Seasonal activity patterns of seven vespertilionid bat species in Polish lowlands

Data on seasonal dynamics of bat activity in central Europe are scarce, mostly restricted to either summer period or autumn swarming. Few studies provide extensive interspecific comparisons of temporal activity patterns. Through broadband ultrasound detection, temporal variation of flight activity was studied in seven insectivorous bat species in N Poland for the first time. Seasonal activity pattern ofMyotis daubentonii (Kuhl, 1817) was clearly bimodal with the higher peak of activity in April and the second, smaller peak in August–September. The first peak is possibly associated with post-hibernal restoration of fat reserves, while the second one might result either from pre-hibernal fat accumulation, increase in energy demands of males during spermatogenesis or from dispersal of newly weaned juveniles. The highest flight activity ofNyctalus, Eptesicus andPipistrellus bats was noted in summer months, reflecting mainly an increase in energy demands between pregnancy and lactation. However, a distinct, second peak in activity ofN. noctula appeared at the end of September, probably matching the late migration wave of individuals from E Europe. The cluster analysis of species’ activity patterns reflected division on different hunting tactics, but not migratory behaviour.     

Bats of Lithuania: distribution, status and protection

The Lithuanian bat fauna includes 14 species. Myotis daubentoni, Pipistrellus nathusii, Plecotus auritus and Eptesicus serotinus are the most abundant and widespread species, although recently P. auritus has disappeared from some hibernacula. There are still abundant populations of Myotis nattereri, Myotis brandti and Barbastella barbastellus in hibernacula, while their status in summer is unknown. Myotis dasycneme is probably very rare and endangered. The status of Myotis mystacinus and Nyctalus leisleri is not clear, but they are most likely very rare because very few specimens have been found. So far little is known about status of Nyctalus noctula, Pipistrellus pipistrellus, Eptesicus nilssoni and Vespertilio murinus because these species are common only during autumn bat migration along the Baltic Sea coast. Two other species, Myotis bechsteini and Rhinolophus hipposideros, have been rejected from the list of bats of Lithuania, because old references to records of these species were not reliable. From what is currently known it seems that: (i) the northern limits of distribution of B. barbastellus and E. serotinus reach the middle of Lithuania between 55°N and 56°N, which may also be the southern limit of abundance of E. nilssoni; (ii) the wintering site with the largest numbers of bats in Lithuania is the vaults of Kaunas fortress, where every year eight species are found hibernating in numbers estimated as follows: M. daubentoni 400–500, M. nattereri 200–300, M. brandti 80–100, B.barbastellus 200–300, P. auritus 40–60, M. dasycneme 15–20 and a few E. serotinus and E. nilssoni. In Lithuania nine bat species have been protected by law since 1991, as species included in the Red Data Book. Also 11 bat reserves have been designated in Kaunas fortress to protect the most important hibernation sites in Lithuania.     

Habitat associations of bats in a working rangeland landscape

Land‐use change has resulted in rangeland loss and degradation globally. These changes include conversion of native grasslands for row‐crop agriculture as well as degradation of remaining rangeland due to fragmentation and changing disturbance regimes. Understanding how these and other factors influence wildlife use of rangelands is important for conservation and management of wildlife populations. We investigated bat habitat associations in a working rangeland in southeastern North Dakota. We used Petterson d500x acoustic detectors to systematically sample bat activity across the study area on a 1‐km point grid. We identified calls using Sonobat autoclassification software. We detected five species using this working rangeland, which included Lasionycteris noctivagans (2,722 detections), Lasiurus cinereus (2,055 detections), Eptesicus fuscus (749 detections), Lasiurus borealis (62 detections), and Myotis lucifugus (1 detection). We developed generalized linear mixed‐effects models for the four most frequently detected species based on their ecology. The activity of three bat species increased with higher tree cover. While the scale of selection varied between the four species, all three investigated scales were explanatory for at least one bat species. The broad importance of trees to bats in rangelands may put their conservation needs at odds with those of obligate grassland species. Focusing rangeland bat conservation on areas that were treed prior to European settlement, such as riparian forests, can provide important areas for bat conservation while minimizing negative impacts on grassland species.     

Bat casualties on a road crossing a mosaic landscape

A year-round study was conducted on a 16.6-km road section crossing Kampinos National Park near Warsaw (central Poland). We found 61 road-killed bats belonging to seven species. The most abundant were: Nyctalus noctula, Plecotus auritus, and Barbastella barbastellus. Bats were found between the middle of April and the end of October with peaks in July/August and October. The density of bat casualties differed slightly in various habitats surrounding the road—lower values than expected were found only for windbreaks and bushes. The prediction that low-flying species are killed more frequently was not confirmed—the most abundant N. noctula usually flies at heights over 10 m above the ground. N. noctula, Myotis nattereri, and Pipistrellus nathusii were killed more frequently while Eptesicus serotinus less frequently than could be expected from the frequency with which they were captured in mist-nets on forest lanes.     

Predictive Occurrence Models for Bat Species in California

Abstract: The ability to accurately predict the potential occurrence of species of management concern is useful for wildlife managers, particularly for those whose management activities involve large areas where sampling is difficult due to logistical or financial constraints. During the summers of 2002 and 2003, we used mist nets to capture bats (Myotis yumanensis, M. californicus, M. evotis, M. thysanodes, Eptesicus fuscus, Lasionycteris noctivagans, Tadarida brasiliensis, Antrozous pallidus, Lasiurus borealis, and Lasiurus cinereus) in Whiskeytown National Recreation Area in north-central California, USA. We used landscape-scale variables, logistic regression, and Akaike's Information Criterion (AIC_c) to model species distributions and produce spatially discerning predictive occurrence maps. We developed a priori models that we used to determine which landscape-scale variables best discriminated between capture sites and non-capture sites. The odds of capturing a bat were 3.3 greater when total edge increased by 10,000 m, whereas for Yuma myotis (Myotis yumanensis), the odds of predicting presence were 0.2 greater when distance to lakes and ponds decreased by 2,000 m. Elevation was important in predicting the distribution of silver-haired bats (Lasionycteris noctivagans) and big brown bats (Eptesicus fuscus). Increasing elevation by 400 m decreased the odds of capturing a silver-haired bat by 0.1 and a big brown bat by 0.4. Classification accuracy for our models ranged from 80.9% for all bat species combined to 72.3% for Yuma myotis and silver-haired bats. Predictive occurrence models can be valuable to bat conservation efforts because they provide spatial data important for evaluating the effects of management activities on species distributions.     

Habitat Characteristics of Eurytemora lacustris (Poppe, 1887) (Copepoda,Calanoida): The Role of Lake Depth,Temperature,Oxygen Concentration and Light Intensity

Field observations, laboratory experiments and a literature survey were conducted to evaluate the habitat characteristics of Eurytemora lacustris (Poppe 1887), a freshwater calanoid copepod species. Combined effects of temperature and oxygen concentration in the deep water of thermally stratifying lakes seem to be the ultimate factors governing the occurrence of the species throughout its home‐territory. E. lacustris is largely restricted to relatively deep lakes (>30 m) providing a hypolimnetic refuge characterised by low temperatures (<∼10 °C) and oxygenated water during summer. Therefore, although the species is spread over much of Europe it was only found in a small number of lakes. Long‐term records in different lakes revealed E. lacustris to be perennial with relatively high biomasses occurring from May to September. During thermal stratification on average 87% of the nauplii and 72% of the copepodite biomass was found in hypolimnetic waters colder than 10 °C. Diurnal vertical migration was observed for the copepodid stages, but the migration amplitude clearly decreased from May to September. The migration amplitude was significantly related to light intensity. According to its special habitat requirements, E. lacustris might be considered a glacial relict sensitive to temperature increase and oxygen depletion. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Estimating population density of insectivorous bats based on stationary acoustic detectors: A case study

1. Automated recording units are commonly used by consultants to assess environmental impacts and to monitor animal populations. Although estimating population density of bats using stationary acoustic detectors is key for evaluating environmental impacts, estimating densities from call activity data is only possible through recently developed numerical methods, as the recognition of calling individuals is impossible.
2. We tested the applicability of generalized random encounter models (gREMs) for determining population densities of three bat species (Common pipistrelle Pipistrellus pipistrellus, Northern bat Eptesicus nilssonii, and Natterer's bat Myotis nattereri) based on passively collected acoustical data. To validate the results, we compared them to (a) density estimates from the literature and to (b) Royle–Nichols (RN) models of detection/nondetection data.
3. Our estimates for M. nattereri matched both the published data and RN‐model results. For E. nilssonii, the gREM yielded similar estimates to the RN‐models, but the published estimates were more than twice as high. This discrepancy might be because the high‐altitude flight of E. nilssonii is not accounted for in gREMs. Results of gREMs for P. pipistrellus were supported by published data but were ~10 times higher than those of RN‐models. RN‐models use detection/nondetection data, and this loss of information probably affected population estimates of very active species like P. pipistrellus.
4. gREM models provided realistic estimates of bat population densities based on automatically recorded call activity data. However, the average flight altitude of species should be accounted for in future analyses. We suggest including flight altitude in the calculation of the detection range to assess the detection sphere more accurately and to obtain more precise density estimates.

     

The Cercal Organ May Provide Singing Tettigoniids a Backup Sensory System for the Detection of Eavesdropping Bats

Conspicuous signals, such as the calling songs of tettigoniids, are intended to attract mates but may also unintentionally attract predators. Among them bats that listen to prey-generated sounds constitute a predation pressure for many acoustically communicating insects as well as frogs. As an adaptation to protect against bat predation many insect species evolved auditory sensitivity to bat-emitted echolocation signals. Recently, the European mouse-eared bat species Myotis myotis and M. blythii oxygnathus were found to eavesdrop on calling songs of the tettigoniid Tettigonia cantans. These gleaning bats emit rather faint echolocation signals when approaching prey and singing insects may have difficulty detecting acoustic predator-related signals. The aim of this study was to determine (1) if loud self-generated sound produced by European tettigoniids impairs the detection of pulsed ultrasound and (2) if wind-sensors on the cercal organ function as a sensory backup system for bat detection in tettigoniids. We addressed these questions by combining a behavioral approach to study the response of two European tettigoniid species to pulsed ultrasound, together with an electrophysiological approach to record the activity of wind-sensitive interneurons during real attacks of the European mouse-eared bat species Myotis myotis. Results showed that singing T. cantans males did not respond to sequences of ultrasound pulses, whereas singing T. viridissima did respond with predominantly brief song pauses when ultrasound pulses fell into silent intervals or were coincident with the production of soft hemi-syllables. This result, however, strongly depended on ambient temperature with a lower probability for song interruption observable at 21°C compared to 28°C. Using extracellular recordings, dorsal giant interneurons of tettigoniids were shown to fire regular bursts in response to attacking bats. Between the first response of wind-sensitive interneurons and contact, a mean time lag of 860 ms was found. This time interval corresponds to a bat-to-prey distance of ca. 72 cm. This result demonstrates the efficiency of the cercal system of tettigoniids in detecting attacking bats and suggests this sensory system to be particularly valuable for singing insects that are targeted by eavesdropping bats.     

Migration of the Nathusius’ pipistrelle<Emphasis Type="Italic">Pipistrellus nathusii</Emphasis> (Vespertilionidae) along the Vistula Split

Migration ofPipistrellus nathusii (Keyserling and Blasius, 1839) was studied from 1995 to 1998 at the Vistula Split, northern Poland. The direction of bat movements during the night were distinguished by two ultrasound detectors facing in opposite directions and connected into a stereo system. To obtain information about fluctuations in the relative density of bats in the study area, bird nest boxes and bat boxes were checked as well. A combination of the results of these two methods allowed the identification of seasonal movements. Spring migration started at the beginning of May and continued until the end of the month. Autumn migration started in mid-July and lasted until mid-September. The peaks in spring and late summer migrations resulted from longer migration activity during nights.     

Bat rabies in Illinois: 1965 to 1986

From 1968 to 1986, Illinois (USA) citizens and agencies submitted 4,272 bats to the Illinois Department of Public Health for rabies testing. Of this number, 6% tested positive, a rate comparable to similar studies from other parts of North America. Due to sampling biases, the true infection rate among bats in Illinois is probably lower than 6%. Additional analysis relied on a subsample (n = 2,433) of the specimens collected from 1965 to 1986. Prevalences were significantly different among years, but no linear trends were found over the study period. Evidence for a local outbreak of bat rabies was found. Prevalences for the species with sample sizes adequate for statistical analysis were, from high to low: hoary bat (Lasiurus cinereus), 11%; red bat (L. borealis), 5%; silver-haired bat (Lasionycteris noctivagans), 4%; little brown bat (Myotis lucifugus), 4%; big brown bat (Eptesicus fuscus), 3%; Keen's bat (Myotis keenii), 2%; and evening bat (Nycticeius humeralis), 2%. The higher prevalences found among the non-colonial species (hoary, red and silver-haired bats) were consistent with similar studies. Considerable annual variation in prevalences was found within species, and the prevalence rankings of the species varied over the study period. Prevalences were significantly higher in females (6%) than in males (4%) when species were pooled, but no significant differences between sexes were found within species. In contrast to the other species analyzed, all of which had sex ratios favoring females, the big brown bat sample had a large majority of males. Prevalences were significantly higher in adults (6%) than in juveniles (3%) when species were pooled. Within individual species, significant differences between age groups were found only for hoary and red bats; in two species, juveniles had higher prevalences. Above average prevalences were observed in May and August to November. Southern Illinois had the highest prevalences; prevalences were intermediate in the north and lowest in the central region. Overall, the patterns of rabies prevalence among bats submitted by the public in Illinois from 1965 to 1986 were similar to those reported from other parts of North America.     

Bat species diversity in a lake archipelago in central Sweden

The bat fauna of 35 islands in a large lake in central Sweden were examined using ultrasound detectors. We tested the hypothesis that there is no difference in species number between the mainland and the island fauna. Eight species were found. Species numbers were analysed against island area, area of some habitats (coniferous forest, deciduous forest, semi-open habitats and open habitats), degree of isolation (distance from mainland and from stepping stones) and time spent searching for bats. Species number increased with area of deciduous forest. Presence of houses tended to increase species number. There seems to be a negative relationship between species number and degree of isolation (nearly significant). The results suggest that at least three species, Myotis brandti (Eversmann, 1845), M. mystacinus (Kuhl, 1819) and Plecotus auritus (Linnaeus, 1758), are negatively affected by forest patchiness. These species occurred mainly on large islands. Thus, the results do not support the hypothesis. The reasons why some species avoid open habitats are discussed.     

Use of foraging habitats by bats in a Mediterranean area determined by acoustic surveys: conservation implications

We determined habitat use by foraging bats by broad-band acoustic surveys in 10 habitat types from a Mediterranean area (southern Italy). We applied discriminant functions to identify time-expanded echolocation calls from free-flying bats.
Moon phase and cloud cover had no effect on bat activity. Only Hypsugo savii was influenced by temperature, and activity of Myotis daubentonii and Myotis capaccinii was reduced at higher wind speeds. Both total numbers of bat passes and feeding buzzes were highest over rivers and lakes. Pipistrellus kuhlii and H. savii were most frequently recorded. Pipistrellus kuhlii , Pipistrellus pipistrellus and Tadarida teniotis proved generalists in using foraging habitats.
Water sites and conifer plantations were respectively the most and the least used habitats by H. savii . Rivers were especially important to Myotis bats, Miniopterus schreibersii and Pipistrellus pygmaeus . Unlike P. kuhlii , P. pipistrellus was frequent in beech woodlands; P. pygmaeus made a considerable use of chestnut woodlands and Myotis spp. were moderately active in both these woodland types.
A large number of endangered or vulnerable species featured in riparian habitats, broadleaved woodlands and olive groves. Riparian and woodland habitats constitute an important target for conservation. Typical land use forms such as woodlands used for chestnut production and traditionally managed olive groves should be encouraged in conservation plans. The negative impact of urbanisation on bats might be counteracted by fostering trees, gardens and small cultivated patches. Farmland practices should encourage landscape complexity and limit the use of pesticides.     

Assessing road effects on bats: the role of landscape, road features, and bat activity on road-kills

Recent studies suggest that roads can significantly impact bat populations. Though bats are one of the most threatened groups of European vertebrates, studies aiming to quantify bat mortality and determine the main factors driving it remain scarce. Between March 16 and October 31 of 2009, we surveyed road-killed bats daily along a 51-km-long transect that incorporates different types of roads in southern Portugal. We found 154 road-killed bats of 11 species. The two most common species in the study area, Pipistrellus kuhlii and P. pygmaeus, were also the most commonly identified road-kill, representing 72 % of the total specimens collected. About two-thirds of the total mortality occurred between mid July and late September, peaking in the second half of August. We also recorded casualties of threatened and rare species, including Miniopterus schreibersii, Rhinolophus ferrumequinum, R. hipposideros, Barbastella barbastellus, and Nyctalus leisleri. These species were found mostly in early autumn, corresponding to the mating and swarming periods. Landscape features were the most important variable subset for explaining bat casualties. Road stretches crossing or in the vicinity of high-quality habitats for bats—including dense Mediterranean woodland (“montado”) areas, water courses with riparian gallery, and water reservoirs—yielded a significantly higher number of casualties. Additionally, more road-killed bats were recorded on high-traffic road stretches with viaducts, in areas of higher bat activity and near known roosts.     

Seasonal variation in use of winter roosts by five bat species in south-east Finland

We studied seasonal variation in the use of winter roosts by five bat species (Eptesicus nilssonii, Myotis brandtii/mystacinus, Myotis daubentonii and Plecotus auritus) in south-east Finland during the winters of 2003/2004 and 2004/2005. At the beginning of the bat hibernation season all species used higher temperatures and humidity than by the season’s end. Hibernacula were at their coldest in mid-hibernation season and became warmer towards the end of the season. However, no species hibernated in warmer locations at the end of the season than in mid-season. Results suggest that bats tend to use different strategies throughout the hibernation season, minimizing the cost of hibernation early in the season by hibernating in warmer locations and minimizing energy expenditure later in the season by hibernating in colder locations. M. brandtii/mystacinus were found in locations with stable temperature and humidity, moving to increasingly stable conditions (chambers, crevices, clusters, ceiling) towards spring. All other species hibernated in more variable microclimates throughout the hibernation season.     

北京房山发现华南水鼠耳蝠

目前我国基础资源调查中有关翼手目物种多样性及其分布的项目正在开展,着手建立翼手目物种多样性和分布数据库,对翼手目物种在中国的分布情况亟需广泛调查和深入研究。我们于2021年9月在北京市开展翼手目物种调查时,在北京房山十渡镇四御洞使用竖琴网捕获8只蝙蝠,经过COI和Cyt b序列比对和系统发育关系重建以及外部形态数据鉴定为华南水鼠耳蝠（Myotis laniger）。此次发现华南水鼠耳蝠是北京市翼手目物种分布新记录种。     

Influences of Landscape Features on Bat Activity in North Dakota

Land conversion and modification threatens many wildlife and plant species in the northern Great Plains, including bats. Our objective was to assess the association of bat species with landscape features in the northern Great Plains of North Dakota, USA, taking the first step towards understanding the habitat needs of bats in this region. We examined patterns of bat activity across different landscapes, identified those landscape features associated with high levels of bat activity, and determined which specific land features (i.e., vegetation and water types) were most commonly associated with each bat species. We used passive acoustic monitoring to measure bat activity at sites across North Dakota, and assessed detailed land characteristics at each site. We used nonmetric multidimensional scaling and multivariate regression tree analysis to examine relationships between bat activity and landscape variables. Bat foraging activity was influenced by structural landscape characteristics and the availability of specific water resources. High levels of bat activity were associated with riparian forested areas of varying structural complexity, ponds, and, to a lesser extent, open riparian lands. Individual bat species were influenced by land type and water resources differently. We identified big brown bats (Eptesicus fuscus) and little brown bats (Myotis lucifugus) as indicators of open riparian and pond landscapes, respectively. These results highlight the importance of prairie riparian landscapes and maintaining heterogeneity across the landscape for conservation and management of bat communities. Further, we identified ponds as an important landscape feature for little brown bats, a species of conservation concern, indicating that this specific feature should be a focus of conservation efforts on prairie wetlands. © 2019 The Wildlife Society.     

Patterns in the use of rainforest vertical space by Neotropical aerial insectivorous bats: all the action is up in the canopy

In tropical rainforests environmental conditions vary dramatically from the ground to the canopy, resulting in a marked stratification in the way vertical space is used by organisms, but research work is often limited to the understorey layer. Aerial insectivorous bats are a highly diverse group that plays key roles in the ecology of rainforests, but their use of vertical space remains elusive. Using automatic ultrasound recording stations placed in the canopy, subcanopy and understorey we tested if bat activity and species diversity are vertically stratified, both in the forest interior and near the edges of water bodies. These patterns were tested separately for individual species, and for two functional groups – open space and edge space bats. Insectivorous bat activity increased by roughly seven fold, and species diversity doubled, from the understorey to the canopy. Both edge space and open space bats were more active in the upper strata, but this tendency was much more accentuated in the latter. Myotis riparius was the only species with greater activity near the understorey. These patterns were altered at the edges of water bodies, where vertical stratification was much less marked. The observed patterns are parsimoniously explained by constraints imposed by vegetation clutter that change across strata, which affect bat species differently. Only bats better adapted to closed spaces are usually capable of foraging within the understorey, whereas the majority of species can exploit the free spaces immediately below the canopy; open space bats seem to concentrate their activity above the canopy. This importance of the inter strata open spaces for bat foraging highlights the need to preserve pristine stratified rainforests, as even selective logging usually disrupts vertical stratification. Moreover, the concentration of insectivorous bats at the upper strata of rainforests underlines the need to include canopy level sampling in ecological studies.     

Curtailment and acoustic deterrents reduce bat mortality at wind farms

The impacts of wind energy on bat populations is a growing concern because wind turbine blades can strike and kill bats, and wind turbine development is increasing. We tested the effectiveness of 2 management actions at 2 wind-energy facilities for reducing bat fatalities: curtailing turbine operation when wind speeds were <5.0 m/second and combining curtailment with an acoustic bat deterrent developed by NRG Systems. We measured the effectiveness of the management actions using differences in counts of bat carcasses quantified by daily and twice-per-week standardized carcass searches of cleared plots below turbines, and field trials that estimated searcher efficiency and carcass persistence. We studied turbines located at 2 adjacent wind-energy facilities in northeast Illinois, USA, during fall migration (1 Aug–15 Oct) in 2018. We estimated the effectiveness of each management action using a generalized linear mixed-effects model with several covariates. Curtailment alone reduced overall bat mortality by 42.5% but did not reduce silver-haired bat (Lasionycteris noctivagans) mortality. Overall bat fatality rates were 66.9% lower at curtailed turbines with acoustic deterrents compared to turbines that operated at manufacturer cut-in speed. Curtailment and the deterrent reduced bat mortality to varying degrees between species, ranging from 58.1% for eastern red bats (Lasiurus borealis) to 94.4 for big brown bats (Eptesicus fuscus). Hoary (Lasiurus cinereus) and silver-haired bat mortality was reduced by 71.4% and 71.6%, respectively. Our study lacked a deterrent-only treatment group because of the expense of acoustic deterrents. We estimated the additional reduction in mortality with concurrent deployment of the acoustic deterrent and curtailment under the assumption that curtailment and the acoustic deterrent would have reduced mortality by the same percentage at adjacent wind-energy facilities. Acoustic deterrents resulted in 31.6%, 17.4%, and 66.7% additional reductions of bat mortality compared to curtailment alone for eastern red bat, hoary bat, and silver-haired bat, respectively. The effectiveness of acoustic deterrents for reducing bat mortality at turbines with rotor-swept area diameters >110 m is unknown because high frequency sound attenuates quickly, which reduces coverage of rotor-swept areas. Management actions should consider species differences in the ability of curtailment and deterrents to reduce bat mortality and increase energy production.     

Road mortality of pond-breeding amphibians during spring migrations in the Mazurian Lakeland, NE Poland

The effects of road traffic mortality on amphibian populations are in many cases hard to estimate and speculate, primarily due to the inaccuracy of the methods employed in studies. We have analyzed amphibian road mortality during two breeding seasons on selected road sections adjoining spawning ponds and have critically reviewed methods used for estimating the impact of road traffic on migrating amphibians. The mortality rates of particular amphibian species differed significantly and varied according to year, site, and traffic volume. The highest mortality was recorded for Bufo bufo and the lowest for Lissotriton vulgaris. Species-specific parameter estimates of mortality, evaluated on a daily basis counts of roadkills, were positively correlated with the mean body mass of the amphibian species. The share of a given species among carcasses found on the road, commonly used in such studies, proved to be an unreliable measure of mortality. We found that nearly 60% of amphibian roadkill victims had disappeared within 24?h of exposure, and the number of missing carcasses was inversely related to body mass.     

Seasonal Shifts in Nocturnal Habitat Use by Coastal Bat Species

Sensitivity of bats to land use change depends on their foraging ecology, which varies among species based on ecomorphological traits. Additionally, because prey availability, vegetative clutter, and temperature change throughout the year, some species may display seasonal shifts in their nocturnal habitat use. In the Coastal Plain of South Carolina, USA, the northern long-eared bat (Myotis septentrionalis), southeastern myotis (Myotis austroriparius), tri-colored bat (Perimyotis subflavus), and northern yellow bat (Lasiurus intermedius) are species of conservation concern that are threatened by habitat loss. Our objective was to identify characteristics of habitat used by these species during their nightly active period and compare use between summer and winter. We conducted acoustic surveys at 125 sites during May–August and at 121 of the same 125 sites December–March 2018 and 2019 in upland forests, bottomland forests, fields, ponds, and salt marsh and used occupancy models to assess habitat use. The northern long-eared bat and southeastern myotis (i.e., myotis bats) used sites that were closer to hardwood stands, pine stands, and fresh water year-round. We did not identify any strong predictors of tri-colored bat habitat use in summer, but during winter they used bottomland forests, fields, and ponds more than salt marsh and upland forests. During summer and winter, northern yellow bats used sites close to fresh water and salt marsh. Additionally, during summer they used fields, ponds, and salt marsh more than upland and bottomland forests, but in winter they used bottomland forests, fields, and ponds more than upland forest and salt marsh. Our results highlight important land cover types for bats in this area (e.g., bottomland forests, ponds, and salt marsh), and that habitat use changes between seasons. Accounting for and understanding how habitat use changes throughout the year will inform managers about how critical habitat features may vary in their importance to bats throughout the year. © 2021 The Wildlife Society.