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.     

Impact of landscape fragmentation on a specialised woodland bat,Rhinolophus hipposideros

For habitat specialists, fragmentation has major consequences as it means less suitable habitat for the species to live in. In a fragmented landscape, we would expect larger, but spatially more clustered, foraging ranges. We studied the impact of landscape fragmentation on the foraging range and habitat exploitation of a specialised forest bat by radiotracking 16 female lesser horseshoe bats Rhinolophus hipposideros in a landscape with connected woodland structures and in a highly fragmented landscape in Carinthia, Austria.Contrary to our expectations, spatial foraging behaviour was not influenced by fragmentation. No differences in the behaviour of the bats between the sites were evident for the foraging ranges (minimum convex polygon, MCP), the core foraging areas (50% kernel), nor the mean or the maximum distances from the roost. However, in the highly fragmented landscape, the foraging activity of individuals was spatially more clustered and the overall MCP of all bats of a colony was greater compared to the less fragmented landscape.Woodland was the most important foraging habitat for the lesser horseshoe bats at both study sites. Habitat selection at the individual MCPs was evident only at the site with low fragmentation. However, in the core foraging areas, woodland was significantly selected over all other habitat types at both study sites.We conclude that (1) conservation measures for colonies of lesser horseshoe bats should be undertaken within 2.5 km of the nursery roost, (2) woodland is the key foraging habitat particularly in the vicinity of the roost, and (3) any loss of woodland near the colonial roosts are likely to negatively influence the colony, since these bats do not seem to be able to adapt their spatial foraging behaviour in a degraded landscape. The inflexible spatial behaviour of this specialised bat highlights the need to compensate for any habitat loss within the foraging range of a bat colony.     

Use of predictive distribution models to describe habitat selection by bats in Colorado,USA

Numerous processes operating at landscape scales threaten bats (e.g., habitat loss, disease). Temperate bat species are rarely examined at commensurate scales because of logistical and modeling constraints. Recent modeling approaches now allow for presence-only datasets, like those often available for bats, to assist with the development of predictive distribution models. We describe the use of presence-only data and rigorous predictive distribution models to examine habitat selection by bats across Colorado, USA. We applied hierarchical Bayesian models to bat locations from 1906–2018 to examine relationships of 13 species with landscape covariates. We considered differences in type of activity (foraging, roosting, hibernation), seasonality (summer vs. winter), and scale (1, 5, 10, and 15-km buffers). These findings generated statewide probability of use models to guide management of bat species in response to threats (e.g., white-nose syndrome [WNS]). Analysis of buffers suggest selection of land cover and environmental covariates occurs at different scales depending on the species and activity. Pinyon (Pinus spp.)-juniper (Juniperus spp.) appeared as a positive association in the highest number of models, followed by montane woodland, supporting the importance of these forest types to bats in Colorado. Other covariates commonly associated with bats in Colorado include westerly longitudes, and negative associations with montane shrubland. Mechanical treatments within pinyon-juniper and montane woodlands should be conducted with caution to avoid harming bat communities. We developed hibernation models for only 2 species, making apparent the lack of winter records for bat species in the state. We also provide a composite predictive surface of small-bodied bats in Colorado that delineates where these species, vulnerable to WNS, converge. This tool provides managers with focal points to apply surveillance and response strategies for the impending arrival of the disease.     

Turning to the dark side: LED light at night alters the activity and species composition of a foraging bat assemblage in the northeastern United States

Artificial light at night (ALAN) is a rapidly intensifying form of environmental degradation that can impact wildlife by altering light‐mediated physiological processes that control a broad range of behaviors. Although nocturnal animals are most vulnerable, ALAN''s effects on North American bats have been surprisingly understudied. Most of what is known is based on decades‐old observations of bats around street lights with traditional lighting technologies that have been increasingly replaced by energy‐efficient broad‐spectrum lighting, rendering our understanding of the contemporary effects of ALAN on North American bats even less complete. We experimentally tested the effects of broad‐spectrum ALAN on presence/absence, foraging activity, and species composition in a Connecticut, USA bat community by illuminating foraging habitat with light‐emitting diode (LED) floodlights and comparing acoustic recordings between light and dark conditions. Lighting dramatically decreased presence and activity of little brown bats (Myotis lucifugus), which we detected on only 14% of light nights compared with 65% of dark (lights off) and 69% of control (lights removed) nights. Big brown bat (Eptesicus fuscus) activity on light nights averaged only half that of dark and control nights. Lighting did not affect presence/absence of silver‐haired bats (Lasionycteris noctivagans), but decreased their activity. There were no effects on eastern red bats (Lasiurus borealis) or hoary bats (L. cinereus), which have been described previously as light‐tolerant. Aversion to lighting by some species but not others caused a significant shift in community composition, thereby potentially altering competitive balances from natural conditions. Our results demonstrate that only a small degree of ALAN can represent a significant form of habitat degradation for some North American bats, including the endangered little brown bat. Research on the extent to which different lighting technologies, colors, and intensities affect these species is urgently needed and should be a priority in conservation planning for North America''s bats.     

Long‐term changes in occurrence,relative abundance,and reproductive fitness of bat species in relation to arrival of White‐nose Syndrome in West Virginia,USA

White‐nose syndrome (WNS) is a disease caused by the fungus Pseudogymnoascus destructans which has resulted in the deaths of millions of bats across eastern North America. To date, hibernacula counts have been the predominant means of tracking the spread and impact of this disease on bat populations. However, an understanding of the impacts of WNS on demographic parameters outside the winter season is critical to conservation and recovery of bat populations impacted by this disease. We used long‐term monitoring data to examine WNS‐related impacts to summer populations in West Virginia, where WNS has been documented since 2009. Using capture data from 290 mist‐net sites surveyed from 2003 to 2019 on the Monongahela National Forest, we estimated temporal patterns in presence and relative abundance for each bat species. For species that exhibited a population‐level response to WNS, we investigated post‐WNS changes in adult female reproductive state and body mass. Myotis lucifugus (little brown bat), M. septentrionalis (northern long‐eared bat), and Perimyotis subflavus (tri‐colored bat) all showed significant decreases in presence and relative abundance during and following the introduction of WNS, while Eptesicus fuscus (big brown bat) and Lasiurus borealis (eastern red bat) responded positively during the WNS invasion. Probability of being reproductively active was not significantly different for any species, though a shift to earlier reproduction was estimated for E. fuscus and M. septentrionalis. For some species, body mass appeared to be influenced by the WNS invasion, but the response differed by species and reproductive state. Results suggest that continued long‐term monitoring studies, additional research into impacts of this disease on the fitness of WNS survivors, and a focus on providing optimal nonwintering habitat may be valuable strategies for assessing and promoting recovery of WNS‐affected bat populations.     

Use of native woodlands and traditional olive groves by foraging bats on a Mediterranean island: consequences for conservation

We recorded bat activity on Zakynthos island (Greece) to test the hypotheses that (1) olive ( Olea europea ) groves and native woodlands provide comparable foraging habitat for insectivorous bats, (2) lower foraging activity occurs in olive groves treated with insecticide chemicals. We acoustically sampled bat activity (passes per minute) in four wooded habitats (organic and non-organic olive groves, oak woodland ( Quercus ilex and Quercus coccifera ) and pine ( Pinus halepensis ) woodland from June to August 2005. Habitat type did not affect overall bat activity. A single application of insecticide chemicals annually did not affect activity over traditional olive groves. Habitat use on the island differed in several ways from that reported in studies at mainland sites. Most strikingly, pine woodland supported higher bat activity than expected relative to other habitat types, and we recorded unexpectedly high levels of M. capaccinii activity in woodland habitats. We suggest that traditional olive groves buffer some bat species from the effects of deforestation. Conservation plans for Mediterranean bats should consider the biodiversity value of these groves along with the need to conserve small woodland patches. Finally, understanding island-specific patterns of habitat use is essential to bat conservation on small off-shore islands.     

Differential Responses to Woodland Character and Landscape Context by Cryptic Bats in Urban Environments

Urbanisation is one of the most dramatic forms of land use change which relatively few species can adapt to. Determining how and why species respond differently to urban habitats is important in predicting future biodiversity loss as urban areas rapidly expand. Understanding how morphological or behavioural traits can influence species adaptability to the built environment may enable us to improve the effectiveness of conservation efforts. Although many bat species are able to exploit human resources, bat species richness generally declines with increasing urbanisation and there is considerable variation in the responses of different bat species to urbanisation. Here, we use acoustic recordings from two cryptic, and largely sympatric European bat species to assess differential responses in their use of fragmented urban woodland and the surrounding urban matrix. There was a high probability of P. pygmaeus activity relative to P. pipistrellus in woodlands with low clutter and understory cover which were surrounded by low levels of built environment. Additionally, the probability of recording P. pygmaeus relative to P. pipistrellus was considerably higher in urban woodland interior or edge habitat in contrast to urban grey or non-wooded green space. These results show differential habitat use occurring between two morphologically similar species; whilst the underlying mechanism for this partitioning is unknown it may be driven by competition avoidance over foraging resources. Their differing response to urbanisation indicates the difficulties involved when attempting to assess how adaptable a species is to urbanisation for conservation purposes.     

Patterns of island occupancy in bats: influences of area and isolation on insular incidence of volant mammals

Aim  The influence of landscape structure on the distribution patterns of bats remains poorly understood for many species. This study investigates the relationship between area and isolation of islands and the probability of occurrence of six bat species to determine whether persistence and immigration abilities vary among bat species and foraging guilds.
Location  Thirty-two islands in the Gulf of California near the Baja California peninsula in north-west Mexico.
Methods  Using logistic regression and Akaike information criterion (AIC) model selection, we compared five a priori models for each of six bat species to explain patterns of island occupancy, including random patterns, minimum area effects, maximum isolation effects, additive area and isolation effects and compensatory area and isolation effects.
Results  Five species of insectivorous bats ( Pipistrellus hesperus , Myotis californicus , Macrotus californicus , Antrozous pallidus and Mormoops megalophylla ) displayed minimum area thresholds on incidence. The probability of occurrence tended to decrease at moderate distances of isolation ( c . 10–15 km) for these species (excepting A. pallidus ). The distributions of two non-insectivorous species ( Leptonycteris curasoae and Myotis vivesi ) were not influenced by island size and isolation.
Main conclusions  Minimum area thresholds on incidence suggest that island occupancy by insectivorous bats may be limited by resource requirements. Islands smaller than 100 ha typically did not support occupancy or use by insectivorous bats, except at minimal isolation distances. Insectivorous bat species may also be more sensitive to moderate levels of habitat isolation in some landscape contexts than previously expected. Our results suggest that differences in foraging habits may have important implications for understanding the distribution patterns of bats.     

Natterer's bats prefer foraging in broad-leaved woodlands and river corridors

We studied habitat selection by radio tracking Natterer's bats Myotis nattereri foraging in a grassland–woodland landscape. We tested the hypothesis that selection of foraging habitat is random at two levels: firstly, the selection of individual foraging ranges and secondly, the choice of foraging habitats made by individuals within these foraging ranges. Habitat selection was random at neither level. When selecting foraging ranges, bats maximized the area of semi-natural broad-leaved woodland and improved grassland and minimized that of dense coniferous plantations. During foraging, semi-natural broad-leaved woodland and river corridors were preferred, while dense coniferous plantations were avoided. Within individual foraging ranges, the intensity of foraging activity over river corridor habitat and semi-natural broad-leaved woodland was 8.2 and 3.8 times higher, respectively, than that over improved grassland. For successful management of Natterer's bat populations, semi-natural broad-leaved woodland should be retained. Clear felling of large blocks of native broad-leaved woodland should be avoided and conifers should not be used for reforestation. Tree cover along river banks should be encouraged and protected.     

The spatial ecology of the whiskered bat (Myotis mystacinus) at the western extreme of its range provides evidence of regional adaptation

Although widespread, the ecology of the whiskered bat, Myotis mystacinus in Europe remains poorly understood. Ireland is positioned at the most western extreme of this species’ range. To ascertain the ecology of M. mystacinus at its geographic range extreme, the roosting behaviour, home range and habitat use of females in a maternity roost in Ireland was investigated by radio-tracking. M. mystacinus were active in a diversity of habitats: namely, mixed woodland, riparian vegetation, arable land and rough grassland. However, only mixed woodland and riparian habitats were selected as core foraging areas. This is in contrast to a previous study from Britain where only pasture was utilised but is in agreement with data from Slovakia, where woodland was also selected, whilst riparian areas were also utilised by this species in Germany. A high degree of overlap in the foraging areas of individuals was observed. A total of seven roosts were utilised by tracked bats and roost switching behaviour was observed. We discuss our contrasting results in respect to range limitations, regional variability in landscape structure and the composition of bat communities. The present results have implications for the conservation of M. mystacinus within Ireland and other parts of its range, highlighting the need for range wide ecological studies. Regional variability in the ecology of bats related to landscape factors is an important consideration for bat conservation and therefore must be incorporated into future management plans.     

Ecology and conservation of insectivorous bats in fragmented areas of macadamia production in eastern Australia

Microbats perform important ecological services in agro‐ecosystems, but several species are globally threatened by loss of roosting and breeding habitats. The successful conservation of bats in agricultural land requires adequate knowledge of their ecology. Using ultrasonic recorders, we studied the activity of insectivorous bats in areas of macadamia production in eastern Australia at two spatial scales: across woodland‐orchard transects at the local scale and across three levels of fragmentation at the landscape scale. At the local scale, activity patterns of ‘clutter’ and ‘edge’ specialists were consistently higher in woodland patches, gradually decreasing towards isolated orchards, where only a few ‘open’ specialists were active. At the landscape scale, bat community activity was affected by the level of fragmentation, partly because three of the most recorded taxa (Austronomus australis, Saccolaimus flaviventris and Miniopterus australis) had their highest activity in less‐fragmented areas. A distance‐based model explained 24% of the bat community activity based on a combination of six environmental variables. Canonical correspondence analysis showed that a number of bat taxa were associated with open areas of macadamia, whereas other taxa were associated with increasing values of landscape composition, and arthropod and water availability. In addition, total bat activity was highly correlated with foraging rate. These results suggest that most bat taxa were influenced by proximity to woodland and the degree of fragmentation, and only few taxa were able to exploit isolated orchards. Environmental factors that promote bat activity could be exploited to strengthen conservation efforts. Preserving remnant woodland and promoting habitat heterogeneity will benefit several bat species. In particular, the foraging activity of ‘edge’ specialists could be fostered by increasing landscape connectivity and maintaining unobstructed water bodies near macadamia orchards. Considering that bats forage as they navigate these areas, conservation efforts could also bring benefits to farmers through pest‐reduction services.     

Disease‐related population declines in bats demonstrate non‐exchangeability in generalist predators

The extent to which persisting species may fill the functional role of extirpated or declining species has profound implications for the structure of biological communities and ecosystem functioning. In North America, arthropodivorous bats are threatened on a continent‐wide scale by the spread of white‐nose syndrome (WNS), a disease caused by the fungus Pseudogymnoascus destructans. We tested whether bat species that display lower mortality from this disease can partially fill the functional role of other bat species experiencing population declines. Specifically, we performed high‐throughput amplicon sequencing of guano from two generalist predators: the little brown bat (Myotis lucifugus) and big brown bat (Eptesicus fuscus). We then compared changes in prey consumption before versus after population declines related to WNS. Dietary niches contracted for both species after large and abrupt declines in little brown bats and smaller declines in big brown bats, but interspecific dietary overlap did not change. Furthermore, the incidence and taxonomic richness of agricultural pest taxa detected in diet samples decreased following bat population declines. Our results suggest that persisting generalist predators do not necessarily expand their dietary niches following population declines in other predators, providing further evidence that the functional roles of different generalist predators are ecologically distinct.     

Effectiveness of an acoustic lure for surveying bats in British woodlands

1. A field experiment was used to test the effectiveness of a synthesized bat call as an acoustic lure to attract bats into mist nets in woodlands in southeast England. The stimulus was modelled on a social call of the rare Bechstein's bat Myotis bechsteinii. 2. In the Test condition, when the synthesized call was played, 23 bats of four species were captured, including six Bechstein's bats. In the Control condition, when no calls were played, only one bat was caught. 3. The bat call synthesizer is an effective tool for increasing capture rates for bats. Used as part of a systematic survey programme, it has the potential to provide the first baseline data on the distribution of bats in British woodlands.     

Emergence activity at hibernacula differs among four bat species affected by white‐nose syndrome

Prior to the introduction of white‐nose syndrome (WNS) to North America, temperate bats were thought to remain within hibernacula throughout most of the winter. However, recent research has shown that bats in the southeastern United States emerge regularly from hibernation and are active on the landscape, regardless of their WNS status. The relationship between winter activity and susceptibility to WNS has yet to be explored but warrants attention, as it may enable managers to implement targeted management for WNS‐affected species. We investigated this relationship by implanting 1346 passive integrated transponder (PIT) tags in four species that vary in their susceptibility to WNS. Based on PIT‐tag detections, three species entered hibernation from late October to early November. Bats were active at hibernacula entrances on days when midpoint temperatures ranged from −1.94 to 22.78°C (mean midpoint temperature = 8.70 ± 0.33°C). Eastern small‐footed bats (Myotis leibii), a species with low susceptibility to WNS, were active throughout winter, with a significant decrease in activity in mid‐hibernation (December 16 to February 15). Tricolored bats (Perimyotis subflavus), a species that is highly susceptible to WNS, exhibited an increase in activity beginning in mid‐hibernation and extending through late hibernation (February 16 to March 31). Indiana bats (M. sodalis), a species determined to have a medium–high susceptibility to WNS, remained on the landscape into early hibernation (November 1 to December 15), after which we did not record any again until the latter portion of mid‐hibernation. Finally, gray bats (M. grisescens), another species with low susceptibility to WNS, maintained low but regular levels of activity throughout winter. Given these results, we determined that emergence activity from hibernacula during winter is highly variable among bat species and our data will assist wildlife managers to make informed decisions regarding the timing of implementation of species‐specific conservation actions.     

Roosting and Foraging Social Structure of the Endangered Indiana Bat (Myotis sodalis)

Social dynamics are an important but poorly understood aspect of bat ecology. Herein we use a combination of graph theoretic and spatial approaches to describe the roost and social network characteristics and foraging associations of an Indiana bat (Myotis sodalis) maternity colony in an agricultural landscape in Ohio, USA. We tracked 46 bats to 50 roosts (423 total relocations) and collected 2,306 foraging locations for 40 bats during the summers of 2009 and 2010. We found the colony roosting network was highly centralized in both years and that roost and social networks differed significantly from random networks. Roost and social network structure also differed substantially between years. Social network structure appeared to be unrelated to segregation of roosts between age classes. For bats whose individual foraging ranges were calculated, many shared foraging space with at least one other bat. Compared across all possible bat dyads, 47% and 43% of the dyads showed more than expected overlap of foraging areas in 2009 and 2010 respectively. Colony roosting area differed between years, but the roosting area centroid shifted only 332 m. In contrast, whole colony foraging area use was similar between years. Random roost removal simulations suggest that Indiana bat colonies may be robust to loss of a limited number of roosts but may respond differently from year to year. Our study emphasizes the utility of graphic theoretic and spatial approaches for examining the sociality and roosting behavior of bats. Detailed knowledge of the relationships between social and spatial aspects of bat ecology could greatly increase conservation effectiveness by allowing more structured approaches to roost and habitat retention for tree-roosting, socially-aggregating bat species.     

Foraging activity of Rhinolophus hipposideros on the Island of Herrenchiemsee, Upper Bavaria

We studied the foraging behaviour of Rhinolophus hipposideros on the island “Herrenchiemsee” in Lake Chiemsee (Upper Bavaria) during summer 2001. The island offers extensively managed woodlands, highly structured open landscapes and a broad reed belt around the shore. On average the flight activity of the 6 radio tracked females outside the roost lasted 229 min per night. The home range size varied between 6.8 and 62.7 ha (mean 25.2 ha). The size of the activity centres varied between 2.8 and 8.2 ha (mean 5.3) and all except one were located almost exclusively in woodland. Within woodlands the bats did not select for specific spatial structures (different age classes of the stands or canopy densities). Only two bats regularly foraged in additional habitats outside woodlands. One of these bats used orchards and tree rows; the other foraged over artificial ponds and gardens adjoining to its woodland foraging area. We never found the bats foraging over the lake or the reed belt. Longer linear landscape elements as tree lines were used during commuting flights but there was no indication of a continuous foraging activity along these elements. Two females left the island to forage on the mainland in August after the fledging of juveniles. To reach the mainland shore, the bats had to fly at least 1.2 km across the lake.

Assuming that most foraging flights on the island occur in woodlands, a bat density in this habitat type of 0.7 bats/ha can be calculated.     

Seeing the Forest through the Trees: Considering Roost-Site Selection at Multiple Spatial Scales

Conservation of bat species is one of the most daunting wildlife conservation challenges in North America, requiring detailed knowledge about their ecology to guide conservation efforts. Outside of the hibernating season, bats in temperate forest environments spend their diurnal time in day-roosts. In addition to simple shelter, summer roost availability is as critical as maternity sites and maintaining social group contact. To date, a major focus of bat conservation has concentrated on conserving individual roost sites, with comparatively less focus on the role that broader habitat conditions contribute towards roost-site selection. We evaluated roost-site selection by a northern population of federally-endangered Indiana bats (Myotis sodalis) at Fort Drum Military Installation in New York, USA at three different spatial scales: landscape, forest stand, and individual tree level. During 2007–2011, we radiotracked 33 Indiana bats (10 males, 23 females) and located 348 roosting events in 116 unique roost trees. At the landscape scale, bat roost-site selection was positively associated with northern mixed forest, increased slope, and greater distance from human development. At the stand scale, we observed subtle differences in roost site selection based on sex and season, but roost selection was generally positively associated with larger stands with a higher basal area, larger tree diameter, and a greater sugar maple (Acer saccharum) component. We observed no distinct trends of roosts being near high-quality foraging areas of water and forest edges. At the tree scale, roosts were typically in American elm (Ulmus americana) or sugar maple of large diameter (>30 cm) of moderate decay with loose bark. Collectively, our results highlight the importance of considering day roost needs simultaneously across multiple spatial scales. Size and decay class of individual roosts are key ecological attributes for the Indiana bat, however, larger-scale stand structural components that are products of past and current land use interacting with environmental aspects such as landform also are important factors influencing roost-tree selection patterns.     

Barriers and benefits: implications of artificial night-lighting for the distribution of common bats in Britain and Ireland

Artificial lighting is a particular problem for animals active at night. Approximately 69% of mammal species are nocturnal, and one-third of these are bats. Due to their extensive movements—both on a nightly basis to exploit ephemeral food supplies, and during migration between roosts—bats have an unusually high probability of encountering artificial light in the landscape. This paper reviews the impacts of lighting on bats and their prey, exploring the direct and indirect consequences of lighting intensity and spectral composition. In addition, new data from large-scale surveys involving more than 265 000 bat calls at more than 600 locations in two countries are presented, showing that prevalent street-lighting types are not generally linked with increased activity of common and widespread bat species. Such bats, which are important to ecosystem function, are generally considered ‘light-attracted’ and likely to benefit from the insect congregations that form at lights. Leisler''s bat (Nyctalus leisleri) may be an exception, being more frequent in lit than dark transects. For common pipistrelle bats (Pipistrellus pipistrellus), lighting is negatively associated with their distribution on a landscape scale, but there may be local increases in habitats with good tree cover. Research is now needed on the impacts of sky glow and glare for bat navigation, and to explore the implications of lighting for habitat matrix permeability.     

Bat Response to Woodland Restoration within Urban Forest Fragments

In urban environments, woodland areas are typically fragmented and subject to invasive species encroachment, woody overgrowth, and natural succession. In response to negative impacts, conservationists and land managers have implemented restoration strategies to enhance the integrity of woodlands. Because woodland habitat is important for bats (Order Chiroptera), alterations to forest structures may affect how bats utilize forest fragments in urban environments. We evaluated relationships among restoration efforts, microhabitat characteristics and overall bat activity, and interspecific variation among bats in response to woodland characteristics. We monitored bats in nine woodland forest preserves representing various stages of restoration within the Chicago metropolitan area in 2004 and 2005. Overall bat activity was positively related to prescribed burning, invasive species removal, and small tree density (7.7‐20 cm dbh) and inversely related to shrub density and clutter at 0‐6 m heights. There was interspecific variation in response to alterations in woodland structure, with Lasiurus borealis (L. borealis) positively associated with small and medium (20.1‐33 cm) tree densities and inversely related to clutter at 0‐9 m; Myotis spp. positively associated with canopy cover, clutter at 6‐9 m, and small and medium tree densities; and Lasionycteris noctivagans (L. noctivagans) positively associated with more open forests. Eptesicus fuscus (E. fuscus) activity was not strongly associated with any measured vegetation variable. Our results demonstrate bats positively respond to some forms of woodland restoration in urban landscapes. However, species‐specific responses to vegetation differed and should be taken into consideration when developing management plans.     

A mosaic of opportunities? Spatio-temporal patterns of bat diversity and activity in a strongly humanized Mediterranean wetland

The Baixo Vouga Lagunar (BVL) landscape, in the Portuguese central-west coast, harbours a mosaic of wetland habitat types, interspersed by intensive and extensive agricultural fields, pastures, production forests and urban areas. In this study, we aimed to determine the species composition and the structure of the bat assemblages of the different habitats that constitute this heterogeneous landscape and to investigate seasonal changes in the patterns of bat diversity and activity across habitats. We acoustically sampled bats across 24 sampling sites representative of the eight main habitat types that shape the landscape—Bocage, forests, maize fields, marshlands, reed beds, rice fields, sea rushes and urban settlements. We compared bat richness, diversity and evenness across habitat types and seasons. We analysed habitat-specific and season-specific overall bat activity, and because habitat selection by bats is known to reflect morphological characters, foraging strategies and echolocation call structures, we also analysed the activity of individual species and of eco-morphological guilds. From 1,544 bat-passes recorded, we identified 12 species. Pipistrellus pygmaeus, Pipistrellus pipistrellus and Eptesicus serotinus/Eptesicus isabellinus were the most frequently recorded. Species composition and activity were similar across habitats, whilst exhibiting strong seasonal dynamics within habitats. Our results suggest that the mosaicism of the landscape provides several opportunities for bats, enabling them to explore different resources in distinct habitat patches. However, it may also reflect a forced exploitation of less optimal habitats and resources by bats, due to the scarcity of opportunities provided by fragmented landscapes.