Total Bat Activity Research Articles

Factors impacting bat activity and species richness in protected parks in the oak openings region of Northwest Ohio.

Protected areas are important for wildlife, especially in heavily developed areas. Bats are one group utilizing protected areas, but it is unclear what makes an ideal place for bats to live in parks, especially since preferences vary between open and forest foraging species and at different scales. The main objective of this study was to determine the landscape and vegetation factors at multiple scales most associated with higher bat activity and species richness in protected parks. Total bat activity, species richness, and activity for open and forested foraging species were compared to small-scale data vegetation structure collected in the field and larger-scale landscape data calculated in ArcGIS and FRAGSTATS. Bat activity and species richness increased with higher percentages of dry and open land cover types such as sand barrens, savanna, cropland, and upland prairie and decreased with higher percentages of forest and wet prairies. Patch richness, understory height, and clutter at the 3-6.5 m level were negatively associated with total bat activity. The most important variables for bats differed depending on spatial scale measured and if species were open or forest adapted. When managing for bats in parks, it would be advantageous to restore open land cover types such as savanna and mid-level clutter, and excessive fragmentation. Whether species are open or forest adapted and scale-specific differences should also be considered.

Little brown bat activity patterns and conservation implications in agricultural landscapes in boreal Yukon, Canada

AbstractAgriculture can threaten the persistence of bat populations by removing forests and wetlands and by intensifying production. Both processes are underway in expanding agricultural landscapes of boreal North America. To inform land planning and agricultural practices aimed at maintaining a viable population of the little brown bat (Myotis lucifugus), we assessed the use by bats of human‐modified (open fields, forest‐field edges, and cleared edges of ponds) and unmodified (forest ponds and forest interior) habitat features in agricultural landscapes in southern Yukon, Canada (60° N–61° N), using acoustic recordings. We summarized bat activity (number of 3‐s acoustic files with ≥1 pass/night) and bat feeding (files with >1 feeding buzz/night) at grouped sets of habitat features (sites) and used generalized linear mixed models to test predictions about relative use of habitats. The active season for bats was late April to early October. Little brown bat feeding was strongly correlated with general activity, but feeding comprised a significantly higher proportion of all activity at forest ponds and forest interiors compared to field edges, open fields, and ponds in fields. Total bat activity was highest at forest ponds, followed by field edges, and substantially less in forest interiors and open fields. Forest ponds were used more than the edges of nearby ponds with some riparian clearing for fields. Bats increased use of forest interiors and decreased use of fields as duration of darkness decreased close to summer solstice. We recommend exclusion of ponds, lakes, and other wetlands from future agricultural land disposition, and retention of a riparian forested buffer of ≥40 m around current water bodies on farms. We also recommend retention of strips or patches of forest bordering fields and connected to riparian areas and to more extensive forests on public lands. A relatively young agricultural landscape can avoid some of the risks of intensive agriculture with proactive planning and stewardship.

Insect Pest Pheromone Lures May Enhance the Activity of Insectivorous Bats in Mediterranean Vineyards and Apple Orchards

Insectivorous bats may play a significant role in regulating populations of agricultural pests. Currently, few methods are available to enhance the activity of bats in agroecosystems. We asked whether synthetic sex pheromones, used in integrated pest management (IPM) to impede the mating success of major moth pests in vineyards and apple orchards, could also enhance the activity and richness of insectivorous bats, their natural enemies. We hypothesized that applying concentrated sex pheromones of pest moths will alter the movement patterns of male moths, indirectly affecting bat richness and activity. We compared the effect of sex pheromones on bats under two different agricultural management systems: conventional farming and IPM. We used synthetic sex pheromones of Lobesia botrana or Cydia pomonella; both are among the most destructive moth pests in vineyards and apple orchards, respectively. Using passive acoustic monitoring, we compared species richness and bat activity in plots without and with additional pheromones. In both IPM vineyards and IPM apple orchards, total bat activity and species richness significantly increased after applying the pheromone treatment, with a positive correlation between total bat activity and the numbers of moth pests in the vineyards. In conventional vineyards, bat species richness increased significantly, but not total bat activity. IPM vineyards had significantly higher species richness than conventional vineyards, both before and after the pheromone treatment. Our study shows that moth pheromone lures, commonly used as a pest control method, may also attract insectivorous bats, which in turn may further suppress the pests. These findings highlight the potential of insectivorous bats as pest control agents and call for further research directed at integrating them in IPM practices.

Influence of underground mining with explosives on a hibernating bat population

AbstractBats arouse from hibernation both naturally and in response to disturbances. Frequent bat arousals can decrease survival due to increased energetic costs. An active sand mine in west‐central Wisconsin hosted over 52,000 hibernating bats of 4 species in inactive tunnels, and regularly blasted with explosives to remove sand. We collected environmental and acoustic data at this mine during two hibernation seasons (November 1 through February 28 in 2013–2014 and 2014–2015) to examine the effect of blasting on echolocation calls (bat activity), a measure of bat arousal from hibernation. We used total bat activity recorded 7 h before and 7 h after blast time as the response variable, assigned it to a binary category and used that as a fixed effect. We used explosive charge per delay (kg), number of blasts per day, number of consecutive blast days, barometric pressure, temperature, and hibernation season as fixed effects. We used generalized linear mixed models with a negative binomial distribution and Bayesian information criterion (BIC) for model selection. The BIC‐optimal model did not include any of the variables associated with blasting, but included activity timing, temperature, barometric pressure, and season as fixed effects, of which all were significant. Blasting did not influence bat activity significantly in this mine.

Bat Activity in Organic Rice Fields Is Higher Than in Conventional Fields in Landscapes of Intermediate Complexity

The extent to which organic farming can support biodiversity has been extensively studied. However, most of the research has been conducted on organic farms in temperate regions, with the focus mainly being on birds, insects, and plants and rarely on insectivorous bats, especially in Southeast Asia. We studied pairs of matched organic and conventional rice fields along a gradient of landscape complexity in the Songkhla Lake Basin and conducted acoustic surveys using bat detectors to analyze the influence of farming system and landscape characteristics on bat activity and prey availability. We also tested the “intermediate landscape complexity” hypothesis, which states that local conservation efforts are most effective in landscapes of intermediate complexity compared to extremely simple or extremely complex landscapes. We detected no difference in bat species richness, total bat activity, feeding activity, and insect prey abundance between organic fields and conventional fields. Even though organic farming did not increase bat activity on its own, it was most beneficial to bat activity in landscapes of intermediate complexity. Our findings suggest that landscape traits contribute more to bat activity than farm management and that insectivorous bats have species- and guild-specific responses to various landscape contexts. We also found that disturbance caused by tropical storms negatively impacts the activity of insectivorous bat.

Next‐generation ultrasonic recorders facilitate effective bat activity and distribution monitoring by citizen scientists

AbstractTime and budgetary resources are often a limiting factor in the collection of large‐scale ecological data. If data collected by citizen scientists were comparable to data collected by researchers, it would allow for more efficient data collection over a broad geographic area. Here, we compare the quality of data on bat activity collected by citizens (high school students and teachers) and researchers. Both researchers and citizen scientists used the same comprehensive instructions when choosing study sites. We found no statistically significant difference in total bat activity minutes recorded by citizens and researchers. Instead, citizen scientists collected data from a wider variety of habitats than researchers. Involvement of citizens also increased the geographical coverage of data collection, resulting in the northernmost documentation of the Nathusius’s pipistrelle so far in Finland. Therefore, bat research can benefit from the use of citizen science when participants are given precise instructions and calibrated data collection equipment. Citizen science projects also have other far‐reaching benefits, increasing, for example, the scientific literacy and interest in natural sciences of citizens. Involving citizens in science projects also has the potential to enhance their willingness to conserve nature.

Going beyond species richness and abundance: robustness of community specialisation measures in short acoustic surveys

Passive Acoustic Monitoring offers promising opportunities for biodiversity assessments and species conservation and is still in development. The robustness of community metrics depends on sampling effort and acoustic surveys should be adjusted for cost-effectiveness. Using a large-scale acoustic survey of bat assemblages conducted along 5487 survey nights across France, we assessed the effect of sampling duration on the level of confidence of four community metrics (total bat activity, species of conservation concern activity, species richness, and community specialisation index). We further investigated whether this effect varied across habitats and seasons. Overall, a high level of confidence (i.e., 95% similarity between cumulated survey nights) was reached after 2 to >20 sampling nights, depending on the community metric, the habitat and the season considered. CSI required the lowest sampling duration. A higher sampling duration was required in three-dimensionally structured habitats (e.g., forests) and habitats unfavourable to bats (e.g., intensive farmlands), while a high degree of confidence was reached earlier in more favourable habitats and non-intensive farmlands, and during the season of higher activity. Beyond providing recommendations for the design of context-dependent minimum sampling duration in acoustic surveys, we show that weighted community indices such as the CSI are efficient summary measures, and advocate for their use when monitoring resources are limited.

Mono-specific forest plantations are valuable bat habitats: implications for wind energy development

Near-natural or semi-natural forests such as relatively undisturbed and old deciduous or mixed woodland are considered worth protecting and ecologically valuable habitats for bat conservation. In contrast, mono-specific forest plantations are considered ecologically less valuable; thus, decision-makers recommend these plantations as suitable locations for wind power stations and therefore want to further expand wind turbines in these habitats. This is expected to have a strong negative impact on the landscape because forests would be cleared for wind turbine pads and access roads and wind turbines rise above the trees with adverse impacts for bats. Therefore, we argue that, in light of bat conservation, the suitability of forest plantations for wind energy development is not, per se, warranted and that implications of wind power stations, even in mono-specific forest plantations, should be assessed and evaluated. We conducted long-term bat activity monitoring and recorded bat echolocation calls above the canopies of different forest sites (coniferous monoculture plantations and semi-natural mixed deciduous forests) in Germany and compared different forest types in terms of species richness, total bat activity, activity of the three bat species groups and species composition. Generalised linear models revealed that forest type and the amount of forest biotopes did not enhance bat activity. Ordination showed that species composition was not affected by forest type, location and connectivity. Mono-specific forest plantations can harbour a diverse bat fauna with high species activity and are, therefore, valuable bat habitats just as near-natural or semi-natural woodlands are. Environmental impact assessment and mitigation measures are vital in all forest types before and after planning for wind energy turbines. In particular, future planning and approval processes must consider the importance of mono-specific forest plantations for bat species protection.

Changes in bat activity over 10 years in silviculturally treated wet sclerophyll forest

A range of silvicultural treatments are applied to timber production forests, resulting in varied vegetation structural complexity. We compared the bat assemblage across three silvicultural treatments (unlogged forest, unthinned regrowth and thinned regrowth), two locations (on and off track) and three time periods (pre-thin, plus one and six years post-thinning) in wet sclerophyll forests, with treatments implemented at a small catchment scale. Linear edges provided important habitat for bats as total bat activity was substantially greater on tracks than off tracks, especially in unlogged and unthinned regrowth forest. Bat activity off track was greater in unlogged areas than in thinned and unthinned regrowth. Activity and species richness off track were greater in thinned than unthinned regrowth, but the time by treatment interaction was not significant for activity, indicating this difference cannot be ascribed to thinning alone. Thinning also led to a species composition that more closely resembled unlogged forest than unthinned regrowth. These patterns in bat activity across silvicultural treatments in wet sclerophyll forests were broadly consistent with other forest types, but subtleties, such as a subdued response to thinning, requires more replication to resolve. Nevertheless, differences between forest types need to be considered when developing management strategies.

Abiotic and spatiotemporal factors affect activity of European bat species and have implications for detectability for acoustic surveys

Bat activity surveys are essential in the contexts of scientific research, conservation, assessment of ecosystem health, monitoring progress towards sustainable development goals, and legislative compliance in development and infrastructure construction. However, environmental conditions have the potential to influence bat activity and, in turn, their detectability in acoustic surveys. Here we use 3242 hours of acoustic survey data from 323 nights of bat monitoring at 14 sites over a 4-year period to explore the influence of spatiotemporal factors, lunar phase and weather conditions on bat activity. All spatiotemporal and abiotic factors analysed (site, hour post sunset, length of night, duration of moonlight, temperature, rain, wind and cloud cover) contributed to the optimal multivariate model for at least one bat species/genus; all factors except cloud cover and temperature were significant in the optimal model for total bat activity. However, there were notable species-specific differences. Among the key findings were differences between Pipistrellus species, with periods of rainfall being negatively related to soprano pipistrelle Pipistrellus pygmaeus registrations but not those of common pipistrelle Pipistrellus pipistrellus. In addition, overcast conditions showed a strong positive relationship with the number of Myotis registrations while duration of moonlight was positively correlated with common pipistrelle. Temperature was only important for Nyctalus species. These findings demonstrate that understanding the effect multifaceted and interlinked environmental factors on the activity of different bat species is a vital step in developing maximally effective survey protocols, which, in turn, will improve the reliability of conservation and planning decisions underpinned by survey data.

Artificial illumination near rivers may alter bat-insect trophic interactions

Artificial illumination at night represents an increasingly concerning threat to ecosystems worldwide, altering persistence, behaviour, physiology and fitness of many organisms and their mutual interactions, in the long-term affecting ecosystem functioning. Bats are very sensitive to artificial light at night because they are obligate nocturnal and feed on insects which are often also responsive to lights. Here we tested the effects of LED lighting on prey-predator interactions at riverine ecosystems, using bats and their insect prey as models, and compared bat and insect reactions in terms of bat activity and prey insect abundance and diversity, respectively, on artificially lit vs. unlit nights. Artificial light influenced both insect and bat assemblages in taxon-specific directions: insect abundances increased at lit sites, particularly due to an increase in small dipterans near the light source. Composition of insect assemblages also differed significantly between lit and unlit sites. Total bat activity declined at lit sites, but this change was mainly due to the response of the most abundant species, Myotis daubentonii, while opportunistic species showed no reaction or even an opposite pattern (Pipistrellus kuhlii). We show that artificial lighting along rivers may affect trophic interactions between bats and insects, resulting in a profound alteration of community structure and dynamics.

Long‐term effects of repeated fuel‐reduction burning and logging on bats in south‐eastern Australia

AbstractFire regimes have a major influence on biodiversity in many ecosystems around the globe, yet our understanding of the longer‐term response of fauna is typically poor. We sampled bats with ultrasonic detectors in three different years in dry sclerophyll forests of south‐eastern Australia in a long‐term, management‐scale experiment. Frequent low‐intensity burning (every 2 or 4 years plus unburnt) and logging (with 33% retention of the original unlogged tree basal area) were manipulated to assess their effects on bats. We found that both the fire regime and regrowth after logging influenced the local bat community. The routine burning treatment (burnt every 4 years) in unlogged forest was consistently related to higher total bat activity (2–3 times) and species richness when compared to unburnt controls and logging treatments. Foraging activity was more variable, but it was typically lowest in Unlogged Unburnt Controls. These patterns were evident at both the detector site scale and the block scale and were probably due to a reduction in understorey stem density with burning, especially in unlogged forest. Bat activity was significantly lower across the entire study area (including controls) in 1 year, when sampling occurred within 6 months of burning. When pooled across burning treatments, unlogged forest supported higher bat activity (1.5 times) and species richness than logged forest (12‐ to 17‐year‐old regrowth), again most likely because of a negative association with high stem density in regrowth after logging. We conclude that low‐intensity burning had positive benefits for echolocating bats, most notably in unlogged forest. However, careful planning is required to generate heterogeneous vegetation patterns that are likely to be most suitable for a range of taxa.

Remnant trees increase bat activity and facilitate the use of vineyards by edge-space bats

Conversion of natural habitats to vineyard monoculture is rapidly increasing both globally and on the California central coast. Although agricultural expansion typically decreases species diversity and abundance, landscape heterogeneity can maintain biodiversity, ecosystem function, and provide pest control services within agricultural systems. Large remnant oak trees are sometimes retained within vineyards, yet little is known about their value to biodiversity or the beneficial services to grape growers. While insectivorous bats (order: Chiroptera) are natural predators of agricultural pests and commonly utilize trees for foraging and roosting, no study has quantified the influence of remnant trees within vineyards on bat abundance and diversity. During 2014 and 2015, we recorded bat activity and species richness as well as insect abundance at isolated remnant trees and paired open areas within 14 vineyards in coastal central California. We used generalized linear mixed models to assess the influence of remnant trees on total and species-specific bat activity and insect abundance, and how these effects were influenced by individual tree and landscape-scale characteristics. We recorded 11,465 bat passes representing 11 bat species. Overall, bat activity rates were 1.5 times greater at trees compared to open areas. Activity levels of low-frequency echolocators adapted to open habitats did not differ between trees and open areas; however, activity levels of high frequency echolocators adapted to edge habitats were 2.4 times higher at trees than open areas. Bat activity at trees increased with larger tree size, closer neighboring remnant trees, and lower remnant tree density in the surrounding landscape. Our study indicates that remnant trees within vineyards provide important habitat value for bats at the landscape-scale by allowing edge-space adapted bat species access to vineyards. Retention of individual large trees can help to maintain biodiversity and ecological function in vineyard landscapes, a benefit for both conservation and agricultural production.

A small-scale response of urban bat activity to tree cover

Bats in urban areas depend on trees, and bat activity increases with tree cover. To effectively manage bat habitat in cities, it is important to know the distance to which tree cover most strongly influences bats (i.e., the ‘scale of effect’). The aim of this study was to estimate the scale of effect of tree cover on bats in Toronto, Canada. To achieve this, we measured bat activity at 52 sampling sites across the city. We then examined the relationships between bat activity and percent tree cover measured within each of 19 scales, 0.025 to 3.5 km in radius, surrounding each sampling site. We found that the scale of effect of percent tree cover on total bat and individual species activity ranged from 0.025 to 0.25 km among species. Our results suggest that adding or removing urban trees influences bats up to 0.25 km away. Urban tree management decisions should consider the impacts to bats beyond the site of management and within the surrounding landscape of a 250 m-radius scale.

Responses of aerial insectivorous bats to landscape composition and heterogeneity in organic vineyards

Landscape composition and heterogeneity are considered important factors for enhancing biodiversity and their associated ecosystem services in human-modified landscapes. Despite their roles in pest suppression in agricultural areas, insectivorous bats have been poorly represented in studies assessing the effects of landscape structural changes, particularly in the Neotropics. We evaluated how the composition and heterogeneity of the landscape, at several spatial scales, influenced the diversity and activity of aerial insectivorous bats in organic vineyards. Bat activity was quantified using acoustic surveys at 16 vineyards distributed across the central zone of Chile, where landscape composition and heterogeneity were determined by spatial analysis (GIS). Data were analyzed using partial least square regressions (PLS). The diversity and activity of aerial insectivorous bats in vineyards increased with the compositional and configurational heterogeneity of the landscape. Bat diversity and species richness in vineyards increased as the area covered by native vegetation increased, and urban areas decreased. Total bat activity, feeding activity and the activity of the dominant species T. brasiliensis increased with the diversity of cover types in the landscape, and also as the area covered by annual crops and rural areas increased. This study highlights the importance of agricultural landscape composition and heterogeneity for aerial insectivorous bats in organic vineyards. Effective conservation efforts and management strategies in this crop should aim to increase cover diversification at the landscape scale. In addition, retaining native forest remnants around or within vineyards may promote bat conservation and their role as suppressors of crop pests in these production landscapes.

Effect of fire on insectivorous bat activity in northern Australia: does fire intensity matter on a local scale?

Fire is notably becoming more intense, frequent and widespread due to climate change. In northern Australia, inappropriate fire regimes have been implicated in mammal declines, yet nothing is known about how different aspects of fire regimes affect bats in this region. This study aimed to determine how fire intensity, associated with seasonality, affects insectivorous bats on a local scale. An experimental M BACI approach was used on five site replicates across Cape York Peninsula, where ultrasonic detectors were used to determine the activity of insectivorous bats in response to low intensity burns (LIBs) and high intensity burns (HIBs) on a local scale. Total bat activity increased due to LIBs, but showed no response to HIBs. Activity of edge-open guild bats also increased due to LIBs but decreased in response to HIBs. Activity of open guild bats was unaffected by LIBs, but exhibited a strong positive response to HIBs. Activity of closed guild bats showed no response to fire, or fire intensity. Responses were likely derived from changes in habitat structure and prey availability. Given that each bat guild responded differently to each fire intensity, this lends support to the ‘pyrodiversity begets biodiversity’ concept, which is currently the basis for many fire management practices for conservation in northern Australia.

The importance of grassland patches and their associated rainforest ecotones to insectivorous bats in a fire-managed tropical landscape

Abstract ContextEcotones are recognised globally as areas of high biodiversity, yet relatively little is known about how fauna use different types of ecotone. Tropical rainforest–grassland ecotones are shaped through particular fire regimes, creating both gradual and abrupt ecotones. Insectivorous bats contribute considerably to mammalian diversity, and their capacity for flight allows them to use ecotones in a three-dimensional way, making them an informative faunal group for evaluating ecotone use. AimsTo critically evaluate how insectivorous bats use gradual and abrupt ecotones between rainforest and grassland habitats. MethodsBat detectors were placed every 50m, along 200-m transects, through five gradual and five abrupt rainforest–grassland ecotones. The activity of all insectivorous bats, as well as open, edge–open and closed foraging guilds (defined by echolocation call type), was compared among grassland and rainforest habitats, gradual and abrupt ecotones and positions across the ecotones. Key resultsMean total bat activity, mean open and edge–open foraging guild activity were significantly higher in grassland positions, followed by the edge, and were lowest in the rainforest. Closed foraging guild bats showed no preference for either habitats, but had significantly higher activity in gradual compared with abrupt ecotones. Mean activity of edge–open foraging guild bats was affected strongly by the interaction between ecotone type and position along the ecotone. Gradual ecotones had a more even proportion of all three bat foraging guilds along the ecotone compared with abrupt ecotones. Most of these findings were likely driven by the structural complexity of gradual ecotones that fulfilled microhabitat requirements for all three foraging guilds, but may also have been influenced by insect prey abundance. ConclusionsThe present study demonstrated the importance of grassland patches in a tropical, rainforest landscape, and of gradual rainforest–grassland ecotones for insectivorous bats. Gradual ecotones promote complex habitat mosaics to allow closed foraging guild species to take advantage of food resources provided by grasslands, and provide all bats proximity to potential roosting and foraging sites. ImplicationsThe data clearly suggest that a suitable fire regime should be used to maintain current grassland patches within a rainforest landscape, and to promote gradual ecotones for use by insectivorous bats.

Summer activity patterns of four resident south Texas bat species

Although the activity patterns of bats are recognized to vary widely, both, temporally and spatially, the underlying drivers for those patterns remain poorly understood. Presently, studies focusing on foraging bat ecology have only generalized activity and influence of the environment (across sampling periods, sampling nights, or seasons). The influence of environmental features on foraging bat activity on a finer temporal scale (e.g., throughout a single sampling night) is markedly less studied. The recent emergence of Pseudogymnoascus destructans, a cold-adapted fungus and the causative agent of white-nose syndrome (WNS), has led to the precipitous declines in North American bat populations since its arrival in 2006. P. destructans has been recently documented in 10 Texas counties and, although WNS primarily affects hibernation cycles, it is recognized to have significant detrimental impacts on summer bat activity. It is imperative we understand and provide a baseline of summer bat activity patterns prior to the arrival of WNS to better manage and protect these, relatively understudied, populations of bat species in south Texas. We used a mixed model approach and acoustic monitoring to quantify how shrub density, canopy height, distance to water, roads, and bare ground coverage influenced nightly foraging activities of four summer resident bat species in south Texas: Eastern Red Bat (Lasirius borealis), Cave Myotis (Myotis velifer), Evening Bat (Nycticeius humeralis), and Brazilian Free-tailed Bat (Tadarida brasiliensis). Total bat activity peaked at 2:00-a for all species included in our study. A secondary, smaller peak was notable between 5:00-a and 6:00-a and activity decreased sharply immediately following 6:00-a. However, the trend for total bat activity differed substantially from trends exhibited by the individual species. Eastern red-bats and Evening bats exhibited bimodal nightly activity patterns and showed variable associations with water proximity whereas Cave bats and Brazilian free-tailed bats exhibited unimodal activity patterns and strong associations with canopy height and roads. Our results support the concept that insectivorous bats partition resources, temporally and spatially, in the presence of other sympatric species.

Bats as potential suppressors of multiple agricultural pests: A case study from Madagascar

The conversion of natural habitats to agriculture is one of the main drivers of biotic change. Madagascar is no exception and land-use change, mostly driven by slash-and-burn agriculture, is impacting the island's exceptional biodiversity. Although most species are negatively affected by agricultural expansion, some, such as synanthropic bats, are capable of exploring newly available resources and benefit from man-made agricultural ecosystems. As bats are known predators of agricultural pests it seems possible that Malagasy bats may be preferentially foraging within agricultural areas and therefore provide important pest suppression services. To investigate the potential role of bats as pest suppressors, we conducted acoustic surveys of insectivorous bats in and around Ranomafana National Park, Madagascar, during November and December 2015. We surveyed five landcover types: irrigated rice, hillside rice, secondary vegetation, forest fragment and continuous forest. 9569 bat passes from a regional assemblage of 19 species were recorded. In parallel, we collected faeces from the six most common bat species to detect insect pest species in their diet using DNA metabarcoding. Total bat activity was higher over rice fields when compared to forest and bats belonging to the open space and edge space sonotypes were the most benefited by the conversion of forest to hillside and irrigated rice. Two economically important rice pests were detected in the faecal samples collected - the paddy swarming armyworm Spodoptera mauritia was detected in Mops leucogaster samples while the grass webworm Herpetogramma licarsisalis was detected from Mormopterus jugularis and Miniopterus majori samples. Other crops pests detected included the sugarcane cicada Yanga guttulata, the macadamia nut-borer Thaumatotibia batrachopa and the sober tabby Ericeia inangulata (a pest of citrus fruits). Samples from all bat species also contained reads from important insect disease vectors. In light of our results we argue that Malagasy insectivorous bats have the potential to suppress agricultural pests. It is important to retain and maximise Malagasy bat populations as they may contribute to higher agricultural yields and promote sustainable livelihoods.

Agroecological farming practices promote bats

Intensive agriculture is a major driver of biodiversity loss, and a critical part of creating sustainable food systems is finding ways to balance production and conservation. While practices characteristic of agricultural intensification tend to erode biodiversity, agroecological farming practices can potentially support biodiversity and enhance pest suppression services. Bats are important predators of agricultural pests, yet little is known about how prescriptive management practices can be used to support bats and their associated pest-suppression services. We investigate how bats use natural habitat and conventional and organic farms in an agricultural landscape, ask which on-farm management practices may benefit bats, and examine how these management practices influence bats by mediating changes in habitat quality. We conducted acoustic surveys at 54 sites in the California Central Coast Region, a productive region with high ecological and economic value. We found higher bat activity in natural habitat compared to farms for total bat activity and clutter-adapted, but not open space bats, and slightly higher bat diversity in natural habitat compared to conventional farms. We found no effect of habitat type on species richness and a weak effect of habitat type on bat diversity, although bat community composition differed significantly between natural habitat and farms. Crop diversification increased the activity of all bat species and clutter-adapted, but not open space bats, regardless of the amount of semi-natural habitat surrounding farms. Both crop diversification and less frequent pesticide applications increased prey biomass, and the activity of clutter-adapted bats was positively correlated with greater Lepidoptera biomass. We suggest that improving habitat quality (increasing abundance of insect prey) through vegetative diversification and/or less frequent pesticide applications offers flexible management options to growers by considering both bat ecology and the constraints of regional agricultural management practices.