@article {53435, title = {Hot spots of ecoacoustics in Greece and the issue of background noise}, journal = {Journal of Ecoacoustics}, volume = {2}, year = {2018}, month = {Sep-24-20182172}, pages = {U3XBIY}, abstract = {

Biodiversity monitoring and assessment across a variety of gradients, could be achieved with the aid of the ecoacoustics discipline. Acoustic monitoring approaches can provide results regarding the species richness of birds, bats, frogs and insects including cicadas (Cicadoidea) and katydids (Tettigoniidae) with results similar to the ones provided by classical ecological methods (e.g. visual point count methods). The risk of extinction of several species has led to the creation of the Natura 2000 Network in the European Union\’s territory. Greece provides a number of 202 Special Protection Areas (SPA\’s) and 241 Sites of Community Importance (SCI), 239 of which are considered as Special Areas of Conservation (SAC). The specific areas provide both, an opportunity for ecoacoustics practice and an opportunity for ecoacoustic research. Even though the specific field of ecology has proven to be a valuable biodiversity assessment tool, areas that provide a variety of ecoacoustic events are yet to be documented. The goal of the specific article is to highlight these special conservation areas and propose a monitoring network using the non-invasive approach of ecoacoustics. For the specific research, the Greek protected areas were visualized in order to highlight sonotopes and soundtopes worthy of future research. Finally, in order to highlight the neglected issue of background noise regarding conservation efforts, the Kalloni\’s salt pans were selected as a case study area. Noise measurements and sound recordings were conducted. Furthermore, noise and sound maps were created, in order to visualize the effects of noise.

}, keywords = {Natura 2000; ecoacoustics; monitoring network; noise map; isobel map; Kalloni{\textquoteright}s Bay}, doi = {10.22261/JEA10.22261/JEA.U3XBIY}, author = {Matsinos, Yiannis G. and Tsaligopoulos, Aggelos} } @article {53063, title = {Field observations of ecoacoustic dynamics of a Japanese bush warbler using an open-source software for robot audition HARK}, journal = {Journal of Ecoacoustics}, volume = {2}, year = {2018}, abstract = {

We report on a simple and practical application of HARK, an easily available and portable system for bird song localization using an open-source software for robot audition HARK, to a deeper understanding of ecoacoustic dynamics of bird songs, focusing on a fine-scaled temporal analysis of song movement \— song type dynamics in playback experiments. We extended HARKBird and constructed a system that enables us to conduct automatic playback and interactive experiments with different conditions, with a real-time recording and localization of sound sources. We investigate how playback of conspecific songs and playback patterns can affect vocalization of two types of songs and spatial movement of an individual of Japanese bush-warbler, showing quantitatively that there exist strong relationships between song type and spatial movement. We also simulated the ecoa- coustic dynamics of the singing behavior of the focal individual using a software, termed Bird song explorer, which provides users a virtual experi- ence of acoustic dynamics of bird songs using a 3D game platform Unity. Based on experimental results, we discuss how our approach can contribute to ecoacoustics in terms of two different roles of sounds: sounds as tools and subjects.

}, doi = {10.22261/jea.eyaj46}, author = {Reiji Suzuki and Shinji Sumitani and Naren and Shiho Matsubayashi and Takaya Arita and Kazuhiro Nakadai and Hiroshi G. Okuno} } @article {52855, title = {Acoustic indices as rapid indicators of avian diversity in different land-use types in an Indian biodiversity hotspotAbstract}, journal = {Journal of Ecoacoustics}, volume = {2}, year = {2018}, month = {Jan-18-2018}, abstract = {

Passive acoustic monitoring is a potentially valuable tool in biodiversity hotspots, where surveying can occur at large scales across land conversion types. However, in order to extract meaningful biological information from resulting enormous acoustic datasets, rapid analytical techniques are required. Here we tested the ability of a suite of acoustic indices to predict avian bioacoustic activity in recordings collected from the Western Ghats, a biodiversity hotspot in southwestern India. Recordings were collected at 28 sites in a range of land-use types, from tea, coffee, and cardamom plantations to remnant forest stands. Using 36 acoustic indices we developed random forest models to predict the richness, diversity, and total number of avian vocalizations observed in recordings. We found limited evidence that acoustic indices predict the richness and total number of avian species vocalizations in recordings (R2 \< 0.51). However, acoustic indices predicted the diversity of avian species vocalizations with high accuracy (R2 = 0.64, mean squared error = 0.17). Index models predicted low and high diversity best, with the highest residuals for medium diversity values and when continuous biological sounds were present (e.g., insect sounds \>8\ sec). The acoustic complexity index and roughness index were the most important for predicting avian vocal diversity. Avian species richness was generally higher among shade-grown crops than in the open tea plantation. Our results suggest that models incorporating acoustic indices can accurately predict low and high avian species diversity from acoustic recordings. Thus, ecoacoustics could be an important contributor to biodiversity monitoring across landscapes like the Western Ghats, which are a complex mosaic of different land-use types and face continued changes in the future.

}, keywords = {diversity, landscape, passive acoustic monitoring, shade-grown crop, species richness, Western Ghats}, doi = {10.22261/JEA10.22261/JEA.GWPZVD}, url = {https://www.veruscript.com/journals/journal-of-ecoacoustics/acoustic-diversity-in-an-indian-hotspot/}, author = {Agnihotri, Samira and Robin, V. V. and Goel, Anurag and Rohini Balakrishnan} } @article {52749, title = {What do insects, anurans, birds, and mammals have to say about soundscape indices in a tropical savanna}, journal = {Journal of Ecoacoustics}, volume = {2}, year = {2018}, month = {Sep-18-20182245}, pages = {PVH6YZ}, abstract = {

The application of acoustic indices is incipient and still needs validation before it can reliably characterize soundscapes and monitor rapidly disappearing hot-spot areas as the Brazilian tropical savanna (Cerrado). Here we investigate which of six acoustic indices better correlate with the 24 h zoophony richness of insects, anurans, birds, and mammals. We sampled one minute every 30 minutes for seven days on three sites in Serra da Canastra National Park (Minas Gerais state, Brazil) and extracted the sonotype richness and six indices based on recordings with a bandwidth of up to 48 kHz. The Acoustic Diversity, Evenness, Entropy, and Normalized Difference Soundscape indices followed the temporal trends of the sonotype richness of insects and anurans. The Acoustic Complexity (ACI) and Bioacoustic (BIO) indices did not correlated with sonotype richness. ACI and BIO were influenced by sonic abundance and geophony. We emphasize the need to include insects and anurans on soundscape and acoustic ecology analyses and to avoid bias on avian fauna alone. We also suggest that future studies explore measures of sonic abundance and acoustic niche occupation of sonotypes to complement measures of zoophony richness and better understand what each faunal group is telling us about indices.

}, doi = {10.22261/JEA10.22261/JEA.PVH6YZ}, url = {https://www.veruscript.com/api/files/veruscript_PVH6YZ.pdf}, author = {Ferreira, Luane M. and Oliveira, Eliziane G. and Lopes, Lara C. and Brito, Marcos R. and Baumgarten, J{\'u}lio and Rodrigues, Fl{\'a}vio H. and Sousa-lima, Renata S.} } @article {52600, title = {Spatiotemporal patterns of avian vocal activity in relation to urban and rural background noise}, journal = {Journal of Ecoacoustics}, volume = {1}, year = {2017}, month = {Apr-26-20172062}, pages = {Z9TQHU}, abstract = {

Background noise can interfere with and influence acoustic communication behavior. Signal interference is dependent on the amplitude and spectral characteristic of background noise, which varies over space and time. The likelihood of signal interference is greater when background noise is concentrated within the same frequency bands of an animal\’s vocalization, but even a partial masking effect can elicit signaling behavior modification. Relative to a rural landscape, background noise in an urban landscape is disproportionately comprised by anthropogenic sound, which fluctuates in amplitude throughout the day and occurs primarily in low frequencies (0\–2 kHz). In this study, we examined if urban-rural differences in vocal activity patterns exist in a species Zonotrichia leucophrys nuttalli that communicates above the frequency range of anthropogenic noise (2\–8 kHz). We tested whether vocal activity patterns changed in relation to sound in the high or low frequency bands within and between urban and rural locations. Automated acoustic recording devices (ARDs) continuously recorded throughout the morning song chorus, 0500 to 1,100 h, during the 2014 breeding season in San Francisco (urban) and Marin (rural) Counties, CA. Supervised learning cluster analysis was used to quantify vocal activity by totaling the number of songs. In general, vocal activity was greater in urban locations compared to rural locations. However, within rural and urban study sites, we found vocal activity decreased where low frequency noise levels were higher. There was not a relationship between vocal activity and high frequency, biotic sound. In both urban and rural locations, low frequency noise levels increased through the morning, while vocal activity remained relatively consistent. Our results demonstrate how patterns of vocal activity can change with low frequency, abiotic noise, even when there is no direct spectral overlap with the acoustic signal.

}, doi = {10.22261/JEA10.22261}, author = {Gentry, Katherine E.} } @article {52599, title = {Changes in the acoustic structure and composition along a tropical elevational gradient }, journal = {Journal of Ecoacoustics}, volume = {1}, year = {2017}, month = {Sep-24-20172070}, pages = {PNCO7I}, abstract = {

Elevational gradients influence the distribution and composition of animal species and can provide useful information for the development of conservation strategies in the context of climate change. Despite an increase in studies of species diversity along elevational gradients, there is still a lack of information about community responses to environmental gradients, in part because of the logistical limitations of sampling multiple taxa simultaneously. One solution is to use passive acoustic monitoring (PAM) to acquire and analyze information from different animal taxa simultaneously along an entire elevational gradient. To improve our understanding of how environmental gradients influence patterns of animal communities and to test the relationship between soundscapes and animal composition we investigated how variation in bird and anuran composition affect the acoustic structure and composition of the soundscapes along an elevation gradient. We used PAM deploying portable acoustic recorders along three elevational transects in the Luquillo Mountains (LM), Puerto Rico. We found that elevation plays a major role in structuring the acoustic community and that the soundscape composition reflected the same patterns of anuran and bird distribution and composition along the elevational gradient. This study shows how different animal taxa respond to environmental gradients and provide strong evidence for the use of soundscapes as a tool to describe and compare species distribution and composition across large spatial scales.

}, doi = {10.22261/JEA10.22261/JEA.PNCO7I}, author = {Campos-Cerqueira, Marconi and T. Mitchell Aide} } @article {52598, title = {Environmental factors could constrain the use of long-range vocal signals in solitary tuco-tucos (Ctenomys; Rodentia, Ctenomyidae) reproduction }, journal = {Journal of Ecoacoustics}, volume = {1}, year = {2017}, month = {Oct-24-20172112}, pages = {R7YFP0}, abstract = {

Ctenomys are mainly solitary subterranean rodents. Life underground has advantages (protection against predators, environmental control and reduced competition) but also implies disadvantages (digging costs, coping with hypercapnia, physiological and sensory changes, and communication problems) that can affect the social structure. Reproduction is a critical moment in the use of the signal repertoire, because individuals should locate in space, travel to, contact and copulate with a suitable partner. Energy expenditure involved in digging (connecting) tunnels makes difficult to attain a partner burrow system, but predation risk involved in moving above ground can counterbalance it and coupled with the spatial structure of the population, can determine the best communicative strategy to contact and locate a potential partner. Vocalisations allow to communicate over longer distances an with a reduced risk, while chemical signals, mostly aimed at vomerolfaction involve proximity or direct contact with the sample odour thus making information gathering more risky. As Ctenomys can use different signal types to gather different types of information leading to copulation, we propose that the use of these signals would be flexible, depending mostly on population spatial structure and type of predators living in the zone. This is because differences among species and/or populations in the use and characteristics of long-range vocalisations could be induced by environmental and/or social factors. This variation could be considered as a case of phenotypic plasticity, determining communication strategies variability in reproductive context, mostly dependent on long-range communication signals and the behaviour of males.

}, doi = {10.22261/JEA10.22261/JEA.R7YFP0}, author = {Francescoli, Gabriel} } @article {52597, title = {Vocalizing during gaps in anthropogenic noise is an uncommon trait for enhancing communication in songbirds}, journal = {Journal of Ecoacoustics}, volume = {1}, year = {2017}, month = {Jul-06-20172238}, pages = {TLP16D}, abstract = {

Mounting evidence suggests that anthropogenic noise negatively impacts many wildlife species, including songbirds. One mechanism by which noise affects songbirds may be through acoustic obstruction to their systems of vocal communication. However, many species increase the amplitude or pitch of their vocalizations, which may partially mitigate the impact of high noise levels. When the amplitude of anthropogenic noise varies over time, such as near a moderate-use highway, short gaps between noise events may also provide an important opportunity for communication. But, whether songbirds adjust vocalization rates rapidly to avoid overlap with noise is unknown for most species. We used acoustic playback to expose songbirds to simulated road noise during the dawn chorus in otherwise quiet habitats. We measured vocalization rates under ambient conditions and during quiet gaps embedded within playback of road noise to assess whether a community of songbirds, and nineteen individual species, vocalize more regularly during noise gaps. There were no significant differences in community-wide acoustic output. Species-specific analysis revealed that only four species altered their vocal rates during quiet gaps in noise, but that the direction of the effect varied by species. Point count results revealed that birds generally remained on site for the duration of the experiment, suggesting that abandonment of noisy locations was unlikely to confound our results. In sum, increasing vocal output during short gaps in noise occurred in only a handful of species, perhaps contributing to the limited number of species that are found within noisy habitats.

}, doi = {10.22261/JEA10.22261/JEA.TLP16D}, author = {Proppe, Darren S. and Finch, Emily} } @article {52596, title = {Temporal variation in acoustic and visual signalling as a function of stream background noise in the Bornean foot-flagging frog, Staurois parvus}, journal = {Journal of Ecoacoustics}, volume = {1}, year = {2017}, month = {Jul-06-20172238}, pages = {X74QE0}, abstract = {

High background noise can interfere with signal detection and perception. Bornean foot-flagging frogs, Staurois parvus, live along noisy streams and use both acoustic and visual signals to communicate. It remains unclear why acoustic signalling is retained given that visual signalling appears to have clear advantages under these noisy conditions. We hypothesized that temporal dynamics in stream noise have shaped the multimodal communication system in S. parvus with acoustic signalling at an advantage under more quiet conditions, whereas visual signals will prevail when the noise of rushing water is high after rains. We found that as predicted, male S. parvus increased foot flagging and decreased advertisement calling when presented with playbacks of stream noise compared to less noisy pre-playback conditions. Such context-dependent dynamic-selection regimes are recently gaining wider attention and enhance our understanding of the flexibility seen in the use of multimodal signals in S. parvus.

}, doi = {10.22261/JEA10.22261/JEA.X74QE0}, author = {Grafe, T. Ulmar and Tony, Joremy A.} }