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Estimating the abundance of unmarked animal populations from acoustic data is challenging due to the inability to identify individuals and the need to adjust for observation biases including detectability (false negatives), species misclassification (false positives), and sampling exposure. Acoustic surveys conducted along mobile transects were designed to avoid counting individuals more than once, where raw counts are commonly treated as an index of abundance. More recently, false‐positive abundance models have been developed to estimate abundance while accounting for imperfect detection and misclassification. We adapted these methods to model summertime abundance and trends of three species of bats at multiple spatial scales using acoustic recordings collected along mobile transects by partners of the North American Bat Monitoring Program (NABat) from 2012 to 2020. This multiscale modeling spanned individual transect routes, larger NABat grid cells (10 km × 10 km), and across the entire extent of modeled species ranges. We estimated relationships between species abundances and a suite of abiotic and biotic predictors (landcover types, climatological variables, physiographic diversity, building density, and the impacts of white‐nose syndrome [WNS]) and found varying levels of support between species. We present clear evidence of substantial declines in populations of tricolored bats (Perimyotis subflavus) and little brown bats (Myotis lucifugus), declines that corresponded in space and time with the progression of WNS, a devastating disease of hibernating bats. In contrast, our analysis revealed that similar population‐wide declines probably have not occurred in big brown bats (Eptesicus fuscus), a species known to be less affected by WNS. This study provides the first abundance‐based species distribution predictions and population trends for bats in their summer ranges in North America. These models will probably be applicable to assessing wildlife populations in other monitoring programs where acoustic data are used or where false‐negative and false‐positive detections are present. Finally, our abundance framework (as a spatial point pattern process) can serve as a foundation from which more sophisticated integrated species distribution models that incorporate additional streams of monitoring data (e.g., stationary acoustics, captures) can be developed for North American bats. [ABSTRACT FROM AUTHOR]

Recognizing delineations of gene flow among groups of animals can be challenging but is necessary for conservation and management. Of particular importance is the identification of species boundaries. Several physical and genetic traits have been used with mixed success to distinguish Myotis keenii (Merriam, 1895) (Keen's myotis) and Myotis evotis (H. Allen, 1864) (long-eared myotis), but it is unclear whether species distinction is biologically warranted. We generated 12-14 microsatellite locus genotypes for 275 long-eared Myotis representing four species--M. keenii, M. evotis, Myotis septentrionalis (Trouessart, 1897) (northern myotis), and Myotis thysanodes Miller, 1897 (fringed myotis)--from across northwestern North America and 23 Myotis lucifugus (Le Conte, 1831) (little brown myotis) as the outgroup. Population genetic analyses revealed four well-defined groups (species): M. septentrionalis, M. thysanodes, M. lucifugus, and a single group comprising M. keenii and M. evotis. We document high rates of gene flow within M. evotis/M. keenii. Cytochrome b gene(mtDNA) sequencing failed to resolve morphologically identifiable species. We highlight the importance of geographically thorough investigation of genetic connectivity (nuclear markers) when assessing taxonomic status of closely related groups. We document a morphometric cline within M. evotis/M. keenii that may in part explain earlier analyses that led to the description of the smaller bodied M. keenii (type locality: Haida Gwaii). We conclude that M. keenii does not qualify as a genetic or biological species. Key words: Myotis keenii, Keen's myotis, Myotis evotis, long-eared myotis, Myotis thysanodes, fringed myotis, Myotis septentrionalis, northern myotis, Myotis lucifugus, little brown myotis, microsatellites, taxonomy. Si elle peut s'averer difficile, la determination des traces de flux de genes entre groupes d'animaux est neanmoins necessaire pour la conservation et la gestion. L'etablissement des frontieres entre especes est particulierement important. Si plusieurs caracteres physiques et genetiques ont ete utilises avec un succes mitige pour distinguer Myotis keenii (Merriam, 1895) (vespertilion de Keen) et Myotis evotis (H. Allen, 1864) (vespertilion a longues oreilles), la pertinence, du point de vue biologique, de distinguer ces deux especes demeure incertaine. Nous avons produit des genotypes de 12-14 loci microsatellites pour 275 vespertilions a longues oreilles representant quatre especes--M. keenii, M. evotis, Myotis septentrionalis (Trouessart, 1897) (vespertilion nordique) et Myotis thysanodes Miller, 1897 (vespertilion a queue frangee)--provenant de tout le nord-ouest de l'Amerique du Nord et 23 Myotis lucifugus (Le Conte, 1831) (vespertilion brun) hors groupe. Les analyses de la genetique des populations revelent quatre groupes bien definis, a savoir M. septentrionalis, M. thysanodes, M. lucifugus et un seul groupe comprenant M. keenii et M. evotis. Nous documentons des taux eleves de flux genetique au sein de M. evotis/M. keenii. Le sequencage du gene du cytochrome b (ADNmt) ne permet pas de distinguer des especes identifiables sur une base morphologique. Nous soulignons l'importance d'un examen geographiquement exhaustif de la connectivite genetique (marqueurs genetiques) pour l'evaluation du statut taxonomique de groupes etroitement relies. Nous documentons un cline morphometrique au sein de M. evotis/M. keenii qui pourrait en partie expliquer des analyses passees qui ont mene a la description du plus petit M. keenii (localite type : Haida Gwaii). Nous concluons que M. keenii ne constitue pas une espece genetique ou biologique. [Traduit par la Redaction] Mots-cles: Myotis keenii, vespertilion de Keen, Myotis evotis, vespertilion a longues oreilles, Myotis thysanodes, vespertilion a queue frangee, Myotis septentrionalis, vespertilion nordique, Myotis lucifugus, vespertilion brun, microsatellites, taxonomie., Introduction In animals whose morphological evolution is constrained, convergence of traits has made taxonomy difficult (Lowe et al. 2004). Microchiropteran bats are a classic example of shared ecological constraints, with [...]

White-nose syndrome (WNS) has notably affected the abundance of Myotis lucifugus (little brown myotis) in North America. Thus far, substantial mortality has been restricted to the eastern part of the continent where the cause of WNS, the invasive fungus Pseudogymnoascus destructans, has infected bats since 2006. To date, the state of Washington is the only area in the Western US or Canada (the Rocky Mountains and further west in North America) with confirmed cases of WNS in bats, and there the disease has spread more slowly than it did in Eastern North America. Here, we review differences between M. lucifugus in western and eastern parts of the continent that may affect transmission, spread, and severity of WNS in the West and highlight important gaps in knowledge. We explore the hypothesis that western M. lucifugus may respond differently to WNS on the basis of different hibernation strategies, habitat use, and greater genetic structure. To document the effect of WNS on M. lucifugus in the West most effectively, we recommend focusing on maternity roosts for strategic disease surveillance and monitoring abundance. We further recommend continuing the challenging work of identifying hibernation and swarming sites to better understand the microclimates, microbial communities, and role in disease transmission of these sites, as well as the ecology and hibernation physiology of bats in noncavernous hibernacula. [ABSTRACT FROM AUTHOR]

In multihost disease systems, differences in mortality between species may reflect variation in host physiology, morphology, and behavior. In systems where the pathogen can persist in the environment, microclimate conditions, and the adaptation of the host to these conditions, may also impact mortality. White‐nose syndrome (WNS) is an emerging disease of hibernating bats caused by an environmentally persistent fungus, Pseudogymnoascus destructans. We assessed the effects of body mass, torpid metabolic rate, evaporative water loss, and hibernaculum temperature and water vapor deficit on predicted overwinter survival of bats infected by P. destructans. We used a hibernation energetics model in an individual‐based model framework to predict the probability of survival of nine bat species at eight sampling sites across North America. The model predicts time until fat exhaustion as a function of species‐specific host characteristics, hibernaculum microclimate, and fungal growth. We fit a linear model to determine relationships with each variable and predicted survival and semipartial correlation coefficients to determine the major drivers in variation in bat survival. We found host body mass and hibernaculum water vapor deficit explained over half of the variation in survival with WNS across species. As previous work on the interplay between host and pathogen physiology and the environment has focused on species with narrow microclimate preferences, our view on this relationship is limited. Our results highlight some key predictors of interspecific survival among western bat species and provide a framework to assess impacts of WNS as the fungus continues to spread into western North America. [ABSTRACT FROM AUTHOR]

The role of the skin microbiome in resistance and susceptibility of wildlife to fungal pathogens has been examined from a taxonomic perspective but skin microbial function, in the context of fungal infection, has yet to be studied. Our objective was to understand effects of a bat fungal pathogen site infection status and course of invasion on skin microbial function. We sampled seven hibernating colonies of Myotis lucifugus covering three-time points over the course of Pseudogymnoascus destructans (Pd) invasion and white nose syndrome (pre-invasion, epidemic, and established). Our results support three new hypotheses about Pd and skin functional microbiome: (1) there is an important effect of Pd invasion stage, especially at the epidemic stage; (2) disruption by the fungus at the epidemic stage could decrease anti-fungal functions with potential negative effects on the microbiome and bat health; (3) the collection site might have a larger influence on microbiomes at the pre-invasion stage rather than at epidemic and established stages. Future studies with larger sample sizes and using meta-omics approaches will help confirm these hypotheses, and determine the influence of the microbiome on wildlife survival to fungal disease., (© The Author(s) 2024. Published by Oxford University Press on behalf of FEMS.)