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Bats are vital for ecosystem stability, yet their natural habitats are increasingly threatened by urbanization, resulting in marked population declines. While some species have adapted to artificial structures as roosting sites, public fear and prejudice often lead to bat displacement, exacerbating human-bat conflicts. Therefore, exploring feasible solutions to increase bat roosting habitats in urban areas is urgent. On July 25, 2019, 40 individuals of Vespertilio sinensis (20 adults and 20 subadults) were artificially translocated from residential areas in Changchun, Jilin Province, to a new building using bat box. Over the 114-day observation period, the population dynamics of V. sinensis roosting in the bat box exhibited five distinct phases, characterized by a gradual decline in total bat numbers. In the year of installation, activity levels of Pipistrellus abramus and Hypsugo alaschanicus substantially decreased but returned to pre-installation levels the following year. Continuous monitoring from 2020 to 2022 indicated that although the activity levels of V. sinensis increased, not many V. sinensis individuals continued to use the bat box. The results of this study provide foundational data for the establishment of artificial bat roosts in urban areas and offer scientific insights for mitigating human-bat conflicts and promoting harmonious urban ecosystem development.

Abstract Background Adipocyte-derived hormones play a role in insulin sensitivity and energy homeostasis. However, the relationship between circulating fibroblast growth factor 21 (FGF21), adipocytokines and cold-induced supraclavicular brown adipose tissue (sBAT) activation is underexplored. Objective Our study aimed to investigate the relationships between cold-induced sBAT activity and plasma FGF21 and adipocytokines levels in healthy adults. Design Nineteen healthy participants underwent energy expenditure (EE) and supraclavicular infrared thermography (IRT) within a whole-body calorimeter at baseline and at 2 hours post-cold exposure. 18F-fluorodeoxyglucose (18F-FDG) positron-emission tomography/magnetic resonance (PET/MR) imaging scans were performed post-cold exposure. PET sBAT mean standardized uptake value (SUV mean), MR supraclavicular fat fraction (sFF), anterior supraclavicular maximum temperature (Tscv max) and EE change (%) after cold exposure were used to quantify sBAT activity. Main Outcome Measures Plasma FGF21, leptin, adiponectin, and tumor necrosis factor alpha (TNFα) at baseline and 2 hours post-cold exposure. Body composition at baseline by dual-energy x-ray absorptiometry (DXA). Results Plasma FGF21 and adiponectin levels were significantly reduced after cold exposure in BAT-positive subjects but not in BAT-negative subjects. Leptin concentration was significantly reduced in both BAT-positive and BAT-negative participants after cold exposure. Adiponectin concentration at baseline was positively strongly associated with sBAT PET SUV mean (coefficient, 3269; P = 0.01) and IRT Tscv max (coefficient, 6801; P  = 0.03), and inversely correlated with MR sFF (coefficient, −404; P  = 0.02) after cold exposure in BAT-positive subjects but not in BAT-negative subjects. Conclusion Higher adiponectin concentrations at baseline indicate a greater cold-induced sBAT activity, which may be a novel predictor for sBAT activity in healthy BAT-positive adults. Highlights A higher adiponectin concentration at baseline was associated with higher cold-induced supraclavicular BAT PET SUV mean and IRT Tscv max, and lower MR supraclavicular FF. Adiponectin levels maybe a novel predictor for cold-induced sBAT activity.

Urbanization is one of the most abrupt mechanisms of land use change. This process can generate significant impacts on biodiversity, and its effects on bat activity patterns need further exploration due to the importance of these animals in controlling insect populations and maintaining ecological balance. This study aims to evaluate and describe the activity patterns of insectivorous bats in the Brazilian Cerrado, using environmental variables such as moon phase (full and new), season (dry and wet), and the level of urbanization. The level of urbanization was defined through an urbanization index and then classified into urban, suburban, and natural habitats to elucidate the impacts of this process on biological communities. We used ultrasonic recorders to sample insectivorous bats and count passes to measure activity in the study areas. A decrease in the activity of aerial insectivorous bat assemblages in the Cerrado was observed with decreasing urbanization. Additionally, bats exhibited higher activity during dry seasons and lower activity during full moon periods, suggesting lunar phobia. We identified significant effects of the time of night and the season of the year on the detectability of these bats, with a higher probability of detection in the first half of the night and during the dry season. Understanding these patterns in urban areas is crucial in the context of expanding cities. This knowledge aids in the maintenance and protection of insectivorous bat species that are fundamental to the balance of ecosystems and the provision of essential ecosystem services in both urban and natural areas of the Cerrado.

Relatively high mortality of migratory bats at wind energy facilities has prompted research to understand the underlying spatial and temporal factors, with the goal of developing more effective mitigation approaches. We examined acoustic recordings of echolocation calls at 12 sites and post-construction carcass survey data collected at 10 wind energy facilities in Ontario, Canada, to quantify the degree to which timing and regional-scale weather predict bat activity and mortality. Rain and low temperatures consistently predicted low mortality and activity of big brown bats (Eptesicus fuscus) and three species of migratory tree bats: hoary bat (Lasiurus cinereus), eastern red bat (L. borealis), and silver-haired bat (Lasionycteris noctivagans). Bat activity occurred in waves with distinct peaks through the season; regardless of seasonal timing, most activities occurred in the first half of the night. We conclude that wind energy facilities could adopt a novel and more effective curtailment strategy based on weather and seasonal and nocturnal timing that would minimize mortality risks for bats while increasing the opportunities for power generation, relative to the mitigation strategy of increasing cut-in wind speed to 5.5 m/s.

Bats are acknowledged as suppliers of essential ecosystem services such as insect pest control in agroecosystems. Little is known, however, on how bat assemblages respond to the gradients imposed by anthropogenic landscapes and farming practices and how these environmental effects translate into changes in bat foraging. In this study, we use cider apple crop in northern Spain as a model to address the filtering effects of landscape composition and orchard management on, simultaneously, quantitative and qualitative characteristics of bat local assemblages and their foraging activity. For that, we carried out acoustic monitoring of bats and sampled pest moth abundance across a wider range of apple orchards covering different landscape contexts and local management conditions. We found that bat assemblages markedly varied across orchards, according mostly to landscape composition gradients but with contrasting landscape effects on different assemblage characteristics. Namely, higher levels of rural urbanization and lower cover of seminatural woody habitats around orchards promoted bat total activity and the number of bat species/species complexes. However, this also altered bat assemblage composition, increasing dominance by the most abundant species, and decreased bat functional diversity. Additionally, a greater cover of apple tree canopy within the orchards decreased bat total activity. Landscape gradients led into predictable variations of bat foraging activity, suggesting a potential persistence of pest control services even in landscapes with limited seminatural habitat cover. The present study highlights the differential responses of bat assemblages to apple crop landscape and orchard‐scale conditions, hindering the establishment of straightforward management guidelines. Further analysis on the relationship between bat assemblage characteristics and pest control is necessary to understand how ecosystem services can be promoted through management in the apple agroecosystem. Resumen Los murciélagos son reconocidos proveedores de servicios ecosistémicos esenciales como el control de insectos plaga en los agroecosistemas. Sin embargo, apenas se conoce cómo los conjuntos locales de murciélagos responden a los gradientes impuestos por los paisajes antropogénicos y el manejo agrícola, y cómo estos efectos ambientales se traducen en cambios en el aprovisionamiento de los murciélagos. En este estudio utilizamos el cultivo de manzano de sidra del norte de España como modelo para evaluar los efectos de la composición del paisaje y el manejo de las plantaciones en, simultáneamente, distintas características cuantitativas y cualitativas de los conjuntos de murciélagos, así como en su actividad de aprovisionamiento. Para ello llevamos a cabo monitoreo acústico y muestreos de abundancia de polillas plaga en un amplio rango de plantaciones representativo de diferentes contextos paisajísticos y condiciones de manejo local. Encontramos que los conjuntos de murciélagos variaron notablemente a lo largo de las plantaciones, de acuerdo principalmente a gradientes de composición paisajística, aunque con efectos contrastados del paisaje sobre diferentes características de los conjuntos. En concreto, un mayor grado de urbanización rural y una menor cobertura de hábitats leñosos seminaturales alrededor de las plantaciones aumentaron la actividad total de los murciélagos y el número de especies/complejos de especies, pero modificaron la composición de murciélagos, incrementando la dominancia de la especie más abundante, y disminuyeron la diversidad funcional de los murciélagos. Una mayor cobertura de dosel de manzano dentro de las plantaciones disminuyó la actividad total de los murciélagos. Los gradientes paisajísticos generaron variaciones predecibles en la actividad de aprovisionamiento de los murciélagos, lo que sugiere una persistencia potencial de los servicios de control de plagas incluso en paisajes con baja cobertura de hábitats seminaturales. Este estudio destaca las respuestas diferenciales de los conjuntos de murciélagos al paisaje y a las condiciones locales del cultivo de manzano, lo que dificulta el establecimiento de directrices de manejo sencillas. Es necesario un análisis adicional sobre la relación entre las características de los conjuntos de murciélagos y el control de plagas para comprender cómo se pueden promover servicios ecosistémicos mediante la gestión adecuada del agroecosistema del manzano.

Agriculture can threaten the persistence of bat populations by removing forests and wetlands and by intensifying production. Both processes are underway in expanding agricultural landscapes of boreal North America. To inform land planning and agricultural practices aimed at maintaining a viable population of the little brown bat (Myotis lucifugus), we assessed the use by bats of human‐modified (open fields, forest‐field edges, and cleared edges of ponds) and unmodified (forest ponds and forest interior) habitat features in agricultural landscapes in southern Yukon, Canada (60° N–61° N), using acoustic recordings. We summarized bat activity (number of 3‐s acoustic files with ≥1 pass/night) and bat feeding (files with >1 feeding buzz/night) at grouped sets of habitat features (sites) and used generalized linear mixed models to test predictions about relative use of habitats. The active season for bats was late April to early October. Little brown bat feeding was strongly correlated with general activity, but feeding comprised a significantly higher proportion of all activity at forest ponds and forest interiors compared to field edges, open fields, and ponds in fields. Total bat activity was highest at forest ponds, followed by field edges, and substantially less in forest interiors and open fields. Forest ponds were used more than the edges of nearby ponds with some riparian clearing for fields. Bats increased use of forest interiors and decreased use of fields as duration of darkness decreased close to summer solstice. We recommend exclusion of ponds, lakes, and other wetlands from future agricultural land disposition, and retention of a riparian forested buffer of ≥40 m around current water bodies on farms. We also recommend retention of strips or patches of forest bordering fields and connected to riparian areas and to more extensive forests on public lands. A relatively young agricultural landscape can avoid some of the risks of intensive agriculture with proactive planning and stewardship.

We examined the potential for urban water sources, specifically golf course ponds, to act as centers for rabies transmission from bats to mesocarnivores in the arid southwestern United States where surface water is often limited. Because residential housing can act as den and roost sites for both mesocarnivores and bats, we also examined the effect of housing density around water sources on activity. Using ultrasonic acoustic recorders to assess bat activity and camera traps to estimate mesocarnivore activity, we compared 14 pairs of wet and dry locations over two years by surveying twice during the summer, once prior to summer monsoons and once during the monsoon season, when surface waters were more available. Number of calls for all bat species combined were greater at wet sites compared to dry sites and calls of two bat species often associated with rabies, big brown bat (Eptesicus fuscus) and silver-haired bat (Lasionycteris noctivagans), were recorded more at wet sites than dry sites in the monsoon season. In both years, raccoons (Procyon lotor) were photographed more often at wet sites while striped skunks (Mephitis mephitis) and gray foxes (Urocyon cinereoargenteus) were less likely to be detected at wet sites. Bat, fox and raccoon activity was not associated with housing density while striped skunks showed a positive correlation. Finally, we examined potential for contact between mesocarnivores and big brown bats, a species implicated in cross-species rabies transmission in our area, by combining call activity of this bat species and photo detections of mesocarnivores during individual hours of the night into a Potential Contact Index (PCI) and found no significant effect of season (pre-monsoon vs. monsoon), species, or treatment (dry versus wet) but did find a significant species by treatment interaction, with raccoon PCI 3–30 times higher at wet sites and no effect on the other two mesocarnivores’ PCI. Overall, we found higher activity of bats at urban waters could increase potential for cross-species transmission of rabies from bats to raccoons but not for gray foxes and striped skunks.

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.

Few reports have been published on detection distances of bat calls because the evaluation of detection distance is complicated. Several of the approaches used to measure detection distances are based on the researcher’s experience and judgment. More recently, multiple microphones have been used to model flight path. In this study, the validity of a low-cost and simple detectability metric was tested. We hypothesize that the duration of an echolocating-bat-pass within the area of an ultrasonic bat detector is correlated with the distance of detection. Two independent datasets from a large-scale acoustic bat survey—a total of 25,786 bat-passes from 20 taxa (18 species and two genera)—were measured. We found a strong relationship between these measures of bat-pass duration and published detection distances. The advantages of bat-pass duration measures are that, for each study, experimenters easily produce their own proxy for the distance of detection. This indirect measure of the distance of detection could be mobilized to monitor the loss in microphone sensitivity used to monitor long-term population trends. Finally, the possibility of producing an index for distance of detection provides a weight for each bat species’ activity when they are aggregated to produce a bat community metric, such as the widely used “total activity”.

Previous research has shown diverse vertical space use by various taxa, highlighting the importance of forest vertical structure. Yet, we know little about vertical space use of tropical forests, and we often fail to explore how this three-dimensional space use changes over time. Here we use canopy tower systems in French Guiana and passive acoustic monitoring to measure Neotropical bat activity above and below the forest canopy throughout nine nights. We use a Bayesian generalized linear mixed effect model and kernel density estimates to demonstrate patterns in space-use over time. We found that different bats use both canopy and understory space differently and that these patterns change throughout the night. Overall, bats were more active above the canopy (including and ), but multiple species or acoustic complexes (when species identification was impossible) were more active in the understory (such as and ). We also found that most bats showed temporally-changing preferences in hourly activity. Some species were less active (e.g., and ), whereas others were more active ( , and ) on nights with higher moon illuminance. Here we show that Neotropical bats use habitat above the forest canopy and within the forest understory differently throughout the night. While bats generally were more active above the forest canopy, we show that individual groups of bats use space differently over the course of a night, and some prefer the understory. This work highlights the need to consider diel cycles in studies of space use, as animals use different habitats during different periods of the day.