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1.
Karst cave systems are well developed in Wales (UK) and, in some instances, constitute important bat roosts. Ogof Draenen, near Blaenavon in south-east Wales, is the most recent major cave discovery (1994) with already > 70 km of passages explored spanning a vertical range of 148 m.With the exception of one small chamber (Siambre Ddu) located directly above the main Ogof Draenen system, very few bats have been noticed inside. Extensive accumulations of guano, attributable to Rhinolophus hipposideros, are however found in parts of the Ogof Draenen system. In places covering many square metres and sometimes building heaps > 0.5 m thick, these represent volumes not yet found in any other cave system in the British Isles.Although the date of the abandonment of the main Ogof Draenen system as a bat roost remains unknown, six radiocarbon dates on guano from Ogof Draenen place the occupation in the Iron Age to Medieval period at least. Palynological analysis was undertaken on ten samples distributed through the cave. Comparisons were made with a moss polster and a lake mud sample from the area to provide a first approximation of the regional modern pollen rain and with two modern guano samples, one from Siambre Ddu and one from Agen Allwedd cave (5 km to the north-west) to provide a temporal comparison with the fossil guano. Agen Allwedd cave currently is one of the largest active roosts for Lesser Horseshoe bats in Britain and lies close to the present northern limit of this endangered species in Europe.The main results are that (1) the cave appears to have been used both as a summer and a winter roost; (2) most of the Ogof Draenen guano is formed within c. 1600 14C years and, if the largest heap is continuous, it has accumulated within 750 14C years, i. e. 0.16 mm yr− 1; 3) the fossil guano samples reflect a relatively closed oak forest with more abundant ivy (Hedera) and holly (Ilex) than at present; (4) insect-pollinated plants such as Ilex, Acer, Hedera and Impatiens glandulifera are over-represented in the guano samples; (5) in addition to the usual causes of bat roost decline (pesticides, pollution), in the case of Ogof Draenen, we may add entrance blocked by rock collapse and decline of the local forest cover as well as change in its composition.  相似文献   

2.
Carbon and nitrogen stable isotopes were used to track major dietary variations in arthropods found in a cave located in a neotropical savanna in Central Brazil. We determined the δ13C and δ15N for cave crickets, cockroaches, spiders, guano of a hematophagous bat, and leaf litter found on the ground near the cave entrance. The δ13C and δ15N for the cricket and cockroaches showed that bat guano was not the only food item for these arthropods. They had intermediate δ13C and δ15N between bat guano and leaf litter, which means that they consumed additional food resources other than guano in their diet, independent of distribution of guano deposits in the cave. The spiders, predators with great mobility, seemed to not have a preferential diet item since their isotope signals indicated they hunt both crickets and cockroaches. The δ13C of the bat guano (?15.4‰) indicated that the diet of these hematophagous bats relied on animals fed with C4 plants. The conversion of native savanna vegetation of which the debris is mostly from C3 plants, to pasture, based on C4 African grass, a remarkably common land use transformation in the region, is indirectly influencing the diet of hematophagous bats, which basically relied on exotic fauna. The C and N stable isotope ratios showed that the arthropods inside the cave do not rely solely on bat guano for their diet, but interact directly with the external environment, through litter debris, indicating a significant exchange of energy and matter between the cave environment and the surrounding area.  相似文献   

3.
Pollen was analysed from bat guano from nine caves in southeastern Spain and surface soils in their immediate surroundings. We compare the pollen spectra of 34 modern dung samples from the nine caves with one modern surface pollen sample from each cave. The contents suggest reasonable pollen diversity and richness, including anemophilous and zoophilous pollen types. Since the latter is usually under-represented in atmospheric pollen, the guano spectra therefore appear to reflect the vegetation more effectively than normal surface soil samples. Despite health hazards such as histoplasmosis, the difficulties of obtaining bat guano in deep caves and possible interpretational concerns relating to behaviour and feeding habits of different bat species, this material can be very useful in palaeoecological research provided that the dung was fossilized under favourable environmental conditions that allowed the preservation of pollen.  相似文献   

4.
Large numbers of bats are killed by collisions with wind turbines and there is at present no accepted method of reducing or preventing this mortality. Following our demonstration that bat activity is reduced in the vicinity of large air traffic control and weather radars, we tested the hypothesis that an electromagnetic signal from a small portable radar can act as a deterrent to foraging bats. From June to September 2007 bat activity was compared at 20 foraging sites in northeast Scotland during experimental trials (radar switched on) and control trials (no radar signal). Starting 45 minutes after sunset, bat activity was recorded for a period of 30 minutes during each trial and the order of trials were alternated between nights. From July to September 2008 aerial insects at 16 of these sites were sampled using two miniature light-suction traps. At each site one of the traps was exposed to a radar signal and the other functioned as a control. Bat activity and foraging effort per unit time were significantly reduced during experimental trials when the radar antenna was fixed to produce a unidirectional signal therefore maximising exposure of foraging bats to the radar beam. However, although bat activity was significantly reduced during such trials, the radar had no significant effect on the abundance of insects captured by the traps.  相似文献   

5.

New Zealand's short‐tailed bat (Mystacina tuberculata Gray, 1843) feeds on fruit, insects, and possibly nectar in North Island kauri (Agathis australis) forest. Fruits eaten by members of a colony of 500 bats in May included those of Freycinetia baueriana (Pandanaceae), Collospermum hastatum, and C. microspermum (Liliaceae). Pollen analyses of bat guano, and of the stomach contents of 4 short‐tailed bats from Omahuta Forest (Lat. 35°10'S) and 3 from Stewart Island and adjacent islands (Lat. 47°15'S), showed that most of the pollen was from flowers of Metrosideros and Leptospermum (Myrtaceae), Knightia excelsa (Proteaceae), and Collospermum, and that spores of the tree fern Cyathea (Cyatheaceae) were present also. Both Metrosideros and Knightia have abundant nectar. The partially extensile tongue of Mystacina is tipped with a brush of fine papillae, possibly to extract nectar and pollen; but the pollen and spores in the bat stomachs and guano could have come from insects eaten by the bats. Transverse ridges on the tongue may assist removal of juice from ripe fruits. These bats may disperse the small seeds of Freycinetia baueriana. The anatomical modifications of Mystacina for terrestrial and arboreal locomotion may have evolved primarily in response to its frugivorous and suspected nectarivorous habits.  相似文献   

6.
《新西兰生态学杂志》2011,30(2):267-272
We analysed pollen in short-tailed bat guano samples from Rangataua Forest and from guano and pollen found in bat holding bags used in the Kaimanawa Range, central North Island. Fifty seven percent of the pollen from Rangataua was from a previously unrecorded source and was tentatively identified as Trachycarpus fortunei (Chinese windmill palm). The significant remaining pollen was identified as Collospermum (15%) and Nothofagus (14%) from Rangataua, and Collospermum (90%) and Nothofagus (6%) from Kaimanawa. While the presence of Collospermum from both sites is consistent with previous work, pollen from T. fortunei, an exotic palm growing near Rangataua Forest, has not previously been found in association with short-tailed bats. Despite nocturnal surveillance with automated bat detectors and infra-red video cameras, we failed to confirm bat visitation to these palms. Nothofagus is wind-pollinated and pollen extracted from samples taken from both sites is probably wind-borne contamination. A collation of data from all available studies on the pollen found associated with short-tailed bats throughout New Zealand reveals that flowers from just four plant groups appear to be regularly used by bats: Collospermum spp., Knightia excelsa, Metrosideros spp. and, apparently, T. fortunei.  相似文献   

7.
ABSTRACT

The presence of bat species is commonly determined by placing acoustic bat detectors that record bat echolocation calls in the habitat they are likely to use. Detection rates are affected by variables including type of detection unit used. We compared detection rates of long-tailed bat (Chalinolobus tuberculatus) echolocation calls between two types of automated bat detectors: Wildlife Acoustics SMZC Zero Crossing Bat Recorders (ZC), and Frequency Compression Automated Bat Monitoring units (FC) produced by New Zealand’s Department of Conservation. Units were placed in locations where bats were known to be present, but not all detected bats. The median number of bat passes recorded by FC units over 10 nights was 20 compared with a median of 3 bat passes for ZC units. ZC units also detected bats over significantly fewer nights than FC units. These results suggest FC units are more sensitive and therefore better to use where long-tailed bats are expected to be at low abundance or only present infrequently. Because of inconsistencies in detection rates, we recommend the use of only one model of the detector within a monitoring project. Our data also suggests that surveys should take place over long periods to maximise likelihood of detecting bats, if present.  相似文献   

8.
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.  相似文献   

9.

Background

Most tropical and subtropical plants are biotically pollinated, and insects are the major pollinators. A small but ecologically and economically important group of plants classified in 28 orders, 67 families and about 528 species of angiosperms are pollinated by nectar-feeding bats. From a phylogenetic perspective this is a derived pollination mode involving a relatively large and energetically expensive pollinator. Here its ecological and evolutionary consequences are explored.

Scope and Conclusions

This review summarizes adaptations in bats and plants that facilitate this interaction and discusses the evolution of bat pollination from a plant phylogenetic perspective. Two families of bats contain specialized flower visitors, one in the Old World and one in the New World. Adaptation to pollination by bats has evolved independently many times from a variety of ancestral conditions, including insect-, bird- and non-volant mammal-pollination. Bat pollination predominates in very few families but is relatively common in certain angiosperm subfamilies and tribes. We propose that flower-visiting bats provide two important benefits to plants: they deposit large amounts of pollen and a variety of pollen genotypes on plant stigmas and, compared with many other pollinators, they are long-distance pollen dispersers. Bat pollination tends to occur in plants that occur in low densities and in lineages producing large flowers. In highly fragmented tropical habitats, nectar bats play an important role in maintaining the genetic continuity of plant populations and thus have considerable conservation value.  相似文献   

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

11.
We document white‐nose syndrome (WNS), a lethal disease of bats caused by the fungus Pseudogymnoascus destructans (Pd), and hibernacula microclimate in New Brunswick, Canada. Our study area represents a more northern region than is common for hibernacula microclimate investigations, providing insight as to how WNS may impact bats at higher latitudes. To determine the impact of the March 2011 arrival of Pd in New Brunswick and the role of hibernacula microclimate on overwintering bat mortality, we surveyed bat numbers at hibernacula twice a year from 2009 to 2015. We also collected data from iButton temperature loggers deployed at all sites and data from HOBO temperature and humidity loggers at three sites. Bat species found in New Brunswick hibernacula include Myotis lucifugus (Little Brown Bat) and M. septentrionalis (Northern Long‐eared Bat), with small numbers of Perimyotis subflavus (Tricolored Bat). All known hibernacula in the province were Pd‐positive with WNS‐positive bats by winter 2013. A 99% decrease in the overwintering bat population in New Brunswick was observed between 2011 and 2015. We did not observe Psubflavus during surveys 2013–2015 and the species appears to be extirpated from these sites. Bats did not appear to choose hibernacula based on winter temperatures, but dark zone (zone where no light penetrates) winter temperatures did not differ among our study sites. Winter dark zone temperatures were warmer and less variable than entrance or above ground temperatures. We observed visible Pd growth on hibernating bats in New Brunswick during early winter surveys (November), even though hibernacula temperatures were colder than optimum for in vitro Pd growth. This suggests that cold hibernacula temperatures encountered near the apparent northern range limit for Pd do not sufficiently slow fungal growth to prevent the onset of WNS and associated bat mortality over the winter.  相似文献   

12.
Fruits are N-poor items and their availability in the tropics varies throughout the year. Field and experimental studies debate whether frugivorous bats have to switch to N-rich sources of food during part of the year or if they are able to subsist on a fruit-only diet. Different strategies to meet their N requirements may influence the way in which frugivorous bats partition food resources allowing the coexistence of numerous species in tropical communities. We examined the extent to which five species of frugivorous bats relied on plant and insect sources of assimilated protein using stable-N isotope analysis. We assumed that bats only had access to fruits and insects in our analysis but we also collected fecal samples to examine the presence of other food items. We conducted the study during at least 1 full year depending on the species of bat in a tropical rain forest in southern Mexico. In the five species of bats examined, plant sources (i.e. fruits) provided most of the protein assimilated during the year, although there was a general trend for all species to show a decrease in relative plant contribution at the end of the rainy season and beginning of the dry season. In Artibeus jamaicensis, Uroderma bilobatum and Dermanura phaeotis, plants were still a major source of protein during this period, but in some individuals of Sturnira lilium and Carollia brevicauda insects represented an important contribution to their diet. Fecal samples of most bats presented fruit remains, and insects and pollen were found in small proportions. Bat reproductive activity was detected at the end of the dry season and in the middle of the rainy season, and plants were the major source of protein during this period with the exception of pregnant S. lilum and one pregnant D. phaeotis during the dry season. Our findings showed that frugivorous bats might differ in their strategies to satisfy their N demands with some species relying almost completely on fruits during most of the year and some species switching to insects when fruits were less abundant.  相似文献   

13.
Bats and their associated guano microbiota provide important terrestrial and subterranean ecosystem services and serve as a reservoir for a wide range of epizootic and zoonotic diseases. Unfortunately, large‐scale studies of bats and their guano microbiotas are limited by the time and cost of sample collection, which requires specially trained individuals to work at night to capture bats when they are most active. Indirectly surveying bat gut microbiota through guano deposits could be a more cost‐effective alternative, but it must first be established whether the postdefecation exposure to an aerobic environment has a large impact on the guano microbial community. A number of recent studies on mammalian feces have shown that the impact of aerobic exposure is highly species specific; therefore, it is difficult to predict how exposure will affect the bat guano microbiota without empirical data. In our study, we collected fresh guano samples from 24 individuals of 10 bat species that are common throughout the arid environments of the American southwest and subjected the samples to 0, 1, and 12 hr of exposure. The biodiversity decreased rapidly after the shift from an anaerobic to an aerobic environment—much faster than previously reported in mammalian species. However, the relative composition of the core guano microbiota remained stable and, using highly sensitive targeted PCR methods, we found that pathogens present in the original, non‐exposed samples could still be recovered after 12 hr of exposure. These results suggest that with careful sample analysis protocols, a more efficient passive collection strategy is feasible; for example, guano could be collected on tarps placed near the roost entrance. Such passive collection methods would greatly reduce the cost of sample collection by allowing more sites or roosts to be surveyed with a fraction of trained personnel, time, and effort investments needed.  相似文献   

14.
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.  相似文献   

15.
The importance of bat pollination has been demonstrated for many plant species. Yet this mutualism has rarely been studied on a community–wide level. In this paper we present results of a yearlong study of a bat–flower community in cloud forests on the western slopes of the Ecuadoran Andes. Of eight plant–visiting bat species caught, only Anoura caudifera and A. geoffroyi were carrying pollen. These species of Anoura supplement their diets with insects. Unlike glossophagines in other environments, however, which switch completely to a frugivorous or insectivorous diet during certain seasons, they are nectarivorous year–round and were never found with seeds or fruit pulp in their feces. Of the 13 morphotypes of pollen carried by the bats, 11 were identified to genus and 7 to species. Floral characteristics of all of these plants fit the traditional chiropterophilous syndrome well. Our study represents the first direct evidence of bat pollination for those plants identified to species, including four species of Burmeistera (Campanulaceae), as well as the first record of bat pollination for a plant of the genus Meriania (Melastomataceae). While overlap in the diets of the two Anoura was high, significant differences in visitation frequencies to particular plant species were detected. The larger bat species (A. geoffroyi) preferred large flowers, whereas the smaller species (A. caudifera) preferred small flowers.  相似文献   

16.
During a two year population ecology study in a cave environment, 15 Eurycea (= Typhlotriton) spelaea were observed ingesting bat guano. Furthermore, E. spelaea capture numbers increased significantly during the time that grey bats (Myotis grisescens) deposited fresh guano. We investigated the hypothesis that this behaviour was not incidental to the capture of invertebrate prey, but a diet switch to an energy-rich detritus in an oligotrophic environment. Stable isotope assays determined that guano may be assimilated into salamander muscle tissue, and nutritional analyses revealed that guano is a comparable food source to potential invertebrate prey items. This is the first report of coprophagy in a salamander and in any amphibian for reasons other than intestinal inoculation. Because many temperate subterranean environments are often energy poor and this limitation is thought to select for increased diet breadth, we predict that coprophagy may be common in subterranean vertebrates where it is not currently recognized.  相似文献   

17.
In a hypothesis that has remained controversial since its inception, Darwin suggested that long-tubed flowers and long-tongued pollinators evolved together in a coevolutionary race, with each selecting for increasing length in the other. Although the selective pressures that flowers impose on tongue length are relatively straightforward, in that longer tongues allow access to more nectar, selective pressures that pollinators impose on flower length are less clear. Here, we test for such selective pressures in the highly specialized mutualism between the nectar bat Anoura fistulata, which can extend its tongue twice as far as other nectar bats, and Centropogon nigricans, which has flowers of a similar length (8–9 cm). We used flight cage experiments to examine the effects of artificially manipulated flower lengths on (i) bat behaviour and (ii) pollen transfer. Increased length produced longer visits, but did not affect the force bats applied during visits. In the second experiment, flower length increased both the male and female components of flower function: long male flowers delivered more pollen grains and long female flowers received more pollen grains. However, pollen transfer was not correlated with visit duration, so the mechanism behind differences in pollen transfer remains unclear. By demonstrating that bats select for increasing flower length, these results are consistent with the hypothesis that A. fistulata evolved its remarkable tongue in a coevolutionary race with long-tubed flowers similar to that envisioned by Darwin.  相似文献   

18.
Bats, in terms of variety of species and their absolute numbers, are the most successful mammals on earth. The anatomical and functional peculiarities of Microchiroptera are not confined only to the auditory system; the wings (hands) of bats are unique both from an anatomical point of view as from a sensorial one. They are much thinner than those of birds and their bony structure is much more similar to a primate hand than to the forelimb of other mammals of the bat's size; the thumb, is very small and on its distal end there is a little claw that bats use for crawling and manipulating food. However, despite this very frequent use of the hands for food catching and for walking, nothing is known about the existence of a preferential use of the hands in Microchiroptera. The present study investigates the existence of handedness in the Schreiber's Long-Fingered Bat by recording the preferential use of the hand while climbing the walls of a plastic cylinder. This bat species is lateralized at population level and shows a left forelimb bias when using hands for climbing/grasping. This result is the first evidence of population-level handedness in an echolocating bat species.  相似文献   

19.
D. Blake    A. M. Hutson    P. A. Racey    J. Rydell    J. R. Speakman 《Journal of Zoology》1994,234(3):453-462
Roads illuminated by white streetlamps attracted three times more foraging bats (mostly Pipistrellus pipistrellus ) than did roads lit by orange streetlamps or unlit roads (3.2, 1.2 and 0.7 bat passes/km, respectively). More insects flew around white lamps than around orange lamps (mean 0.67 and 0.083 insects per lamp, respectively). The mean number of bat passes recorded in any 1-km section of road was positively correlated to the number of white streetlamps along the section, and also, independently, to the amount of trees and hedgerows. Bat activity was not related to the number of houses along the road, ambient temperature or cloud cover. The attractive effect of the lamps on the bats was diminished in windy weather.  相似文献   

20.
Bat populations continue to decline worldwide because of myriad human activities. To enhance bat conservation, human behavior needs to change. Such change can occur, in part, through an understanding of what motivates human actions toward bats. We used a Bat Attitude Questionnaire (BAQ) to investigate attitudes toward bats in people (n = 394) living around Arabuko-Sokoke Forest (ASF), Kenya. Belief in myths seemed to prevail among those surveyed and that these myths were significantly associated with low tolerance of bats (ordinal regression, p < 0.05). Older and more educated people reported more positive attitudes toward bats than others. Multiple linear regression revealed that females showed more negative attitudes toward, and more belief in, myths about bats than males (both p < 0.01). Ordinal regression showed that hostile behavior toward bats was more common among males (p < 0.001). Nearly one-third of the respondents reported actively killing bats or destroying bat roosts. A similar proportion did not see any benefits of bats to humans, while the majority of respondents associated bats with the destruction of farmers’ fruits. To address prevailing negative attitudes about bats, we recommend conducting evening school-based bat study tours, specifically targeting youths in schools around the forest, to examine whether physical contacts with bats would help positively influence human attitudes toward bats. Additionally, since mango (Mangifera indica) farming is an important source of income to people around ASF, an assessment of the quantity of mangoes destroyed by bats would be important to determine whether there is a need for controlling bat access to crops through appropriate schemes.  相似文献   

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