Bat Roosts Research Articles

The effect of logging on fission-fusion behaviour of tree-dwelling bats explored by an agent-based model

Logging is one of the greatest threats to global biodiversity, while forests are one of the most important habitats for bats. Bats that roost in tree cavities require a large number of potential roosts due to their frequent roost switching. However, the density of tree cavities and hollows sufficient to sustain large populations of bat species in forests is unknown. The fission-fusion dynamics of bat groups in forest environment is associated with ritualised dawn swarming behaviour at potential tree cavities that serves to exchange information in a non-centralised decision-making process. We used a computer model based on the swarm algorithm, SkyBat, that resembles this complex process and aimed to determine how population size changes over time when cavity trees are removed from roosting territory of the local population of Leisler's bats (Nyctalus leisleri), which inhabit a forest habitat in Central Europe. Simulations revealed that social bonds between bats, maintained by frequent switching among groups, play an important role in this highly dynamic system. When strong social contact was not considered, reducing the original number of trees with cavities (20 cavities × ha−1) to 50% was still acceptable to bats, but further interventions and/or increased demand for social contact would have led to local extinction of the species. Results suggest that potential bat roosts in mature forest stands should be preserved as much as possible and that non-intensive logging and management can be beneficial to tree-dwelling bats.

Public Health Awareness on Bat Rabies among Bat Handlers and Persons Residing near Bat Roosts in Makurdi, Nigeria.

Rabies is a neglected disease endemic in Asia and Africa but is still a significant public and veterinary health threat. Whilst a key delicacy for the local diet, bats are a natural reservoir host for many viral zoonotic agents including lyssaviruses, the causative agent of rabies. Studies on knowledge and practices linked to the disease will help to identify gaps and define preventive strategies that may subsequently result in a reduction and the potential elimination of human rabies. In order to assess the public health awareness of bat rabies among specific population groups in Makurdi (Nigeria), structured questionnaires (n = 154) were administered by face-to-face interviews to bat handlers and persons residing near bat roost sites. A total of 59.7% of the respondents were persons residing near bat roost sites, 13% were bat hunters, 25.3% were bat meat consumers and 1.9% were university researchers. Only 6.5% of respondents reported using some form of personal protective equipment (PPE) ranging from hand gloves, face/nose masks and protective boots to lab coats/coveralls while handling bats, whilst the majority (93.5%) did not use any form of PPE. With a mean knowledge score of 8.34 out of a possible 12 points, 50.6% of respondents had good knowledge of bats and their disease-carrying potential, 39.6% had fair knowledge, while 9.7% had poor knowledge. Log linear models showed significant associations between knowledge score and level of education, as well as knowledge score and occupation. The latter highlights the requirement to enhance public education among bat handlers and persons residing near bat roosts on the need to protect themselves better, while handling bats particularly during processing of bats for food and on steps to take when exposed to bites from bats.

Finding Bat Roosts along Cliffs: Using Rock Climbing Surveys to Identify Roosting Habitat of Bats

When white-nose syndrome arrived in eastern North America, bat colonies declined at an alarming rate and the large-scale mortality events were obvious at caves and mines. However, there is concern that the disease and its impacts will be more difficult to detect in western North America where there are fewer winter roosts with thousands of bats. Thus, documenting and responding to precipitous declines will be more challenging. To allow population-level monitoring, western biologists and land managers need to expand search efforts for colonies. One roosting resource that is under-sampled is cliffs, and although we know bats roost along cliffs, biologists know little about roost-site characteristics or the colonies that reside there. Two methods of identifying bat roosts along cliff systems are to collaborate with rock-climbing citizen scientists who report bat encounters, and another is to conduct rock-climbing surveys for bats. We conducted acoustic surveys, thermal videography, and climber-based surveys along the Front Range of northern Colorado, USA, to find bats and describe their roosting habitat. We climbed 48 routes and located two roosts, and received an additional citizen-science record of a third roost. Bats use cracks that were east facing and approximately 12 m above the ground. Climber-based surveys can locate bats and roosting habitat along cliffs, and identify large colonies to be monitored. Targeting climber-based surveys in areas with recreational-climbing citizen-science records may increase the likelihood of finding bat roosts and bat colonies.

Why link diverse citizen science surveys? Widespread arboreal habits of a terrestrial amphibian revealed by mammalian tree surveys in Britain.

Terrestrial anurans, with their typically short limbs, heavy-set bodies and absent claws or toe pads are incongruous tree climbers, but even occasional arboreal locomotion could offer substantial advantages for evading predators or accessing new shelter or food resources. Despite recent interest, arboreal behaviour remains rarely and unsystematically described for terrestrial amphibians in Europe, likely due to fundamental differences in survey methods and therefore a lack of field data. However, other taxa surveys specifically target trees and tree cavities. We undertook collaborations and large-scale data searches with two major citizen science projects surveying for arboreal mammals in Britain to investigate potential tree climbing by amphibians at a national scale. Remarkably, we found widespread arboreal usage by amphibians in England and Wales, with occupancy of hazel dormouse (Muscardinus avellenarius) nest boxes, tree cavities investigated as potential bat roosts and even a bird nest, by common toads (Bufo bufo), but few additional records of frogs or newts. Of the 277–400 sites surveyed annually for dormice since 2009 at least 18 sites had amphibians recorded in nest boxes while of the 1388 trees surveyed for bats a total 1.4% (19 trees) had toads present. Common toads were found using cavities in seven tree species and especially goat willow (Salix caprea). Toads are potentially attracted to tree cavities and arboreal nests because they provide safe and damp microenvironments which can support an abundance of invertebrate prey but the importance of such tree microhabitats for toad conservation remains unknown and our results should be interpreted cautiously. We encourage expanding and linking of unrelated biodiversity monitoring surveys and citizen science initiatives as valuable tools for investigating ecological traits and interactions.

Nipah Virus Detection at Bat Roosts after Spillover Events, Bangladesh, 2012-2019.

Knowledge of the dynamics and genetic diversity of Nipah virus circulating in bats and at the human-animal interface is limited by current sampling efforts, which produce few detections of viral RNA. We report a series of investigations at Pteropus medius bat roosts identified near the locations of human Nipah cases in Bangladesh during 2012–2019. Pooled bat urine was collected from 23 roosts; 7 roosts (30%) had >1 sample in which Nipah RNA was detected from the first visit. In subsequent visits to these 7 roosts, RNA was detected in bat urine up to 52 days after the presumed exposure of the human case-patient, although the probability of detection declined rapidly with time. These results suggest that rapidly deployed investigations of Nipah virus shedding from bat roosts near human cases could increase the success of viral sequencing compared with background surveillance and could enhance understanding of Nipah virus ecology and evolution.

Changes in hibernating tricolored bat (Perimyotis subflavus) roosting behavior in response to white-nose syndrome.

Understanding animals' behavioral and physiological responses to pathogenic diseases is critical for management and conservation. One such disease, white‐nose syndrome (WNS), has greatly affected bat populations throughout eastern North America leading to significant population declines in several species. Although tricolored bat (Perimyotis subflavus) populations have experienced significant declines, little research has been conducted on their responses to the disease, particularly in the southeastern United States. Our objective was to document changes in tricolored bat roost site use after the appearance of WNS in a hibernaculum in the southeastern U.S. and relate these to microsite temperatures, ambient conditions, and population trends. We censused a tricolored bat hibernaculum in northwestern South Carolina, USA, once each year between February 26 and March 2, 2014–2021, and recorded species, section of the tunnel, distance from the entrance, and wall temperature next to each bat. The number of tricolored bats in the hibernaculum dropped by 90.3% during the first 3 years after the arrival of WNS. However, numbers stabilized and slightly increased from 2018 to 2021. Prior to the arrival of WNS, 95.6% of tricolored bats roosted in the back portion of the tunnel that was the warmest. After the arrival of WNS, we observed a significant increase in the proportion of bats using the front, colder portions of the tunnel, particularly during the period of population stabilization and increase. Roost temperatures of bats were also positively associated with February external temperatures. Our results suggest that greater use of the colder sections of the tunnel by tricolored bats could have led to increased survival due to slower growth rates of the fungus that causes WNS in colder temperatures or decreased energetic costs associated with colder hibernation temperatures. Thus, management actions that provide cold hibernacula may be an option for long‐term management of hibernacula, particularly in southern regions.

Multifaceted DNA metabarcoding of guano to uncover multiple classes of ecological data in two different bat communities.

DNA contained in animal scat provides a wealth of information about the animal, and DNA metabarcoding of scat collections can provide key information about animal populations and communities. Next‐generation DNA sequencing technologies and DNA metabarcoding provide an efficient means for obtaining information available in scat samples. We used multifaceted DNA metabarcoding (MDM) of noninvasively collected bat guano pellets from a Myotis lucifugus colony on Fort Drum Military Installation, New York, USA, and from two mixed‐species bat roosts on Fort Huachuca Military Installation, Arizona, USA, to identify attributes such as bat species composition, sex ratios, diet, and the presence of pathogens and parasites. We successfully identified bat species for nearly 98% of samples from Fort Drum and 90% of samples from Fort Huachuca, and identified the sex for 84% and 67% of samples from these same locations, respectively. Species and sex identification matched expectations based on prior censuses of bat populations utilizing those roosts, though samples from some species were more or less common than anticipated within Fort Huachuca roosts. Nearly 62% of guano samples from Fort Drum contained DNA from Pseudogymnoascus destructans, where bats with wing damage from White‐nose Syndrome were commonly observed. Putative dietary items were detected in a majority of samples from insectivorous bats on Fort Drum (81%) and Fort Huachuca (63%). A minority of guano samples identified as the nectarivorous Leptonycteris yerbabuenae (28%) provided DNA sequences from putative forage plant species. Finally, DNA sequences from both putative ecto‐ and endoparasite taxa were detected in 35% and 56% of samples from Fort Drum and Fort Huachuca, respectively. This study demonstrates that the combination of noninvasive sampling, DNA metabarcoding, and sample and locus multiplexing provide a wide array of data that are otherwise difficult to obtain.

Autumn roost-site selection by male hoary bats (Lasiurus cinereus) in northern California

Abstract Effective conservation and management of a species relies upon understanding its habitat throughout its full annual cycle. For hoary bats, Lasiurus cinereus, their ecology is largely known from summer with the exception that they move long distances during autumn and spring and maintain some level of activity year-round. Autumn is a critically important period for hoary bats as they complete long-distance migrations between summer and winter range and they mate, both of which are energetically expensive. We studied hoary bat roost selection during autumn in a migratory stopover area in redwood habitat in northwestern California. We hypothesized that hoary bats select day roosts during autumn migration that minimize energetic expenditures and improve mating opportunities. We located 24 day roost sites of male hoary bats and evaluated site-level roost selection by comparing roosts with 120 random locations. We used multiple logistic regression to compare remotely sensed habitat features derived from LiDAR and other spatial data. The three most important variables for distinguishing roost from random locations were distance to creek, roads, and meadow. We speculate that selection of roosts in proximity to open spaces and flyways facilitated social behaviors related to mating that are commonly observed in this area.

Larger trees may support larger Indiana bat maternity colonies in a dynamic landscape

AbstractIndiana bats (Myotis sodalis), federally listed as endangered, are of management concern in eastern North America. While researchers quantified the habitat affinities of the species throughout the range, few studies have occurred in regions where populations are at high risk for wind energy development and changing climes. Central Illinois, USA, is a dynamic landscape where forest area has been increasing in recent decades (on public and private land) because of changing farming practices and increased habitat protections. The increasing availability of large diameter trees, increasing forest biomass, and changing forest compositions have the potential to influence Indiana bat roost habitat preferences. We assessed Indiana bat maternity roost selection at the tree and forest plot scale to characterize patterns of use in this region from 2017–2018. We predicted that large trees on the landscape would support large colonies of Indiana bats. We located bats in multiple species of trees including elm (Ulmus spp.), cottonwood (Populus deltoides), and shagbark hickory (Carya ovata). We documented larger maternity colonies sharing roosts than in previous studies from the 1980s in the same region. We suggest managers and regulatory agencies monitor Indiana bats in dynamic landscapes such as those with changing forest composition and biomass.

Place your bets: small prey faces large predators

Abstract Interspecific aggression is common between species that live together. We describe such behaviour in a mixed-species bat roost. A single small-bodied (approx. 15 g) frugivorous bat, Carollia perspicillata, aggressively antagonized a group of much larger (approx. 34 g) bats, Trachops cirrhosus, in defence of a roosting site, resulting in the larger T. cirrhosus relinquishing the site. This interaction was striking as T. cirrhosus are known to consume C. perspicillata. The small ‘prey’ individual caused the group of larger ‘predators’ to leave the roosting area by intensely vocalizing, rapidly flapping its wings, hitting the faces of the other bats with its wings, and flinging its body at the other bats. To our knowledge, this type of interspecies agonistic behaviour has never been observed before in bats and highlights the importance of intensively studying behavioural interactions in nature.

Seasonal variation in age, sex, and reproductive status of Mexican free‐tailed bats

AbstractIn North America, Mexican free‐tailed bats (Tadarida brasiliensis mexicana) consume vast numbers of insects contributing to the economic well‐being of society. Mexican free‐tailed bats have declined due to historic guano mining, roost destruction, and bioaccumulation of organochlorine pesticides. Long‐distance migrations and dense congregations at roosts exacerbate these declines. Wind energy development further threatens bat communities worldwide and presents emerging challenges to bat conservation. Effective mitigation of bat mortality at wind energy facilities requires baseline data on the biology of affected populations. We collected data on age, sex, and reproductive condition of Mexican free‐tailed bats at a cave roost in eastern Nevada located 6 km from a 152‐MW industrial wind energy facility. Over 5 years, we captured 46,353 Mexican free‐tailed bats. Although just over half of the caught individuals were nonreproductive adult males (53.6%), 826 pregnant, 892 lactating, 10,101 post‐lactating, and 4327 nonreproductive adult females were captured. Juveniles comprised 11.5% of captures. Female reproductive phenology was delayed relative to conspecific roosts at lower latitudes, likely due to cooler temperatures. Roost use by reproductive females and juvenile bats demonstrates this site is a maternity roost, with significant ecological and conservation value. To our knowledge, no other industrial scale wind energy facilities exist in such proximity to a heavily used bat roost in North America. Given the susceptibility of Mexican free‐tailed bats to wind turbine mortality and the proximity of this roost to a wind energy facility, these data provide a foundation from which differential impacts on demographic groups can be assessed.

Coastal onshore wind turbines lead to habitat loss for bats in Northern Germany

Wind energy production is particularly rewarding along coastlines, yet coastlines are often important as migratory corridors for wildlife. This creates a conflict between energy production from renewable sources and conservation goals, which needs to be considered during environmental planning. To shed light on the spatial interactions of a high collision risk bat species with coastal wind turbines (WT), we analysed 32 tracks of 11 common noctule bats (Nyctalus noctula) in Northern Germany with miniaturized global positioning system units yielding 6266 locations. We used three spatial models to infer on the preferred and avoided landscape features in interaction with WT. We found 3.4% of all locations close to WT, with bats preferring areas with high levels of impervious surface, identified as farmhouses. Common noctule bats were also more present close to WT adjacent to paths and waterbodies. At the local scale, >70% of common noctule bats avoided WT, yet if bats approached WT we counted more positions at large WT, specifically close to known roosts. Our study highlights that coastal WT should not be placed next to feeding grounds and bat roosts. Additionally, avoidance of WT by bats indicates that foraging bats may suffer from habitat loss in coastal landscapes with high turbine densities. To mitigate the conflict between wind energy power production and conservation goals at coastal sites, wind turbines should be placed at distance to habitat features preferred by bats and turbine densities should be limited.

Evaluation of different monitoring methods at maternity roosts of greater mouse-eared bats (Myotis myotis)

In recent years, biodiversity has declined faster than ever before in human history. Appropriate monitoring methods are needed to detect the decline of populations in time to be able to take conservation measures. Information on population dynamics can only be obtained by conducting standardised monitoring programmes, and the quality of the data depends on the survey method used. The present study aims to provide scientifically sound recommendations for the selection of a suitable survey method for emerging flights at greater mouse-eared bat (Myotis myotis) maternity roosts. For this purpose, three survey methods, namely infrared video recordings, counting by light barriers and visual counting of emerging bats, were used simultaneously for 4–5 nights at three different maternity roosts in 2019 and comparatively evaluated. Besides the quality of the counting data, the requirements and limitations of the different methods were compared and discussed. The results of this study showed that the number of emerging flights detected with all three survey methods were closely correlated, regardless of location, number of emerging flights per night (between 300 and 800) and season. Furthermore, it was shown that the presence of the observer and infrared video recordings had no significant influence on the emergence behaviour of the bats recorded by light barriers concerning the time of emergence, the duration of activity and the number of counts. As the three methods differed with regard to additional parameters, such as the need for technical equipment or qualified personnel, the time required, the costs and the error-proneness individual settings and requirements should be taken into account when deciding about the method used. However, for the continuous monitoring of greater mouse-eared bats at their maternity roosts, which is part of the monitoring requirements under the European Union Habitats Directive, the use of light barriers proved to be the method of choice, in particular as it allows to promptly detect changes in the bats’ activity as a basis for conservation measures.

Bat Inventories at Caves and Mines on the Islands of Aruba, Bonaire and Curaçao, and Proposed Conservation Actions

Bats play key ecological roles on the islands of Aruba, Bonaire and Curaçao (ABC islands), Caribbean Netherlands; however, most bat species on these islands are either threatened or their conservation status is unknown. We investigated the use of roosts by cave-dwelling bats in this insular system to propose conservation measures aimed at their protection. We conducted bi-monthly species inventories of cave-dwelling bats in 13 of the best-known caves and mines used as day and maternity roosts on the ABC islands. Bats were captured with mist nets and a harp trap (only one cave) placed either inside or at the entrance of the roosts during the first hours (3 to 5 hrs) after sunset. For Aruba and Curaçao, bat monitoring comprised two years of sampling. In the case of Bonaire, depending on the cave, bat monitoring involved one, two or four years of sampling. We identified six species of cave-dwelling bats associated with these roosts, Mormoops megalophylla, Pteronotus davyi, Natalus tumidirostris, Myotis nesopolus, Glossophaga longirostris and Leptonycteris curasoae. All the examined caves and mines were occupied year-round. The two abandoned mines were inhabited exclusively by the nectar-feeding G. longirostris and L. curasoae, whereas caves containing hot chambers were occupied by up to five species of bats, including insect-feeding M. megalophylla, P. davyi, M. nesopolus and N. tumidirostris, and migratory L. curasoae. Nursery roosts occupied by insect-feeding bats were Quadirikiri on Aruba; Orizjan, Pos di watapana and Pos di Antoin on Bonaire; and Raton and Noordkant on Curaçao. Nectar-feeding bats used all the caves and mines examined as day roosts, nursery roosts or both. All the cave-dwelling bats studied had a single annual reproductive period. In the case of insectivorous bats, pregnancy and lactation occurred mainly between July and December, overlapping with the rainy season. For nectar-feeding bats, pregnancy and lactation took place between March and September, overlapping with the flowering and fruiting seasons of chiropterophilous cacti. Most of the examined bat roosts require protection due to one or more of the following conditions: (1) the presence of multiple species dependent on hot chambers, (2) their use as nursery roosts, and (3) the presence of large colonies of L. curasoae.

Tree Girdling for Potential Bat Roost Creation in Northwestern West Virginia

Cavity/crevice tree-roosting bats in North America face an uncertain future with many factors impacting their populations. To benefit crevice/cavity roosting bat species, forests are often enhanced with the use of tree girdling. In October 2015, 20 maples, 22 oaks, and 18 hickories were girdled using a method with fell cut and herbicide (frilling) or double-girdling with a chainsaw. From 2016–2021, targeted trees were observed and the tree’s decay state was collected. The average time for trees to display suitable roosting characteristics for frilling trees was 3.23 years while it was 4.46 years for double girdling. The average time frilling trees contained suitable roosting characteristics was 3.20 years while it was 1.63 years for double girdling. The frilling method resulted in a quicker kill of trees than double girdling and frilling trees had suitable roosting characteristics for a longer duration. Frilling was effective killing all three types of trees, while the double girdling was less effective, especially on oaks. When grouping species and treatment in analysis, only average decay states between maple frill and oak double girdling and hickory frill and oak double girdling were significantly different. This evaluation demonstrates that roost tree creation relating to tree species and girdling methodology has a temporal component that should be considered when managing for crevice/cavity bat roosts and multiple habitat creation methods should be used in conjunction with snag creation to provide sustainable bat habitat over longer time periods.

Do bats use scent cues from guano and urine to find roosts?

Selection of habitat is a key determinant of reproductive success, and the process of finding and choosing these sites is often influenced by the presence of conspecifics. Many bats frequently switch roosts, and some bats repeatedly find new roosts. To find roosts with conspecifics or group members, bats can use social cues. However, most research on how bats use social cues for roost-finding has focused on acoustic cues. Here, we review and discuss the evidence for bat roost selection using scent cues from guano and urine stains, which are present at most bat roosts. We outline reasons why bats might, or might not, use scent in roost detection and selection, and we review evidence on the possible use of guano and urine in roost-finding from eight studies with 12 bat species (across four families). Overall, the sparse evidence that exists indicates that scent cues from guano and urine are not a strong and consistent lure in the species and situations that were tested. Most studies had unclear results or found no effect. Two of the eight studies found weak experimental evidence for bats using guano or urine to select a roosting site. Even if guano and urine can indicate the presence of bats at a roost, it is possible that the resulting olfactory cues do not contain sufficient social information to be used in roost selection, in contrast to olfactory cues from scent marking. Studies of how bats use sensory cues beyond sound could contribute to a better understanding of bat social behavior and roosting ecology.

Importance of anthropogenic winter roosts for endangered hibernating bats

We aimed to assess the importance of anthropogenic roosts for bats hibernating in the Roztocze National Park (south-east Poland), based on data collected from 2009 to 2021. We recorded 310 bats from nine species hibernating in 27 artificial underground roosts (root cellars and basements of buildings). The most abundant and constantly recorded species were Plecotus auritus (60.2%), Barbastella barbastellus (20.6%) and Myotis nattereri (14.2%), while the remaining species can be considered of secondary importance; Plecotus austriacus (1.3%), Myotis myotis (1.9%), Myotis bechsteinii (1.3%), M. daubentonii (0.3%), Myotis mystacinus sensu lato (0.3%) and Eptesicus serotinus (1.3%). An estimate of the Shannon diversity index gave a mean H = 0.947 (SD = 0.247, range 0.377-1.352), while the Buzas and Gibson´s evenness index gave values of E = 0.695 (SD = 0.125, range 0.551-0.940). The Shannon index was positively correlated with the number of recorded bats and varied substantially among years.

Diverse moth prey identified in the diet of the critically endangered southern bent-wing bat (Miniopterus orianae bassanii) using DNA metabarcoding of scats

Context Globally, insectivorous bats are important moderators of insect populations, including agricultural pests. However, in human-modified environments, changes to insect diversity and abundance may have detrimental impacts on bat populations. The southern bent-wing bat (SBWB; Miniopterus orianae bassanii), is a critically endangered, cave-dwelling bat with a restricted distribution across south-eastern Australia, an area now dominated by agricultural land uses. Understanding SBWB diet may highlight the role of bats in influencing insect populations in surrounding agricultural land, while simultaneously providing crucial data for conservation management of this critically endangered species. Aim To investigate the SBWB’s diet using arthropod DNA metabarcoding of scats and guano collected from seven caves across the species’ range. Methods We collected scats from bat roosts and from guano piles on cave floors during late summer and early autumn of 2019. We used PCR to amplify two short, overlapping arthropod mtDNA cytochrome oxidase subunit 1 barcodes and sequenced these using the Illumina MiSeq to identify arthropod diet species. Key results Moths (order Lepidoptera) were the most prevalent insect identified in all samples and from all sites. Many of the 67 moth species identified were associated with agricultural land use (e.g. pasture webworm (Hednota pedionoma) and armyworm (Persectania dyscrita)), and several, including the bogong moth (Agrotis infusa), are migratory, suggesting the SBWB’s diet changes seasonally. Conclusion By describing the diet of the SBWB, we have fulfilled one recommendation of the national recovery plan for the species. The SBWB preys predominantly on moths, and its diet has likely been impacted by the increase in agricultural land use across its range. Further research is required to understand its foraging habitat requirements. Implications Our findings suggest the SBWB may play a role in controlling populations of moth species considered to be agricultural pests. The wide variety of moths consumed by SBWBs could afford the species some resilience to landscape changes affecting moth assemblages. The methodological framework developed here could be applied to investigate how land-use changes may contribute to bat population declines, but also how insectivorous bats may provide important ecosystem services by controlling pest insect species in modified landscapes.

Bats of Central Ukraine: a Synopsis

Here, we represent the first review of the bat fauna of the large territory of Central Ukraine (to the west from Dnieper River). The review is based on results of the original survey in 1999–2021 and data from all available sources (publications, museum collections). Fauna of the region includes 24 bat species: Eptesicus, 2 species; Barbastella, 1; Myotis, 10; Nyctalus, 3; Pipistrellus, 4; Plecotus, 2; Vespertilio, 1; Rhinolophus, 1. For each species there is a short description of its distribution (illustrated by a map), used roosts, seasonality of presence and reproductive status within the study area. The bat fauna composition is analysed by three distinguished subregions, from north to south: of mixed forests, the forest-steppe, and the Dniester river. The estimation of prevalence and comparative abundance of the species in the region is given. The general review of bat roosts, by their types (under- and overground), seasonality of usage, and sheltered species is presented. The paper is supplemented with the extensive array of original, earlier unpublished, primary data on bat records in the region.

Effect of roost management on populations trends of Rhinolophus hipposideros and Rhinolophus ferrumequinum in Britain and Ireland

After a significant population decline during the 20th century, populations of both greater and lesser horseshoe bats have increased over recent decades in Britain and populations of lesser horseshoe bats have increased in Ireland. Vincent Wildlife Trust (VWT) acquired 37 bat reserves since the 1980s with the aim to safeguard the sites and enhance the roosting and hibernation conditions in buildings that were often derelict and sub-optimal for bats. These measures have resulted in a strong population size increase of all colonies. However, populations have also been increasing throughout Britain and Ireland as a consequence of legal protection and milder winters resulting in higher survival rates. Therefore, it is not clear whether the measures that have taken place in VWT reserves have led to a greater increase than roosts that have not benefited from the same type of management. We aimed to compare population trends of horseshoe bat roosts under VWT management and non-VWT management from 1999 to 2020 in order to assess its effectiveness. For this, we analysed population trends at sites under different management types (VWT and non-VWT) for lesser horseshoe bats in Britain and Ireland and greater horseshoe bats in Britain. Our results indicated that populations in Britain under VWT management have increased by 366% (CI 225% - 580%) for greater horseshoe bats and 188% (CI 125% - 283%) for lesser horseshoe bats. Roosts that did not benefit from the same levels of management increased respectively by 164% (CI 132% - 199%) and 51% (CI 40% - 60%). In Ireland, populations of lesser horseshoe bats in VWT managed roosts increased by 217% (CI 118% - 364%) while non-VWT managed roosts remained stable (-0.44%; CI -23% - 29%). We conclude that management actions carried out by VWT of greater and lesser horseshoe bat roosts have helped populations recover at a faster rate by securing the integrity of buildings, improving access points and by providing optimal microclimatic conditions within the buildings.