The Tricolored Bat (Perimyotis subflavus) has suffered significant population declines in much of its geographic range due to white-nose syndrome (WNS). Our aim was to describe the torpor patterns of tricolored bats within the southeastern United States to further our understanding of their winter ecology and potential susceptibility to WNS in currently unimpacted areas based on data from bats in both a WNS-affected hibernaculum and an unaffected hibernaculum. We placed temperature-sensitive radio transmitters on tricolored bats in a site in northwestern South Carolina that was WNS-positive and another site in northwestern Florida that was WNS-negative, and determined torpid and arousal skin temperatures (TSK), torpor bout duration (TBD), and arousal duration (AD) during 3 winters. Mean hibernacula temperature (TH) and vapor pressure deficit (VPDH) in both hibernacula were within the range of optimal Pseudogymnoascus destructans (Pd) growth (TH = 12.7 to 13.6 degrees C, VPDH = 0.028 to 0.059 kPA). Mean torpid TSK was 15.7 +/- 0.1 degrees C and mean TBD was 4.1 +/- 0.2 days across sites. Sex was the best predictor of TBD with males having significantly longer TBD than females. Torpid TSK was positively related to TH and negatively related to VPDH. Because the TSK of a bat was similar to the optimal growth temperatures of Pd, our findings suggest that even though winters in the southeastern United States are more benign than in other parts of the Tricolored Bat range, the warmer temperatures in southern hibernacula may provide optimal conditions for the growth of Pd. Greater understanding of the physiological responses of tricolored bats in hibernacula across their range will provide important data on the potential for WNS morbidity and mortality in unaffected areas and allow for a better distribution of resources for prevention and treatment of WNS. Our findings suggest that warmer temperatures in southern hibernacula may provide optimal conditions for growth of Pseudogymnoascus destructans (Pd), the fungus that causes white-nose syndrome. Should Pd reach the southernmost hibernacula, research will be needed to determine whether white-nose syndrome develops and how lethal it will be. El pipistrelo del este americano (Perimyotis subflavus) ha sufrido importantes disminuciones poblacionales en gran parte de su distribuci & oacute;n geogr & aacute;fica debido al s & iacute;ndrome de la nariz blanca (WNS). Nuestro objetivo fue describir los patrones de torpor del murci & eacute;lago tricoloreado en el sureste de EE. UU. para mejorar nuestra comprensi & oacute;n de su ecolog & iacute;a invernal y su susceptibilidad potencial al WNS en & aacute;reas actualmente no afectadas, con base en datos de murci & eacute;lagos en sitios afectados y no afectados por el WNS. Colocamos transmisores de radio sensibles a la temperatura en pipistrelos del este americano en dos hibern & aacute;culos, uno en el noroeste de Carolina del Sur que fue positivo para WNS, y el otro en el noroeste de Florida que fue negativo para WNS, y determinamos las temperaturas cut & aacute;neas (TSK) de torpor y al despertar, la duraci & oacute;n del evento de torpor (TBD) y la duraci & oacute;n del despertar (AD) durante tres inviernos. La temperatura media del hibern & aacute;culo (TH) y el d & eacute;ficit de presi & oacute;n de vapor (VPDH) en ambos hibern & aacute;culos estuvieron dentro del rango de crecimiento & oacute;ptimo del hongo pat & oacute;geno Pseudogymnoascus destructans [Pd] (TH = 12.7-13.6 degrees C, VPDH = 0.028-0.059 kPA). La TSK media durante el torpor fue de 15.7 +/- 0.1 degrees C y la TBD media fue de 4.1 +/- 0.2 d & iacute;as en todos los sitios. El sexo fue el mejor predictor de la TBD, con los machos teniendo una TBD significativamente m & aacute;s prolongada que las hembras. La TSK durante el torpor tuvo relaci & oacute;n positiva con la TH y negativa con el VPDH. Debido a que la TSK de los murci & eacute;lagos fue similar a las temperaturas & oacute;ptimas de crecimiento de Pd, nuestros hallazgos sugieren que, aunque los inviernos en el sureste de EE. UU. son m & aacute;s benignos que en otras partes de la distribuci & oacute;n del murci & eacute;lago tricoloreado, las temperaturas m & aacute;s c & aacute;lidas en los hibern & aacute;culos del sur pueden proporcionar condiciones & oacute;ptimas para el crecimiento de Pd. Una mejor comprensi & oacute;n de las respuestas fisiol & oacute;gicas de los murci & eacute;lagos tricoloreados en hibern & aacute;culos en toda su & aacute;rea de distribuci & oacute;n proporcionar & aacute; informaci & oacute;n importante sobre el potencial de morbilidad y mortalidad por WNS en & aacute;reas no afectadas y permitir & aacute; una mejor distribuci & oacute;n de recursos para la prevenci & oacute;n y el tratamiento del WNS.
DNA contained in animal scat provides a wealth of information about the animal, and DNA metabarcoding of scat collections can provide key information about animal populations and communities. Next-generation DNA sequencing technologies and DNA metabarcoding provide an efficient means for obtaining information available in scat samples. We used multifaceted DNA metabarcoding (MDM) of noninvasively collected bat guano pellets from a Myotis lucifugus colony on Fort Drum Military Installation, New York, USA, and from two mixed-species bat roosts on Fort Huachuca Military Installation, Arizona, USA, to identify attributes such as bat species composition, sex ratios, diet, and the presence of pathogens and parasites. We successfully identified bat species for nearly 98% of samples from Fort Drum and 90% of samples from Fort Huachuca, and identified the sex for 84% and 67% of samples from these same locations, respectively. Species and sex identification matched expectations based on prior censuses of bat populations utilizing those roosts, though samples from some species were more or less common than anticipated within Fort Huachuca roosts. Nearly 62% of guano samples from Fort Drum contained DNA from Pseudogymnoascus destructans, where bats with wing damage from White-nose Syndrome were commonly observed. Putative dietary items were detected in a majority of samples from insectivorous bats on Fort Drum (81%) and Fort Huachuca (63%). A minority of guano samples identified as the nectarivorous Leptonycteris yerbabuenae (28%) provided DNA sequences from putative forage plant species. Finally, DNA sequences from both putative ecto- and endoparasite taxa were detected in 35% and 56% of samples from Fort Drum and Fort Huachuca, respectively. This study demonstrates that the combination of noninvasive sampling, DNA metabarcoding, and sample and locus multiplexing provide a wide array of data that are otherwise difficult to obtain.
This special report reviews current scientific literature to identify the most commonly cited metrics used to describe the macrohabitat criteria important for Chiroptera presence in the United States. The review evaluates 69 scientific articles from 1994 to 2018. The most commonly cited metrics were divided into four main categories: tree-species-level metrics, landscape-level metrics, distance metrics, and topographic and atmospheric metrics. Of all metrics found, the top six most common metrics noted across all articles were percent canopy cover, diameter at breast height (DBH), forest type, distance to water, distance to roads or other urban features, and tree density. In addition, 27 of the 47 (57%) bat species located within the United States were represented. These metrics provide important insight into the regional or national species-level distribution and assist with modeling the relationship between species distribution and habitat change.
Bats play crucial ecological roles and provide valuable ecosystem services, yet many populations face serious threats from various ecological disturbances. The North American Bat Monitoring Program (NABat) aims to use its technology infrastructure to assess status and trends of bat populations, while developing innovative and community-driven conservation solutions. Here, we present NABat ML, an automated machine-learning algorithm that improves the scalability and scientific transparency of NABat acoustic monitoring. This model combines signal processing techniques and convolutional neural networks (CNNs) to detect and classify recorded bat echolocation calls. We developed our CNN model with internet-based computing resources ('cloud environment'), and trained it on >600,000 spectrogram images. We also incorporated species range maps to improve the robustness and accuracy of the model for future 'unseen' data. We evaluated model performance using a comprehensive, independent, holdout dataset. NABat ML successfully distinguished 31 classes (30 species and a noise class) with overall weighted-average accuracy and precision rates of 92%, and >= 90% classification accuracy for 19 of the bat species. Using a single cloud-environment computing instance, the entire model training process took Synthesis and applications. Our convolutional neural network (CNN)-based model, NABat ML, classifies 30 North American bat species using their recorded echolocation calls with an overall accuracy of 92%. In addition to providing highly accurate species-level classification, NABat ML and its outputs are compatible with Bayesian and other statistical techniques for measuring uncertainty in classification. Our model is open-source and reproducible, enabling future implementations as software on end-user devices and cloud-based web applications. These qualities make NABat ML highly suitable for applications ranging from grassroots community science initiatives to big-data methods developed and implemented by researchers and professional practitioners. We believe the transparency and accessibility of NABat ML will encourage broad-scale participation in bat monitoring, and enable development of innovative solutions needed to conserve North American bat species.
This special report provides a selection process for choosing priority species using the specific focus of high-elevation, forested habitats in the North Atlantic to demonstrate the process. This process includes criteria for choosing invasive species to incorporate into models, given the predicted spread of invasive plant species because of climate change. Discussed in this report are the US Army Corps of Engineers’ Threatened and Endangered Species Team portal, the US Fish and Wildlife Service’s Information for Planning and Consultation Portal, the nonprofit organization Partners in Flight’s watch list, the US Geological Survey’s Biodiversity Information Serving Our Nation model, and NatureServe’s interagency effort Landfire. The data linked this montane habitat with a species of conservation concern, Cartharus bicknelli and the endangered squirrel Glaucomys sabrinus as target species and with Elaeagnus umbellate, Robinia pseudoacacia, Rhamnus cathartica, and Acer planoides as invasive species. Incorporating these links into the climate change framework developed by Davis et al. (2018) will create predictive models for the impacts of climate change on TER-S, which will affect land management decisions in the region.
Bat guano is a noninvasive, data-rich genetic resource. However, the constituent bat DNA is relatively scant, degraded, and complexed with polymerase chain reaction inhibitors. It also is comingled with a rich pool of nontarget DNA from microbes, parasites, and dietary items. We designed and tested new DNA assays for bat species identification (COX1-Bat) and sex identification (XGXYC) for use with guano and other challenging samples. We reviewed previously published assays that can be used with guano samples to obtain the same species and sex data. and attempted to validate these assays for species in which they had not previously been tested. Our results demonstrate that guano-derived DNA can be used successfully to 1) identify nearly all US and Canadian bats at the species level, or to one of three Myotis species clusters, and 2) identify the sex of at least 23 US and Canadian bat species. Our newly developed assays, and validation of previously published assays, for guano-based identification of species and sex in bats, significantly enhance the power of noninvasive sampling and genetic analysis for bat studies, management, and conservation.
We assessed parentage within and among maternity colonies of northern long-eared bats (Myotis septentrionalis (Trouessart, 1897)) in north-central Kentucky, USA, from 2011 to 2013 to examine colony social structure, formation, and membership dynamics. We intensively sampled colonies in close and remote (>10 km) proximity before and after targeted day-roost removal. Colonies were not necessarily composed of closely related individuals, although natal philopatry was common. Adjacent colonies often contained maternally related individuals, indicating that some pups did disperse, albeit not far from their natal home range. Whereas some young had been sired by males also collected on site, most had not, as would be expected since the species mates in fall near hibernacula across a wider landscape. The number of parentages that we inferred among colonies, however, suggests that outside the maternity season, social groups may be relatively flexible and open. Analysis of microsatellite DNA data showed a low FST(0.011) and best fit to a model of one multilocus genotypic cluster across the study area. We observed high turnover in colony membership between years in all colonies, regardless of roost-removal treatment. Our results suggest that female northern long-eared bats exhibit fidelity to a general geographic area and complex, dynamic social–genetic structure.
First posted June 14, 2018 For additional information, contact: Center Director, Fort Collins Science CenterU.S. Geological Survey2150 Centre Ave., Bldg. CFort Collins, CO 80526-8118 The North American Bat Monitoring Program (NABat) aims to improve the state of conservation science for all species of bats shared by the United States, Canada, and Mexico. To accomplish this goal, NABat offers guidance and standardized protocols for acoustic monitoring of bats. In this document, "A Guide to Processing Bat Acoustic Data for the North American Bat Monitoring Program (NABat)," we provide general recommendations and specific workflows for the process of identifying bat species from acoustic files recorded using the NABat stationary point and mobile transect acoustic monitoring protocols.
As multiple species of bats are currently experiencing dramatic declines in populations due to white-nose syndrome (WNS) and other factors, conservation managers have an urgent need for data on the ecology and overall status of populations of once-common bat species. Standard approaches to obtain data on bat populations often involve capture and handling, requiring extensive expertise and unavoidably resulting in stress to the bats. New methods to rapidly obtain critical data are needed that minimize both the stress on bats and the spread of WNS. Guano provides a noninvasive source of DNA that includes information from the bat, but also dietary items, parasites, and pathogens. DNA metabarcoding is a high-throughput, DNA-based identification technique to assess the biodiversity of environmental or fecal samples. We investigated the use of multifaceted DNA metabarcoding (MDM), a technique combining next-generation DNA sequencing (NGS), DNA barcodes, and bioinformatic analysis, to simultaneously collect data on multiple parameters of interest (bat species composition, individual genotype, sex ratios, diet, parasites, and presence of WNS) from fecal samples using a single NGS run. We tested the accuracy of each MDM assay using samples in which these parameters were previously determined using conventional approaches. We found that assays for bat species identification, insect diet, parasite diversity, and genotype were both sensitive and accurate, the assay to detect WNS was highly sensitive but requires careful sample processing steps to ensure the reliability of results, while assays for nectivorous diet and sex showed lower sensitivity. MDM was able to quantify multiple data classes from fecal samples simultaneously, and results were consistent whether we included assays for a single data class or multiple data classes. Overall, MDM is a useful approach that employs noninvasive sampling and a customizable suite of assays to gain important and largely accurate information on bat ecology and population dynamics.
Fission-fusion dynamics appear common among temperate bats where females form roost groups that change in size and composition, as females switch roosts almost daily. One hypothesis for frequent roost switching is that females move to find suitable thermal conditions as ambient conditions change. Tests of this hypothesis have, however, been conducted mostly at roosts in artificial structures where microclimate is relatively stable. The goal of our study was to determine whether roost switching and roost use by northern long-eared bats, Myotis septentrionalis, that roost in trees are related to ambient conditions. We used generalized linear fixed effects models to explore the influence of roost characteristics and changes in ambient conditions on the likelihood of roost switching. We used canonical correlation analyses to examine the relationship between ambient conditions and roost characteristics. Roost switching was indeed linked to ambient conditions together with characteristics of roosts on the previous day; the best descriptors of roost switching differed between the two geographical regions we analysed. In Nova Scotia, females were less likely to switch roosts when it rained, particularly if they were in roosts below surrounding canopy whereas they were more likely to switch roosts when they were in roosts of high decay. Females roosted in shorter trees in earlier decay classes on warm days, as well as on windy and rainy days. In Kentucky, females were more likely to switch roosts at high temperatures, particularly when they were in roosts in high decay. Females roosted in shorter, decayed trees on warm days, and in less decayed trees with small diameter on windy and rainy days. Our results suggest bats switch roosts in response to changes in ambient conditions to select suitable roosting conditions, which may explain some of the proximate factors shaping fission-fusion dynamics of bats. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Though characterization of, and understanding determinants of, social structure in bats is increasing, little is known about how bat social groups respond to disturbance resulting in roost loss. Given that many species of bats roost in ephemeral or transitory resources such as plants, it is clear that bat social groups can tolerate some level of roost loss. Understanding responses of bat social groups to roost loss can provide insight into social structure that have applied conservation use. Herein, we review the existing literature on the effects of disturbance on bat social groups, and present a parameterizable agent-based model that can be used to explore the relationships among roost dynamics, population dynamics, and social behavior.