Euderma Research Articles

Once upon a time in Mexico: Holocene biogeography of the spotted bat (Euderma maculatum).

Holocene-era range expansions are relevant to understanding how a species might respond to the warming and drying climates of today. The harsh conditions of North American deserts have phylogenetically structured desert bat communities but differences in flight capabilities are expected to affect their ability to compete, locate, and use habitat in the face of modern climate change. A highly vagile but data-deficient bat species, the spotted bat (Euderma maculatum), is thought to have expanded its range from central Mexico to western Canada during the Holocene. With specimens spanning this latitudinal extent, we examined historical demography, and used ecological niche modeling (ENM) and phylogeography (mitochondrial DNA), to investigate historic biogeography from the rear to leading edges of the species' range. The ENM supported the notion that Mexico was largely the Pleistocene-era range, whereas haplotype pattern and Skyline plots indicated that populations expanded from the southwestern US throughout the Holocene. This era provided substantial gains in suitable climate space and likely facilitated access to roosting habitat throughout the US Intermountain West. Incongruent phylogenies among different methods prevented a precise understanding of colonization history. However, isolation at the southern-most margin of the range suggests a population was left behind in Mexico as climate space contracted and are currently of unknown status. The species appears historically suited to follow shifts in climate space but differences in flight behaviors between leading edge and core-range haplogroups suggest range expansions could be influenced by differences in habitat quality or climate (e.g., drought). Although its vagility could facilitate response to environmental change and thereby avoid extinction, anthropogenic pressures at the core range could still threaten the ability for beneficial alleles to expand into the leading edge.

Informing wind energy development: Land cover and topography predict occupancy for Arizona bats.

Wind energy is a growing source of renewable energy with a 3-fold increase in use globally over the last decade. However, wind turbines cause bat mortality, especially for migratory species. The southwest United States has high bat species diversity and is an important area for migratory species, although little is known about their seasonal distribution. To examine potential risk to bats in areas proposed for wind energy development, we characterized bat occupancy spatially and temporally across northern Arizona, identifying use during summer when bats are reproductively active and fall during the migratory season. Our objectives were to determine occupancy of migratory species and species of greatest conservation need and develop a probability of occupancy map for species to identify areas of potential conflict with wind energy development. We selected 92 sites in 10 clusters with potential for development and used acoustic detectors to sample bats in the summer and fall of 2016 and 2017 for 6 nights per site per year. We predicted response of migratory bat species and species of special concern to 9 landscape variables using Program MARK. During summer, higher densities of forest on the landscape resulted in a higher probability of occupancy of migratory species such as hoary bats (Lasiurus cinereus), silver-haired bats (Lasionycteris noctivagans), big free-tailed bats (Nyctinomops macrotis), and species of conservation need such as spotted bats (Euderma maculatum). During the fall, higher concentration of valleys on the landscape predicted occupancy of hoary bats, big free-tailed bats, and spotted bats. High bat occupancy in the fall was also associated with higher elevation and close proximity to forests. We recommend that wind turbines be placed in open, flat grasslands away from forested landscapes and concentrations of valleys or other topographic variation.

Spatial Gaussian processes improve multi‐species occupancy models when range boundaries are uncertain and nonoverlapping

Abstract Species distribution models enable practitioners to analyze large datasets of encounter records and make predictions about species occurrence at unsurveyed locations. In omnibus surveys that record data on multiple species simultaneously, species ranges are often nonoverlapping and misaligned with the administrative unit defining the spatial domain of interest (e.g., a state or province). Consequently, some species display differentially restricted extents within a study area. Assuming hard boundaries based on expert opinion or published range maps to restrict species occurrence predictions implies a false sense of certainty in model‐based inferences. We propose a multi‐species occupancy model with a spatial Gaussian process on site‐specific effects for each species as a model‐based solution. Specifying informative Bayesian hyperpriors on the spatial hyperparameters encapsulates broad‐scale correlation among site occupancy probabilities for each species. We fit this model to acoustic detection/nondetection data collected with autonomous recording units during summer of 2016–2019 throughout Oregon and Washington, USA, on 15 bat species. We found vast improvements in spatial predictions of spotted bat (Euderma maculatum), canyon bat (Parastrellus hesperus), and Brazilian free‐tailed bat (Tadarida brasiliensis) when the available environmental predictors were insufficient for characterizing their restricted ranges within the region. In contrast, widespread species (Lasionycteris noctivagans, Myotis californicus, Myotis evotis, Myotis volans) were appropriately modeled using only environmental predictors, such as percentage forest cover and cliff and canyon cover. Utilizing spatial Gaussian processes within a community or multi‐species model incorporates uncertainty in range boundaries and allows for simultaneous predictions for the entire faunal assemblage even if species have nonoverlapping or restricted ranges within a spatial domain of interest. Such modeling improvements are essential if species distribution models are to accurately inform monitoring, species recovery plans, and other conservation efforts.

Seasonal Activity and Diets of Bats at Uranium Mines and Adjacent Areas near the Grand Canyon

Little information exists on the habitat use and feeding ecology of insectivorous bats in arid ecosystems, especially at and near uranium mines in northern Arizona, within the Grand Canyon watershed. In 2015–2016, we conducted mist-netting, nightly acoustic monitoring (>1 year), and diet analyses of bats, as well as insect sampling, at 2 uranium mines (Pinenut and Arizona 1) with water containment ponds. Because of physical barriers and limited general access to areas within the mine yard, mist-netting was limited to outside of the perimeter fence and away from the containment ponds. Mist-netting also occurred at 2 nearby sites that served as proxies to the mines. Bats captured directly at the mines included one pregnant Antrozous pallidus and 3 adult male Parastrellus hesperus. At the proxy sites, we captured 45 individuals identified as A. pallidus, Corynorhinus townsendii, Eptesicus fuscus, Euderma maculatum, Lasionycteris noctivagans, Myotis californicus, Myotis ciliolabrum, P. hesperus, and Tadarida brasiliensis. The nightly and seasonal presence of bats, as shown through acoustic recordings at each mine, coincided with the seasonal migratory and hibernation behaviors of the bat species. Statistical comparisons of acoustic recordings with precipitation data collected over one year show that seasonal monsoon rains generally had a negative effect on the nightly activity and presence of bats. Diets of P. hesperus from both mines were comprised mostly of coleopterans but also included smaller volumes of Hymenoptera, Hemiptera, Lepidoptera, Diptera, and Neuroptera. The diet of A. pallidus was comprised solely of Coleoptera. Diets of bat species from the proxy sites were characteristic of their known feeding ecology, which ranged from the consumption of soft-bodied insects (e.g., moths) by C. townsendii to the consumption of hard-bodied insects (e.g., beetles) by E. fuscus. Ultimately, the increased knowledge of the natural history of bats through multiple methods of data collection allows for a better understanding of complex arid ecosystems. It also provides resources needed for the management of habitat associated with alternative energy, such as uranium mining.

Audible bats provide opportunities for citizen scientists

AbstractBat conservation has been impeded by a lack of basic information about species' distributions and abundances. Public participation in closing this gap via citizen (community) science has been limited, but bat species that produce low‐frequency calls audible to the unaided human ear provide an overlooked opportunity for collaborative citizen science surveys. Audible bats are rare in regional faunas but occur globally and can be under‐surveyed by traditional methods. During 2019–2020, we were joined by community members to conduct aural surveys and expand our knowledge of rare audible desert bats in western North America through a structured survey design broadly adaptable for practitioners across the globe where audible bats occur. Our study was integrated into a statistically robust but flexible master sample in use by the North American Bat Monitoring Program (NABat), ensuring representativeness of data contributions. We used survey results to update a Bayesian species distribution model for the rare spotted bat, Euderma maculatum, accounting for imperfect detection and including land cover occupancy predictors. Detection probability was estimated ~0.7 ± 0.1. Informative priors from a previous attempt to model E. maculatum were leveraged with the new citizen science data to support spatial predictions of occurrence previously impeded by data sparsity and which reinforced the biogeographic importance of arid cliffs and canyons. Our results are preliminary but encouraging, and future surveys can scale up through the NABat design structure and Bayesian modeling framework. We encourage future surveys to use recording devices to obtain voucher calls and double‐observer methods to address false‐positive detection errors that arise with inexperienced volunteers. Our design and model supported approach to integrating citizen science surveys into bat conservation programs can strengthen both the scientific understanding of rare species and public engagement in conservation practices.

Rapid Biodiversity Sampling for Bat Assemblages in Northwestern Nevada

Abstract Bat (Chiroptera) assemblages in the western North America remain understudied despite their importance to ecosystem function and vulnerability to multiple anthropogenic stressors. We present the first large-scale survey that we are aware of for bat fauna in the Black Rock Plateau of northwestern Nevada in the northern Great Basin Desert. We conducted surveys using both acoustic and mist net methods, documenting 14 species across 19 sites sampled during a four-night period in August 2016. We surveyed over water sources, usually surrounded by cliff and canyon habitat, and in salt desert scrub, sagebrush, and woodland habitats, detecting multiple sensitive bat species (spotted bat Euderma maculatum, little brown bat Myotis lucifugus, canyon bat Parastrellus hesperus) in the canyon habitats of the High Rock region. We analyzed regional species diversity and present the utility of using multiple detection methods to enhance understanding of Chiroptera biodiversity at both local and regional scales. Our results demonstrate the utility of “BioBlitz” approaches in documenting local and regional diversity and provide insight into areas with species assemblages or vulnerable species. Knowledge of these sites is increasingly important for future disease surveillance and population monitoring.

Attempted predation of a diurnally active Spotted Bat (<em>Euderma maculatum</em>) by a Belted Kingfisher (<em>Megaceryle alcyon</em>)

Most species of bats (Chiroptera) are nocturnal, and diurnal activity is only occasionally reported. I observed a Spotted Bat (Euderma maculatum) flying along a lakeshore in the Okanagan Valley of southcentral British Columbia, Canada, in mid-afternoon. The Spotted Bat flew along the shoreline and drank from the lake. During the course of its flight, the Spotted Bat was attacked by a Belted Kingfisher (Megaceryle alcyon), but it escaped. This is the first reported observation of a Spotted Bat active during the daytime. It is also the first reported observation of attempted predation of a bat by a Belted Kingfisher. It is not known how prevalent daytime activity is in Spotted Bats, but this observation supports the hypothesis that predation risk may be high for bats that are active during the day.

Spotted bat (Euderma maculatum) microsatellite discovery using illumina sequencing

The spotted bat (Euderma maculatum) is a rarely-encountered species for which behavior and population attributes are largely unknown. Using next-generation sequencing, we identified and characterized 17 microsatellite loci, which were screened for 31 individuals from northern Arizona. Allelic diversity, observed heterozygosity, and power of discrimination were high (NA: 5–8 alleles per locus; HO: 0.55–0.90; P ID : 1.2 × 10−15). All loci were in HWE, there was no evidence of null alleles or linkage disequilibrium, and five loci amplified and were variable in another Vespertillionid (Eptesicus fuscus). We will use these loci to evaluate gene flow and genetic diversity across the range of the spotted bat and determine population size in northern Arizona. The latter information is important to resource managers, who attempt to set mortality thresholds for bats at wind energy facilities in this region.

Roosts and home ranges of spotted bats (Euderma maculatum) in northern Arizona

Roosting ecology and foraging behavior of spotted bats ( Euderma maculatum (J.A. Allen, 1891)) are poorly known. We captured 47 spotted bats at three locations in northern Arizona and attached radio transmitters to 16 bats to identify roosts and home ranges. We identified 14 roosts for 12 bats. Female roosts faced south; males did not select a roost aspect. Bats used a mean of 1.4 roosts during 10 days. Mean distances from capture site and nearest perennial water source to roosts were 15.1 and 5.8 km, respectively. Maximum and minimum distances from capture to roost site were 36.3 and 2.3 km, respectively. Home ranges (95% use, minimum convex polygon method) for bats averaged 297 km2, which was much larger than reported for spotted bats elsewhere in their range and other insectivorous bats. Maximum flight speed was 53 km/h. Most foraging locations were in desert scrub vegetation, but bats also used woodlands and forests, perhaps seeking seasonal prey or cooler sites to reduce water stress. Maternity roosts were remote, difficult to access, and within protected areas in northern Arizona. Foraging areas and ponds used for drinking, however, included private and public lands managed for a variety of uses.

Bats of Mesa Verde National Park, Colorado: Composition, Reproduction, and Roosting Habits

We determined the bat fauna at Mesa Verde National Park (Mesa Verde) in 2006 and 2007, characterized bat elevational distribution and reproduction, and investigated roosting habits of selected species. We captured 1996 bats of 15 species in mist nets set over water during 120 nights of sampling and recorded echolocation calls of an additional species. The bat fauna at Mesa Verde included every species of bat known west of the Great Plains in Colorado, except the little brown bat (Myotis lucifugus). Some species showed skewed sex ratios, primarily due to a preponderance of males. Thirteen species of bats reproduced at Mesa Verde. Major differences in spring precipitation between the 2 years of our study were associated with differences in reproductive rates and, in some species, with numbers of juveniles captured. Reduced reproductive effort during spring drought will have a greater impact on bat populations with the forecasted increase in aridity in much of western North America by models of global climate change. We radiotracked 46 bats of 5 species to roosts and describe the first-known maternity colonies of spotted bats (Euderma maculatum) in Colorado. All 5 species that we tracked to diurnal roosts relied almost exclusively on rock crevices rather than trees or snags, despite the presence of mature forests at Mesa Verde and the use of trees for roosts in similar forests elsewhere by some of these species. Comparisons with past bat surveys at Mesa Verde and in surrounding areas suggest no dramatic evidence for effects of recent stand-replacing fires on the composition of the bat community.

Diet of spotted bats (Euderma maculatum) in Arizona as indicated by fecal analysis and stable isotopes

We assessed diet of spotted bats ( Euderma maculatum (J.A. Allen, 1891)) by visual analysis of bat feces and stable carbon (δ13C) and nitrogen (δ15N) isotope analysis of bat feces, wing, hair, and insect prey. We collected 33 fecal samples from spotted bats and trapped 3755 insects where bats foraged. Lepidopterans averaged 99.6% of feces by volume; other insects were not a major component of diet. The δ13C and δ15N values of bat feces were similar to those of moths from families Noctuidae (N), Lasiocampidae (L), and Geometridae (G), but differed from Arctiidae (A) and Sphingidae (S). We used a mixing model to reconstruct diet; three families (N, L, G) represented the majority (88%–100%) of the diet with A + S representing 0%–12%. Although we compared δ13C and δ15N values of wing, hair, and feces of spotted bats, feces best represented recent diet; wing and hair were more enriched than feces by 3‰ and 6‰, respectively. This pattern was consistent with that reported for other bat species. We suggest that spotted bats persist across a wide latitudinal gradient partly because they can forage on a variety of noctuid, geometrid, and lasiocampid moths. Using visual fecal inspection with stable isotope analysis provided information on families of moths consumed by an uncommon bat species.

Bats Associated with Inactive Mines in the Western Great Basin

ABSTRACT. We surveyed bats using echolocation calls near inactive mines in the western Great Basin from 2003 to 2007. We identified 14 species of bats during our surveys, with Myotis lucifugus and Lasionycteris noctivagans found at 9 sites and Myotis evotis and Tadarida brasiliensis at 7 sites; all other species were found at less than one-half of the sites. Euderma maculatum, a state-protected species in Nevada, was recorded at 2 sites. Our work provides information that will be useful in managing bat habitat, especially with regard to mining activities.

Spotted Bats (Euderma maculatum) from Mt. Taylor, New Mexico

The spotted bat (Euderma maculatum) is an elusive and rarely captured species in western North America. In the United States, it is known from 12 western states. In New Mexico, few individuals have been reported in recent years, and multiple individuals are known from 9 of 12 capture sites. This study reports on additional captures of E. maculatum from Mt. Taylor (Cibola County) for 2 consecutive summers and includes evidence of a reproducing population in the area. On 30 June/1 July 2006, I captured 4 individuals of E. maculatum, including a lactating female, and on 5 June 2007, I captured a nonreproductive female. The flight of this species was directional and deliberate; I captured 5 of 6 spotted bats that came low over the earthen pond. This study demonstrates how human-made sources of water in an arid region provide opportunities for many species of bats to drink.

DOCUMENTATION OF AN URBAN WINTER ROOST OF THE SPOTTED BAT (EUDERMA MACULATUM)

We report the first documented use of a building as a winter roost by Euderma maculatum. We suggest that sufficient numbers of E. maculatum have been encountered in urban settings that researchers should consider these areas during the course of investigations of species occurrence. We recommend that urban settings in the vicinity of large cliff features be sampled systematically for the presence of E. maculatum.

A Record of the Spotted Bat (Euderma maculatum) from Crescent Bar, Washington

bia, Idaho, and Oregon (Watkins 1977; Nagorsen and Brigham 1993; Verts and Carraway 1998). Sarell and McGuinness (1993) presented the first reports of spotted bats in north-central Washington State. Subsequent surveys have noted spotted bats at additional locations, including sites in Douglas, Grant, and Okanogan counties (John Fleckenstein, Natural Heritage Program, Washington Department of Natural Resources, Olympia, WA, pers. comm.; Neal Hedges, Bureau of Land Management, Wenatchee, WA, pers. comm.). However, limited information is available about the distribution

Distribution of the Spotted Bat (Euderma maculatum) in Nevada, Including Notes on Reproduction

Distribution of the Spotted Bat (Euderma maculatum) in Nevada, Including Notes on Reproduction

Distribution of the Spotted Bat, Euderma maculatum, in California

There were 14 records, including the type, for Euderma maculatum in California between 1891–1991. All involved salvage of single bats; most indviduals were dead or moribund. In surveys from 1992 to 1997, using primarily acoustic sampling at possible foraging sites within a few kilometers of fractured resistant rock cliffs, 23 additional localities were identified, including a range extension into the Klamath Mountains of northwestern California. E. maculatum typically was encountered foraging in meadows on the edge of forests in mixed conifer-hardwood habitat at elevations of 800–1,500 m, but observations extend to 2,926 m in the Sierra Nevada. Usually one E. maculatum was observed at a foraging site, but occasionally two or three were present simultaneously. These records suggest that the species, while typically at low density within a few kilometers of geomorphically defined roosts, occurs more widely than previously realized. Although its foraging style and characteristics of its call are distinctive, E. maculatum overlaps extensively both in geographic range and use of roosts in rock cliffs with several other species of bat, notably Eumops perotis, which also has an audible echolocation call. The linked pattern of rarity, patchy distribution, and restrictive roosting requirements place this species at risk.

Phylogeny of Plecotine Bats: Reevaluation of Morphological and Chromosomal Data

Recent systematic studies of the tribe Plecotini have generated two alternative phylogenetic hierarchies: ( Barbastella ( Corynorhinus ( Plecotus ( Idionycteris Euderma )))); and ( Euderma \[including Idionycteris \] ( Barbastella ( Plecotus Corynorhinus ))). To test these hypotheses we examined 44–45 morphological and 11 karyological characters of 10 plecotine species, including Otonycteris hemprichii . Character states for the hypothetical ancestor were inferred by evaluation of selected outgroup taxa: Rhogeessa tumida, Nycticeius humeralis, Eptesicus fuscus, Myotis lucifugus, M. ciliolabrum , and Miniopterus schreibersi . The most parsimonious trees, identical in topology but different in character-state optimization, were congruent with the systematic hierarchy of Plecotini suggested by the first hypothesis. Otonycteris branched off before Corynorhinus . These results strongly support separation of Corynorhinus as an independent genus and limitation of Plecotus to Palaearctic species. The two highly derived taxa, Idionycteris phyllotis and Euderma maculatum , seem to be sufficiently different from each other to be regarded as genetically distinct. It is proposed that the tribe Plecotini originated in the eastern hemisphere.

The echolocation calls of the spotted bat Euderma maculatum are relatively inaudible to moths

Previous studies of the spotted bat Euderma maculatum have demonstrated that this bat emits echolocation calls that are lower in frequency, shorter in duration and fainter in intensity compared with those of most other insectivorous bats, acoustic characteristics which should render it less conspicuous to eared moths. We tested this prediction by monitoring electrophysiologically the ears of sympatric noctuoid (noctuid, arctiid and notodontid) moths in a site in western Canada. Auditory threshold curves demonstrate that most of the moths tested are less responsive to the calls of Eu. maculatum than to those of another sympatric bat, Eptesicus fuscus. Playbacks to moth ears of pre-recorded search- and approach-phase echolocation calls of Eu. maculatum and Ep. fuscus further demonstrate that the calls of Eu. maculatum are poorly detectable to moths and, in some cases, completely inaudible. We estimate that, in the wild, an average noctuoid moth would detect the calls of Eu. maculatum at distances of less than 1 m as opposed to the calls of Ep. fuscus which should be first heard at distances of 20­25 m. Although most moths are unable to adequately hear Eu. maculatum, the observation that two individuals possessed ears sensitive to this bat's calls suggests the existence of auditory pre-adaptation to this type of echolocation.

Flexible bat echolocation: the influence of individual, habitat and conspecifics on sonar signal design

Acoustic signals which are used in animal communication must carry a variety of information and are therefore highly flexible. Echolocation has probably such functions and could prove as flexible. Measurable variabitlity can indicate flexibility in a behaviour. To quantify variability in bat sonar and relate to behavioural and environmental factors, I recorded echolocation calls of Euderma maculatum, Eptesicus fuscus, Lasiurus borealis and L. cinereus while the bats hunted in their natural habitat. I analysed 3390 search phase calls emitted by 16 known and 16 unknown individuals foraging in different environmental and behvioural situations. All four species used mainly multiharmonic signals that showed considerable intra- and inter-individual variability in the five signal variables I analysed (call duration, call interval, highest and lowest frequency and frequency with maximum energy) and also in the shape of the sonagram. A nested multivariate analysis of variance identified the influences of individual, hunting site, close conspecifics and of each observation on the frequency with maximum energy in the calls, and on other variables measured. Individual bats differed in multiple comparisons, most often in the main call frequency and least often in call interval. In a discriminant function analysis with resubstitution, 56–76% of a species' calls were assigned to the correct individual. Distinct individual call patterns were recorded in special situations in all species and the size of foraging areas in forested areas influenced temporal and spectral call structure. Echolocation behaviour was influenced by the presence of conspecifics. When bats were hunting together, call duration decreased and call interval increased in all species, but spectral effects were less pronounced. The role of morphometric differences as the source of individually distinct vocalizations is discussed. I also examined signal adaptations to long range echolocation and the influence of obstacle distance on echolocation call design. My results allow to discuss the problems of echo recognition and jamming avoidance in vespertilionid bats.