Myotis Septentrionalis Research Articles

Geographic Distribution, Reproduction, and Seasonal Activity of Bats in Iowa

From 2002 to 2018, we conducted 525 events to survey bats (nights of mist-netting and visits to bridges, mines, caves, etc.) and captured or observed 6119 bats, including all 9 species that regularly reside in Iowa. Our captures include a total of 142 new county records, and we located an additional 11 county records in specimens deposited in museums; we present at least 8 county records for each species in the state. Since the geographic distributions of most species span the entire state, many of these county records simply fill in gaps within hypothesized distributions. Records for Lasionycteris noctivagans, Lasiurus borealis, Myotis lucifugus, Myotis septentrionalis, Myotis sodalis, Nycticeius humeralis, and Perimyotis subflavus, however, extend the known range for these species or fill large gaps in their suspected distribution. Additionally, our captures provide evidence of reproduction occurring across the state for most species. Previously, little information had been published on the geographic extent of reproduction for bats in Iowa. Lastly, we report new information regarding timing of seasonal activities for bats in Iowa. For most species, we present new early and/or late records for lactation, postlactation, appearance of flying young, and flight activity outside of hibernation. Collectively, these records expand our knowledge of the biology of bats in Iowa.

Mitogenome of northern long-eared bat

The complete mitogenome of the northern long-eared bat (Myotis septentrionalis) was determined to be 17,362 bp and contained 22 tRNA genes, 2 rRNA genes and one control region. The whole genome base composition was 33.8% GC. Phylogenetic analysis suggests that M. septentrionalis be positioned next to M. auriculus in the Nearctic subclade of the Myotis genus. This complete mitochondrial genome provides essential molecular markers for resolving phylogeny and future conservation efforts.

Systematic Review of the Roost-Site Characteristics of North American Forest Bats: Implications for Conservation

Continued declines in North American bat populations can be largely attributed to habitat loss, disease, and wind turbines. These declines can be partially mitigated through actions that boost reproductive success; therefore, management aimed at promoting availability of high-quality roosting habitat is an important conservation goal. Following the principles of the umbrella species concept, if co-occurring species share similar roost-tree preferences, then management practices targeting one species may confer conservation benefits to another. We conducted a systematic review of roost-site characteristics of thirteen species inhabiting eastern temperate forests to: (1) synthesize existing knowledge across species; (2) assess niche overlap among co-occurring species; and (3) evaluate the potential for currently protected species to serve as conservation umbrellas. We performed multivariate ordination techniques to group species based on the seven most-reported roost-site characteristics, including tree species, diameter at breast height, tree health, roost type, tree height, canopy closure, and roost height. Species sorted into three roosting guilds: (1) southern wetland inhabitants; (2) foliage specialists; and (3) dead tree generalists. Myotis septentrionalis and Perimyotis subflavus had significant roost-niche overlap with five and four other species respectively, and their existing protections make them suitable umbrellas for other bats in the North American eastern temperate forests.

Winter Use of a Rock Crevice by Northern Long-Eared Myotis (Myotis septentrionalis) in Nebraska

We used a combination of acoustic detectors, thermal imaging cameras, and mist netting to confirm the use of a rock crevice by northern long-eared myotis (Myotis septentrionalis) in winter in northeastern Nebraska. Bats roosted in a large crevice in a rock face along the Missouri River, and 5 individuals were captured emerging from the opening of the crevice in March 2017. Our study is the first to confirm the use of a rock-crevice hibernaculum by M. septentrionalis and adds to the growing literature on the winter use of rock crevices by hibernating bats in North America. As white-nose syndrome (WNS) continues to spread across North America and decimate populations of M. septentrionalis, more knowledge of hibernation requirements is necessary to develop an effective recovery plan and to monitor this threatened species.

Antifungal Norditerpene Oidiolactones from the Fungus Oidiodendron truncatum, a Potential Biocontrol Agent for White-Nose Syndrome in Bats.

White-nose syndrome (WNS) is a devastating disease of hibernating bats caused by the fungus Pseudogymnoascus destructans. We obtained 383 fungal and bacterial isolates from the Soudan Iron Mine, an important bat hibernaculum in Minnesota, then screened this library for antifungal activity to develop biological control treatments for WNS. An extract from the fungus Oidiodendron truncatum was subjected to bioassay-guided fractionation, which led to the isolation of 14 norditerpene and three anthraquinone metabolites. Ten of these compounds were previously described in the literature, and here we present the structures of seven new norditerpene analogues. Additionally, this is the first report of 4-chlorophyscion from a natural source, previously identified as a semisynthetic product. The compounds PR 1388 and LL-Z1271α were the only inhibitors of P. destructans (MIC = 7.5 and 15 μg/mL, respectively). Compounds were tested for cytotoxicity against fibroblast cell cultures obtained from Myotis septentrionalis (northern long eared bat) and M. grisescens (gray bat) using a standard MTT viability assay. The most active antifungal compound, PR 1388, was nontoxic toward cells from both bat species (IC50 > 100 μM). We discuss the implications of these results in the context of the challenges and logistics of developing a substrate treatment or prophylactic for WNS.

Variation in Reproductive Timing for the Northern Long-Eared Myotis (Myotis septentrionalis) Across Nebraska

The northern long-eared myotis (Myotis septentrionalis), a federally threatened species, occurs in extreme northern, eastern, and southern Nebraska. These regions vary in climate due to geographic location, topography, and elevation. During a 1-week period in early July 2015, we surveyed bats across the state and observed striking variation in the reproductive status for M. septentrionalis. We examined whether or not growing degree days, an abiotic climatic factor used mainly for agricultural practices, was associated with this reproductive variation in a mammalian species. In early July, we captured only pregnant females in the Pine Ridge region of northwestern Nebraska, the region with the lowest number of growing degree days. In contrast, we captured both lactating females and flying young along the Republican River in south-central Nebraska near the border with Kansas, an area with a high, but intermediate number of growing degree days. Along the Missouri River, in extreme east-central Nebraska, along the border with Iowa, we documented lactating females with no evidence of volant young. This locality had the highest number of growing degree days. Phenotypic plasticity in timing of births for M. septentrionalis appears to be, in part, related to climatic differences across Nebraska, a relationship commonly observed for plants and invertebrates. Our study demonstrates that reproductive phenology can vary significantly across the distribution of a species and needs to be considered when making management decisions for imperiled species. Delayed reproduction in cooler regions of the species' range presents risks to reproductive female M. septentrionalis and their nonvolant offspring, even with current protective measures. In areas with short growing seasons, restrictions on the timing of tree-cutting should be expanded beyond 31 July in more northerly parts of the species' distribution, so as not to hinder reproductive success during the time when juvenile bats are unable to fly.

Predicting landscape-scale summer resource selection for the northern long-eared bat (Myotis septentrionalis) in Iowa

AbstractThe northern long-eared bat (Myotis septentrionalis) is currently listed as threatened under the U.S. Endangered Species Act largely due to population declines resulting from the spread of white-nose syndrome in North America. White-nose syndrome was confirmed in Iowa in 2015, emphasizing a need to closely monitor populations of M. septentrionalis statewide. We applied presence-only models to predict landscape-scale resource selection by M. septentrionalis using roost tree observations and mist net captures from various research and environmental assessment projects in Iowa (2003–2015). We used a simultaneous autoregressive (SAR) model to account for residual spatial autocorrelation in our compiled data set and estimate the proportional probability of use of summer habitats for M. septentrionalis. We estimated SAR models using four environmental predictor variables measured at two landscape scales (0.5- and 2.4-km) representative of M. septentrionalis home range sizes in North America. The SAR models resulted in high predictive fit with withheld test observations and an independent data set of acoustic detections of M. septentrionalis from recent surveys (2016–2018), indicating a significant positive relationship existed between habitat quality (as an index of selection) and distribution of M. septentrionalis at landscape scales. At both spatial scales, M. septentrionalis showed positive selection of closed canopy interior forest, bottomland hardwood forest, and total perennial stream length, whereas at the 0.5-km scale, M. septentrionalis also showed a positive association with open canopy forest. Our models indicated that up to 7.0% and 8.5% of the state was comprised of potentially suitable forested summer habitats for M. septentrionalis for 0.5- and 2.4-km scales, respectively. Our models also indicated the distribution of highly selected habitats at landscape scales in Iowa and accurately predicted independent observations of M. septentrionalis in areas of the state where no capture efforts have occurred. This study provides methods to predict landscape-scale resource selection and distribution for bats where multiple fine-scale data sources exist across broad geographic regions.

Changes in a summer bat community in southeastern Pennsylvania

Abstract Bat population changes are poorly understood, making it difficult to establish management priorities. In 2017, a summer mist-netting survey previously conducted in 2004 at Fort Indiantown Gap was replicated to evaluate temporal changes in the local bat community. The authors hypothesized that captures of species most affected by white-nose syndrome (WNS) would decline between survey periods, and that community structure would shift. The results showed a 100% decline in captures of northern long-eared Myotis (Myotis septentrionalis) and little brown Myotis (M. lucifugus), no change in captures of eastern red bats (Lasiurus borealis), a 276% increase in captures of big brown bats (Eptesicus fuscus), and a considerable shift in community structure. These results are consistent with expected effects of WNS on Myotis populations. Increases in big brown bat populations may result from ecological release after the decline of Myotis species, or from local or large-scale habitat change over time.

Roost selection by male northern long-eared bats (Myotis septentrionalis) in a managed fire-adapted forest

Wildlife conservation in multi-use landscapes requires identifying and conserving critical resources that may otherwise be destroyed or degraded by human activity. Summer day-roost sites are critical resources for bats, so conserving roost sites is a focus of many bat conservation plans. Studies quantifying day-roost characteristics typically focus on female bats due to their much stronger influence on reproductive success, but large areas of species’ ranges can be occupied predominantly by male bats due to sexual segregation. We used VHF telemetry to identify and characterize summer day-roost selection by male northern long-eared bats (Myotis septentrionalis) in a ponderosa pine (Pinus ponderosa) forest in South Dakota, USA. We tracked 18 bats to 43 tree roosts and used an information-theoretic approach to determine the relative importance of tree- and plot-level characteristics for roost site selection. Bats selected roost trees that were larger in diameter, more decayed, and under denser canopy than other trees available on the landscape. Much like studies of female northern long-eared bats have shown, protecting large-diameter snags within intact forest is important for the conservation of male northern long-eared bats. Unlike female-specific studies, however, many roosts in our study (39.5%) were located in short (≤3 m) snags. Protecting short snags may be a low-risk, high-reward strategy for conservation of resources important to male northern long-eared bats. Other tree-roosting bat species in fire-prone forests may benefit from forest management practices that promote these tree characteristics, particularly in high-elevation areas where populations largely consist of males.

Population genetics revealMyotis keenii(Keen’s myotis) andMyotis evotis(long-eared myotis) to be a single species

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.

Bats of the Boston Harbor Islands

Insectivorous bats are an integral part of ecosystems because they consume significant quantities of nocturnal insects. White-nose syndrome is decimating populations of susceptible bat species in North America; thus, inventorying and monitoring bats are critical first steps in managing these important populations. We inventoried bat species at Boston Harbor Islands National Recreation Area (BOHA), MA, from 2010 to 2011. Using a combination of capture and acoustic methods, we documented 6 bat species, including Eptesicus fuscus (Big Brown Bat), Lasiurus borealis (Eastern Red Bat), Lasiurus cinereus (Hoary Bat), Lasionycteris noctivagans (Silver-haired Bat), Myotis lucifugus (Little Brown Bat), and Myotis septentrionalis (Northern Long-eared Bat). Bats occurred at all inventoried islands, although most activity of Northern Long-eared Bat, a species Federally listed as threatened, was documented at a mainland site in Worlds End, near Ice Pond. Although the full extent of bat use on the islands remains unclear, we provide evidence of bats roosting and foraging on the islands. During long-term acoustic monitoring at Thompson and Lovells Islands, we assessed the effects of weather and season on bat activity; the latter analysis provided evidence of bats migrating through the area in spring and autumn.

Bat species distribution and habitat associations in northern Ontario, Canada

Bats are facing threats from disease, wind power development, and climate change, which are causing populations of many species to decline. The northern range limits of many temperate species are not well characterized, but the true distribution of threatened bat species is critical information for their conservation. We used passive acoustic monitoring and false-positive occupancy models to estimate the distributions of six species of bats in northern Ontario (north of ca. 50.5°N). We confirmed the presence of big brown bats (Eptesicus fuscus), hoary bats (Lasiurus cinereus), eastern red bats (Lasiurus borealis), silver-haired bats (Lasionycteris noctivagans), little brown myotis (Myotis lucifugus), northern long-eared myotis (Myotis septentrionalis), and tri-colored bats (Perimyotis subflavus) in our study area. We found that big brown bats, hoary bats, and little brown myotis likely are more widespread and common in northern Ontario than previously thought. Our models also provided evidence of associations between temperature and habitat types and bat occupancy probabilities. Our occupancy probability maps for each species support bat conservation by providing much finer-scale distribution information than previously available. These results provide a much-needed baseline for future studies of the distribution of these bat species in northern Ontario against which to measure the effects of white-nose syndrome, resource development, and climate change.

Relatedness within and among northern long-eared bat (Myotis septentrionalis) colonies at a local scale

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.

False-positive occupancy models produce less-biased occupancy estimates for a rare and elusive bat species

Confirming presence and distribution of a species is necessary for effective conservation. However, obtaining robust occupancy estimates and confidently identifying factors important to occupancy may be difficult for rare and elusive species. Further, in surveys to assess presence, false-positive detections bias results; however, false-positive occupancy models can resolve this bias and, thus, better support conservation. We assessed the performance of false-positive versus standard occupancy models and important factors predicting presence for a low-density bat population in the southern Appalachian Mountains. From May to August 2013–2015, we surveyed 35 sites for northern long-eared bats (Myotis septentrionalis) using both mist-net and acoustic methods. We compared AICcvalues for 13 standard occupancy models and 13 corresponding false-positive occupancy models. In our model comparison, false-positive models received more support, while none of the standard occupancy models were plausible. False-positive occupancy models produced a wider range of probability of occupancy estimates (0.004–0.998) and lower mean occupancy estimate (0.62) than standard models (0.482–0.970, mean = 0.86). Weighted parameter estimates for important predictors in two plausible false-positive occupancy models indicated the probability of occupancy for northern long-eared bats was higher at less-rugged, lowerelevation sites. In contrast, there was more ambiguity regarding the most plausible standard occupancy models and important predictors of occupancy from standard models. Due to low capture rates and the uncertainty of acoustic identifications, we recommend coupling a certain method with uncertain methods when surveying rare and elusive bat species. Applying false-positive occupancy models to our data yielded less-biased site-specific occupancy estimates and informative predictors, and, hence, more reliable predictions to inform conservation management plans.

Bat activity following repeated prescribed fire in the central Appalachians, USA

BackgroundTo restore and manage fire-adapted forest communities in the central Appalachians, USA, land managers are now increasingly prioritizing use of prescribed fire. However, it is unclear how the reintroduction of fire following decades of suppression will affect bat communities, particularly where white-nose syndrome-related population declines of many cave-hibernating bat species have occurred. To address this concern, we monitored and compared bat activity in burned and unburned habitat across a temporal gradient in western Virginia.ResultsWe found evidence for slightly positive fire effects on activity levels of the northern long-eared bat (Myotis septentrionalis [Trouessart, 1897]), Indiana bat (Myotis sodalis [Miller and Allen, 1928]), little brown bat (Myotis lucifugus [Le Conte, 1831]), big brown bat (Eptesicus fuscus [Palisot de Beauvois, 1796])/silver-haired bat (Lasionycteris noctivagans [Le Conte, 1831]) group, all high-frequency bats, and all bat species combined. We observed temporal effects only for the big brown bat, with a negative relationship between activity and time since fire.ConclusionBecause response of bat activity was neutral to weakly positive relative to burned forest condition, our results suggest that bats are not a resource that would impede the use of this management tool in the central Appalachians.

Bat Use of an Island off the Coast of Massachusetts

Nantucket, Massachusetts, could provide unique habitat for bats, but few data are available regarding bat populations on the island. We conducted passive acoustic surveys in 2015 and 2016 to inventory bat species and identify seasonal activity patterns. We detected at least 6 species of bats on Nantucket. Lasiurus cinereus (Hoary Bat) and Lasionycteris noctivagans (Silver-haired Bat) were detected as probable migrants, and Lasiurus borealis (Eastern Red Bat), Eptesicus fuscus (Big Brown Bat), and Myotis species were also present in summer. We detected Perimyotis subflavus (Tricolored Bat) in fall and early winter, suggesting that the species may hibernate on the island. In 2016, we mist-netted and radio-tagged Myotis septentrionalis (Northern Long-eared Bat), and documented individuals reproducing and hibernating on Nantucket. Given the persistence of this rare species on the island, we suggest that land-conservation organizations should consider maintenance of mature forest stands in their suite of planned management activities.

Landscape Characteristics Related to Use of Artificial Roosts by Northern Long-Eared Bats in North-Central West Virginia

In the eastern US, research is needed on the establishment and evaluation of conservation measures for forest-dwelling bats, in general, and for the newly listed Myotis septentrionalis (Northern Long-Eared Bat), in particular. Our objectives were to evaluate the overall use of 3 artificial roosting structures—rocket box, nursery box, and artificial bark—by bats and to relate this use to local landscape characteristics in north-central West Virginia. We monitored 306 structures during summer 2016 and detected use (i.e., presence of guano, visual identification, capture of bats) at 132 (43%) roosts, of which 55 (42%) were confirmed, through capture or visual identification, to contain Northern Long-eared Bats. Nursery boxes were used more than expected based on availability (60%), but rocket boxes accounted for 40 (73%) of the roosts confirmed to be occupied by Northern Long-eared Bats, with 70% being used by maternity colonies of this species. We utilized binomial generalized linear models and an information theoretic approach to examine use of artificial roosts by maternity colonies of Northern Long-eared Bats. Our best-supported model differentiating structures occupied by maternity colonies from those that housed individual bats showed relationships to elevation, slope, area solar radiation, and distance to streams and large (>200 ha) forests. Our study provides initial guidance for land and wildlife managers on implementing an effective conservation and management technique for bats within this region.

Landscape-scale distribution of tree roosts of the northern long-eared bat in Mammoth Cave National Park, USA

ContextThe roosting habits of many temperate zone bats are well documented at microhabitat scales, but fewer studies have included multi-scale assessments of landscape patterns in bat roost site selection.ObjectivesTo identify and assess at the landscape-scale the location of spring and early season maternity roosts of female northern long-eared bats (Myotis septentrionalis) from 2015 to 2016 at Mammoth Cave National Park (MACA), Kentucky, USA.MethodsWe used mist-nets and radiotelemetry to catch and track bats to roost trees across the landscape of MACA. Data on roosting sites were evaluated using spatial point pattern analysis to examine distributional trends of roosts. A variety of spatial covariates were used to model the effect of landscape pattern, including: forest type, elevation, and proximity to hibernacula, water, and road corridors.ResultsData indicate that roost locations of female northern long-eared bats in MACA were typically situated within 2000 m of known winter hibernacula, occurring more often at higher elevations in mesic upland deciduous forests, and in close proximity to water sources and roads. We present hypotheses to account for the patterns observed in relation to landscape features and habitat resources in the Park.ConclusionsOur data indicate that a more comprehensive understanding of habitat requirements which includes empirically-based, landscape-scale patterns, and not solely considerations at stand or local levels, could lead to better informed management policies targeting conservation of maternity habitat of forest-dwelling bats, including the northern long-eared bat, a species in decline throughout much of its distribution in North America.

Shifts in Assemblage of Foraging Bats at Mammoth Cave National Park following Arrival of White-nose Syndrome

The arrival of white-nose syndrome (WNS) to North America in 2006, and the subsequent decline in populations of cave-hibernating bats have potential long-term implications for communities of forest-dwelling bats in affected regions. Severe declines in wintering populations of bats should lead to concomitant shifts in the composition and relative abundance of species during the staging, maternity, and swarming seasons in nearby forested habitats. We examined capture rates of bats collected in mist nets from 2009 to 2016 to evaluate summer patterns in abundance of species pre- and post-arrival of WNS to Mammoth Cave National Park, KY. The data demonstrated a significant change in overall relative abundances. Myotis septentrionalis (Northern Long-eared Myotis) was the most commonly captured species pre-WNS but declined to 18.5% of its original abundance. Nycticeius humeralis (Evening Bat), uncommonly caught in mist nets pre-WNS, demonstrated the largest increase in capture success following arrival of WNS to the Park, followed by Eptesicus fuscus (Big Brown Bat) and Lasiurus borealis (Eastern Red Bat). These data suggest that losses of cave-hibernating bats to WNS may be leading to a restructuring of foraging bat assemblages in nearby forested habitats, with species less affected by WNS potentially exploiting niche space vacated by bats succumbing to infection with WNS.

Night-Roosting Behaviors for the Northern Long-Eared Myotis (Myotis septentrionalis) Under a Bridge Revealed by Time-Lapse Photography

The northern long-eared myotis (Myotis septentrionalis) occurs across much of eastern North America and is listed as federally threatened in the United States due to pervasive population declines. Limited data are available about roosting behaviors for this imperiled species. We report on night-roosting behaviors for the northern long-eared myotis under a bridge in northwestern Nebraska. Grooming, short visits, and feeding were the most frequently observed behaviors. Grooming, inactivity, and nursing had the longest durations, albeit all averaged <15 min per event. We also documented movement and urination infrequently. Prey manipulation associated with feeding was a frequent behavior and consisted of individuals facing upward or downward, culling wings, elytra, and legs of large prey items. When facing upward wing and tail membranes formed a cup against the abutment wall that likely limited loss of prey. Individuals used the bridge throughout the night but roosted most frequently at 4 and 8 h after sunset (00:15 and 04:15 h, respectively), with early morning activity dominated by feeding/prey manipulation. Our study showed night roosts were used frequently for many reasons, especially for grooming and consumption of large prey. Our observations represent the first description of night-roosting behaviors for the northern long-eared myotis.