@article {58485, title = {The effect of inundation on frog communities and chorusing behaviour}, journal = {Ecological Indicators}, volume = {145}, year = {2022}, abstract = {

Globally, river regulation has degraded wetlands, including parts of the Murray-Darling Basin (MDB), an ecologically significant basin in Australia. Frogs in a floodplain environment largely depend on habitats created by river flows, but little is known about how frogs in the northern MDB are impacted by river regulation. We tested how wetland inundation affected frogs in a catchment of the northern MDB. We surveyed frogs between 2015 and 2019 to determine long-term changes in the community composition associated with wetland inundation from river flows. Additionally, we recorded nightly soundscapes for four days before and after the arrival of river flows between 2019 and 2020. The abundance and richness of frog species increased during larger inundation events leading to altered community composition (beta diversity). Warmer temperatures increased frog species richness, and frog community dominance decreased with decreasing vegetation cover (i.e., the relative abundance became more even across species). The abundance of five frog species (Limnodynastes tasmaniensis, Limnodynastes fletcheri, Crinia parinsignifera, Litoria peronii, and Litoria latopalmata) was higher in response to increased inundation extent. The total species richness of chorusing frogs increased after the arrival of river flows; six species chorused over the four nights preceding flow, whereas eight species chorused following the flow arrival, but the responses varied among species and sites. Frog species richness increased at three sites after flows, but not at others. After inundation, the choruses of Limnodynastes tasmaniensis increased whereas Limnodynastes fletcheri decreased. Our findings indicate that wetland inundation is beneficial for frog communities and suggest that chorusing behaviour varied in response to river flows inundating floodplain wetlands.

}, keywords = {Environmental watering, False-colour Spectrograms, Floodplain wetlands, Long term survey, passive acoustic monitoring, River regulation}, doi = {10.1016/j.ecolind.2022.109640}, author = {Mohammad Abdur Razzaque Sarke and Donald T. McKnight and Darren Ryder and Amelia Walcott and Joanne F. Ocock and Jennifer A. Spencer and David Preston and Sheryn Brodie and Deborah S. Bower} } @article {58418, title = {Silent winters and rock-and-roll summers: The long-term effects of changing oceans on marine fish vocalization}, journal = {Ecological Indicators}, volume = {125}, year = {2021}, month = {Jan-06-2021}, pages = {107456}, abstract = {

The analysis of temporal trends and spatial patterns of marine sounds can provide crucial insights to assess the abundance, distribution, and behavior of fishes and of many other species. However, data on species-specific temporal and seasonal changes are still extremely limited. We report here the result of the longest recording ever conducted (five years, from 2014 to 2018) on fish vocalization. Findings from the Eastern Taiwan Strait (ETS) revealed a periodic fish chorusing pattern, with peaks in summer and almost complete silence, for ~2 months, during winter. Chorusing pattern was influenced by abiotic parameters, including temperature, tides and moon phase. We also report, for the first time, that extreme weather events (e.g., typhoons, storms with sediment resuspension) caused the cessation of the chorusing. The chorusing pattern explored in this long-term study provides important baseline data to understand the impact of climate change and of climate-driven extreme/episodic events on the phenology of fishes; this work also provides evidence that changes in the ambient conditions might significantly alter the phenology of vocalizing marine species.

}, keywords = {acoustic indices, Behavior, Climate-driven episodic events, Fish vocalization, Marine soundscape, Passive acoustic recordings}, issn = {1470160X}, doi = {10.1016/j.ecolind.2021.107456}, url = {https://linkinghub.elsevier.com/retrieve/pii/S1470160X21001217}, author = {Siddagangaiah, Shashidhar and Chen, Chi-Fang and Hu, Wei-Chun and Danovaro, Roberto and Pieretti, Nadia} } @article {57351, title = {An optimised passive acoustic sampling scheme to discriminate among coral reefs{\textquoteright} ecological states}, journal = {Ecological Indicators}, volume = {107}, year = {2019}, month = {Jan-12-2019}, pages = {105627}, abstract = {

In the present era of rapid global change, innovative monitoring methods can greatly enhance our ability to detect ecological disturbances and prioritise conservation areas in a timely and cost-effective manner. While Passive Acoustic Monitoring (PAM) has recently emerged as a promising tool for monitoring ecological states in marine environments, the specifics of how to apply this method remains poorly defined. In this study we examined how different combinations of sampling settings (frequency bandwidth, time of sampling (day/night), and sample duration) influenced the ability of two acoustic indices, the Sound Pressure Level (SPL) and the Acoustic Complexity Index (ACI), to discriminate different ecological states (ecostates) of coral reefs. We applied an iterative approach to select the most efficient and consistent combinations of sampling settings to use for these two acoustic indices, depending on the stability of their discriminating power across different time scales (successive days, moon phases, and seasons), and the minimum sampling effort required for reliable ecostate assessment. The ability of SPL and ACI to discriminate ecostate-specific soundscapes was more stable and required less sampling effort at nighttime. For indices calculated in the higher frequency band (\>2 kHz), very short recording times (\≤20 min divided into 5 s samples) were sufficient to discriminate ecostates, whereas longer recording times (\≥200 min divided into 5 min samples) were necessary when using indices calculated in the lower frequency bands (\<1 kHz). An optimised sampling scheme, i.e. the group of the five best combinations of settings to discern among coral reef ecostates, was determined at Reunion Island, Indian Ocean, then tested at New Caledonia, Pacific Ocean. Here, the classifications obtained through visual surveys and with the optimised acoustic sampling scheme were congruent. The concordance of our results with visual fish counts confirms the potential of ecoacoustics to rapidly and reliably characterise coral reefs\’ ecostate, allowing managers to prioritise conservation areas among numerous sites, and detect ecological changes over time. Our study provides clear guidelines for monitoring soundscapes by means of the ecoacoustic indices most widely used in the marine realm.

}, keywords = {Coral reefs, Ecoacoustic indices, Ecological state (ecostate), Marine habitats, passive acoustic monitoring, Sampling scheme}, issn = {1470160X}, doi = {10.1016/j.ecolind.2019.105627}, author = {Elise, Simon and Bailly, Arthur and Urbina-Barreto, Isabel and Mou-Tham, G{\'e}rard and Chiroleu, Fr{\'e}d{\'e}ric and Vigliola, Laurent and Robbins, William D. and Bruggemann, J. Henrich} } @article {57345, title = {Assessing key ecosystem functions through soundscapes: A new perspective from coral reefs}, journal = {Ecological Indicators}, volume = {107}, year = {2019}, month = {Jan-12-2019}, pages = {105623}, abstract = {

The functioning of tropical coral reefs is imperilled by climate change, overfishing, and decreasing water quality. Maintaining their capacity to provide goods and services will critically depend on our ability to monitor their functioning at appropriate spatial and temporal scales. Given the constraints of traditional methods to respond to those needs, the potential of complementary tools such as Passive Acoustic Monitoring (PAM) is emerging. Coral reef soundscapes (i.e. ambient sound) encompass sounds produced by numerous organisms. Soundscape characteristics quantified by ecoacoustic indices have been found to reflect general ecosystem properties, such as diversity and abundance of fishes, and coral cover. The present study tested, on the virtually pristine coral reefs around Europa Island, South-West Indian Ocean, the capacity of acoustic indices to assess key ecosystem functions. Soundscapes were recorded during 2 h, and ecosystem functions were evaluated using video footage of the fish assemblages and underwater photogrammetry of the benthic landscapes. We found significant and strong correlations between six ecoacoustic indices and six key ecosystem functions, including habitat features and fish assemblage characteristics. The six ecoacoustic indices were representative of several combinations of frequency, amplitude and time analysis domains, highlighting the diversity of the functional information conveyed by soundscapes. Our findings reveal that a 2 h daytime recording on a coral reef could provide sufficient acoustic information to characterise major ecosystem functions of a site. This should facilitate the detection of functional disturbances at temporal and spatial scales adapted to the rapidity of upcoming climate changes. Our results also highlight the potential of ecoacoustics to bring novel and relevant insights in the functioning of ecosystems.

}, keywords = {conservation, Coral reefs, Ecoacoustic indices, Key ecosystem functions, passive acoustic monitoring, Soundscape}, issn = {1470160X}, doi = {10.1016/j.ecolind.2019.105623}, author = {Elise, Simon and Urbina-Barreto, Isabel and Pinel, Romain and Mahamadaly, Vincent and Bureau, Sophie and Penin, Lucie and Adjeroud, Mehdi and Kulbicki, Michel and Bruggemann, J. Henrich} } @article {53447, title = {Differential and additive effects of natural biotic and anthropogenic noise on call properties of Odontophrynus americanus (Anura, Odontophryinidae): Implications for the conservation of anurans inhabiting noisy environments}, journal = {Ecological Indicators}, volume = {99}, year = {2019}, month = {Jan-04-2019}, pages = {67 - 73}, abstract = {

Successful reproduction in most anurans is associated to acoustic communication and negative effects of auditory masking by natural biotic and anthropogenic noise are known in this group. However, the potential additive effect of both noise types has been scarcely studied. We examine in situ the acoustic variation of 135 males (n = 975 calls) of Odontophrynus americanus in areas from Central Argentina with (TN) and without traffic noise (N-TN) and in presence (Ch) or absence (N-Ch) of chorus. The effect of noise condition on four call properties (call duration [CD], intercall interval [ICI], pulse rate [PR] and dominant frequency [DF]) were analyzed using linear mixed models (LMM and GLMM). A Principal Component Analysis (PCA) was performed to identify the acoustical properties that best accounted for variation among all possible noise conditions (N-TN/N-Ch; N-TN/Ch; TN/N-Ch and TN/Ch). PR and DF showed significant higher values in TN than N-TN sites while a significant increase in ICI and a decrease in DF were found in chorus situation. Analyzing combined effects, PR significantly increased in N-TN/N-Ch condition and decreased under TN/Ch. ICI was significantly higher in N-TN/N-Ch condition. PCA showed a separation of males calling in noisy condition mainly associated to higher values of DF and CD. The acoustic variation observed in noisy environments could have implications in the reproductive strategies of the individuals although new studies should be conducted to analyze the effect of this variation on the recognition and choice by females. Our outcomes highlight the importance of conducting in situ behavioral studies considering the additive effects of different environmental noise sources.

}, keywords = {acoustic communication, advertisement call, Auditory masking, Chorus noise, Noise pollution, Road traffic noise}, issn = {1470160X}, doi = {10.1016/j.ecolind.2018.12.014}, url = {https://linkinghub.elsevier.com/retrieve/pii/S1470160X18309464https://api.elsevier.com/content/article/PII:S1470160X18309464?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S1470160X18309464?httpAccept=text/plain}, author = {Grenat, Pablo R. and Pollo, Favio E. and Ferrero, Mar{\'\i}a A. and Martino, Adolfo L.} } @article {53425, title = {An evaluation of the efficiency of passive acoustic monitoring in detecting deer and primates in comparison with camera traps}, journal = {Ecological Indicators}, volume = {98}, year = {2019}, month = {Jan-03-2019}, pages = {753 - 762}, abstract = {

In recent years, camera traps have rapidly become popular for the large-scale monitoring of wildlife distributionand population; however, we should not ignore the uncertainty regarding the reliability of camera-basedmonitoring by inexperienced data gatherers. This study introduces passive acoustic monitoring (PAM) as aneasier technique for monitoring terrestrial mammals that uses the sound cues that they produce. To validate theefficacy of PAM, we quantitatively compared the detection areas and rates between sound cues (from PAM) andvisual cues (from camera traps) of two mammals\—the sika deerCervus nipponand the Japanese macaqueMacacafuscata\—across seven study sites in eastern Japan with different population densities. To collect sound cues, weset up multiple autonomous recording units at the sites and continuously recorded ambient sounds, following apre-determined schedule. The total recording time reached 9081 h for deer and 8235 h for macaques. We thenbuilt sound recognizers to automatically detect eight target call types from the recorded data. To collect visualcues, we also set multiple camera traps at the same sites and for the same observation periods. The keyfindingswere as follows: (1) the fully automated procedures that only used the recognizers to detect sound cues producednumerous false positive detections when the call type possessed vocal plasticity and variations; (2) the semi-automated procedures, which included an additional step to validate the automated detections by manualscreening, exhibited a great improvement in the detectability and recall rates of the half of the target calls,reaching \> 0.70; (3) when using the semi-automated procedures, the frequency of deer and macaque detectionsper trap-day derived from the sound cues were in most cases approximately dozens of times and several times,respectively, higher than that derived from the visual cues; (4) the main advantage of PAM may be its superiordetection areas, which were 100\–7000 times wider than those of camera traps; and (5) the current success of therecognition of different call types of each species could broaden the use of PAM, which is not possible for cameratraps. PAM could provide socio-behavioral data (i.e., the frequencies and types of inter-individual vocal com-munications) that could help understand the status of population dynamics and the group compositions, inaddition to information related to the presence or absence of species.

}, keywords = {Cervus nippon, Ecoacoustic monitoring, Lag-phase management, Macaca fuscata, passive acoustic monitoring}, issn = {1470160X}, doi = {10.1016/j.ecolind.2018.11.062}, url = {https://linkinghub.elsevier.com/retrieve/pii/S1470160X18309257https://api.elsevier.com/content/article/PII:S1470160X18309257?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S1470160X18309257?httpAccept=text/plain}, author = {Enari, Hiroto and Enari, Haruka S. and Okuda, Kei and Maruyama, Tetsuya and Okuda, Kana N.} } @article {53065, title = {Assessing biological and environmental effects of a total solar eclipse with passive multimodal technologies}, journal = {Ecological Indicators}, volume = {95}, year = {2018}, month = {Jan-12-2018}, pages = {353 - 369}, abstract = {

On 21 August 2017, a total solar eclipse crossed the continental United States, providing a unique natural experiment to observe how wildlife and plants respond to rapid and drastic changes in photic conditions using a multi-modal suite of tools. We installed passive time-lapse and infrared cameras, sound recorders, and data loggers in the Central Platte River Valley of Nebraska to study this phenomenon. The eclipse lasted about three hours, and complete obscuration of the sun (totality) lasted for about 2 min and 30 sec. Light values, measured with time-lapse camera systems, decreased 67\% on average during totality relative to the daily mean light value. Ambient temperatures decreased by 6.7 \°C on average (12\% of the daily mean) approximately 11\–16 min after totality; concurrently, humidity increased by an average of 12\% of the daily mean. We found evidence for altered acoustic activity in response to the eclipse, including site and species-specific changes in the call activities of late season breeding birds and insects in the orders orthoptera and hemiptera. In addition, acoustic indices were differentially correlated with changes in photic and thermal conditions. However, we did not observe changes in flowering plants nor detect bat activity at known night roost and foraging areas. Historically, observations during rare occurrences, such as a total solar eclipse, were anecdotal or limited in scope, and thus, how they changed the light, sound, and meteorological conditions on the landscape were difficult to validate and measure. In comparison, anthropogenic disturbances, including impacts from light pollution and climate change, often take place slowly over long periods, and therefore, can be complex and challenging to assess. Documentation of this stochastic occurrence, with an immediate change in environmental conditions, highlights the utility of passive multimedia technologies to increase our capacity to monitor ecosystem dynamics and chronicle the variations of abiotic properties of a landscape and concomitant responses of organisms with varying sensory abilities.

}, keywords = {Animal response, image analysis, Light, Passive monitoring, Soundscape, Total solar eclipse}, issn = {1470160X}, doi = {10.1016/j.ecolind.2018.07.017}, url = {https://linkinghub.elsevier.com/retrieve/pii/S1470160X18305375https://api.elsevier.com/content/article/PII:S1470160X18305375?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S1470160X18305375?httpAccept=text/plain}, author = {Brinley Buckley, Emma M. and Caven, Andrew J. and Gottesman, Benjamin L. and Harner, Mary J. and Bryan C. Pijanowski and Forsberg, Michael L.} } @article {52679, title = {Estimating animal acoustic diversity in tropical environments using unsupervised multiresolution analysis}, journal = {Ecological Indicators}, volume = {90}, year = {2018}, month = {Jan-07-2018}, pages = {346 - 355}, abstract = {

Ecoacoustic monitoring has proved to be a viable approach to capture ecological data related to animal communities. While experts can manually annotate audio samples, the analysis of large datasets can be significantly facilitated by automatic pattern recognition methods. Unsupervised learning methods, which do not require labelled data, are particularly well suited to analyse poorly documented habitats, such as tropical environments. Here we propose a new method, named Multiresolution Analysis of Acoustic Diversity (MAAD), to automate the detection of relevant structure in audio data. MAAD was designed to decompose the acoustic community into few elementary components (soundtypes) based on their time\–frequency attributes. First, we used the short-time Fourier transform to detect regions of interest (ROIs) in the time\–frequency domain. Then, we characterised these ROIs by (1) estimating the median frequency and (2) by running a 2D wavelet analysis at multiple scales and angles. Finally, we grouped the ROIs using a model-based subspace clustering technique so that ROIs were automatically annotated and clustered into soundtypes. To test the performance of the automatic method, we applied MAAD to two distinct tropical environments in French Guiana, a lowland high rainforest and a rock savanna, and we compared manual and automatic annotations using the adjusted Rand index. The similarity between the manual and automated partitions was high and consistent, indicating that the clusters found are intelligible and can be used for further analysis. Moreover, the weight of the features estimated by the clustering process revealed important information about the structure of the acoustic communities. In particular, the median frequency had the strongest effect on modelling the clusters and on classification performance, suggesting a role in community organisation. The number of clusters found in MAAD can be regarded as an estimation of the soundtype richness in a given environment. MAAD is a comprehensive and promising method to automatically analyse passive acoustic recordings. Combining MAAD and manual analysis would maximally exploit the strengths of both human reasoning and computer algorithms. Thereby, the composition of the acoustic community could be estimated accurately, quickly and at large scale.

}, keywords = {Acoustic community, Ecoacoustic monitoring, Nocturnal soundscape, Unsupervised machine learning, Wavelets}, issn = {1470160X}, doi = {10.1016/j.ecolind.2018.03.026}, url = {http://linkinghub.elsevier.com/retrieve/pii/S1470160X1830181X}, author = {Ulloa, Juan Sebastian and Aubin, Thierry and Llusia, Diego and Bouveyron, Charles and Sueur, Jerome} } @article {52674, title = {Automatic identification of rainfall in acoustic recordings}, journal = {Ecological Indicators}, volume = {75}, year = {2017}, month = {Jan-04-2017}, pages = {95 - 100}, abstract = {

The rainfall regime is one of the main abiotic components that can cause modifications in the breeding activity of animal species. It has a direct effect on the environmental conditions, and acts as a modifier of the landscape and soundscape. Variations in water quality and acidity, flooding, erosion, and sound distortion are usually related with the presence of rain. Thereby, ecological studies in populations and communities would benefit from improvements in the estimation of rainfall patterns throughout space and time.

In this paper, a method for automatic detection of rainfall in forests by using acoustic recordings is proposed. This approach is based on the estimation of the mean value and signal to noise ratio of the power spectral density in the frequency band in which the sound of the raindrops falling over the vegetation layers of the forest is more prominent (i.e. 600\–1200 Hz). The results of this method were compared with human auditory identification and data provided by a pluviometer. We achieved a correlation of 95.23\% between the data provided by the pluviometer and the predictions of a regression model. Furthermore, we attained a general accuracy between 92.90\% and 99.98\% when identifying different intensity levels of rainfall on recordings.

Nowadays, passive monitoring recorders have been extensively used to study of acoustic-based breeding processes of several animal species. Our method uses the signals acquired by these recorders in order to identify and quantify rainfall events in short and long time spans. The proposed approach will automatically provide information about the rainfall patterns experienced by target species based on audio recordings.

}, keywords = {bioacoustics, Environmental monitoring, Precipitation measuremen, Rain detection, Soundscape ecology}, issn = {1470160X}, doi = {10.1016/j.ecolind.2016.12.018}, url = {http://linkinghub.elsevier.com/retrieve/pii/S1470160X16307117}, author = {Bedoya, Carol and Isaza, Claudia and Daza, Juan M. and L{\'o}pez, Jos{\'e} D.} } @article {47292, title = {Testing the performances of automated identification of bat echolocation calls: A request for prudence}, journal = {Ecological Indicators}, volume = {78}, year = {2017}, month = {Jan-07-2017}, pages = {416 - 420}, abstract = {

Echolocating bats are surveyed and studied acoustically with bat detectors routinely and worldwide, yet identification of species from calls often remains ambiguous or impossible due to intraspecific call variation and/or interspecific overlap in call design. To overcome such difficulties and to reduce workload, automated classifiers of echolocation calls have become popular, but their performance has not been tested sufficiently in the field. We examined the absolute performance of two commercially available programs (SonoChiro and Kaleidoscope) and one freeware package (BatClassify). We recorded noise from rain and calls of seven common bat species with Pettersson real-time full spectrum detectors in Sweden. The programs could always (100\%) distinguish rain from bat calls, usually (68\–100\%) identify bats to group ( Nyctalus/Vespertilio/Eptesicus, Pipistrellus, Myotis, Plecotus, Barbastella ) and usually (83\–99\%) recognize typical calls of some species whose echolocation pulses are structurally distinct ( Pipistrellus pygmaeus , Barbastella barbastellus ). Species with less characteristic echolocation calls were not identified reliably, including Vespertilio murinus (16\–26\%), Myotis spp. (4\–93\%) and Plecotus auritus (0\–89\%). All programs showed major although different shortcomings and the often poor performance raising serious concerns about the use of automated classifiers for identification to species level in research and surveys. We highlight the importance of validating output from automated classifiers, and restricting their use to specific situations where identification can be made with high confidence. For comparison we also present the result of a manual identification test on a random subset of the files used to test the programs. It showed a higher classification success but performances were still low for more problematic taxa.

}, keywords = {Biosonar, methodology, software, species identification, ultrasound}, issn = {1470160X}, doi = {10.1016/j.ecolind.2017.03.023}, url = {http://linkinghub.elsevier.com/retrieve/pii/S1470160X17301401}, author = {Rydell, Jens and Nyman, Stefan and Ekl{\"o}f, Johan and Jones, Gareth and Russo, Danilo} }