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Abstract: Limestone karst landscapes are important for biodiversity yet are increasingly threatened by development activities such as mining. Furthermore, karsts are often scattered and isolated by agriculture, and are rarely considered in landscape planning because of a paucity of biodiversity data. We determined the conservation significance of an isolated limestone karst outcrop for insectivorous bats by quantifying the influence of this roosting resource on local assemblage structure across a fragmented landscape in peninsular Malaysia. Using a combination of rank abundance, gradient and randomisation analyses, we demonstrate that bat assemblages at nine forest sites are structured following a spatial gradient of increasing distance from a karst roosting resource. The assemblage at our karst site was dominated by a superabundance of three cave-roosting species, two of which were also found to dominate assemblages up to 11km away. Cave-roosting bats exhibited a significant decay in abundance related to the distance from karst, with sites closest to karst also characterised by a rarity of tree cavity/foliage-roosting species that were otherwise common. Gradient analysis revealed that differences in assemblage composition were largely associated with the distance from the karst and, to a lesser extent, forest isolation and area. Our findings suggest that isolated karst outcrops can serve as important population reservoirs for cave-roosting bats, which subsidise diversity levels in forest fragments that might otherwise be expected to decline over time. While conservation efforts need to focus on maintaining large areas of connected forest, landscape management needs to ensure protection of karsts as point resources for cave-roosting bats. [Copyright &y& Elsevier]

• We present a hierarchical framework for designing automated bat call classifiers. • Our classifier identifies 85% of calls correctly to 1 of 4 ecological ensembles. • Our classifier reduces 95% of acoustic files for 3 of the most common species. • Our framework reduces the total number of files to process by 86%. • Ecological ensembles can serve as indicators where we lack species reference calls. Bats comprise a quarter of all mammal species, provide key ecosystem services and serve as effective bioindicators. Automated methods for classifying echolocation calls of free-flying bats are useful for monitoring but are not widely used in the tropics. This is particularly problematic in Southeast Asia, which supports more than 388 bat species. Here, sparse reference call databases and significant overlap among species call characteristics makes the development of automated processing methods complex. To address this, we outline a semi-automated framework for classifying bat calls in Southeast Asia and demonstrate how this can reliably speed up manual data processing. We implemented the framework to develop a classifier for the bats of Borneo and tested this at a landscape in Sabah. Borneo has a relatively well-described bat fauna, including reference calls for 52% of all 81 known echolocating species on the island. We applied machine learning to classify calls into one of four call types that serve as indicators of dominant ecological ensembles: frequency-modulated (FM; forest-specialists), constant frequency (CF; forest-specialists and edge/gap foragers), quasi-constant frequency (QCF; edge/gap foragers), and frequency-modulated quasi constant frequency (FMqCF; edge/gap and open-space foragers) calls. Where possible, we further identified calls to species/sonotype. Each classification is provided with a confidence value and a recommended threshold for manual verification. Of the 245,991 calls recorded in our test landscape, 85% were correctly identified to call type and only 10% needed manual verification for three of the call types. The classifier was most successful at classifying CF calls, reducing the volume of calls to be manually verified by over 95% for three common species. The most difficult bats to classify were those with FMqCF calls, with only a 52% reduction in files. Our framework allows users to rapidly filter acoustic files for common species and isolate files of interest, cutting the total volume of data to be processed by 86%. This provides an alternative method where species-specific classifiers are not yet feasible and enables researchers to expand non-invasive monitoring of bat species. Notably, this approach incorporates aerial insectivorous ensembles that are regularly absent from field datasets despite being important components of the bat community, thus improving our capacity to monitor bats remotely in tropical landscapes. [ABSTRACT FROM AUTHOR]

Forested landscapes in Southeast Asia are becoming increasingly fragmented, making this region a conservation and research priority. Despite its importance, few empirical studies of effects of fragmentation on biodiversity have been undertaken in the region, limiting our ability to inform land-use regimes at a time of increased pressure on forests. We estimated the biodiversity value of forest fragments in peninsular Malaysia by studying fragmentation impacts on insectivorous bat species that vary in dependence of forest. We sampled bats at seven continuous forest sites and 27 forest fragments, and tested the influence of fragment isolation and area on the abundance, species richness, diversity, composition and nestedness of assemblages, and the abundance of the ten most common species. Overall, isolation was a poor predictor of these variables. Conversely, forest area was positively related with abundance and species richness of cavity/foliage-roosting bats, but not for that of cave-roosting or edge/open space foraging species. The smallest of fragments (<150ha) were more variable in species composition than larger fragments or continuous forest, and larger fragments retained substantial bat diversity, comparable to continuous forest. Some fragments exhibited higher bat abundance and species richness than continuous forest, though declines might occur in the future because of time lags in the manifestation of fragmentation effects. Our findings suggest that fragments >300ha contribute substantially to landscape-level bat diversity, and that small fragments also have some value. However, large tracts are needed to support rare, forest specialist species and should be the conservation priority in landscape-level planning. Species that roost in tree cavities or foliage may be more vulnerable to habitat fragmentation than those that roost in caves. [Copyright &y& Elsevier]

Abstract: Literature searches and recent surveys of the bat fauna of Singapore indicate that of the 24 species of Microchiroptera and six species of Megachiroptera documented for this small equatorial island just 15 and 5, respectively, are still present. These recorded declines in chiropteran species richness almost certainly understate the true losses as extensive land transformation/habitat loss (>95%) and biota loss occurred early in Singapore’s colonial history before comprehensive surveys of bats were made. In an effort to reconstruct the pre-settlement bat fauna, we inferred an upper bound of pre-settlement species richness using a checklist from a well-known bat assemblage in neighbouring Peninsular Malaysia, and a lower bound based on species common to Peninsular Malaysia, Borneo and Sumatra. The Singapore records were compared with these two species list predictions. Based on this analysis, we infer that between 60 and 72 species would have inhabited Singapore before 1819. We also estimate that between 33% (based on the confirmed inventory) and 72% of the species (based on the upper-bound estimate of species richness) are now locally extinct. For Microchiroptera the data suggest that the documented local extinction rate of 38% may project to between 69% and 75%. Forest-dependant bats are particularly affected and comprise a much lower proportion of the bat fauna than is seen in intact forest in Peninsular Malaysia. All hipposiderids and 40% of the documented rhinolophid taxa have been lost and almost half (6) of the surviving microchiropteran species are locally endangered. Projected local extinction rates for Megachiroptera raise the documented value (17%) to about 60%, with most of the survivors being widespread species known to forage in cultivated or secondary forest habitats or to commute long distances between fragmented resources. The dramatic decline in Singapore bat species richness and a concomitant change in chiropteran guild and trophic structure (Microchiroptera vs. Megachiroptera) reflect patterns of diversity change seen elsewhere in the region in response to loss of forest habitat. In Singapore, the decline in diversity (species richness and abundances) for both mega- and microbats may also relate to urbanisation and deliberate or accidental destruction of bats and their roost sites in a land that has one of the highest human population densities on the planet. Although these losses (actual and inferred) represent a microcosm of mainly local extinctions, a wider geographical extrapolation over the 21st century indicates that heavy deforestation in progress in Southeast Asia might be expected to lead to extinction of many bat taxa, with upper-bound estimates of regional species losses exceeding 40% and global extirpation anticipated for at least 23% of Southeast Asia’s bat fauna by 2100. [Copyright &y& Elsevier]

Cave ecosystems are subterranean biodiversity hotspots, but limited knowledge of the distribution of diversity among caves hampers their conservation. Surveys of surrogate taxa (e.g., keystone species) can identify hotspots of biodiversity when knowledge about an ecosystem is lacking. Bats are keystone species in cave ecosystems because their guano is the primary energy source supporting diverse assemblages of cave-dependent wildlife. However, directly measuring bat diversity is time-consuming and requires expert knowledge; instead, we suggest the use of correlates of bat diversity that can be derived from readily accessible data (e.g., land-use maps) and straightforward methods not requiring expert knowledge (e.g., cave surveys, interviews) as a foundation for prioritizing caves. To identify easily measurable correlates of bat diversity, we compared assemblage composition and species abundances of 21 bat species captured in 56 caves on Bohol Island, Philippines, along gradients in environmental factors and human disturbance. Model- and distance-based methods indicated that surface-level disturbance (i.e., percent non-forested habitat, degree of urbanization and road development) along with cave complexity (i.e., available roosting area, structural heterogeneity, number of entrances and temperature range) were the most influential factors governing cave-roosting bat assemblages, thus representing correlates of bat diversity. Prioritization schemes based on these correlates select combinations of caves with greater species richness than both random selection and selection of caves based on observed richness from intensive bat surveys. The use of easy-to-measure environmental and disturbance correlates of bat diversity is an effective tool to prioritize caves to protect cave-roosting bats and the cave-dependent wildlife they support. [ABSTRACT FROM AUTHOR]

Abstract: Bats are ecologically important mammals in tropical ecosystems; however, their populations face numerous environmental threats related to climate change, habitat loss, fragmentation, hunting, and emerging diseases. Thus, there is a pressing need to develop and implement large-scale networks to monitor trends in bat populations over extended time periods. Using data from a range of Neotropical and Paleotropical bat assemblages, we assessed the ability for long-term monitoring programs to reliably detect temporal trends in species abundance. We explored the magnitude of within-site temporal variation in abundance and evaluated the statistical power of a suite of different sampling designs for several different bat species and ensembles. Despite pronounced temporal variation in abundance of most tropical bat species, power simulations suggest that long-term monitoring programs (⩾20years) can detect population trends of 5% per year or more with adequate statistical power (⩾0.9). However, shorter monitoring programs (⩽10years) have insufficient power for trend detection. Overall, our analyses demonstrate that a monitoring program extending over 20years with four surveys conducted biennially on five plots per monitoring site would have the potential for detecting a 5% annual change in abundance for a suite of bat species from different ensembles. The likelihood of reaching adequate statistical power was sensitive to initial species abundance and the magnitude of count variation, stressing that only the most abundant species in an assemblage and those with generally low variation in abundance should be considered for detailed population monitoring. [ABSTRACT FROM AUTHOR]

Human dimensions (HD) research is a discipline of conservation social sciences that applies social and psychological sciences to understand and influence conservation-relevant human behaviour. An understanding of the human dimensions is particularly required for bats because they are widely maligned and misunderstood and face many threats due to human behaviour. To gain a better understanding of the state of HD studies in bat conservation and address given critiques of social-science research undertaken by natural scientists, we assessed bat-related HD studies on four levels (1) authorships and the professional backgrounds of all authors, (2) conceptual foundations, including the range of contexts studied, the quality of literature reviews and conceptual framing in relation to drivers of human behaviour, (3) the extent to which authors follow social-science best practices and (4) recommendations. Our analysis of 68 papers revealed that compared to papers by natural scientists alone, those by multidisciplinary teams performed better at addressing a broader range of contexts and generating recommendations based on findings, but only slightly better on the conceptual-foundations and literature-review criteria. Our results suggest the need for more interdisciplinarity; specifically, early in the process. We also make ten recommendations for future bat-related HD research. Of these, five are intended to ground the field more firmly in conservation social science and five to prioritize future research. Collectively, our recommendations aim to solidify, accelerate and diversify bat-related HD research. Although bats are the focal animals, this paper's outcomes are potentially applicable to HD research on other taxa. • Human dimensions research is needed for effective bat conservation. • Implementation of HD best practice in bat-conservation literature is variable. • We make 10 recommendations to solidify, accelerate and diversity bat HD research. • More studies needed where bat diversity is greatest and resources are limited. • Advancing HD research requires more interdisciplinarity early in the process. [ABSTRACT FROM AUTHOR]