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Southeast Asia includes several global biodiversity hotspots and bats account for nearly one-third of mammal species currently known in the region. While acoustic methods have become widespread in bat research, basic information is often lacking on the echolocation calls produced by Asian bat species. Since such information can aid a wide variety of research and conservation initiatives, descriptions of the calls emitted by Asian bats are fundamental. The aim of our study was to provide a standardized analysis and description of the Vietnamese bat echolocation calls. We analyzed call recordings of 87 species arranged in eight families. This constitutes 74% of the echolocating bats presently known in Vietnam and includes the first call descriptions for five taxa. Our use of an open-source software and the deposition of recordings in the ChiroVox repository will facilitate comparative studies in Asia and the information we provide represents one of the most comprehensive bioacoustic databases for Asian bats to date. [ABSTRACT FROM AUTHOR]

Bats are among the least well-known mammals, particularly in terms of their behavior and activity patterns during the winter. Here, we use passive acoustic monitoring to overcome some of the challenges inherent in surveying cryptic forest bats during the wet season to quantify overwintering behavior for 11 species in California coast redwood forests under varying microclimates. Because different species are active at different forest heights, we also examined the effect of acoustic detector placement (treetop or ground level). Generalized linear mixed models were used to relate acoustic detection probability for 8 species to daytime and nighttime temperature, relative humidity, water vapor pressure, and detector placement. The results indicate that daytime maximum temperature best explained variation in nightly probability of detection, and temperature threshold at which bats were predicted to be detected varied considerably across species. By using more precise species detection methods, we were able to resolve significant differences in activity patterns between Myotis yumanensis and M. californicus , 2 species with similar acoustic signatures that are often lumped together. Myotis californicus was predicted to have a 50% probability of detection at maximum daytime temperature as low as 12.5 °C, whereas M. yumanensis was not predicted to have 50% detection probability until maximum daytime temperature was at least 22 °C, suggesting that M. californicus spends less time in torpor. Also, monitoring at the top of the canopy revealed 4 migratory species to be present in the ecosystem on significantly more monitoring nights than could be observed using conventional ground-based monitoring methods. Improving winter bat survey methods provides evidence that diverse bat species are more active in redwood forests during the winter than previously documented. This finding suggests that coastal forests could provide important winter bat habitat for both resident and migratory species. [ABSTRACT FROM AUTHOR]

Context. Biodiversity is declining worldwide, with many species decreasing in both number and range. Acoustic monitoring is rapidly becoming a common survey method in the ecologist's toolkit that may aid in the conservation of endangered species, but effective analysis of long-duration audio recordings is still challenging. Aims. The aims of this study were to: (1) develop and test call recognisers for the endangered southern black-throated finch (Poephila cincta cincta) as well as the similar sounding, but non-endangered, double-barred finch (Taeniopygia bichenovii); and (2) compare the ability of these recognisers to detect these species with that of on-ground bird surveys at under-surveyed locations in the Desert Uplands bioregion which is at the edge of the known range of the black-throated finch. Methods. A range of convolutional neural network call recognition models were built and tested for both target species, before being deployed over new audio recordings collected at 25 sites during 2020, 2021 and 2022, and compared with the results of on-ground bird surveys at those same sites. Key results. Call recognisers for both species performed well on test datasets from locations in the same area as the training data with an average area under the precision-recall curve (PRAUC) of 0.82 for black-throated finch and 0.87 for double-barred finch. On-ground bird surveys in the Desert Uplands bioregion detected black-throated finches at two locations in different years, and our call recognisers confirmed this with minimal post-validation of detections. Similar agreement between methods were obtained for the double-barred finch, with site occupancy in the Desert Uplands bioregion confirmed with audio recognition in all nine surveys with on-ground detections, as well as during four additional surveys that had no on-ground detections. Conclusions. Using call recognisers to survey new locations for black-throated finch presence was equally successful as on-ground surveys, and with further refinements, such as retraining models with examples of commonly misclassified vocalisations added to the training data, minimal validation should be required to detect site presence. Implications. Acoustic monitoring should be considered as a valuable tool to be used alongside manual surveys to allow effective monitoring and conservation of this endangered species. [ABSTRACT FROM AUTHOR]

Abstract Southeast Asia includes several global biodiversity hotspots and bats account for nearly one-third of mammal species currently known in the region. While acoustic methods have become widespread in bat research, basic information is often lacking on the echolocation calls produced by Asian bat species. Since such information can aid a wide variety of research and conservation initiatives, descriptions of the calls emitted by Asian bats are fundamental. The aim of our study was to provide a standardized analysis and description of the Vietnamese bat echolocation calls. We analyzed call recordings of 87 species arranged in eight families. This constitutes 74% of the echolocating bats presently known in Vietnam and includes the first call descriptions for five taxa. Our use of an open-source software and the deposition of recordings in the ChiroVox repository will facilitate comparative studies in Asia and the information we provide represents one of the most comprehensive bioacoustic databases for Asian bats to date.

BACKGROUND: Forest ecosystems are under constant threat from wood‐boring pests such as the Emerald ash borer (EAB), which remain elusive owing to their hidden life cycles within tree trunks. Early detection is vital to mitigate economic and ecological damage. The main current monitoring method is manual detection which is ineffective at early stages of infestation. This study introduces VibroEABNet, a deep learning‐based joint recognition network designed to enhance the detection of EAB boring vibration signals, with a novel approach integrating denoising and recognition modules. RESULTS: The proposed VibroEABNet model demonstrated exceptional performance, achieving an average accuracy of 98.98% across multiple signal‐to‐noise ratios (SNRs) in test datasets and a remarkable 97.5% accuracy in real forest datasets, surpassing traditional models and other deep learning networks evaluated in this study. These findings were supported by rigorous noise resistance analysis and real dataset evaluation, indicating the model's robustness and reliability in practical applications. Furthermore, the model's efficiency was highlighted by its inference time of 26 ms and a compact model size of 8.43 MB, underscoring its suitability for deployment in resource‐limited environments. CONCLUSION: The development of VibroEABNet marks a significant advancement in pest detection methodologies, offering a scalable, accurate and efficient solution for early monitoring of wood‐boring pests. The integration of a denoising module within the network structure addresses the challenge of environmental noise, one of the primary limitations in acoustic monitoring of pests. Currently, this research is limited to a specific pest. Future work will focus on the applicability of this network to other wood‐boring pests. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Pacific fin whales (Balaenoptera physalus velifera), once the most abundant cetacean species in British Columbia (BC), were also one of the most heavily targeted by commercial whaling. Much of what we know about their phenology and ecology is from catch records, but their current status has not yet been summarized in Canadian waters. Here, we collated evidence from dedicated surveys, opportunistic sightings, and passive acoustic records that had not been reported before and reviewed them in the context of past data. This was to add new findings to what is known, and to establish if the population was showing signs of recovery. This is particularly relevant considering discussions of downlisting their population status in Canada from endangered to threatened. We then asked if this rebounding was consistent with what is known about pre-whaling presence and movement patterns, or if changes in whale distribution reflected altered oceanic regimes, prey availability, or increased anthropogenic pressures. The evidence suggested that fin whale populations in the northeast Pacific Ocean are repopulating areas along the BC coast recognized as part of their historic range. However, they are recovering in a different ocean than they were removed from, which makes them increasingly vulnerable to new anthropogenic threats. The sightings data suggested that, at least for the west coast of Vancouver Island, this repopulation has occurred over a relatively short period, with fin whales still absent from regular surveys as recent as the early 2000's. The recent acoustic recordings suggested their presence is not transitory, but that fin whales may be using locales along the BC coast for feeding and breeding activities. [ABSTRACT FROM AUTHOR]

Simple Summary: Our research focuses on the franciscana dolphin, the most threatened dolphin in the southwestern Atlantic, mainly due to its frequent entanglement in artisanal gillnets. This has led to their classification as vulnerable. To better understand their sounds and communication, we recorded and analysed the sounds of both wild dolphins and those in a rehabilitation centre. We found that neonate dolphins emit sounds that differ from those of juveniles. Interestingly, the sounds made by juvenile dolphins are similar to those of wild dolphins. We also discovered patterns in the way dolphins produce clicks, sounds which are important for feeding and communication. Our findings highlight the need to protect calf dolphins and suggest that it might be possible to create tools to identify dolphins by their age, based on their sounds. This research is important for conservation efforts and could help in creating better protection strategies for these dolphins. The franciscana dolphin is a small, vulnerable species often caught in artisanal gillnets. This study aims to provide a comprehensive assessment of their acoustic capabilities by using advanced equipment to collect a large dataset of wideband, continuous recordings. We examined the detailed acoustic signals of franciscana dolphins, comparing the sounds from rehabilitated dolphins in captivity with those of wild dolphins near fishing nets. Significant differences in acoustic characteristics were found between neonates and older dolphins, with juvenile and wild dolphins showing similar features. For the first time, repetition patterns in click production were identified, highlighting the importance of understanding the context of these sounds in regards to feeding and communication. This study emphasizes the need for detecting neonates for species protection and suggests the potential for developing acoustic classifiers specific to different age groups. Our findings offer valuable insights for conservation efforts and the development of protection strategies for franciscana dolphins. [ABSTRACT FROM AUTHOR]

Climate refugia, areas where climate is expected to remain relatively stable, can offer a near‐term safe haven for species sensitive to warming temperatures and drought. Understanding the influence of temperature, moisture, and disturbance on sensitive species is critical during this time of rapid climate change. Coastal habitats can serve as important refugia. Many of these areas consist of working forestlands, and there is a growing recognition that conservation efforts worldwide must consider the habitat value of working lands, in addition to protected areas, to effectively manage large landscapes that support biodiversity. The sensitivity of forest bats to climate and habitat disturbance makes them a useful indicator taxon. We tested how microclimate and forest management influence habitat use for 13 species of insectivorous bats in a large climate refugium in a global biodiversity hotspot. We examined whether bat activity during the summer dry season is greater in forests where coastal fog provides moisture and more stable temperatures across both protected mature stands and those regularly logged. Acoustic monitoring was conducted at a landscape scale with 20 study sites, and generalized linear mixed models were used to examine the influence of habitat variables. Six species were positively associated with warmer nighttime temperature, and 5 species had a negative relationship with humidity or a positive relationship with climatic moisture deficit. Our results suggest that these mammals may have greater climate adaptive capacity than expected, and, for now, that habitat use may be more related to optimal foraging conditions than to avoidance of warming temperatures and drought. We also determined that 12 of the 13 regionally present bat species were regularly detected in commercial timberland stands. Because forest bats are highly mobile, forage over long distances, and frequently change roosts, the stewardship of working forests must be addressed to protect these species. [ABSTRACT FROM AUTHOR]

Herein, we describe the genus Dentotibium gen. nov. and the species D. ramucantoris sp. nov , a toothed foretibia katydid within the subfamily Pseudophyllinae from Colombia. This new katydid is a forest dweller inhabiting oak woodlands between 1600 and 2300 m above sea level, only found in the western slopes of the Eastern Andes of Boyacá Department, Colombia. This new species burrows in woody branches and shows big heads in both sexes. The appearance of Dentotibium gen. nov. is similar to that of Trichotettix Stål, 1873 but differs in having tubercles over the dorsal margin of the foretibiae. It is also close to Nastonotus Bolívar, 1890, but differs from in lacking the three black stripes in the vertex and having a less marked frontal suture and smoother face. Males sing all night long, and their calling song consists of periodic syllables with three differentiable phases. Seasonal calling activity lowers remarkably during the dry season (Jun–Aug). DNA barcoding sequences for the paratypes made available in a previous study are included here. [ABSTRACT FROM AUTHOR]

The Induction Motor (IM) is one of the most frequently used prime movers in most industrial and transportation systems. The motor's stable and safe operation directly influences the secure and reliable operation of such prime movers. Developing an intelligent fault diagnosis system for such motors is very significant. This paper presents an intelligent fault diagnosis method based on the improved functionality of a Convolutional Neural Network (CNN) through its hyperparameter optimization using a nature‐inspired Artificial Bee Colony Optimization (ABCO) algorithm. The proposed diagnostic method introduces and analyses various possible mechanical and electrical faults in the IM. The validation of the proposed method is presented with three different modalities, including vibration, acoustic, and infrared thermography, with their comparative performance analysis. Vibration and acoustic‐based detection are done with time‐frequency scalograms using Constant Q Transform (CQT), which provides enhanced time resolution for lower and higher frequencies. The obtained result indicates that the infrared thermography‐based anomaly detection outperforms the vibration and acoustic‐based diagnosis with 100% classification accuracy. The results signify the potential to diagnose different mechanical and electrical faults in IM with substantial reliability and robustness. [ABSTRACT FROM AUTHOR]

Bedload transport is a natural process that strongly affects the Earth's surface system. An important component of quantifying bedload transport flux and establishing early warning systems is the identification of the onset of bedload motion. Bedload transport can be monitored with high temporal resolution using passive acoustic methods, for example, hydrophones. Yet, an efficient method for identifying the onset of bedload transport from long‐term continuous acoustic data is still lacking. Benford's Law defines a probability distribution of the first‐digit of data sets and has been used to identify anomalies. Here, we apply Benford's law to continuous acoustic recordings from Baiyang hydrometric station, a tributary of Liwu River, Taroko National Park, Taiwan at the frequency of 32 kHz from stationary hydrophones deployed for 3 years since 2019. We construct a workflow to parse sound combinations of bedload transportation and analyze them in the context of hydrometric sensing constraining the onset, and recession of bedload transport. We identified three separate sound classes in the data related to the noise produced by the motion of pebbles, water flow, and air. We identify two bedload transport events that lasted 17 and 45 hr, respectively, covering about 0.35% of the total recorded time. The workflow could be transferred to other different catchments, events, or data sets. Due to the influence of instrument and background noise on the regularity of the residuals of the first‐digit, we recommend identifying the first‐digit distribution of the background noise and ruling it out before implementing this workflow. Plain Language Summary: Long‐term, high‐frequency monitoring of Earth surface processes brings huge data sets that can be of high quality. Benford's Law defines the specific probability distribution of the first‐digit of the data sets and has been used to identify anomalies and high‐energy events. We provide a workflow for applying Benford's Law to identify the onset of the motion of coarse sediment along the river bed at a time resolution of seconds. Since Benford's Law has demonstrated usefulness in acoustic amplitude analysis in this study, it could serve as a tool for identifying anomalous events in any kind of real‐time data series, which could be beneficial for generating event samples for machine learning applications. Key Points: Long‐term, high‐frequency acoustic monitoring constitutes huge‐volume data sets with a low signal‐to‐noise ratioThe distinct first‐digit distribution between signal and noise can used to filter out 99% of background noise from acoustic recordingsWe applied the method to a three‐year‐long acoustic data set in Baiyang, identifying two bedload transportation events [ABSTRACT FROM AUTHOR]

Urbanization that occurs across a gradient from low‐ to high‐density development, is a primary driver of landscape change that can affect biodiversity. Animals balance trade‐offs in obtaining resources and avoiding anthropogenic disturbances across the gradient of urbanization to maximize their fitness. However, additional research is necessary to understand seasonal variations in how animals respond to urbanization, particularly in arid regions, where resource availability shifts drastically across seasons. Our objective was to evaluate the response of a suite of bat species to urbanization and whether species shift their response to urbanization across seasons. We predicted that the response of bats to urbanization would differ among species, with some species being more sensitive to urbanization than others. We also predicted that bat species would increase the use of moderate and highly urbanized areas in the summer season where food and water resources were assumed to be greater compared with wildland areas. To evaluate these predictions, we used a stratified random sampling design to sample 50 sites with stationary acoustic bat monitors across the gradient of urbanization in the Phoenix metropolitan area, Arizona, USA during four seasons. We identified a total of 14 bat species during 1000 survey nights. Consistent with predictions, bat species exhibited different responses to urbanization, with most species exhibiting a negative relationship with urbanization, and some species exhibiting a quadratic or positive relationship with urbanization. Counter to predictions, most species did not appear to shift their response to urbanization across seasons. Consistent with predictions, plant productivity and water were important for some species in the summer season. Differences in the response of bat species to urbanization was likely related to species traits (e.g., wing morphology and echolocation call characteristics) and behavioral strategies that influence a species' sensitivity to anthropogenic disturbances and ability to access available resources in urbanized areas. Ultimately, to promote the management and conservation of bats, it is likely important to maintain resources in urbanized areas for bats that are more tolerant of urbanization and to conserve areas of undeveloped high‐quality habitat with low anthropogenic disturbance in wildland areas for bats that are sensitive to urbanization. [ABSTRACT FROM AUTHOR]

Acoustic indices have been proposed as a tool to estimate animal biodiversity and abundance, as well as habitat types and vegetation structure. However, recent studies have reported inconsistent relationships between acoustic indices and environmental metrics. In this study, we recorded soundscapes across different forest types and calculated six of the most commonly used acoustic indices to evaluate their effectiveness in predicting bird species richness, bird community composition and temperate forest characteristics.We observed that bird species richness did not significantly differ between forest types, soil moisture, forest age, the Normalized Difference Vegetation Index (NDVI), the area covered by standing dead trees, or forest protection. In contrast, acoustic indices showed significant differences between forest types, soil moisture levels, forest age, and NDVI. In general, acoustic complexity increased with the progression of forest productivity and moisture, was the lowest in the youngest forests, decreased with increasing NDVI, did not differ between protected and unprotected areas, and was not affected by the amount of standing dead trees. The dissimilarity of the acoustic structure of the environment correlated more strongly with dissimilarity of bird community composition than with bird species richness, but it best explained the differences in forest characteristics obtained from satellite data. These correlations were weak, in contrast to the moderate dependency observed between differences in bird community composition and satellite data describing forest characteristics.Our study revealed that in temperate forests, soundscape enables discrimination between forest types, based on productivity, moisture, or age. Furthermore, the acoustic structure of the environment better explains differences in characteristics of the forest obtained from satellite data than differences in bird community composition or bird species richness. This suggests that soundscape complexity depends on forest characteristics and is shaped by species richness, community composition, and the abundance of individual bird species. Therefore, the soundscape can serve as an indicator of temperate forest quality and disturbance levels.

Passive monitoring of wildlife has proven to be a highly effective tool in management and conservation. This work describes an end-to-end system for acoustic localization within the context of a specific use case. The system is described in terms of its constituent modules and the functionality of each module, as it relates to the use case of Northern bobwhite (Colinus virginianus) localization, is detailed. First, we address the field deployment of acoustic recorders in terms of optimal configuration, spacing, and number in a manner that is at once utilitarian and mathematically rigorous. Then, we propose novel methods used to automatically detect the calls from recordings, match the detected calls across recordings, and calculate the time difference of arrivals (TDOAs). Finally, a new hyperbolic localization approach is presented that uses the TDOAs to estimate the position of the calls. Each module is formulated within a theoretical framework, implemented numerically in an efficient manner, and shown to compare favorably against existing methods. Moreover, the performance of the complete system is evaluated using field recorded data and the impact of environmental factors such as field relief, vegetation features, and wind speed are illustrated and discussed. We assert and demonstrate that the factor with the most immediate and profound impact on advancing the state of the art in acoustic monitoring of wildlife is open access to high-volume, diverse field data that is accompanied by high-quality ground truth.

Anthropogenic noise is an inevitable by-product of human activities. However, the potential effects of human noise on terrestrial Antarctica’s ecosystems have been understudied. Documented impacts encompass stress, alterations in behavioural patterns, auditory masking, and, in severe instances, mortality. This Perspective note aims to call attention to human-generated noise as potential sources of impact on Antarctic wildlife and to highlight the potential of soundscape analysis as a flexible, cost-effective tool for environmental monitoring across Antarctica, complementing other non-invasive approaches. Acoustic monitoring in terrestrial environments has been extensively used in different parts of the world to assess biodiversity, monitor populations’ status and trends, and identify and monitor sources of anthropogenic disturbance. Technological advances in passive acoustic monitoring allow for the gathering of detailed information with little need of human attention, and powerful processing tools and algorithms enable researchers to analyse large collections of audio data. Cold climates limit battery-operated instruments, but solar panels in Antarctic summer trials revealed over 100 days of unattended operation, which is promising for the incorporation of acoustic monitoring in Antarctica’s environmental management toolbox.

Bird populations respond rapidly to environmental change making them excellent ecological indicators. Climate shifts advance migration, causing mismatches in breeding and resources. Understanding these changes is crucial to monitor the state of the environment. Citizen science offers vast potential to collect biodiversity data. We outline a project that combines citizen science with AI-based bird sound classification. The mobile app records bird vocalisations that are classified by AI and stored for re-analysis. Additionally, it shows a shared observation board that visualises collective classifications. By merging long-term monitoring and modern citizen science, this project harnesses the strength of both approaches for comprehensive bird population monitoring. [ABSTRACT FROM AUTHOR]

In the paper, a new method of phase measurement error suppression in a phase-sensitive optical time domain reflectometer is proposed and experimentally proved. The main causes of phase measurement errors are identified and considered, such as the influence of the recording interferometer instabilities and laser wavelength instability, which can cause inaccuracies in phase unwrapping. The use of a Mach–Zender interferometer made by 3 × 3 fiber couplers is proposed and tested to provide insensitivity to the recording interferometer and laser source instabilities. It is shown that using all three available photodetectors of the interferometer, instead of just one pair, achieves significantly better accuracy in the phase unwrapping. A novel compensation scheme for accurate phase measurements in a phase-sensitive optical time domain reflectometer is proposed, and a comparison of the measurement signals with or without such compensation is shown and discussed. The proposed method, using three photodetectors, allows for very good compensation of the phase measurement errors arising from common-mode noise from the interferometer and laser source, providing a significant improvement in signal detection. In addition, the method allows the tracking of slow temperature changes in the monitored fiber/object, which is not obtainable when using a simple low-pass filter for phase unwrapping error reduction, as is customary in several systems of this kind. [ABSTRACT FROM AUTHOR]

The Forestry Reclamation Approach (FRA) is a practical guide to reforesting surface mined lands. Bats, a group of mammals with declining populations, could benefit from mine reforestation. To determine if the FRA can provide suitable bat foraging habitat, we surveyed bat activity at created depressional wetlands on 1-year-old and 8-year-old FRA reforested lands (FRA1; FRA8), wetlands in naturally regenerating forest on traditionally reclaimed mined land (~40 years old; REGEN), and wetlands in mature forest not previously mined (MAT). We passively recorded echolocation calls for 12 nights across 16 sites between June and August 2021. We analyzed bat activity using the number of recordings, pulses, and feeding buzzes in conjunction with nocturnal insect abundance and biomass, microhabitat characteristics, and landscape characteristics via generalized linear mixed effects modeling. Both FRA1 and FRA8 had activity levels similar to MAT. REGEN had significantly greater foraging activity than the other three land classes, possibly due to its distance from roads and proximity to forest edges. Insect abundance and biomass were comparable across sites, indicating FRA practices do not hinder the establishment of a prey base for bats. Overall, bats are utilizing the restored mined land for foraging. Reforestation of mined lands, complemented with wetland creation, provides habitat that could benefit bat species conservation in Appalachia. [ABSTRACT FROM AUTHOR]

Passive acoustic recorders have emerged as powerful tools for ecological monitoring. However, effective monitoring is not simply an act of recording sounds. To have meaning for conservation and management, acoustic monitoring needs to be properly planned and analyzed to yield high quality information. Here, we provide a set of considerations for the design of an effective acoustic monitoring program. We argue that such a program, has the following attributes: (1) has established appropriate partnerships with landowners, Traditional Owners, researchers, or other relevant stakeholders, (2) is based on clear objectives and questions, (3) is explicit in its target sound signals, (4) has considered in‐field sensor placement for a range of factors, including experimental design, statistical power, background noise, and potential impacts on human privacy and animal disturbance, (5) has a justified recording schedule and periodicity, (6) has methods to process sound data in line with objectives, and (7) has protocols for permanent data storage and access. Acoustic monitoring is increasingly used in large‐scale programs and will be important in addressing global biodiversity targets and new biodiversity markets. It is critical that new monitoring programs are designed to effectively and efficiently capture data that address pertinent and emerging issues in conservation. [ABSTRACT FROM AUTHOR]

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We investigated the effect of anthropogenically-driven habitat modifications on insectivorous bat activity and diversity along a stretch of the Eerste River, Stellenbosch, South Africa, by determining insect abundance, water quality and vegetation and river characteristics at four sites of varying anthropogenic impact. Passive acoustic monitoring was used to determine species composition and activity of bats at each of the sites. A total of 14,457 bat passes was recorded, with the same six species being found at each of the sites: four clutter edge foragers (Myotis tricolor, Eptesicus hottentotus, Miniopterus natalensis and Laephotis capensis) and a single clutter forager (Rhinolophus clivosus) and open-air forager (Tadarida aegyptiaca). Bat activity was greater at the lower two most eutrophied sites, and greatest at the residential (urban) site. Laephotis capensis, an urban-adapted species, was by far the most active, probably on account of both insensitivity to light pollution, and roost-site availability. The highest and most pristine site (Eiland) and the lowest and most polluted site (Spier) displayed the greatest diversity, despite highly elevated levels of chloride and nitrate at the latter site. So anthropogenic effects on water quality appear not to have negatively affected bat diversity along this stretch of the Eerste River. As these effects are likely to increase, this study serves as a baseline for future monitoring of bats along its course. [ABSTRACT FROM AUTHOR]

Autonomous sensors provide opportunities to observe organisms across spatial and temporal scales that humans cannot directly observe. By processing large data streams from autonomous sensors with deep learning methods, researchers can make novel and important natural history discoveries. In this study, we combine automated acoustic monitoring with deep learning models to observe breeding-associated activity in the endangered Sierra Nevada yellow-legged frog (Rana sierrae), a behavior that current surveys do not measure. By deploying inexpensive hydrophones and developing a deep learning model to recognize breeding-associated vocalizations, we discover three undocumented R. sierrae vocalization types and find an unexpected temporal pattern of nocturnal breeding-associated vocal activity. This study exemplifies how the combination of autonomous sensor data and deep learning can shed new light on species' natural history, especially during times or in locations where human observation is limited or impossible. [ABSTRACT FROM AUTHOR]

Monitoring biodiversity changes associated with ecological restoration is crucial in the current UN Decade on Restoration. Although several studies highlight the impacts of restoration on ecosystems, it is also important to understand how restoration alters species' behavior, including vocalization. Advances in conservation technology, such as passive acoustic monitoring, facilitate rapid and noninvasive monitoring. In this study, we quantified changes in the vocal behavior of a bird species in response to small‐scale restoration carried out by removing the invasive shrub, Lantana camara (lantana), in a Central Indian tropical dry forest. We examined associations between sites of varying lantana densities and the vocalization of one of its primary dispersers, red‐vented bulbul (RVBU). We found statistically significant differences in note‐length and bandwidth of RVBU vocalizations across sites. A random forest classification model showed that Lantana density was not an important predictor of RVBU vocalizations. Apart from the percentage of forest area and farms in our sites, total human population was the most important predictor for RVBU vocalizations suggesting RVBU's use of human habitations as possible resource hubs. Our findings suggest that lantana removal is not associated with significant changes in RVBU vocalization. This study provides empirical evidence that ecological restoration may not alter species' vocalization in the short term and highlights the importance of moving beyond species presence and understanding the impact of restoration on species behavior. [ABSTRACT FROM AUTHOR]

The Pampa is the least protected and one of the least sampled for bats among the Brazilian domains. This leads to significant Linnean and Wallacean shortfalls for bats in the Brazilian-Uruguayan savanna ecoregion. Here, we aimed to model the occupancy of aerial insectivorous bats in response to landscape structure at different scales, considering the influence of microclimate on bat detection. We acoustically monitored 68 locations during the spring and summer of 2019/2020, gathering data on temperature and humidity associated with each acoustic record using data loggers. We detected at least 11 species of the Molossidae and the Vespertilionidae families, of which 9 were used in the model. The response to landscape structure was species-specific: the occupancy probability of Eptesicus brasiliensis and Molossus cf. currentium increased with landscape connectivity at the 500 m scale while Eptesicus furinalis and Histiotus cf. velatus were negatively affected by landscape connectivity at the 5.0 km scale. Molossus occupancy probability responded negatively to landscape heterogeneity at the 3.0 km scale, while Promops centralis responded positively to landscape heterogeneity at the 5.0 km scale. Molossus rufus responded negatively to native vegetation cover and positively to landscape heterogeneity at the 5.0 km scale. Myotis albescens and Molossops temminckii did not respond significantly to any of the evaluated landscape metrics. Our results show that different bat species perceive the landscape differently, regardless of the guild of use of space -- edge- or open-space forager. Our estimate of projected occupancy for the areas contiguous to those sampled ranged from 0.45 to 0.70 for the whole of the bat taxa, suggesting that the landscape, particularly where it still maintains its native elements, is reasonably favourable to aerial insectivores. [ABSTRACT FROM AUTHOR]

In recent years, attention to the realization of a distributed fiber-optic microphone for the detection and recognition of the human voice has increased, whereby the most popular schemes are based on φ-OTDR. Many issues related to the selection of optimal system parameters and the recognition of registered signals, however, are still unresolved. In this research, we conducted theoretical studies of these issues based on the φ-OTDR mathematical model and verified them with experiments. We designed an algorithm for fiber sensor signal processing, applied a testing kit, and designed a method for the quantitative evaluation of our obtained results. We also proposed a new setup model for lab tests of φ-OTDR single coordinate sensors, which allows for the quick variation of their parameters. As a result, it was possible to define requirements for the best quality of speech recognition; estimation using the percentage of recognized words yielded a value of 96.3%, and estimation with Levenshtein distance provided a value of 15. [ABSTRACT FROM AUTHOR]

Beluga whales, Delphinapterus leucas, are a highly social species with a complex and diverse vocal repertoire. Although extensively studied and classified, to date few attempts have been made to examine geographic variation in their calls. In this study, we examined geographic variation in simple contact calls (SCCs), specifically those that consist only of broadband pulsed trains, among four Canadian beluga populations from the Eastern Beaufort Sea (EBS), the Eastern High Arctic‐Baffin Bay, St. Lawrence Estuary (SLE), and the Western Hudson Bay. Five acoustic parameters were measured for each call and compared among populations using multivariate discriminant analysis. Results of our study indicate that there is a degree of variation in SCCs among these four populations, with the most geographically distant populations of the SLE and EBS displaying the greatest degrees of dissimilarity in SCC structure relative to geographically closer populations. Further, these results align with genetic variation of Canadian beluga populations previously described in the literature. This study is the first descriptive population comparison of SCCs for beluga and establishes a baseline for continued work into this developing area of research. [ABSTRACT FROM AUTHOR]

Despite the high diversity of bats in neotropics, traditional methods such as mist nets, harp traps and roost detection have limitations in capturing that diversity in a landscape, with most detected species restricted to those that forage in the undergrowth or enclosed spaces. Therefore, acoustic records become a tool that complements and enhances the efforts to get more complete bat inventories while avoiding alterations in usual foraging activities and disruption in their life cycles. This study describes the acoustic parameters (spectral and temporal variables) of the echolocation pulses of insectivorous bats to characterise different species of bats in Southwest Colombia acoustically. We recorded echolocation calls between December 2017 and May 2020 in the Andean and Pacific regions of the Department of Nariño. We analysed 81 sequences of echolocation calls from eight bat species belonging to three families: Vespertilionidae, Molossidae and Emballonuridae. We perform recordings on free-flying bats with identity corroboration by capture for recording in flight rooms and examination in the hand. Myotis riparius and Lasiurus blossevillii were recorded for the first time in the Nariño Department. M. albescens, M. keaysi, M. riparius and L. blossevillii (Vespertilionidae) had pulses of frequency modulated (FM) with a quasi-constant frequency (QCF) ending; Molossus molossus, Tadarida brasiliensis and Promops centralis (Molossidae) had pulses with constant frequency (CF) and QCF; and Saccopteryx bilineata (Emballonuridae) had pulses with QCF. This study contributes to the efforts to facilitate the identification of insectivorous bats of the Neotropics using the acoustic monitoring approaches, represents a reference to compare the acoustic studies in Southwestern Colombia and contributes to increasing our knowledge of the bat diversity in the region. [ABSTRACT FROM AUTHOR]

In grassland ecosystems, agriculture and urbanization are two main anthropogenic disturbances to native fauna. Nature preserves at the urban-agricultural interface may include diverse vegetation habitats, providing opportunities for native fauna. Limited research has examined the conservation value of such preserves to bats. We examined bat activity patterns at multiple temporal scales at Glacier Creek Preserve in Omaha, Nebraska, USA, between 2018 and 2020 via acoustic monitoring to identify what functional habitats it might provide to bats. We placed bat detectors along the forest edge and in the open, restored native prairies and open agricultural fields. A total of nine species were recorded at the preserve, including the endangered Myotis septentrionalis. Foraging activities were recorded for six species. The edge habitat had higher overall acoustic activities for three species (Eptesicus fuscus, Lasiurus borealis, and Lasiurus cinereus) and a higher proportion of foraging activities for two species (Lasiurus borealis and Lasiurus cinereus) than the open habitat. Lasiurus cinereus displayed activity peaks early at night, whereas Lasiurus borealis had activity peaks late. Results suggest that a medium-sized nature preserve at the urban-agricultural interface can provide roosts, commuting corridors, and foraging grounds for different bats. The conservation value of such nature preserves should not be overlooked. [ABSTRACT FROM AUTHOR]

Temperate insectivorous bats value high prey abundance and appropriate vegetative structure when selecting foraging habitats. Forests, particularly in the eastern United States, provide prime foraging habitats for bats but can be heavily impacted by non-native plants, which may alter arthropod diversity and abundance, as well as vegetative structure. To investigate the associations between non-native plants and insect abundance, vegetative structure, and, consequently, bat activity, we performed vegetation surveys, insect trapping, and acoustic monitoring at 23 forested plots in northern New Jersey, USA. We predicted that non-native vegetation would either positively influence bat activity by increasing structural openness (thus, facilitating flight) or negatively influence bat activity by lowering the abundance of putative prey. We also hypothesized that vegetative characteristics, and therefore non-native vegetation, impact bats differently depending on their foraging habitat preferences. The percent of non-native cover of the ground and midstory vegetative layers of our study plots ranged from 0 to 92.92% ( x ¯ = 46.94 ± 5.77 SE) and was significantly correlated with structural vegetative characteristics, such as midstory clutter (β = 0.01 ± 0.006 SE), but not putative prey abundance (β = −0.81 ± 2.57 SE). Generalized linear models with only vegetative characteristics best predicted overall bat activity and foraging, which were greatest in areas with a high percent non-native vegetation and low midstory clutter. Although percent non-native vegetation and midstory clutter were also significant effects for bats that prefer to forage in open areas, neither vegetative characteristics nor prey abundance were significant effects for clutter-loving bats. Such findings suggest that vegetative structure is more important than prey availability for predicting overall insectivorous bat activity, but other factors, such as foraging strategy and life history traits, can impact how bat guilds respond to non-native vegetation. Therefore, more research is required to reveal additional mechanisms by which non-native plants impact bats. [ABSTRACT FROM AUTHOR]

Citizen science has become a crucial tool in biodiversity monitoring, often facilitated by the diffusion of mobile devices, such as smartphones and tablets. High costs of professional equipment often limit large-scale monitoring, particularly in bat monitoring programmes based on acoustic surveys. Here we present the potential of using mobile devices for bat monitoring, allowing for large-scale, volunteer-based monitoring programmes. We initially compared mobile devices' performance with a professional bat detector for recording low-frequency bat calls. We then conducted a citizen science pilot study to test the method's feasibility in a real-world setting, recording echolocation and social calls of nine European bat species. We found high similarity in spectrogram quality (0.74 ± 0.09 for Samsung, 0.90 ± 0.01 for Huawei, 0.86 ± 0.09 for Xiaomi, 0.69 ± 0.09 for Apple) and average peak frequency (differences of 0.2 ± 0.5 kHz for Samsung, 0.1 ± 0.7 kHz for Huawei, 0.5 ± 1.0 kHz for Xiaomi, 0.1 ± 0.8 kHz for Apple) between calls recorded by mobile devices and professional bat detectors. The number of recorded bat calls per sampling session was also similar. However, differences in sound quality and effectiveness among mobile device brands were found. iOS devices outperformed professional detectors at recording bat calls at increasing distances. The citizen science pilot study tested 35 mobile device models, all of which effectively recorded bats. This study suggests that mobile devices could be an accessible, no-cost tool for large-scale bat monitoring. Incorporating mobile devices into existing monitoring networks or creating new dedicated programmes could not only enhance data collection, but also boost public knowledge and awareness about bats, ultimately promoting informed decision-making and better conservation strategies. [ABSTRACT FROM AUTHOR]

Abstract Autonomous recording units (ARUs) paired with signal classification software can be used to detect species‐specific calls, making them useful for evaluating patterns in avian occurrence and activity. However, classification of target signals is not always reliable and may be especially challenging for species that vocalize infrequently. We assessed the use of ARUs to identify and monitor habitat for a cryptic and federally threatened distinct population segment, the western yellow‐billed cuckoo (Coccyzus americanus) in mountainous xeroriparian drainages. Using Kaleidoscope Pro, we developed a call‐classifier and processed acoustic data collected in sites also surveyed using traditional human‐observer methods, applying the same spatial and temporal detection criteria to estimate breeding territories for each method. The classifier detected a total of 4,061 true positive calls at 4 sites, had an overall precision score of 0.07, recall score of 0.09, and F‐score (beta = 1) of 0.08, indicating high false positive and false negative classification rates. Our results were, however, consistent with other ARU studies of rare and cryptic species and ARUs estimated occupancy as effectively as human surveys with as little as 2 hours of daily recording. Total detections varied among sites, likely due to differences in cuckoo population densities and the interaction between topography and ARU detection space. Our results suggest that despite performance shortcomings of call‐classifiers, ARUs can be effective for monitoring cuckoos, with potential for providing higher resolution temporal and spatial information on activity and habitat use and may be particularly effective in remote locations where cuckoos often occur.

Pacific fin whales (Balaenoptera physalus velifera), once the most abundant cetacean species in British Columbia (BC), were also one of the most heavily targeted by commercial whaling. Much of what we know about their phenology and ecology is from catch records, but their current status has not yet been summarized in Canadian waters. Here, we collated evidence from dedicated surveys, opportunistic sightings, and passive acoustic records that had not been reported before and reviewed them in the context of past data. This was to add new findings to what is known, and to establish if the population was showing signs of recovery. This is particularly relevant considering discussions of downlisting their population status in Canada from endangered to threatened. We then asked if this rebounding was consistent with what is known about pre-whaling presence and movement patterns, or if changes in whale distribution reflected altered oceanic regimes, prey availability, or increased anthropogenic pressures. The evidence suggested that fin whale populations in the northeast Pacific Ocean are repopulating areas along the BC coast recognized as part of their historic range. However, they are recovering in a different ocean than they were removed from, which makes them increasingly vulnerable to new anthropogenic threats. The sightings data suggested that, at least for the west coast of Vancouver Island, this repopulation has occurred over a relatively short period, with fin whales still absent from regular surveys as recent as the early 2000’s. The recent acoustic recordings suggested their presence is not transitory, but that fin whales may be using locales along the BC coast for feeding and breeding activities.

Abstract Urbanization that occurs across a gradient from low‐ to high‐density development, is a primary driver of landscape change that can affect biodiversity. Animals balance trade‐offs in obtaining resources and avoiding anthropogenic disturbances across the gradient of urbanization to maximize their fitness. However, additional research is necessary to understand seasonal variations in how animals respond to urbanization, particularly in arid regions, where resource availability shifts drastically across seasons. Our objective was to evaluate the response of a suite of bat species to urbanization and whether species shift their response to urbanization across seasons. We predicted that the response of bats to urbanization would differ among species, with some species being more sensitive to urbanization than others. We also predicted that bat species would increase the use of moderate and highly urbanized areas in the summer season where food and water resources were assumed to be greater compared with wildland areas. To evaluate these predictions, we used a stratified random sampling design to sample 50 sites with stationary acoustic bat monitors across the gradient of urbanization in the Phoenix metropolitan area, Arizona, USA during four seasons. We identified a total of 14 bat species during 1000 survey nights. Consistent with predictions, bat species exhibited different responses to urbanization, with most species exhibiting a negative relationship with urbanization, and some species exhibiting a quadratic or positive relationship with urbanization. Counter to predictions, most species did not appear to shift their response to urbanization across seasons. Consistent with predictions, plant productivity and water were important for some species in the summer season. Differences in the response of bat species to urbanization was likely related to species traits (e.g., wing morphology and echolocation call characteristics) and behavioral strategies that influence a species' sensitivity to anthropogenic disturbances and ability to access available resources in urbanized areas. Ultimately, to promote the management and conservation of bats, it is likely important to maintain resources in urbanized areas for bats that are more tolerant of urbanization and to conserve areas of undeveloped high‐quality habitat with low anthropogenic disturbance in wildland areas for bats that are sensitive to urbanization.

Abstract Bedload transport is a natural process that strongly affects the Earth's surface system. An important component of quantifying bedload transport flux and establishing early warning systems is the identification of the onset of bedload motion. Bedload transport can be monitored with high temporal resolution using passive acoustic methods, for example, hydrophones. Yet, an efficient method for identifying the onset of bedload transport from long‐term continuous acoustic data is still lacking. Benford's Law defines a probability distribution of the first‐digit of data sets and has been used to identify anomalies. Here, we apply Benford's law to continuous acoustic recordings from Baiyang hydrometric station, a tributary of Liwu River, Taroko National Park, Taiwan at the frequency of 32 kHz from stationary hydrophones deployed for 3 years since 2019. We construct a workflow to parse sound combinations of bedload transportation and analyze them in the context of hydrometric sensing constraining the onset, and recession of bedload transport. We identified three separate sound classes in the data related to the noise produced by the motion of pebbles, water flow, and air. We identify two bedload transport events that lasted 17 and 45 hr, respectively, covering about 0.35% of the total recorded time. The workflow could be transferred to other different catchments, events, or data sets. Due to the influence of instrument and background noise on the regularity of the residuals of the first‐digit, we recommend identifying the first‐digit distribution of the background noise and ruling it out before implementing this workflow.

Abstract Animal migration is one of nature's most spectacular phenomena, but migratory animals and their journeys are imperilled across the globe. Migratory birds are among the most well‐studied animals on Earth, yet relatively little is known about in‐flight behaviour during nocturnal migration. Because many migrating bird species vocalize during flight, passive acoustic monitoring shows great promise for facilitating widespread monitoring of bird migration. Here, we present Nighthawk, a deep learning model designed to detect and identify the vocalizations of nocturnally migrating birds. We trained Nighthawk on the in‐flight vocalizations of migratory birds using a diverse dataset of recordings from across the Americas. Our results demonstrate that Nighthawk performs well as a nocturnal flight call detector and classifier for dozens of avian taxa, both at the species level and for broader taxonomic groups (e.g. orders and families). It achieves an average precision score above 0.80 for 50 species and a mean average precision of 0.96 across 4 orders. The model accurately quantified nightly nocturnal migration intensity (80% variation explained) and species phenology (78% variation explained) and performed well on data from across North America. Incorporating modest amounts of additional annotated audio (50–120 h) into model training yielded high performance on target datasets from both North and South America (average precision on order Passeriformes >0.99). By monitoring the vocalizations of actively migrating birds, Nighthawk provides a detailed window onto nocturnal bird migration that is not presently attainable by other means (e.g. radar or citizen science). Scientists, managers and practitioners could use acoustic monitoring with Nighthawk for a number of applications, including: monitoring migration passage at wind farms; studying airspace usage during migratory flights; monitoring the changing migrations of species susceptible to climate change; and revealing previously unknown migration routes and behaviours. Overall, this work will empower diverse stakeholders to efficiently monitor migrating birds across the Western Hemisphere and collect data in aid of science and conservation.

Artificial light at night (ALAN) is a major form of anthropogenic pollution, disrupting nocturnal wildlife behaviour and ecosystem function. Large construction sites are typically located at the intersection of urban and natural areas, introducing intense lighting into previously dark natural habitats. This study examines the responses of bats to intense nighttime lighting at a major construction site associated with a linear transport infrastructure (LTI) project. We used passive acoustic monitoring to record bat activity and species richness at the construction site and in adjacent urban and natural areas with different lighting levels. Generalist species, such as Pipistrellus kuhlii and Nyctalus leisleri, were attracted to illuminated areas, likely due to increased prey availability. Conversely, sensitive species, such as those from the Myotis and Plecotus genera, along with Barbastella barbastellus, avoided illuminated areas, particularly the construction site. Species richness was significantly lower at the construction site compared to other environments, reflecting ALAN's barrier effect on movements and habitat accessibility for more sensitive species. The findings highlight the ecological impacts of introducing ALAN to previously unlit natural environments, underscoring the urgent need for implementing ALAN mitigation strategies in urban planning and construction practices to protect biodiversity in urbanising areas. [ABSTRACT FROM AUTHOR]

Forest management rarely considers protecting bats in Fennoscandian regions although all species rely on forest habitat at some point in their annual cycle. This issue is especially evident as wind parks have increasingly been developed inside Fennoscandian forests, against the advice of international bat conservation guidelines. In this study, we aimed to describe and explain bat community dynamics at a Norwegian wind park located in a boreal forest, especially to understand potential avoidance or attraction effects. The bat community was sampled acoustically and described using foraging guilds (short, medium, and long-range echolocators; SRE, MRE, LRE) as well as behavior (commuting, feeding and social calls). Sampling was undertaken at two locations per turbine: 1) the turbine pad and 2) a paired natural habitat at ground level, as well as from a meteorological tower. We used a recently developed method for camera trapping nocturnal flying insects synchronously with bat acoustic activity. Our results reveal trends in feeding and general bat activity across foraging guilds in relation to insect availability, habitat type, wind, temperature, and seasonality. We show how seasonal patterns in behavior across guilds were affected by habitat type, temperature, and wind. We found that SRE commuting and especially feeding activity was highest in natural habitats, whereas LRE overall activity at habitats more season dependent. We found that nocturnal insect availability was positively correlated with total bat feeding activity throughout the night. Our results provide evidence for both direct and indirect risks to bat communities by wind parks: SRE bat habitat is lost to wind energy infrastructure and LRE bat may have an increased risk of fatality. Our findings provide important insights on seasonal and spatial variability in bat activity, which can inform standardizing monitoring of bats acoustically in boreal forests, at wind parks, and in combination with non-invasive insect monitoring. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Field Ornithology is the property of Resilience Alliance and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The European catfish (Silurus glanis) has been described as an invasive species exerting a relevant impact on the native fauna of the ecosystems where it is introduced. However, the lack of long-term data and the low catchability of this species with traditional methods have often made it difficult to evaluate its real impact. The main objective of this study was to investigate the effect of the invasive European catfish on the fish community of the Torrejón reservoir (Tagus River, Spain) using both direct fishing and indirect hydroacoustic methods. This study is the result of eleven years of monitoring. The results evidence the impact of European catfish on the reservoir fish assemblage, especially on the Iberian barbel (Luciobarbus bocagei) which significantly decreased its abundance and biomass from 2010 to 2020. The size structure of the fish assemblages in the reservoir allowed the use of hydroacoustic methodology to discriminate and monitor the population of European catfish. Throughout the 11 years of study, statistically significant differences were identified in the abundance of European catfish as a function of the reservoir´s area (dam - tail axis) and of the limnological period (summer vs. winter), while no significant differences were found in relation to bathymetry (surface - bottom axis). We can conclude that S. glanis has currently established in the Torrejón reservoir leading to the decrease of the Iberian barbel population, the only autochthonous species that persisted in the reservoir and dominated the fish community before the appearance of European catfish. [ABSTRACT FROM AUTHOR]

The concept of a soundscape is found in both ecology and music studies. Nature soundscapes and soundscape compositions are analyzed by both disciplines, respectively, to understand their biological diversity and ecosystem functioning and to interpret their compositional structure. A major challenge for both disciplines is visualizing the information embedded in a large variety of soundscapes and to share it with different audiences, from non-professionals to experts. To analyze soundscapes, both disciplines have independently developed similarity visualizations. However, no attempt has been made yet to combine these two fields of research to improve our ecological and musical perception of environmental sounds through shared similarity analysis methods. In this paper, we introduce a new visualization tool, the soundscape chord diagram (SCD), a circular similarity representation method that can be applied to any type of soundscape, either in ecoacoustics or electroacoustic studies. Our approach consists of visualizing spectral similarities between predefined sound segments based on the computation of a b-diversity acoustic index and on automatic clustering. SCDs were tested on two ecoacoustic forest databases and two electroacoustic soundscape compositions. SCDs were performant for the identification of specific acoustic events and highlighted known diel periods for nature soundscapes and written parts for soundscape compositions. This new visualization tool allows us to easily decipher the structure of musical and ecological acoustic data. SCDs could be applied to a large variety of soundscapes and promote their knowledge and preservation. This study opens a new way of investigating soundscapes at the interface between ecology and music, bringing together science and the arts. [ABSTRACT FROM AUTHOR]

Winter presents environmental and energetic challenges for temperate insectivorous bats as colder temperatures increase metabolic rates while simultaneously reducing resource availability. While bats in northern regions typically hibernate or migrate to circumvent these adverse conditions, there is growing evidence of winter bat activity as weather permits. Bats at lower latitudes may experience shorter, milder winters, increasing opportunities for activity. To better understand the relationship between ambient temperature and winter bat activity, we deployed acoustic detectors in central Louisiana and eastern Texas and examined data at 3 levels of biological organization: overall bat activity, species richness, and species-specific activity. Across 1,576 detector-nights, we recorded 37,435 bat passes. Bats responded positively to warmer temperatures but the temperature threshold for winter activity varied among species, ranging from 7.2 to 15.6 °C. Consequently, observed species richness increased at warmer ambient temperatures. With activity linked to environmental conditions in a species-specific manner, different subsets of the winter bat assemblage may be active from night to night. Additionally, our study adds to a rather limited body of literature of winter bat activity and provides a baseline for future studies as white-nose syndrome and climate change affect North American bat populations. [ABSTRACT FROM AUTHOR]

Increasing popularity in passive acoustic monitoring and the ease with which researchers can accumulate large quantities of acoustic data has resulted in challenges for audio recording storage, archiving, and management. Reductions in file size can be achieved by lowering sample rate and compressing to different formats; however, how these processes affect audio data quality, and the resulting interpretation of wildlife data is not well understood. We investigated the effect of sampling rate and lossy compression of audio recordings to MP3 from their native WAV format on the performance of four commonly applied avian bioacoustic applications: community listening, distance estimation, automated recognition, and acoustic indices. Compression to MP3 decreased the number of detections, including a reduction in total abundance of individuals when transcribing audio files for community listening and lower precision and recall for automated recognisers. Sampling rate reduction introduced systematic bias to acoustic indices and had an influence on precision and recall for recognisers as well. We recommend against the use of MP3 compression to reduce file volume and suggest other lossless forms of audio compression where an exact copy of the original recording can be recovered. [ABSTRACT FROM AUTHOR]

Copyright of Methods in Ecology & Evolution is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We present a machine learning workflow to discover signatures in acoustic measurements that can be utilized to create a low-dimensional model to accurately predict the location of keyhole pores formed during additive manufacturing processes. Acoustic measurements were sampled at 100 kHz during single-layer laser powder bed fusion (LPBF) experiments, and spatio-temporal registration of pore locations was obtained from post-build radiography. Power spectral density (PSD) estimates of the acoustic data were then decomposed using non-negative matrix factorization with custom k -means clustering (NMF k ) to learn the underlying spectral patterns associated with pore formation. NMF k returned a library of basis signals and matching coefficients to blindly construct a feature space based on the PSD estimates in an optimized fashion. Moreover, the NMF k decomposition led to the development of computationally inexpensive machine learning models which are capable of quickly and accurately identifying pore formation with classification accuracy of supervised and unsupervised label learning greater than 95% and 90%, respectively. The intrinsic data compression of NMFk, the relatively light computational cost of the machine learning workflow, and the high classification accuracy makes the proposed workflow an attractive candidate for edge computing toward in-situ keyhole pore prediction in LPBF. [ABSTRACT FROM AUTHOR]

This paper presents the results of experiments on the study of a hydraulic fracture's interaction with a preexisting fracture. A distinctive feature of the conducted experiments is the ability to use ultrasonic transmitting monitoring to measure the fracture propagation and opening simultaneously with the pore pressure measurements at several points of the porous saturated sample. It allows us to obtain the pressure distributions at various experiment stages and to establish a relation between the pore pressure distribution and hydraulic fracture propagation and its interaction with macroscopic natural fractures. The possibilities of active ultrasonic monitoring have been expanded due to preliminary calibration experiments, which make it possible to estimate the fracture opening via attenuation of ultrasonic pulses. The experiment demonstrated the most complex scenario of fracture interactions when a hydraulic fracture intersected with a natural fracture and the natural fracture in the vicinity of the intersection was also opened. The additional complications arise from fracture arrangement: the hydrofracture was normal with respect to the base plane, while the natural fracture was slanted. This led to gradual growth of the intersection zone as the hydrofracture propagated. The experiments show that the natural fracture limited the fracture's propagation. This was caused by the hydraulic fracturing fluid leaking into the natural fracture; thus, both the hydraulic fracture and natural fracture compose a united hydraulic system. [ABSTRACT FROM AUTHOR]