of noisy‐site individuals relative to quiet‐site individuals: faster initiation of phonotaxis under non‐overlapping noise and a stronger aversive response against overlapping noise. However, we showed that, for both noisy‐ versus quiet‐site individuals, both overlapping and non‐overlapping noise treatments resulted in delayed initiation and disorientation of phonotaxis relative to silent control treatments. 5.Our study provides the first evidence to demonstrate that, although prior experience appears to mitigate the negative effects of distraction or aversion to noise, prior experience falls short of fully compensating for disrupted orientation through phonotaxis. Additionally, although most studies have emphasized masking of biologically relevant cues and signals as the most prominent mechanism by which noise negatively affects wild organisms, we show that non‐overlapping noise, which cannot cause signal and cue masking, can have negative consequences via distraction or aversive responses. This finding suggests that noise impacts could extend well beyond contexts involving acoustic cue detection and discrimination and deserves increased attention by researchers. This article is protected by copyright. All rights reserved.
... Research from the field of sensory ecology demonstrates how masking of critical acoustic communications by chronic noise could lead to stress. The distance over which birdsong and other sounds are effectively transmitted, their "active space" (58), is significantly reduced by increases in ambient background noise (1,8,(59)(60)(61). Anthropogenic noise, acting as an acoustic blanket, can reduce or inhibit detection of hetero- (46)(47)(48) and conspecific (62) vocalizations that birds and other animals (45) use to gain information about predation threats. ...
Article
Anthropogenic noise is a pervasive pollutant that decreases environmental quality by disrupting a suite of behaviors vital to perception and communication. However, even within populations of noise-sensitive species, individuals still select breeding sites located within areas exposed to high noise levels, with largely unknown physiological and fitness consequences. We use a study system in the natural gas fields of northern New Mexico to test the prediction that exposure to noise causes glucocorticoid-signaling dysfunction and decreases fitness in a community of secondary cavity-nesting birds. In accordance with these predictions, and across all species, we find strong support for noise exposure decreasing baseline corticosterone in adults and nestlings and, conversely, increasing acute stressor-induced corticosterone in nestlings. We also document fitness consequences with increased noise in the form of reduced hatching success in the western bluebird (Sialia mexicana), the species most likely to nest in noisiest environments. Nestlings of all three species exhibited accelerated growth of both feathers and body size at intermediate noise amplitudes compared with lower or higher amplitudes. Our results are consistent with recent experimental laboratory studies and show that noise functions as a chronic, inescapable stressor. Anthropogenic noise likely impairs environmental risk perception by species relying on acoustic cues and ultimately leads to impacts on fitness. Our work, when taken together with recent efforts to document noise across the landscape, implies potential widespread, noise-induced chronic stress coupled with reduced fitness for many species reliant on acoustic cues.
... Outdoor recreation in public areas leads to more human-wildlife interactions that have consequences, including negative impacts because of human disturbance (Newsome et al. 2013). Human disturbance, the process by which wildlife-human encounters result in alteration of wildlife behavior and/or physiology, has been associated with avoidance behavior (Frid and Dill 2002), physiological stress (Hayward et al. 2011, Strasser and, and impaired sensory perception (Mason et al. 2016). Further, disturbance can lead to changes in habitat use (Gill andSutherland 2000, Webber et al. 2013), interfere with foraging (Fernández-Juricic and Tellería 2000), alter regimes of self-maintenance (Kight and Swaddle 2007), and reduce parental care to young (Fernández andAzkona 1993, Steidl andAnthony 2000). ...
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Disturbance because of human activity, including recreation on wildlands, can affect bird behavior which in turn can reduce breeding success, an important consideration for species of management concern. We observed Golden Eagles (Aquila chrysaetos) during the breeding season to determine whether the probability of flushing was affected by the type of recreationist, distance to encounter, eagle nest attendance, or date. We monitored eagles in 23 nesting territories from distant (600–1,200 m) observation points and recorded recreation activity within 1,200 m of eagles in the Owyhee Front of southwestern Idaho. In most (86%, n¼270) encounters, eagles did not flush in response to recreationists; however, whether an eagle flushed was affected by the type of recreationist and whether an eagle was at or away from the nest. Eagles were 60 times more likely to flush in response to recreationists that stopped a motor vehicle and transitioned to walking (11 of 17 passes) and 4.5 times more likely to flush in response to off-road vehicle (ORV) riders (17 of 121 passes) than during encounters with road vehicles (7 of 107 passes). Flushing was 12 times more likely for eagles away from nests (23 of 87 passes) than eagles at nests (13 of 183 passes). Eagles flushed at greater distances in response to recreationists that transitioned from motor vehicles to walking (lsmean¼620 m) than when responding to either ORV riders (lsmean¼525 m) or road vehicles (lsmean¼318 m). Flushing distances tended to decline throughout the breeding season to suggest seasonal changes in the costs and benefits of responding to disturbance. After flushing from nests, most eagles (77%) spent ,40 mins away, but some (23%) spent .90 mins away from nests. Limiting recreational activities within 650 m and 1,000 m of nest sites may decrease nest-site flushing events by 77% and 100%, respectively. Because eagles seem most sensitive to humans transitioning between motorized and non-motorized recreation, land managers may strike a balance between access needs of recreationists and buffering eagles from disturbance by using a mix of trail closures and no-stopping zones that prevent transitions from motorized to walking activities.
... Some of the most comprehensive studies on the effects of anthropogenic noise on wildlife have focused on impacts of noise from roads and natural gas extraction activities. In these studies, exposure to road noise resulted in reduced body condition of songbirds (Ware et al. 2015, McClure et al. 2017 and noise from gas extraction infrastructure impaired hunting success of Northern Saw-whet Owls (Aegolius acadicus; Mason et al. 2016) and reduced pairing success of Ovenbirds (Seiurus aurocapilla; Habib et al. 2007, Bayne et al. 2008. Given the ubiquity of human-created noise across landscapes, e.g., ~ 88% of the continental USA experiences noise levels elevated because of human activities (Mennitt et al. 2013), it is important for conservation efforts to evaluate the impact of the acoustic environment on avian behavior. ...
Article
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Anthropogenic disturbances can affect species of conservation concern by influencing their behavior. Of special concern is the possibility that noise from anthropogenic structures in grassland habitats, such as wind turbines and roads, may affect the propagation of the low-frequency boom chorus of lekking male Greater Prairie-Chickens (Tympanuchus cupido). We used sound pressure levels from acoustic recordings taken at 10 leks in the Nebraska Sandhills, USA during 2013 and 2014 in a SPreAD-GIS sound propagation model to make spatial projections of the boom chorus under a variety of conditions including landscape composition, conspecific attendance, and weather. We then used sets of linear mixed models in a model selection process to determine how background noise, female and male lek attendance, time of day, relative humidity, air temperature, and wind speed affected the area of chorus propagation. The predicted area of propagation decreased with increasing background noise (β = -0.09, SE = 0.04) and increased with greater female lek attendance (β = 0.09, SE = 0.03), higher levels of relatively humidity (β = 0.07, SE = 0.03), and higher air temperatures (β = 0.05, SE = 0.03). Our analyses provide new insight on how acoustic, social, and meteorological factors influence an important reproductive behavior in an imperiled prairie grouse.
... Sensory pollutants can lead to a wide range of behavioural and physiological responses. Behavioural changes have been demonstrated for processes such as migration 23 , biological timing 24,25 , intraspecific communication 26 , prey detection 27,28 and predator avoidance 29 . A very common behavioural response to light pollution is the attraction to light sources. ...
Article
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Global expansion of human activities is associated with the introduction of novel stimuli, such as anthropogenic noise, artificial lights and chemical agents. Progress in documenting the ecological effects of sensory pollutants is weakened by sparse knowledge of the mechanisms underlying these effects. This severely limits our capacity to devise mitigation measures. Here, we integrate knowledge of animal sensory ecology, physiology and life history to articulate three perceptual mechanisms—masking, distracting and misleading—that clearly explain how and why anthropogenic sensory pollutants impact organisms. We then link these three mechanisms to ecological consequences and discuss their implications for conservation. We argue that this framework can reveal the presence of ‘sensory danger zones’, hotspots of conservation concern where sensory pollutants overlap in space and time with an organism’s activity, and foster development of strategic interventions to mitigate the impact of sensory pollutants. Future research that applies this framework will provide critical insight to preserve the natural sensory world. Anthropogenic sensory pollutants, such as noise, light and chemicals, are affecting biodiversity. This Perspective uses an understanding of animal sensory ecology to explore how these impacts can be mitigated.
... Anthropogenic noise can have negative effects on the fitness of foraging animals by decreasing foraging rates and efficiency (e.g. Luo, Siemers, & Koselj, 2015;Mason, McClure, & Barber, 2016). However, the effects of chronic anthropogenic noise on food intake in wildlife remain largely unknown. ...
Article
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Anthropogenic noise exposure has deleterious effects on the foraging ecology of many animals. However, the effects of chronic anthropogenic noise on food intake and health condition in wildlife remain largely unknown. We tested whether traffic noise exposure over multiple days would change food intake and would have effects on the health of Asian particoloured bats. We broadcast traffic noise to the bats of two noise‐exposure groups (group A, 5 bats; group C, 6 bats) and broadcast silence files to the bats of two control groups (group B, 5 bats; group D, 6 bats) for 12 days. We measured the changes in food intake, body weight, and concentration of faecal triiodothyronine (T3) and thyroxine (T4) in groups A and B. We compared the transcriptional profiles in brain, kidney and liver tissues between bats in groups C and D. The bats exposed to traffic noise had a significantly higher daily food intake and a significantly greater body weight than bats in control group during the period of playback. Faecal T3 and T4 were higher in the noise‐exposure group after playback had been on for more than one day. We found a total of 169 differentially expressed genes (DEGs) between noise‐exposure and control groups. Some DEGs related to stress response were up‐regulated in the bats exposed to noise. The 169 DEGs were mainly enriched in Gene Ontology (GO) terms associated with metabolism, fundamental cellular processes, stress response and immune response. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways affected by noise exposure were linked with metabolism, disease, apoptosis, autophagy, phagosome and ribosome. Synthesis and applications. Our results suggest that bats exposed to chronic traffic noise while roosting may need more energetic intake and have a greater motivation to forage than others not exposed to noise, probably as a result of a stress response. Furthermore, chronic traffic noise may increase the risk of metabolic dysregulation, immune disorders, and other diseases. Management measures for reducing noise disturbance, for example, implementing sound barriers, are essential.
... Only once they have scanned the area will they bite the neck of their prey to kill it (Norberg 1970). Similarly, in videos recorded by Mason et al. (2016) saw-whet owls were observed to strike their prey and immediately look around. Saw-whet owls are a food source for other animals (Voous 1988; Proudfoot GA, personal observation) and this behavior is likely used to search for predators, since the saw-whet owls are vulnerable when they are awkwardly standing on the ground. ...
Article
Northern saw-whet owls (Aegolius acadicus) are nocturnal predators that are able to acoustically localize prey with great accuracy; an ability that is attributed to their unique asymmetrical ear structure. While a great deal of research has focused on open loop sound localization prior to flight in owls (primarily barn owls), directional sensitivity of the ears may also be important in locating moving prey on the wing. Furthermore, directionally sensitive ears may also reduce the effects of masking noise, either from the owls' wings during flight or environmental noise (e.g. wind, leaf rustling, etc.), by enhancing spatial segregation of target sounds and noise sources. Here, we investigated auditory processing of Northern saw-whet owls in three-dimensional space using auditory evoked potentials (AEPs). We simultaneously evoked auditory responses in two channels (right and left ear) with broadband clicks from a sound source that could be manipulated in space. Responses were evoked from 66 spatial locations, separated by 30° increments in both azimuth and elevation. We found that Northern saw-whet owls had increased sensitivity to sound sources directly in front of and above their beaks and decreased sensitivity to sound sources below and behind their heads. The spatial region of highest sensitivity extends from the lower beak to the crown of the head and 30° left or right of the median plane, dropping off beyond those margins. Directional sensitivity is undoubtedly useful during foraging and predator evasion, and may also reduce the effect of masking noise from the wings during flight due to the spatial segregation of the noise and targets of interest.
... (e.g., Forman et al. 2003;Charry and Jones 2009). Even some species that may be attracted to roadsides (e.g., to use as hunting grounds; Hindmarch et al. 2017) may suffer deleterious consequences from traffic noise (Mason et al. 2016;Senzaki et al. 2016). Decisive evidence comes from playback experiments that control for the presence of other confounding factors (e.g., mortality, chemical pollution, habitat fragmentation) associated with roads. ...
Article
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Traffic noise is one of the leading causes of reductions in animal abundances near roads. Acoustic masking of conspecific signals and adventitious cues is one mechanism that likely causes animals to abandon loud areas. However, masking effects can be difficult to document in situ and the effects of infrequent noise events may be impractical to study. Here, we present the Soundscapes model, a stochastic individual-based model that dynamically models the listening areas of animals searching for acoustic resources (“searchers"). The model also studies the masking effects of noise for human detections of the searchers. The model is set in a landscape adjacent to a road. Noise produced by vehicles traveling on that road is represented by calibrated spectra that vary with speed. Noise propagation is implemented using ISO-9613 procedures. We present demonstration simulations that quantify declines in searcher efficiency and human detection of searchers at relatively low traffic volumes, fewer than 50 vehicles per hour. Traffic noise is pervasive, and the Soundscapes model offers an extensible tool to study the effects of noise on bioacoustics monitoring, point-count surveys, the restorative value of natural soundscapes, and auditory performance in an ecological context.
... The increase in food intake that we found supports our second hypothesis, that road noise reduces prey's risk perception or masking hypothesis (Chan & Blumstein, 2011;Chan et al., 2010). An alternative explanation may be that road noise reduces actual owl predation (Mason et al., 2016), and small mammals recognize the reduction in risk and increase their foraging. Large birds like owls are sensitive to noise as it may mask acoustic cues of prey (Francis et al., 2012). ...
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Anthropogenic noise has dramatically increased over the past decades with potentially significant impacts on wildlife and their community interactions. Using giving‐up densities (GUDs) paired with camera traps, we examined the concurrent influence of chronic road noise and predation risk on free‐living small mammals. Specifically, we looked for differences in foraging and vigilance behavior during various noise treatments. We found that small mammals significantly reduced food intake when exposed to predation risk; however, concurrent exposure to road noise eliminated this effect; small mammals increased food intake when exposed to road noise and risk compared to risk alone. Furthermore, road noise reduced the number of visits and time spent at foraging trays while it increased vigilance behavior of small mammals in risky situations, meaning they were able to increase their foraging efficiency. Mice also ate less when moon illumination was greater; however, this had no effect on our overall results. This is one of the first studies to concurrently examine the effects of road noise and predation risk on free‐living prey. It shows the complex responses of prey exposed to chronic noise conditions as they attempt to gain reliable information about predation risk and respond appropriately. We highlight the potential consequences road noise may have on the survival of prey as it interferes with their appropriate risk responses. We tested the influence of road noise on prey responses to predation risk. We found that road noise reduced risk‐induced increases in vigilance and increased risk‐induced reductions in food intake. Our results support the hypothesis that road noise interferes with small mammals' ability to detect predator cues and respond appropriately to predation risk.
... Noise pollution has been found to suppress the distribution of owls (Silva et al. 2012, Fröhlich & Ciach 2018a, 2018b. This is believed to be primarily due to reduced hunting efficiency in noisier environments (Mason et al. 2016, Fröhlich & Ciach 2018a, similar to the effect that rainfall has on hunting success (Lengagne & Slater 2002), with prey detection that much harder. In addition, owls may also suffer enhanced energy costs due to the need for louder and/or more frequent vocalizations in higher ambient noise environments in order to be heard by conspecifics (Lengagne & Slater 2002, Nemeth et al. 2013, Cartwright et al. 2014. ...
... Thus, arthropod communication and perception can be directly affected by noise via airborne sound or substrate-borne vibrations (Lampe et al. 2012, Raboin andElias 2019). Indirect effects are also possible, since noise can disrupt predator-prey interactions (Purser and Radford 2011, Gomes et al. 2016, Mason et al. 2016, Barton et al. 2018, Senzaki et al. 2020, and drives away many arthropod predators, such as birds and bats (Schaub et al. 2008, Francis et al. 2011, McClure et al. 2013, Bunkley and Barber 2015, Gomes et al. 2021b). ...
Article
Anthropogenic noise has received considerable recent attention, but we know little about the role that sources of natural noise have on wildlife abundance and distributions. Rivers and streams represent an ancient source of natural noise that is widespread and covers much of Earth. We sought to understand the role that whitewater river noise plays on arthropod abundance in riparian habitats across a desert landscape. For two summers, we continuously broadcasted whitewater river noise and spectrally-altered river noise (shifted upwards in frequency, but maintaining the same temporal profile) to experimentally tease apart the effects of two characteristics of noise – sound levels and background spectral frequency – on arthropod abundances. We used five types of trapping methods, placed across 20 sites within the Pioneer Mountains of Idaho, USA, to collect and identify 151 992 specimens to the order level. We built Bayesian generalized linear mixed-effects models with noise characteristics and other habitat variables such as riparian vegetation, elevation, temperature, and moonlight. Of the 42 models we built (one for each order-trap type combination), 26 (62%) indicated a substantial response to at least one noise variable – sound pressure level, background spectral frequency, or an interaction between the two. Fourteen of 17 (82%) arthropod orders responded to noise in some capacity: Araneae, Coleoptera, Collembola, Dermaptera, Hemiptera, Hymenoptera, Lepidoptera, Neuroptera, Opiliones, Orthoptera, Plecoptera, Raphidioptera, Thysanoptera and Trichoptera. Only three groups appeared to be unaffected, Acari, Archaeognatha and Diptera. Results from this study suggest that the natural acoustic environment can shape arthropod abundances both directly and indirectly (via predator–prey relationships). Future work should further examine the role that the indirect effects of noise play in food webs. Natural noise should be considered an important ecological niche axis, especially as we continue to alter natural acoustic environments and replace them with anthropogenic ones.
... Both can fundamentally alter spatial orientation and create mismatched biological timings ). These sensory disturbances in turn create a myriad of behavioral alterations, affecting orientation and movement (Slabbekoorn and Bouton 2008;Cabrera-Cruz et al. 2018), communication (Francis and Barber 2013), foraging and hunting efficiency (Bennie et al. 2015;Bunkley and Barber 2015;Mason et al. 2016), altered energy budgets (Read et al. 2014;Touzot et al. 2019), and predation risk (Francis and Barber 2013;Ditmer et al. 2020), along with stress hormone dysregulation (Kleist et al. 2018). Recent research has also shown that variation in these sensory pollutants can better explain patterns of habitat selection than common ecological variables alone, such as landcover (Kleist et al. 2017;Ditmer et al. 2020) and can better reflect the dynamic human footprint relative to other measurements (e.g., housing density; Ditmer et al. 2021a). ...
Article
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Synopsis Global expansion of lighting and noise pollution alters how animals receive and interpret environmental cues. However, we lack a cross-taxon understanding of how animal traits influence species vulnerability to this growing phenomenon. This knowledge is needed to improve the design and implementation of policies that mitigate or reduce sensory pollutants. We present results from an expert knowledge survey that quantified the relative influence of 21 ecological, anatomical, and physiological traits on the vulnerability of terrestrial vertebrates to elevated levels of anthropogenic lighting and noise. We aimed not only to quantify the importance of threats and the relative influence of traits as viewed by sensory and wildlife experts, but to examine knowledge gaps based on the variation in responses. Identifying traits that had less consensus can guide future research for strengthening ecologists’ and conservation biologists’ understanding of sensory abilities. Our findings, based on 280 responses of expert opinion, highlight the increasing recognition among experts that sensory pollutants are important to consider in management and conservation decisions. Participant responses show mounting threats to species with narrow niches; especially habitat specialists, nocturnal species, and those with the greatest ability to differentiate environmental visual and auditory cues. Our results call attention to the threat specialist species face and provide a generalizable understanding of which species require additional considerations when developing conservation policies and mitigation strategies in a world altered by expanding sensory pollutant footprints. We provide a step-by-step example for translating these results to on-the-ground conservation planning using two species as case studies.
... Typically, different methods are used to study natural systems and human systems (visitor experiences) within PAs. PA natural systems acoustic monitoring and research normally focuses on the characterization and measurement of the sound environment in combination with behavioral observation of populations of interest [28][29][30]. The United States National Park Service (USNPS) protocols include objective measures of sound, such as duration and dBA, to measure the extent of particular sounds [31]. ...
Article
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This study examined the potential for Perceived Affective Quality (PAQ; pleasantness, eventfulness, familiarity) soundscape measures developed within urban settings to enrich current soundscape management approaches within protected areas (PAs). Drawing on the premise that people bring experiences from other life contexts into PA settings and PA visitors are increasingly coming from urban areas, research integrated urban visitors’ soundscape perceptions of their home and work acoustic environments with their perceptions of acoustic environments in PAs. Two-phased survey research (n = 333) separated visitors into urban density groups and compared PAQ variables across home, work, and PA contexts. Significant differences resulted, both in ratings of the three acoustic contexts (PA, home, work) for all three PAQ components and between urban density groups. The importance of pleasantness was confirmed across all contexts; however, alone, this dimension lacked sufficient contrast to interpret the complexity of soundscape perceptions, especially considering diverse Healthy Parks, Healthy People (HPHP) visitor experience scenarios and goals. Thus, managers should consider (1) additional PAQ variables that can provide more useful and contrasting information; (2) incorporating methods that integrate PAQ measures across visitors’ different acoustic contexts, and (3) including urban density measures within HPHP research.
... For example, it is well-documented that anthropogenic sound exposure affects wildlife populations. Indeed, noise-induced reductions in foraging efficiency have been demonstrated in bats (Luo et al., 2015), owls (Mason et al., 2016), flounder larvae Pseudopleuronectes americanus (Gendron et al., 2020), and crabs (Wale et al., 2013). Chronic traffic noise can alter gene expression in bats, which associates with metabolic dysregulation and stress (Song et al., 2020). ...
Article
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Globally, anthropogenic sound and artificial light pollution have increased to alarming levels. Evidence suggests that these can disrupt critical processes that impact ecosystems and human health. However, limited focus has been given to the potential effects of sound and artificial light pollution on microbiomes. Microbial communities are the foundations of our ecosystems. They are essential for human health and provide myriad ecosystem services. Therefore, disruption to microbiomes by anthropogenic sound and artificial light could have important ecological and human health implications. In this mini-review, we provide a critical appraisal of available scientific literature on the effects of anthropogenic sound and light exposure on microorganisms and discuss the potential ecological and human health implications. Our mini-review shows that a limited number of studies have been carried out to investigate the effects of anthropogenic sound and light pollution on microbiomes. However, based on these studies, it is evident that anthropogenic sound and light pollution have the potential to significantly influence ecosystems and human health via microbial interactions. Many of the studies suffered from modest sample sizes, suboptimal experiments designs, and some of the bioinformatics approaches used are now outdated. These factors should be improved in future studies. This is an emerging and severely underexplored area of research that could have important implications for global ecosystems and public health. Finally, we also propose the photo-sonic restoration hypothesis: does restoring natural levels of light and sound help to restore microbiomes and ecosystem stability?
... En el caso de los anuros, se han observado patrones similares además de cantos mucho más complejos y con mayores tasas de repetición (Halfwerk et al., 2018). En cuanto a los aspectos ecológicos, existe evidencia que sugiere que el ruido antropogénico reduce el éxito de captura de algunos depredadores (Schaub et al., 2008;Mason et al., 2016), del mismo modo que impide el éxito de las estrategias de evasión de depredadores (Yorzinski y Hermann, 2016). Por ejemplo, se han observado disminuciones en la riqueza de especies y la abundancia relativa de ranas a distancias de 250-1,000 m de carreteras y autopistas, respectivamente (Eigenbrod et al., 2009). ...
Chapter
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Se presentan los resultados de mediciones semicontinuas de ruido ambiental (ruido de fondo) y de ruido antropogénico proveniente de fuentes fijas, semiestacionarias y móviles. Las mediciones se realizaron por cinco meses mediante sonómetros de campo (30-130 dB; 31.5 Hz-8 kHz) y mediante el modulo Sound Mapping para ArcGis 10.4. El promedio de ruido ambiental, libre de contaminación antropogénica, osciló entre los 40 y 42 dB con máximas de 62 dB provenientes de ruidos de insectos y anfibios característicos de la zona. El promedio de ruido generado por las fuentes fijas fue de 40-94 dB, el cual se redujo a niveles de fondo a 270-450 m, mientras que las fuentes móviles presentaron niveles de 69- 90 dB, con un área de influencia de 200-250 m. Las fuentes semiestacionarias presentaron los valores más bajos de ruido y de extensión (45 dB y 80 m).
... Acoustic hunters like owls will likely profit from reduced sound pollution. In fact, traffic noise is known to reduce foraging efficiency (Senzaki et al., 2016); the hunting success of saw-whet owls (Aegolius acadius), for example, drops by 8% per dB increase in anthropogenic noise (Mason et al., 2016). Because traffic noise hampers acoustic communication in other bird species (Derryberry et al., 2020;Leonard and Horn, 2005;Mockford and Marshall, 2009), with negative impacts on their reproductive success (Halfwerk et al., 2011), similar fitness consequences are expected for owls, which use acoustic communication to find mates and defend territories. ...
Article
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Research is underway around the world to examine how a wide range of animal species have responded to reduced levels of human activity during the COVID-19 pandemic. In this perspective article, we argue that raptors are particularly well-suited for investigating potential ‘anthropause’ effects, and that the resulting insights will provide much-needed impetus for global conservation efforts. Lockdowns likely alter many of the extrinsic factors that normally limit raptor populations. These environmental changes are in turn expected to influence – mediated by behavioral and physiological responses – the intrinsic (demographic) factors that ultimately determine raptor population levels and distributions. Using this framework, we identify a range of research opportunities and conservation challenges that have arisen during the pandemic. The COVID-19 anthropause allows raptor researchers to address fundamental and applied research objectives in a large-scale, quasi-experimental, well-replicated manner. Importantly, it will be possible to separate the effects of human disturbance and anthropogenic landscape modifications. We explain how high-quality datasets, accumulated for a diverse range of raptor species before, during, and after COVID-19 lockdowns, can be leveraged for powerful comparative analyses that attempt to identify drivers of particular response types. To facilitate and coordinate global collaboration, we are hereby launching the ‘Global Anthropause Raptor Research Network’ (GARRN). We invite the international raptor research community to join this inclusive and diverse group, to tackle ambitious analyses across geographic regions, ecosystems, species, and gradients of lockdown perturbation. Under the most tragic of circumstances, the COVID-19 anthropause has afforded an invaluable opportunity to significantly boost global raptor conservation.
... Increased levels of artificial noise can mask important signals used in both inter-and intra-specific communication (Barber et al. 2010). For instance, noise can interfere with predator detection of adventitious acoustic cues generated by prey, resulting in reduced hunting success (Mason et al. 2016, Senzaki et al. 2016). The same is likely true for a variety of interactions in which one species takes advantage of public information through eavesdropping on other species. ...
Article
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Anthropogenic noise and artificial night lighting have been shown to have substantial effects on animal behavior, physiology, and species interactions. Despite the large body of previous work, very few studies have studied the combined effects of light and noise pollution, especially experimentally in the field. Rodents are a highly diverse group that are predominantly nocturnal and occupy a wide range of habitats worldwide, frequently in close association with human development, placing them at a heightened risk from sensory disturbances. To test the singular and combined effects of various levels of anthropogenic light and noise exposure on pinyon mouse (Peromyscus truei) activity and body condition, we used standard trapping methods across a gradient of light and noise and the two combined and accounted for variation of moonlight, vegetation structure, and weather. We hypothesized that increased levels of artificial light would decrease trap success and lead to lower body condition due to an increase in perceived predation risk and that increased noise levels would increase trap success and body condition due to a reduction in predation risk and/or release from competition. Pinyon mouse trap success declined as light intensity increased, and the effect was comparable to that of moonlight, which is well known to influence rodent activity and perception of predation risk. Although noise pollution did not alter trap success of pinyon mice, individuals captured in noisier areas at the beginning of the season had lower body condition than those from quieter areas. Body condition was uninfluenced by noise and light later in the season. We also found no evidence of any additive or synergistic effects of the two stimuli. Our results provide evidence that alterations to the sensory environment from anthropogenic activity can affect wild rodents in several ways. As anthropogenic development increases to meet the demands of growing human populations, more ecosystems will be exposed to increased levels of sensory disturbance, making the understanding of how these changes affect wildlife critical to ongoing conservation efforts.
... For those that stay, environmental noise can perturb information processing by predators in two main ways: (i) masking, or energetic masking-the increased difficulty of detecting or discriminating a stimulus of interest due to an alternative source that overlaps the stimulus in spectrum, intensity and time [11]; or (ii) distraction-the increased difficulty of detecting or discriminating a stimulus of interest due to an alternative source that occupies attentional resources and processing power of the organism [12] (although see Dominoni et al. [4] for a third, less common mechanism). While studies across taxa, including fish [13,14], birds [15][16][17] and bats [18][19][20][21][22] have found serious declines in hunting success in noisy environments, the underlying mechanism remains elusive. A deeper, mechanistic understanding can provide insight into the evolutionary biology of how organisms compensate for naturally noisy environments. ...
Article
Predators frequently must detect and localize their prey in challenging environments. Noisy environments have been prevalent across the evolutionary history of predator-prey relationships, but now with increasing anthropogenic activities noise is becoming a more prominent feature of many landscapes. Here, we use the gleaning pallid bat, Antrozous pallidus, to investigate the mechanism by which noise disrupts hunting behaviour. Noise can primarily function to mask-obscure by spectrally overlapping a cue of interest, or distract-occupy an animal's attentional or other cognitive resources. Using band-limited white noise treatments that either overlapped the frequencies of a prey cue or did not overlap this cue, we find evidence that distraction is a primary driver of reduced hunting efficacy in an acoustically mediated predator. Under exposure to both noise types successful prey localization declined by half, search time nearly tripled, and bats used 25% more sonar pulses than when hunting in ambient conditions. Overall, the pallid bat does not seem capable of compensating for environmental noise. These findings have implications for mitigation strategies, specifically the importance of reducing sources of noise on the landscape rather than attempting to reduce the bandwidth of anthropogenic noise.
... This acoustic masking could reduce the success of owls attempting to find a mate and establish a territory (Bayne et al. 2008, Francis et al. 2009, Francis and Barber 2013, Shannon et al. 2016, Shonfield and Bayne 2017. In addition, the effect of noise on nocturnal predators decreases hunting success by reducing their chance of detecting prey (Mason et al. 2016, Ciach and Frö hlich 2017, Frö hlich and Ciach 2018. This buffer effect could explain the avoidance of the area around wind farms and may agree with other studies in which anthropogenic noise affects animal behavior, distribution, and reproductive success (Francis and Barber 2013). ...
Article
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The Tawny Owl (Strix aluco) is the most abundant nocturnal raptor in Europe. It has been thoroughly studied in various regions, but its habitat preferences in Mediterranean environments remain poorly understood. With the aim to present novel information about this aspect of the ecology of the Tawny Owl, we established 115 survey stations in the Special Conservancy Area “Sierras de Talayuelas y Aliaguilla” (Castilla–La Mancha region, eastern Spain) and carried out nocturnal surveys by recording spontaneous calls and vocal responses to call playbacks. We then assessed environmental characteristics (vegetation types, soil type, altitude, potential competitors, and anthropic disturbance) in areas where owls were detected or not detected during the breeding season. Overall, we detected 60 responding owls at 49 survey stations during breeding season in the study area (i.e., density 1.22 owls/km2). We found that Tawny Owls preferred lower altitudes and patchy heterogeneous areas. Owls seemed to avoid natural grasslands and areas characterized by limestone soils and associated vegetation, and preferred areas characterized by clay soils and associated vegetation. Interestingly, we did not detect owls close to wind farms, which seem to create a buffer effect on owls’ occurrence. The noise generated by the turbines might be a limiting factor that could account for this avoidance. Our multivariate results showed that Tawny Owls preferred heterogeneous patchy habitat but avoided non-irrigated arable land. Tawny Owls inhabit Mediterranean landscapes where conditions are favorable, but human activities such as wind farms may limit their distribution. Additional research is needed to determine the drivers of this avoidance and whether Tawny Owls also avoid wind farms in other regions of their range.
... Evidence of how animals respond to anthropogenic noise and the consequences of that exposure is ever accumulating (Jerem & Mathews, 2020;Shannon et al., 2016;Swaddle et al., 2015). Just as anthropogenic noise can alter predator-prey relationships (Gomes et al., 2016;Mason et al., 2016), animal communities (Francis et al., 2009(Francis et al., , 2011 and local abundance (Blickley et al., 2012;Bunkley et al., 2017;Cinto Mejia et al., 2019), it is likely that natural noise, of similar sound levels and spectra, has been doing this since the origins of hearing organs in animals. Thus, we expect intense natural acoustic environments to be a powerful and relevant ecological niche axis. ...
Article
Full-text available
Novel anthropogenic noise has received considerable attention in behavioral ecology, but the natural acoustic environment has largely been ignored as a niche axis. Using arrays of speakers, we experimentally broadcasted whitewater river noise continuously for three summers, and monitored spider abundance and behavior across 15 sites, to test our hypothesis that river noise is an important structuring force as a niche axis. We find substantial evidence that orb‐weaving spiders (Araneidae and Tetragnathidae) are more abundant in high sound level environments, but are not affected by background noise spectrum. We explore multiple possible mechanisms underlying these patterns, such as loss of vertebrate predators and increased prey capture, and assess spider web‐building behavior and body condition in noise. Continued research on the natural and anthropogenic acoustic environment will likely reveal a web of connections hidden within this neglected ecological niche axis.
... This acoustic masking could reduce the success of owls attempting to find a mate and establish a territory (Bayne et al. 2008, Francis et al. 2009, Francis and Barber 2013, Shannon et al. 2016, Shonfield and Bayne 2017. In addition, the effect of noise on nocturnal predators decreases hunting success by reducing their chance of detecting prey (Mason et al. 2016, Ciach and Frö hlich 2017, Frö hlich and Ciach 2018. This buffer effect could explain the avoidance of the area around wind farms and may agree with other studies in which anthropogenic noise affects animal behavior, distribution, and reproductive success (Francis and Barber 2013). ...
Article
Full-text available
The Tawny Owl (Strix aluco) is the most abundant nocturnal raptor in Europe. It has been thoroughly studied in various regions, but its habitat preferences in Mediterranean environments remain poorly understood. With the aim to present novel information about this aspect of the ecology of the Tawny Owl, we established 115 survey stations in the Special Conservancy Area ''Sierras de Talayuelas y Aliaguilla'' (Castilla-La Mancha region, eastern Spain) and carried out nocturnal surveys by recording spontaneous calls and vocal responses to call playbacks. We then assessed environmental characteristics (vegetation types, soil type, altitude, potential competitors, and anthropic disturbance) in areas where owls were detected or not detected during the breeding season. Overall, we detected 60 responding owls at 49 survey stations during breeding season in the study area (i.e., density 1.22 owls/km 2). We found that Tawny Owls preferred lower altitudes and patchy heterogeneous areas. Owls seemed to avoid natural grasslands and areas characterized by limestone soils and associated vegetation, and preferred areas characterized by clay soils and associated vegetation. Interestingly, we did not detect owls close to wind farms, which seem to create a buffer effect on owls' occurrence. The noise generated by the turbines might be a limiting factor that could account for this avoidance. Our multivariate results showed that Tawny Owls preferred heterogeneous patchy habitat but avoided non-irrigated arable land. Tawny Owls inhabit Mediterranean landscapes where conditions are favorable, but human activities such as wind farms may limit their distribution. Additional research is needed to determine the drivers of this avoidance and whether Tawny Owls also avoid wind farms in other regions of their range.
... We focus our analysis on energy-related development and motorized recreation, two noise sources that can substantially increase sound levels in natural areas (e.g., Harrison, Clark & Stankey 1980;Ramirez Jr & Mosley 2015). Noise from natural gas extraction has been shown to reduce species' occupancy from large areas of habitat, interfere with species' hunting behavior, alter species' physiology, and influence trophic interactions (Bradshaw, Boutin & Hebert 1998;Bayne, Habib & Boutin 2008;Francis et al. 2011;Blickley et al. 2012;Mason, McClure & Barber 2016). Recently, noise from gas compressors was shown to be more important than canopy cover in explaining habitat selection in secondary cavity-nesting birds (Kleist et al. 2017). ...
Preprint
Noise pollution is detrimental to a diversity of animal species and degrades natural areas, raising concern over the expanding footprint of anthropogenic noise on ecosystems. To guide management of noise sources, modeling tools have been developed to quantify noise levels across landscapes. We demonstrate how to model anthropogenic noise using sound propagation models, including noise from point, line, and polygon sources. In addition, we demonstrate three ways of evaluating spatially-explicit noise impacts, by identifying where noise 1) exceeds a sound level threshold, 2) is audible, or 3) has the potential to mask species communications. Finally, we examine approaches to mitigate these noise impacts on animal species. Noise sources in locations more favorable to sound propagation (e.g., locations with long, unobstructed lines-of-sight) will have a disproportionate impact on the surrounding area. We demonstrate how propagation models can identify sites with smaller acoustic footprints or sites that would benefit from additional noise-control measures. Modeling decisions, such as choice of sound propagation model, sound source information, and the quality of the input data, strongly influence the accuracy of model predictions. These decisions can be guided by comparing model predictions to empirical data when it is available. Synthesis and applications : Here, we demonstrate an approach for modeling and assessing anthropogenic noise sources across a landscape. Our versatile approach allows refining propagation outputs for species-specific questions as well as the quantitative evaluation of management alternatives. While the results are presented in the context of particular species, these approaches can be applied more generally to a wide range of taxa or used for multispecies assessments.
... It spans several types of ecosystems including terrestrial [23], aquatic [24] and coastal ecosystems [25]. Many types of sounds produced by human activities can represent a form of noise pollution for biodiversity, including traffic [26], ships [27], aircraft [28] and industrial activities [29]. Noise pollution can also act in synergy with other disturbances, for example light pollution [30]. ...
Article
Full-text available
Background Ecological research now deals increasingly with the effects of noise pollution on biodiversity. Indeed, many studies have shown the impacts of anthropogenic noise and concluded that it is potentially a threat to the persistence of many species. The present work is a systematic map of the evidence of the impacts of all anthropogenic noises (industrial, urban, transportation, etc.) on biodiversity. This report describes the mapping process and the evidence base with summary figures and tables presenting the characteristics of the selected articles. Methods The method used was published in an a priori protocol. Searches included peer-reviewed and grey literature published in English and French. Two online databases were searched using English terms and search consistency was assessed with a test list. Supplementary searches were also performed (using search engines, a call for literature and searching relevant reviews). Articles were screened through three stages (titles, abstracts, full-texts). No geographical restrictions were applied. The subject population included all wild species (plants and animals excluding humans) and ecosystems. Exposures comprised all types of man-made sounds in terrestrial and aquatic media, including all contexts and sound origins (spontaneous or recorded sounds, in situ or laboratory studies, etc.). All relevant outcomes were considered (space use, reproduction, communication, etc.). Then, for each article selected after full-text screening, metadata were extracted on key variables of interest (species, types of sound, outcomes, etc.). Review findings Our main result is a database that includes all retrieved literature on the impacts of anthropogenic noise on species and ecosystems, coded with several markers (sources of noise, species concerned, types of impacts, etc.). Our search produced more than 29,000 articles and 1794 were selected after the three screening stages (1340 studies (i.e. primary research), 379 reviews, 16 meta-analyses). Some articles (n = 19) are written in French and all others are in English. This database is available as an additional file of this report. It provides an overview of the current state of knowledge. It can be used for primary research by identifying knowledge gaps or in view of further analysis, such as systematic reviews. It can also be helpful for scientists and researchers as well as for practitioners, such as managers of transportation infrastructure. Conclusion The systematic map reveals that the impacts of anthropogenic noises on species and ecosystems have been researched for many years. In particular, some taxonomic groups (mammals, birds, fishes), types of noise (transportation, industrial, abstract) and outcomes (behavioural, biophysiological, communication) have been studied more than others. Conversely, less knowledge is available on certain species (amphibians, reptiles, invertebrates), noises (recreational, military, urban) and impacts (space use, reproduction, ecosystems). The map does not assess the impacts of anthropogenic noise, but it can be the starting point for more thorough synthesis of evidence. After a critical appraisal, the included reviews and meta-analyses could be exploited, if reliable, to transfer the already synthesized knowledge into operational decisions to reduce noise pollution and protect biodiversity.
... Noise affects behavior, the neuroendocrine system, metabolism, cardiovascular health, and even DNA (Kight and Swaddle 2011;Morley et al. 2014). Animals that communicate acoustically to forage or hunt, migrate, warn of danger, and attract mates may be particularly vulnerable to noise (Morley et al. 2014;Radford et al. 2014;LaZerte et al. 2015;Mason et al. 2016) as it can interfere with their mating and territorial calls and disrupt social cohesion that is created through acoustic communication (Slabbekoorn and Peet 2003;Orci et al. 2016). ...
Article
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Rapidly changing environments impose novel selection pressures on organisms, and sometimes adaptive phenotypic plasticity allows organisms to survive and reproduce in the face of environmental change. However, plastic responses can also be maladaptive. In this study, we investigate whether male reproductive investment responds plastically to varied experience with traffic noise. We exposed male crickets chronically to one of three noise treatments from the 2nd-3rd instar until their natural death: masking traffic noise (including noise that overlaps in frequency with the male crickets’ mating calls), non-masking traffic noise (an identical traffic noise track from which we digitally removed the frequencies that mask the crickets’ mating call), and silence. We dissected and weighed their testes and spermatophore molds. Controlling for body mass, we found that the spermatophore molds of crickets reared in masking and non-masking noise were 29% and 24% lighter, respectively, than those of crickets reared in silence. There were no differences in body mass-adjusted testes mass among treatments. If spermatophore mold mass is positively associated with male reproductive output, this reduction in size could have negative fitness consequences for animals exposed to traffic noise. We encourage future work to investigate impacts of noise on reproductive investment in other study systems that are likely sensitive to anthropogenic noise (e.g., birds, frogs, singing insects). Significance statement Anthropogenic noise is a pervasive pollutant and chronic noise can negatively affect fitness. How does anthropogenic noise influence reproductive investment? Phenotypically plastic responses to noise may increase survival and reproduction in noisy environments. Traffic noise masks the sounds crickets make, potentially changing conspecifics’ perception of population density, mate availability, and the risk of sperm competition. We found that male crickets reared in silence developed significantly larger spermatophore molds (a reproductive structure that delivers the sperm containing packet to the female) than those reared in traffic noise. If the spermatophore mold influences male reproductive output, this reduction in size may have negative impacts on reproductive success of animals exposed to masking traffic noise.
Preprint
Full-text available
Globally, anthropogenic sound and artificial light pollution have increased to alarming levels. Evidence suggests that these can disrupt critical processes that impact ecosystems and human health. However, limited focus has been given to the potential effects of sound and artificial light pollution on microbiomes. Microbial communities are the foundations of our ecosystems. They are essential for human health and provide myriad ecosystem services. Therefore, disruption to microbiomes by anthropogenic sound and artificial light could have important ecological and human health implications. In this mini-review, we provide a critical appraisal of available scientific literature on the effects of anthropogenic sound and light exposure on microorganisms and discuss the potential ecological and human health implications. Our mini-review shows that a limited number of studies have been carried out to investigate the effects of anthropogenic sound and light pollution on microbiomes. However, based on these studies, it is evident that anthropogenic sound and light pollution have the potential to significantly influence ecosystems and human health via microbial interactions. Many of the studies suffered from modest sample sizes, suboptimal experiments designs, and some of the bioinformatics approaches used are now outdated. These factors should be improved in future studies. This is an emerging and severely underexplored area of research that could have important implications for global ecosystems and public health. Finally, we also propose the photo-sonic restoration hypothesis: does restoring natural levels of light and sound help to restore microbiomes and ecosystem stability? Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted:
Chapter
This chapter deals with (1) the basic theory of sound propagation; (2) an overview of noise pollution problem in view of policy and standards by the World Health Organization, the United States, and the European Union; (3) noise exposure sources from aircraft, road traffic and railways, in-vehicle, work, and construction sites, and occupations, and households; (4) the noise pollution impact on human health and the biological environment; (5) modeling of regional noise-affected habitats in protected and unprotected land areas and the marine environment; (6) noise control measures and sustainability in view of sustainable building design, noise mapping, and control measures such as barriers and berms along roadsides, acoustic building materials, roadway vehicle noise source control, road surface, and pavement materials; and (7) environmental noise pollution management measures and their impact on human health.
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Terrestrial mammals are found in all types of natural habitat, and they are also maintained in large numbers in captivity. Much of what is known about the anatomy and physiology of the peripheral auditory system has been learned by studying a variety of laboratory mammals and a smaller collection of exotic and domesticated species. The influence of noise exposure ranges from overt trauma to cochlear structures to nonauditory physiological effects, including outcomes associated with development and behavior. Although most man-made sounds are insufficiently intense or persistent to cause overt trauma to free-ranging terrestrial mammals, recent studies have shown that noise exposures producing reversible hearing loss can still permanently damage synapses between auditory sensory cells and primary auditory nerve fibers and thereby affect hearing function. Harmful effects of noise exposure on nonauditory functions have also been reported, and work on domesticated animals adds further evidence that exposure to noise can induce stress with effects on physiology and behavior. Studies on free-ranging animals have shown that animals are often deterred from busy roads, industrial areas, or noisy recreational activities and that foraging efficiency declines for at least some herbivore species. The wide-ranging diversity of auditory thresholds and spectral ranges of sound detected by terrestrial mammals adds a dimension of complexity in the effort to understand the impact of man-made noise on animals.
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Many animals use sound as a medium for detecting or locating potential prey items or predation threats. Northern saw-whet owls ( Aegolius acadicus ) are particularly interesting in this regard, as they primarily rely on sound for hunting in darkness, but are also subject to predation pressure from larger raptors. We hypothesized that these opposing tasks should favor sensitivity to low-frequency sounds arriving from many locations (potential predators) and high-frequency sounds below the animal (ground-dwelling prey items). Furthermore, based on the morphology of the saw-whet owl skull and the head-related transfer functions of related species, we expected that the magnitude of changes in sensitivity across spatial locations would be greater for higher frequencies than low frequencies (i.e., more “directional” at high frequencies). We used auditory-evoked potentials to investigate the frequency-specific directional sensitivity of Northern saw-whet owls to acoustic signals. We found some support for our hypothesis, with smaller-magnitude changes in sensitivity across spatial locations at lower frequencies and larger-magnitude changes at higher frequencies. In general, owls were most sensitive to sounds originating in front of and above their heads, but at 8 kHz there was also an area of high sensitivity below the animals. Our results suggest that the directional hearing of saw-whet owls should allow for both predator and prey detection.
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Anthropogenic noise has caused tremendous impacts on biodiversity and animal behavior, and has become an indispensable factor causing biodiversity decrease potentially. While there is a lack of relevant research in China, protected area as the first priority for species and biodiversity conservation has been increasingly affected by anthropogenic noise. This paper took Dashanbao Nature Reserves of Yunnan Province as an example and investigated the type, sound level and distribution of anthropogenic noise there. The anthropogenic noise referred to in this study includes traffic noise and tourist noise. The spatial distribution of traffic noise was simulated by GIS and CandaA, while that of tourism noise was predicted according to the standard of Quiet Area in EU Noise Directive. Based on the results acquired, potential impact of anthropogenic noise on the endangered species Grus nigricollis in Dashanbao nature reserves was analyzed. It turned out that tourism noise and tweet sound of Grus nigricollis had a large overlap in the 480-2000Hz range, with the highest overlap at 1000Hz. Tourist noise has a significant impact on Grus nigricollis, and 30 tourists can generate 75dBA noise, with the impact range reaching 480m. Anthropogenic noise can directly affect Grus nigricollis's nocturnal and foraging behaviors, which in turn affects its habitat selection and spatial distribution. Therefore, it is proposed that the nature reserves should strengthen the restrictions on tourist flows and behaviors, increase the concealment of observation facilities and the noise reduction effect, and control traffic flows in key areas, to achieve better protection of Grus nigricollis. Based on this, the research also puts forward suggestions on the protection and management of soundscapes of similar nature reserves.
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Wind power is useful for reducing greenhouse gas emissions, but the construction and operation might have negative effects on biodiversity. The purpose of this study was to investigate any effects of wind farm and power line construction on territory occupancy in the vulnerable Eurasian eagle owl. We investigated 48 eagle owl territories before and after the whole construction period and a short operation period with the use of sound meters. We found that territorial eagle owls within 4-5 km from the wind farm and power line construction disturbance left their territories to a significantly higher extent (41% reduction in the number of territories with eagle owls) compared with the eagle owls in territories further away (23% reduction). The distance from the nest site to the disturbance was significantly shorter for those territories that were abandoned compared with territories where the birds stayed. Possible reasons for this decline might be a higher mortality caused by collisions, desertion and avoidance of wind power areas caused by the noise and disturbance from their construction. In addition, there are possible indirect effects, for example reductions in prey species may force eagle owls to abandon their territories. The construction period lasted much longer than the period with active wind turbines and power lines in this investigation, but we cannot separate the effects of the two because the investigations were only possible in the eagle owl breeding season, and the wind turbines were activated shortly after the construction period. Our results imply that careful investigations are needed to detect the possible occurrence of eagle owls near any type of construction work. Studies of these territories should strongly influence how and when the construction work can be carried out, but more investigations are needed to find details about the influence of distance.
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Anthropogenic noise is an emerging global pollutant. Road networks and energy extraction infrastructure are both spatially extensive and rapidly expanding sources of noise. We predict that predators reliant on acoustic cues for hunting are particularly sensitive to louder environments. Here we examined the foraging efficiency of pallid bats (Antrozous pallidus) when exposed to played-back traffic and gas compressor station noise in the laboratory. We show that both types of noise at each of five exposure levels (58–76 dBA, 10–640 m from source) and low-level amplifier noise (35 dBA) increase the time required for bats to locate prey-generated sounds by twofold to threefold. The mechanism underlying these findings is unclear and, given the potential landscape-level habitat degradation indicated by our data, we recommend continued research into the effects of noise exposure on acoustically specialized predators.
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Maximum likelihood or restricted maximum likelihood (REML) estimates of the parameters in linear mixed-effects models can be determined using the lmer function in the lme4 package for R. As for most model-fitting functions in R, the model is described in an lmer call by a formula, in this case including both fixed- and random-effects terms. The formula and data together determine a numerical representation of the model from which the profiled deviance or the profiled REML criterion can be evaluated as a function of some of the model parameters. The appropriate criterion is optimized, using one of the constrained optimization functions in R, to provide the parameter estimates. We describe the structure of the model, the steps in evaluating the profiled deviance or REML criterion, and the structure of classes or types that represents such a model. Sufficient detail is included to allow specialization of these structures by users who wish to write functions to fit specialized linear mixed models, such as models incorporating pedigrees or smoothing splines, that are not easily expressible in the formula language used by lmer.
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Many authors have suggested that the negative effects of roads on animals are largely owing to traffic noise. Although suggestive, most past studies of the effects of road noise on wildlife were conducted in the presence of the other confounding effects of roads, such as visual disturbance, collisions and chemical pollution among others. We present, to our knowledge, the first study to experimentally apply traffic noise to a roadless area at a landscape scale-thus avoiding the other confounding aspects of roads present in past studies. We replicated the sound of a roadway at intervals-alternating 4 days of noise on with 4 days off-during the autumn migratory period using a 0.5 km array of speakers within an established stopover site in southern Idaho. We conducted daily bird surveys along our 'Phantom Road' and in a nearby control site. We document over a one-quarter decline in bird abundance and almost complete avoidance by some species between noise-on and noise-off periods along the phantom road and no such effects at control sites-suggesting that traffic noise is a major driver of effects of roads on populations of animals.
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Anthropogenic noise is an important environmental stressor that is rapidly gaining attention among biologists, resource managers, and policy makers. Here we review a substantial literature detailing the impacts of noise on wildlife and provide a conceptual framework to guide future research. We discuss how several likely impacts of noise exposure have yet to be rigorously studied and outline how behavioral responses to noise are linked to the nature of the noise stimulus. Chronic and frequent noise interferes with animals’ abilities to detect important sounds, whereas intermittent and unpredictable noise is often perceived as a threat. Importantly, these effects can lead to fitness costs, either directly or indirectly. Future research should consider the range of behavioral and physiological responses to this burgeoning pollutant and pair measured responses with metrics that appropriately characterize noise stimuli. This will provide a greater understanding of the mechanisms that govern wildlife responses to noise and help in identifying practical noise limits to inform policy and regulation.
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On the basis of the literature and my own examination of living and/or dead but fresh owls of 16 species, bilateral asymmetry of external ears in owls is surveyed and ear structure briefly described. Consideration of the probability of origin of various structural similarities and dissimilarities in the ear leads to the conclusion that ear asymmetry has evolved independently in at least five lines, represented by the respective genera (1) Tyto, (2) Phodilus, (3) Bubo, Ciccaba, Strix, (4) Rhinoptynx, Asio, Pseudoscops, and (5) Aegolius. Bubo, Ciccaba, and Strix probably represent more than one line of origin of ear asymmetry. Available evidence suggests that bilateral ear asymmetry in owls serves to make the vertical directional sensitivity patterns different between the two ears for high frequencies, thus making possible vertical localization based on binaural comparison of intensity and spectral composition of sound. When an owl localizes prey by hearing, the direction of the source usually forms a shallow angle with the ground. Therefore, a certain angle of error usually converts into a longer distance along the ground for a vertical error than for a horizontal error. This is a crucial factor that calls for good vertical localization ability of owls which rely on hearing for localization of food. Selection pressure for improvement of the ability of vertical localization of sound is believed to lie behind the evolution of all types of bilateral ear asymmetry in owls. On the basis of comparative ear structure the current subdivision of family Strigidae into subfamily Buboninae and Striginae is rejected. The external ears of Rhinoptynx and Pseudoscops are described for the first time and shown to be very similar to those of Asio otus, demonstrating affinity between these three genera.
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Anthropogenic noise is becoming a dominant component of soundscapes across the world and these altered acoustic conditions may have severe consequences for natural communities. We modeled noise amplitudes from gas well compressors across a 16km2 study area to estimate the influence of noise on avian habitat use and nest success. Using species with noise responses representative of other avian community members, across the study area we estimated gray flycatcher (Empidonax wrightii) and western scrub-jay (Aphelocoma californica) occupancy, and gray flycatcher nest success, which is highly dependent on predation by western scrub-jays. We also explore how alternative noise management and mitigation scenarios may reduce area impacted by noise. Compressor noise affected 84.5% of our study area and occupancy of each species was approximately 5% lower than would be expected without compressor noise. In contrast, flycatcher nest success was 7% higher, reflecting a decreased rate of predation in noisy areas. Not all alternative management and mitigation scenarios reduced the proportion of area affected by noise; however, use of sound barrier walls around compressors could reduce the area affected by noise by 70% and maintain occupancy and nest success rates at levels close to those expected in a landscape without compressor noise. These results suggest that noise from compressors could be effectively managed and, because habitat use and nest success are only two of many ecological processes that may change with noise exposure, minimizing the anthropogenic component of soundscapes should be a conservation priority. KeywordsAnthropogenic noise–Occupancy patterns–Natural gas well compressor–Nest success–Soundscape
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Noise pollution is a novel, widespread environmental force that has recently been shown to alter the behaviour and distribution of birds and other vertebrates, yet whether noise has cumulative, community-level consequences by changing critical ecological services is unknown. Herein, we examined the effects of noise pollution on pollination and seed dispersal and seedling establishment within a study system that isolated the effects of noise from confounding stimuli common to human-altered landscapes. Using observations, vegetation surveys and pollen transfer and seed removal experiments, we found that effects of noise pollution can reverberate through communities by disrupting or enhancing these ecological services. Specifically, noise pollution indirectly increased artificial flower pollination by hummingbirds, but altered the community of animals that prey upon and disperse Pinus edulis seeds, potentially explaining reduced P. edulis seedling recruitment in noisy areas. Despite evidence that some ecological services, such as pollination, may benefit indirectly owing to noise, declines in seedling recruitment for key-dominant species such as P. edulis may have dramatic long-term effects on ecosystem structure and diversity. Because the extent of noise pollution is growing, this study emphasizes that investigators should evaluate the ecological consequences of noise alongside other human-induced environmental changes that are reshaping human-altered landscapes worldwide.
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Noise pollution from human traffic networks and industrial activity impacts vast areas of our planet. While anthropogenic noise effects on animal communication are well documented, we have very limited understanding of noise impact on more complex ecosystem processes, such as predator-prey interactions, albeit urgently needed to devise mitigation measures. Here, we show that traffic noise decreases the foraging efficiency of an acoustic predator, the greater mouse-eared bat (Myotis myotis). These bats feed on large, ground-running arthropods that they find by listening to their faint rustling sounds. We measured the bats' foraging performance on a continuous scale of acoustically simulated highway distances in a behavioural experiment, designed to rule out confounding factors such as general noise avoidance. Successful foraging bouts decreased and search time drastically increased with proximity to the highway. At 7.5 m to the road, search time was increased by a factor of five. From this increase, we predict a 25-fold decrease in surveyed ground area and thus in foraging efficiency for a wild bat. As most of the bats' prey are predators themselves, the noise impact on the bats' foraging performance will have complex effects on the food web and ultimately on the ecosystem stability. Similar scenarios apply to other ecologically important and highly protected acoustic predators, e.g. owls. Our study provides the empirical basis for quantitative predictions of anthropogenic noise impacts on ecosystem processes. It highlights that an understanding of the effects of noise emissions and other forms of 'sensory pollution' are crucially important for the assessment of environmental impact of human activities.
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Humans have drastically changed much of the world's acoustic background with anthropogenic sounds that are markedly different in pitch and amplitude than sounds in most natural habitats. This novel acoustic background may be detrimental for many species, particularly birds. We evaluated conservation concerns that noise limits bird distributions and reduces nesting success via a natural experiment to isolate the effects of noise from confounding stimuli and to control for the effect of noise on observer detection biases. We show that noise alone reduces nesting species richness and leads to different avian communities. Contrary to expectations, noise indirectly facilitates reproductive success of individuals nesting in noisy areas as a result of the disruption of predator-prey interactions. The higher reproductive success for birds within noisy habitats may be a previously unrecognized factor contributing to the success of urban-adapted species and the loss of birds less tolerant of noise. Additionally, our findings suggest that noise can have cascading consequences for communities through altered species interactions. Given that noise pollution is becoming ubiquitous throughout much of the world, knowledge of species-specific responses to noise and the cumulative effects of these novel acoustics may be crucial to understanding and managing human-altered landscapes.
Article
Decades of research demonstrate that roads impact wildlife and suggest traffic noise as a primary cause of population declines near roads. We created a "phantom road" using an array of speakers to apply traffic noise to a roadless landscape, directly testing the effect of noise alone on an entire songbird community during autumn migration. Thirty-one percent of the bird community avoided the phantom road. For individuals that stayed despite the noise, overall body condition decreased by a full SD and some species showed a change in ability to gain body condition when exposed to traffic noise during migratory stopover. We conducted complementary laboratory experiments that implicate foraging-vigilance behavior as one mechanism driving this pattern. Our results suggest that noise degrades habitat that is otherwise suitable, and that the presence of a species does not indicate the absence of an impact.
Article
As use of Akaike's Information Criterion (AIC) for model selection has become increasingly common, so has a mistake involving interpretation of models that are within 2 AIC units (ΔAIC ≤ 2) of the top-supported model. Such models are <2 ΔAIC units because the penalty for one additional parameter is 2 AIC units, but model deviance is not reduced by an amount sufficient to overcome the 2-unit penalty and, hence, the additional parameter provides no net reduction in AIC. Simply put, the uninformative parameter does not explain enough variation to justify its inclusion in the model and it should not be interpreted as having any ecological effect. Models with uninformative parameters are frequently presented as being competitive in the Journal of Wildlife Management, including 72 of all AIC-based papers in 2008, and authors and readers need to be more aware of this problem and take appropriate steps to eliminate misinterpretation. I reviewed 5 potential solutions to this problem: 1) report all models but ignore or dismiss those with uninformative parameters, 2) use model averaging to ameliorate the effect of uninformative parameters, 3) use 95 confidence intervals to identify uninformative parameters, 4) perform all-possible subsets regression and use weight-of-evidence approaches to discriminate useful from uninformative parameters, or 5) adopt a methodological approach that allows models containing uninformative parameters to be culled from reported model sets. The first approach is preferable for small sets of a priori models, whereas the last 2 approaches should be used for large model sets or exploratory modeling.
Article
Advanced technologies in oil and gas extraction coupled with energy demand have encouraged an average of 50,000 new wells per year throughout central North America since 2000. Although similar to past trends (see the graph, this page), the space and infrastructure required for horizontal drilling and high-volume hydraulic fracturing are transforming millions of hectares of the Great Plains into industrialized landscapes, with drilling projected to continue (1, 2). Although this development brings economic benefits (3) and expectations of energy security, policy and regulation give little attention to trade-offs in the form of lost or degraded ecosystem services (4). It is the scale of this transformation that is important, as accumulating land degradation can result in continental impacts that are undetectable when focusing on any single region (5). With the impact of this transformation on natural systems and ecosystem services yet to be quantified at broad extents, decisions are being made with few data at hand (see the graph, this page).
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This report provides a complete summary of what is known about basic hearing capabilities in birds in relation to the characteristics of noise generated by wind turbines. It is a review of existing data on bird hearing with some preliminary estimates of environmental noise and wind turbine noise at Altamont Pass, California, in the summer of 1999. It is intended as a resource in future discussions of the role that hearing might play in bird avoidance of turbines.
Article
We used information compiled by the U.S. Geological Survey's Bird Banding Laboratory and geographic information systems (GIS) analysis to identify trends in annual Northern Saw-whet Owl (Aegolius acadicus) movement across eastern North America. Analysis of 81,584 Northern Saw-whet Owl banding events revealed a southbound annual fall migration front with peak banding activity occurring progressively later in the season as latitude decreases. Northbound owls comprised <9% of owls banded and recaptured elsewhere in the same season, and <5% were recaptured northbound >100 km from banding location. There was no relationship between banding latitude and adult-to-juvenile ratio. However, the proportion of adults versus juveniles banded was not uniform among banding stations, suggesting age-differentiated migration patterns may exist. Information from multiyear foreign recaptures revealed that 72% of owls banded and subsequently recaptured at the same latitude in different years were recaptured <100 km from banding location. A similar trend was found in the Appalachian Mountains, the Great Lakes Basin, and the Atlantic seaboard. This indicates that Northern Saw-whet Owls may exhibit high migration route fidelity. These findings expand the Northern Saw-whet Owl information portfolio and illustrate the versatility of aggregate data sets as a tool for answering large-scale questions regarding migration.
Article
Analyzed the method by which the owl's sense of hearing permits it to catch prey in the dark. Hand-reared, specially trained owls participated in experiments in locating artificial sounds, pure tones, and noises. Findings indicate that the owl needs only a small portion of the frequency spectrum in the prey's rustles in order to accurately locate its prey. It was shown that the small rodents make wideband noises rich in frequencies in the range most suitable for the owl's sound location. Further, studies on sound tracking in flight implied that the owl's wing noises do not interfere with the detection of acoustic clues which would necessitate flight correction, while small rodents cannot readily detect the low frequencies of the approaching owl. A theory of sound location by owls is proposed. (20 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
As use of Akaike's Information Criterion (AIC) for model selection has become increasingly common, so has a mistake involving interpretation of models that are within 2 AIC units (ΔAIC ≤ 2) of the top-supported model. Such models are <2 ΔAIC units because the penalty for one additional parameter is +2 AIC units, but model deviance is not reduced by an amount sufficient to overcome the 2-unit penalty and, hence, the additional parameter provides no net reduction in AIC. Simply put, the uninformative parameter does not explain enough variation to justify its inclusion in the model and it should not be interpreted as having any ecological effect. Models with uninformative parameters are frequently presented as being competitive in the Journal of Wildlife Management, including 72% of all AIC-based papers in 2008, and authors and readers need to be more aware of this problem and take appropriate steps to eliminate misinterpretation. I reviewed 5 potential solutions to this problem: 1) report all models but ignore or dismiss those with uninformative parameters, 2) use model averaging to ameliorate the effect of uninformative parameters, 3) use 95% confidence intervals to identify uninformative parameters, 4) perform all-possible subsets regression and use weight-of-evidence approaches to discriminate useful from uninformative parameters, or 5) adopt a methodological approach that allows models containing uninformative parameters to be culled from reported model sets. The first approach is preferable for small sets of a priori models, whereas the last 2 approaches should be used for large model sets or exploratory modeling.
Article
Extraneous sounds have a variety of effects on animals; they may interfere with communication, cause physical harm, increase wariness, influence settlement decisions, or they may cause distractions in ways that increase vulnerability to predation. We designed a study to investigate the effects of changing both the amplitude and duration of an acoustic stimulus on distraction in a terrestrial hermit crab (Coenobita clypeatus). In experiment 1, we replicated the key findings from a field result: crabs hid more slowly in response to a silent visual stimulus when we simultaneously broadcast a white noise than they did when in a silent condition. In experiment 2, we altered the noise duration and found that a long noise generated greater latencies to hide than a short noise. In experiment 3, we increased the noise amplitude and found that hide latency increased with higher-intensity auditory stimuli. These experiments demonstrate a variety of stimulus factors that influence distraction. Our results suggest that prey animals could be in greater danger from predators when in an environment with auditory distractions.
Article
The effects of human activities in forests are often examined in the context of habitat conversion. Changes in habitat structure and composition are also associated with increases in the activity of people with vehicles and equipment, which results in increases in anthropogenic noise. Anthropogenic noise may reduce habitat quality for many species, particularly those that rely on acoustic signals for communication. We compared the density and occupancy rate of forest passerines close to versus far from noise-generating compressor stations and noiseless well pads in the boreal forest of Alberta, Canada. Using distance-based sampling, we found that areas near noiseless energy facilities had a total passerine density 1.5 times higher than areas near noise-producing energy sites. The White-throated Sparrow (Zonotrichia albicollis), Yellow-rumped Warbler (Dendroica coronata), and Red-eyed Vireo (Vireo olivaceus) were less dense in noisy areas. We used repeat sampling to estimate occupancy rate for 23 additional species. Seven had lower conditional or unconditional occupancy rates near noise-generating facilities. One-third of the species examined showed patterns that supported the hypothesis that abundance is influenced by anthropogenic noise. An additional 4 species responded negatively to edge effects. To mitigate existing noise impacts on birds would require approximately $175 million. The merits of such an effort relative to other reclamation actions are discussed. Nevertheless, given the $100 billion energy-sector investment planned for the boreal forest in the next 10 years, including noise suppression technology at the outset of construction, makes noise mitigation a cost-effective best-management practice that might help conserve high-quality habitat for boreal birds.
Article
The history of the development of statistical hypothesis testing in time series analysis is reviewed briefly and it is pointed out that the hypothesis testing procedure is not adequately defined as the procedure for statistical model identification. The classical maximum likelihood estimation procedure is reviewed and a new estimate minimum information theoretical criterion (AIC) estimate (MAICE) which is designed for the purpose of statistical identification is introduced. When there are several competing models the MAICE is defined by the model and the maximum likelihood estimates of the parameters which give the minimum of AIC defined by AIC = (-2)log-(maximum likelihood) + 2(number of independently adjusted parameters within the model). MAICE provides a versatile procedure for statistical model identification which is free from the ambiguities inherent in the application of conventional hypothesis testing procedure. The practical utility of MAICE in time series analysis is demonstrated with some numerical examples.
lme4: linear mixed-effects models using S4 classes
  • D Bates
  • M Maechler
  • B Bolker
  • S Walker
Bates, D., Maechler, M., Bolker, B., Walker, S., 2014. lme4: linear mixed-effects models using S4 classes. R package version 1.1-6. R. http://CRAN.R-project.org/package= lme4 (doi:).