Ensemble composition and activity levels of insectivorous bats in response to management intensification in coffee agroforestry systems

Shade coffee plantations have received attention for their role in biodiversity conservation. Bats are among the most diverse mammalian taxa in these systems; however, previous studies of bats in coffee plantations have focused on the largely herbivorous leaf-nosed bats (Phyllostomidae). In contrast, we have virtually no information on how ensembles of aerial insectivorous bats--nearly half the Neotropical bat species--change in response to habitat modification. To evaluate the effects of agroecosystem management on insectivorous bats, we studied their diversity and activity in southern Chiapas, Mexico, a landscape dominated by coffee agroforestry. We used acoustic monitoring and live captures to characterize the insectivorous bat ensemble in forest fragments and coffee plantations differing in the structural and taxonomic complexity of shade trees. We captured bats of 12 non-phyllostomid species; acoustic monitoring revealed the presence of at least 12 more species of aerial insectivores. Richness of forest bats was the same across all land-use types; in contrast, species richness of open-space bats increased in low shade, intensively managed coffee plantations. Conversely, only forest bats demonstrated significant differences in ensemble structure (as measured by similarity indices) across land-use types. Both overall activity and feeding activity of forest bats declined significantly with increasing management intensity, while the overall activity, but not feeding activity, of open-space bats increased. We conclude that diverse shade coffee plantations in our study area serve as valuable foraging and commuting habitat for aerial insectivorous bats, and several species also commute through or forage in low shade coffee monocultures.     

Urban bat communities are affected by wetland size,quality, and pollution levels

Wetlands support unique biota and provide important ecosystem services. These services are highly threatened due to the rate of loss and relative rarity of wetlands in most landscapes, an issue that is exacerbated in highly modified urban environments. Despite this, critical ecological knowledge is currently lacking for many wetland‐dependent taxa, such as insectivorous bats, which can persist in urban areas if their habitats are managed appropriately. Here, we use a novel paired landscape approach to investigate the role of wetlands in urban bat conservation and examine local and landscape factors driving bat species richness and activity. We acoustically monitored bat activity at 58 urban wetlands and 35 nonwetland sites (ecologically similar sites without free‐standing water) in the greater Melbourne area, southeastern Australia. We analyzed bat species richness and activity patterns using generalized linear mixed‐effects models. We found that the presence of water in urban Melbourne was an important driver of bat species richness and activity at a landscape scale. Increasing distance to bushland and increasing levels of heavy metal pollution within the waterbody also negatively influenced bat richness and individual species activity. Areas with high levels of artificial night light had reduced bat species richness, and reduced activity for all species except those adapted to urban areas, such as the White‐striped free‐tailed bat (Austronomus australis). Increased surrounding tree cover and wetland size had a positive effect on bat species richness. Our findings indicate that wetlands form critical habitats for insectivorous bats in urban environments. Large, unlit, and unpolluted wetlands flanked by high tree cover in close proximity to bushland contribute most to the richness of the bat community. Our findings clarify the role of wetlands for insectivorous bats in urban areas and will also allow for the preservation, construction, and management of wetlands that maximize conservation outcomes for urban bats and possibly other wetland‐dependent and nocturnal fauna.     

Responses of insectivorous bats and nocturnal insects to local changes in street light technology

Artificial light at night is a pervasive anthropogenic stressor for biodiversity. Many fast‐flying insectivorous bat species feed on insects that are attracted to light‐emitting ultraviolet radiation (10–400 nm). Several countries are currently focused on replacing mercury vapour lamps, which emit ultraviolet light, with more cost‐efficient light‐emitting diode (LED) lights, which emit less ultraviolet radiation. This reduction in ultraviolet light may cause declines in insect densities in cities, predatory fast‐flying bats, and some edge‐foraging and slow‐flying bats. Capitalising on a scheme to update streetlights from high ultraviolet mercury vapour to low ultraviolet LED in Sydney, Australia, we measured the activity of individual bat species, the activity of different functional groups and the bat and insect communities, before and after the change in technology. We also surveyed sites with already LED lights, sites with mercury vapour lights and unlit bushland remnants. Species adapted to foraging in cluttered vegetation, and some edge‐space foraging species, were more active in unlit bushland sites than in all lit sites and decreased in activity at lit sites after the change to LED lights. The change to LED streetlights caused a decrease in the fast‐flying Chalinolobus gouldii but not Miniopterus schreibersii oceanensis, the latter being more influenced by seasonal and environmental variables. Insect biomass was not affected by changing light types, but instead was negatively correlated with the moon's percentage illuminance. Changing streetlights to LEDs could result in a decline in some insectivorous bats in cities. This study confirms that unlit urban bushland remnants are important refuges for high bat diversity, particularly for more clutter‐adapted species and some edge‐space foraging species. Preventing light penetration into unlit bushland patches and corridors remains essential to protect the urban bat community.     

The activity of an insectivorous bat Neoromicia nana on tracks in logged and unlogged forest in tropical Africa

Logging activities and the associated creation of roads and tracks can disturb and fragment forests, which may lead to a loss of forest‐dependent species and possibly favour nonforest generalists and edge species. The effects of such disturbance are poorly known for African insectivorous bats. We studied the activity patterns of insectivorous bats in a tropical African forest at Kibale National Park, Uganda, using an Anabat bat detector. The echolocation calls of the vespertilionid bat Neoromicia nana were the most frequently detected. This species was most active in the first 5 h after sunset with activity declining rapidly after midnight until sampling finished at 01:00 h. There was no difference in activity of N. nana levels between logged or undisturbed forest; however, this species exhibited higher levels of activity along the wide tracks running through the two forests than either 30 m off these tracks or along the narrow forest trails. The wing morphology and echolocation call of N. nana may be constraining it to flying in uncluttered space on the edge of the forest, penetrating mostly along wider tracks and roads. Further research (in particular radio‐telemetry) is required to test and validate these data.     

Bat activity and species richness in different land‐use types in and around Chome Nature Forest Reserve,Tanzania

Bats have important ecological roles in ecosystems, but many species are threatened because of anthropogenic impacts. Tanzania has limited information on how bats respond to habitat modification. This makes it difficult to anticipate which bat species are at risk. Bat activity and species richness were assessed in five land‐use types: forest and banana–coffee (upland habitats), rice paddy, riverine and sisal estate (lowland habitats). Mist nets, harp traps and bat detectors were used to sample bats. Species richness differed between habitats. Bat activity levels were higher in lowland habitats than upland habitats. Riverine and rice paddy habitats were shown to have an important role as foraging sites for many insectivorous bats as bat species richness and activity were generally higher than other habitats. Fruit‐eating bats preferred riverine and banana–coffee habitats. We recommend using organic manure as alternatives to chemical fertilisers, and pesticide use should be avoided in rice paddies. Riparian vegetation along rivers and water bodies should be maintained as important faunal nesting, roosting and/or foraging grounds. The requirement that farming practices be at least 60 m from the river should be strictly enforced. These recommendations will help in the conservation of bats and their habitats in modified agricultural landscapes.     

A landscape perspective on bat foraging ecology along rivers: does channel confinement and insect availability influence the response of bats to aquatic resources in riverine landscapes?

River and riparian areas provide an important foraging habitat for insectivorous bats owing to high insect availability along waterways. However, structural characteristics of the riverine landscape may also influence the location of foraging bats. We used bat detectors to compare bat activity longitudinally along river reaches with contrasting channel confinement, ratio of valley floor width to active channel width, and riparian vegetation, and laterally with distance from the river along three different reach types. We measured rates of insect emergence from the river and aerial insect availability above the river and laterally up to 50-m into the riparian habitat in order to assess the relationship between food resources and insectivorous bat activity. Longitudinally, bat activity was concentrated along confined reaches in comparison to unconfined reaches but was not related to insect availability. Laterally, bats tracked exponential declines in aquatic insects with distance from the river. These data suggest that along the lateral dimension bats track food resources, but that along the longitudinal dimension channel shape and landscape structure determine bat distributions more than food resources.     

Secondary forest buffers the effects of fragmentation on aerial insectivorous bat species following 30 years of passive forest restoration

Passive forest restoration can buffer the effects of habitat loss on biodiversity. We acoustically surveyed aerial insectivorous bats in a whole-ecosystem fragmentation experiment in the Brazilian Amazon over a 2-year period, across 33 sites, comprising continuous old-growth forest, remnant fragments, and regenerating secondary forest matrix. We analyzed the activity of 10 species/sonotypes to investigate occupancy across habitat types and responses to fragment size and interior-edge-matrix (IEM) disturbance gradients. Employing a multiscale approach, we investigated guild (edge foragers, forest specialists, flexible forest foragers, and open space specialists) and species-level responses to vegetation structure and forest cover, edge, and patch density across six spatial scales (0.5–3 km). We found species-specific habitat occupancy patterns and nuanced responses to fragment size and the IEM disturbance gradient. For example, Furipterus horrens had lower activity in secondary forest sites and the interior and edge of the smallest fragments (1 and 10 ha) compared to continuous forest, and only two species (Pteronotus spp.) showed no habitat preference and no significant responses across the IEM and fragment size gradients. Only the Molossus sonotype responded negatively to vegetation structure. We uncovered no negative influence of forest cover or edge density at guild or species-level. Our results indicate that reforestation can buffer the negative effects of fragmentation and although these effects can still be detected in some species, generally aerial insectivorous bats appear to be in recovery after 30 years of passive forest restoration. Our findings reinforce the need to protect regenerating forests while conserving vast expanses of old-growth forest.     

Ecological processes in urban landscapes: mechanisms influencing the distribution and activity of insectivorous bats

Urbanisation affects indigenous fauna in many ways; some species persist and even increase in urban areas, whereas others are lost. The causative mechanisms determining changes in distributions and community structure remain elusive. We investigated three hypothesized mechanisms, which influence success or failure of the insectivorous bat assemblage across the urban landscape of Sydney, Australia; landscape heterogeneity (diversity of land uses), productivity (as indexed by landscape geology) and trait diversity. We present data on species richness and activity (bat passes per night) collected systematically using ultrasonic bat detectors from randomly selected landscapes (each 25 km²). Landscapes were categorized into classes including ‘urban’, ‘suburban’ and ‘vegetated’, where suburban sites were additionally stratified based on geology, as a proxy for productivity. Four landscape elements were sampled within each landscape, including remnant bushland (>2 ha), riparian areas, open space/parkland and residential/built space. We found that there was significantly greater bat activity and more species of bat in areas on fertile shale geologies (p<0.05), supporting the productivity, rather than the heterogeneity hypothesis. Within landscapes, there was no significant effect of the landscape element sampled, although bushland and riparian sites recorded greater bat activity than open space or backyard sites. Using general linear mixed models we found bat activity and species richness were sensitive to landscape geology and increasing housing density at a landscape scale. Using an RLQ analysis a significant relationship was found between these variables and species traits in structuring the community present (p<0.01). Specifically, open‐adapted bats were associated with areas of greater housing density, while clutter‐adapted bats were uncommon in urban areas and more associated with greater amounts of bushland in the landscape. Overall we found greater support for the productivity and traits hypotheses, rather than the heterogeneity hypothesis. The degree of urbanisation and amount of bushland remaining, in combination with landscape geology, influenced bat activity and mediated the trait response. Our findings reflect global trends of species diversity and abundance in urban landscapes, suggesting that processes affecting bat species distribution in urban ecosystems may be predictable at a landscape scale.     

Use of Fruit Essential Oils to Assist Forest Regeneration by Bats

Frugivorous bats can be attracted with essential oils from ripe chiropterochoric fruit. We evaluated the efficiency of these oils to attract bats in degraded areas within the Atlantic Rain Forest, particularly pasture and agricultural land. We hypothesized that induction units (IUs), each containing a rubber septum impregnated with oil, would have more bat activity than their respective control units (CUs; without the oil). To test this hypothesis we monitored bat flight activity with night‐vision infrared visors in eight IU and CU from August 2006 to July 2007. We also verified the probability of arrival of chiropterochoric seeds by analyzing the diet of bats captured in a neighboring forest area. Our initial hypothesis that units with odor would lead to greater bat activity was confirmed. Results indicated a rich community of fruit‐eating bats, and dietary analysis revealed a huge potential for dispersion of a vast amount of seeds from different plant species at the IU. Although our study does not reveal with certainty which bat species are attracted to the oil, the flying patterns coincide with those described for the foraging behavior of fruit‐eating phyllostomids. Furthermore, the fact that the bats spend more time flying around the odor source compared to flying time around CU suggest an increase in seed rain. Taken together, these results suggest that the use of essential oils from chiropterochoric fruits induces a qualitative and quantitative increase in seed dispersal in areas that otherwise would not be frequently visited by frugivorous bats.     

EFFECT OF HABITAT AND FORAGING HEIGHT ON BAT ACTIVITY IN THE COASTAL PLAIN OF SOUTH CAROLINA

Abstract: We compared bat activity levels in the Coastal Plain of South Carolina among 5 habitat types: forested riparian areas, clearcuts, young pine plantations, mature pine plantations, and pine savannas. We used time-expansion radio-microphones and integrated detectors to simultaneously monitor bat activity at 3 heights (30, 10, 2 m) in each habitat type. Variation in vegetative clutter among sampling heights and among habitat types allowed us to examine the differential effect of forest vegetation on the spatial activity patterns of clutter-adapted and open-adapted bat species. Moreover, monitoring activity at 30, 10, and 2 m permitted us to also compare bat activity above and below the forest canopy. We detected calls of 5 species or species groups: eastern red/Seminole bats (Lasiurus borealis/L. seminolus), eastern pipistrelles (Pipistrellus subflavus), evening bats (Nycticeius humeralis), big brown bats (Eptesicus fuscus), and hoary bats (Lasiurus cinerius). At 2 and 10 m, bat activity was concentrated in riparian areas, whereas we detected relatively low levels of bat activity in upland habitats at those heights. Activity was more evenly distributed across the landscape at 30 m. Bat activity levels above the forest canopy were almost 3 times greater than within or below the canopy. We detected significantly greater activity levels of 2 open-adapted species (hoary and big brown bats) above rather than within or below the forest canopy. However, activity levels of 2 clutter-adapted species (eastern red/Seminole bats and eastern pipistrelles) did not differ above, within, or below the forest canopy. Despite classification as a clutter-adapted species, evening bat activity was greater above rather than within or below the forest canopy. We believe our results highlight the importance of riparian areas as foraging habitat for bats in pine-dominated landscapes in the southeastern United States. Although acoustical surveys conducted below forest canopies can provide useful information about species composition and relative activity levels of bats that forage in cluttered environments, our results showing activity above canopy suggest that such data may not accurately reflect relative activity of bats adapted to forage in more open conditions, and therefore may provide an inaccurate picture of bat community assemblage and foraging habitat use.     

Seasonal bat activity related to insect emergence at three temperate lakes

Knowledge of aquatic food resources entering terrestrial systems is important for food web studies and conservation planning. Bats, among other terrestrial consumers, often profit from aquatic insect emergence and their activity might be closely related to such events. However, there is a lack of studies which monitor bat activity simultaneously with aquatic insect emergence, especially from lakes. Thus, our aim was to understand the relationship between insect emergence and bat activity, and investigate whether there is a general spatial or seasonal pattern at lakeshores. We assessed whole‐night bat activity using acoustic monitoring and caught emerging and aerial flying insects at three different lakes through three seasons. We predicted that insect availability and seasonality explain the variation in bat activity, independent of the lake size and characteristics. Spatial (between lakes) differences of bat activity were stronger than temporal (seasonal) differences. Bat activity did not always correlate to insect emergence, probably because other factors, such as habitat characteristics, or bats’ energy requirements, play an important role as well. Aerial flying insects explained bat activity better than the emerged aquatic insects in the lake with lowest insect emergence. Bats were active throughout the night with some activity peaks, and the pattern of their activity also differed among lakes and seasons. Lakes are important habitats for bats, as they support diverse bat communities and activity throughout the night and the year when bats are active. Our study highlights that there are spatial and temporal differences in bat activity and its hourly nocturnal pattern, that should be considered when investigating aquatic–terrestrial interactions or designing conservation and monitoring plans.     

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.     

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.     

Influence of landscape structure and human modifications on insect biomass and bat foraging activity in an urban landscape

Urban landscapes are often located in biologically diverse, productive regions. As such, urbanization may have dramatic consequences for this diversity, largely due to changes in the structure and function of urban communities. We examined the influence of landscape productivity (indexed by geology), housing density and vegetation clearing on the spatial distribution of nocturnal insect biomass and the foraging activity of insectivorous bats in the urban landscape of Sydney, Australia. Nocturnal insect biomass (g) and bat foraging activity were sampled from 113 sites representing backyard, open space, bushland and riparian landscape elements, across urban, suburban and vegetated landscapes within 60 km of Sydney's Central Business District. We found that insect biomass was at least an order of magnitude greater within suburban landscapes in bushland and backyard elements located on the most fertile shale influenced geologies (both p<0.001) compared to nutrient poor sandstone landscapes. Similarly, the feeding activity of bats was greatest in bushland, and riparian elements within suburbs on fertile geologies (p?=?0.039). Regression tree analysis indicated that the same three variables explained the major proportion of the variation in insect biomass and bat foraging activity. These were ambient temperature (positive), housing density (negative) and the percent of fertile shale geologies (positive) in the landscape; however variation in insect biomass did not directly explain bat foraging activity. We suggest that prey may be unavailable to bats in highly urbanized areas if these areas are avoided by many species, suggesting that reduced feeding activity may reflect under-use of urban habitats by bats. Restoration activities to improve ecological function and maintain the activity of a diversity of bat species should focus on maintaining and restoring bushland and riparian habitat, particularly in areas with fertile geology as these were key bat foraging habitats.     

Does interspecific competition drive patterns of habitat use in desert bat communities?

Bodies of water are a key foraging habitat for insectivorous bats. Since water is a scarce and limiting resource in arid environments, bodies of open water may have a structuring effect on desert bat communities, resulting in temporal or spatial partitioning of bat activity. Using acoustic monitoring, we studied the spatial and temporal activity patterns of insectivorous bats over desert ponds, and hypothesised that sympatric bat species partition the foraging space above ponds based on interspecific competitive interactions. We used indirect measures of competition (niche overlap and competition coefficients from the regression method) and tested for differences in pond habitat selection and peak activity time over ponds. We examined the effect of changes in the activity of bat species on their potential competitors. We found that interspecific competition affects bat community structure and activity patterns. Competing species partitioned their use of ponds spatially, whereby each species was associated with different pond size and hydroperiod (the number of months a pond holds water) categories, as well as temporally, whereby their activity peaked at different hours of the night. The drying out of temporary ponds increased temporal partitioning over permanent ponds. Differences in the activity of species over ponds in response to the presence or absence of their competitors lend further support to the role of interspecific competition in structuring desert bat communities. We suggest that habitat use and night activity pattern of insectivorous bats in arid environments reflect the trade-offs between selection of preferred pond type or activity time and constraints posed by competitive interactions.     

Aerial insectivorous bat activity in relation to moonlight intensity

It is commonly assumed that aerial insectivorous bats in the tropics respond to moonlight intensity by decreasing their foraging activity during bright nights due either to an increase in predation risk, or to a reduction in insect availability.The effect of moonlight on bat activity can be measured both between nights and within a single night. However, few studies have simultaneously used both approaches, and most authors generally compare bat activity with lunar phases. Our main aim was to evaluate how moonlight influences aerial insectivorous bat activity at different time scales: between nights and within the same night. Activity of five bat species was measured using autonomous ultrasound recording stations and moonlight intensity percentages retrieved from the Moontool program nightly throughout a 53-day sampling period. Only one species (Myotis riparius) responded negatively to moonlight, while two species (Pteronotus parnellii and Saccopteryx leptura) increased their foraging activity in moonlight. For Cormura brevirostris and S. bilineata, moonlight intensity did not affect activity level. Bat activity was greater for all species at the beginning of the night, independent of the presence of the moon, indicating that foraging just after the sunset is adaptive. Thus, bat response to the effect of moonlight intensity is more apparent between nights than within a single night and may depend on species-specific traits, such as flight speed, flexibility in habitat use and body size.     

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.     

Bats are Not Birds – Different Responses to Human Land‐use on a Tropical Mountain

Land‐use intensification has consequences for biodiversity and ecosystem functioning, with various taxonomic groups differing widely in their sensitivity. As land‐use intensification alters habitat structure and resource availability, both factors may contribute to explaining differences in animal species diversity. Within the local animal assemblages the flying vertebrates, bats and birds, provide important and partly complementary ecosystem functions. We tested how bats and birds respond to land‐use intensification and compared abundance, species richness, and community composition across a land‐use gradient including forest, traditional agroforests (home garden), coffee plantations and grasslands on Mount Kilimanjaro, Tanzania. Furthermore, we asked how sensitive different habitat and feeding guilds of bats and birds react to land‐use intensification and the associated alterations in vegetation structure and food resource availability. In contrast to our expectations, land‐use intensification had no negative effect on species richness and abundance of all birds and bats. However, some habitat and feeding guilds, in particular forest specialist and frugivorous birds, were highly sensitive to land‐use intensification. Although the habitat guilds of both, birds and bats, depended on a certain degree of vegetation structure, total bat and bird abundance was mediated primarily by the availability of the respective food resources. Even though the highly structured southern slopes of Mount Kilimanjaro are able to maintain diverse bat and bird assemblages, the sensitivity of avian forest specialists against land‐use intensification and the dependence of the bat and bird habitat guilds on a certain vegetation structure demonstrate that conservation plans should place special emphasis on these guilds.     

Dietary overlap between the invasive coquí frog (<Emphasis Type="Italic">Eleutherodactylus coqui</Emphasis>) and the Hawaiian hoary bat (<Emphasis Type="Italic">Lasiurus cinereus semotus</Emphasis>) on the Island of Hawai’i

The invasive coquí frog is a likely insectivorous competitor to the native Hawaiian hoary bat. The frog is a sit-and-wait predator native to Puerto Rico, but it has the capacity for producing dense populations in its invasive range and the potential to reduce arthropod populations, including aerial arthropods in the orders Coleoptera, Lepidoptera and Isoptera, which are primary food sources of the Hawaiian hoary bat. Dietary analysis of the coquí frog showed that aerial insects made up 33.8 % of the diet. The dietary similarity of the bat and frog was relatively low (Pianka index = 0.25), however, coquí frogs consumed a wide range of juvenile flying insects. Population densities of coquí frogs at two low elevation sites were projected to range from 750 to 14,000 individuals/hectare, and could consume an estimated 1500–19,000 aerial insects/hectare/night, or nearly 90.6 % of all available aerial insects/hectare. Although direct competition between coquí frogs and Hawaiian hoary bats was not confirmed, the coquí frogs could reduce available prey for bats in newly invaded upland sites where bats appear to be more selective of prey species among available aerial insects.