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.

Introduction

Systematic surveys, especially for cryptic species, are difficult to implement, requiring extensive training and resources from multiple surveyors. Although multispecies inventory efforts are sorely needed in many of the remote locations of the Intermountain West, funding for regional biodiversity assessments is often limited. The “BioBlitz” approach, first used by the National Park Service in 1996, offers a method to gather necessary information in a relatively short time frame (Foster et al. 2013; Parker et al. 2018). Inferences made from these efforts must be tempered with the understanding that surveying a subset of locations for a limited period can yield biased results and an incomplete understanding of regional diversity. Particularly, limited sampling may miss rare or cryptic species and underestimate wildlife use if environmental conditions during sampling are not ideal. However, through careful preplanning to ensure surveys across multiple habitat types, knowledge of life history traits of possible species encountered, and the use of multiple methodologies to detect presence, that is, a BioBlitz approach (or, in the case of bats, a “batblitz”), can inform species–habitat relationships, elucidate particular threats and conservation measures, and provide a platform for future monitoring of biodiversity hotspots or particular species.

North American insectivorous bat communities play critical roles in food webs and the landscape and provide significant ecosystem services to human populations primarily through the suppression of agricultural pests, which may have larger top-down trophic cascade effects than previously realized (Maine and Boyles 2015). In the past decade, North American bat populations have come under serious threat from the fungal pathogen Pseudogymnoascus [Geomyces] destructans–caused white-nose syndrome (WNS) that continues to spread westward across the United States. First originating in New York in 2006, the fungus has killed more than 5.5 million bats (U.S. Fish and Wildlife Service [USFWS] 2012), and WNS is predicted to drive local extinctions of some species (Alves et al. 2014). In July 2019, WNS was confirmed in Plumas County, California, less than 300 mi (483 km) from our study region (Figure S1, Supplemental Material). Impacts from WNS threaten to exacerbate other known bat population stressors, such as wind energy facility mortality, destruction of hibernacula or maternity roosts, and the loss of habitat quality and quantity due to climate change (Weller et al. 2009; Smallwood 2013; Meyer 2015; O'Shea et al. 2016). Across the arid Great Basin, bats are further threatened by land use and land management practices that have failed to protect spring, riparian, and stream habitats in some cases (Dobkin et al. 1998; Sada and Lutz 2016). Vegetation change, including postfire conversion to invasive vegetation and cheatgrass Bromus tectorum (D'Antonio and Vitousek 1992), further impacts species that depend on native vegetation and associated insect communities. Despite these threats and the presence of bats on many state and federal protection lists, little is often known about particular bat species or communities. Systematic and statewide bat monitoring programs are needed in Nevada, and batblitz efforts such as these can help inform survey site selection and timing. In particular, Meyer (2015) suggests that future long-term, regional-scale bat monitoring should focus on changes in species composition or turnover, especially in highly diverse systems. Thalken et al. (2018) used such an approach to document shifts in bat assemblages pre- and post-WNS at a national park in Kentucky. Inventory assessments can help isolate these sites across regions and identify areas dominated by WNS-vulnerable species, such as the little brown bat and other Myotis species.

Because of the high degree of spatial and temporal variability in bat activity, surveying for bats is both time- and labor-intensive, often requiring multiple methods to achieve a comprehensive picture of species diversity and activity (Kuenzi and Morrison 1998; O'Farrell and Gannon 1999; Flaquer et al. 2007). Beyond shared problems such as user error and equipment failure, both passive acoustic surveys and active capture methods can yield a biased picture of species' presence and diversity. The application of acoustic bat detectors is usually a less intensive, more logistically feasible and cost-effective method relative to active capture methods. Despite these benefits, echolocation studies can be impacted by detection probabilities that vary by species, habitats, detector placement, hardware and software used to collect and analyze calls, and user-biased differences in call analysis and vetting, especially for those species that exhibit similar echolocation calls (Duchamp et al. 2006; Adams et al. 2012; Britzke et al. 2013). Despite their limitations, acoustic surveys have been able to document WNS-caused population declines (Jachowski et al. 2014) and are frequently used for inventory and monitoring programs (Loeb et al. 2015).

Live captures provide the opportunity for species confirmation as well as collection of other metrics of local populations (e.g., sex ratio, reproductive phenology, fitness indices, disease surveillance). Examining species in hand can also yield critical information about body condition and disease presence, factors necessary in understanding occurrence and impact of WNS. However, this method only partially provides information about bat communities because some species and individuals are less likely to be trapped in nets (e.g., due to avoidance behavior), and at least four relatively common species are difficult to distinguish in hand. Net placement, number, and type used can also impact trapping effectiveness and bias (Flaquer et al. 2007; Larsen et al. 2007; MacSwiney et al. 2008; Rodhouse et al. 2008; O'Shea et al. 2016). Mist netting is time-intensive, requiring observers to attend to mist nets for long durations (e.g., Weller and Lee [2007] reported 26 surveys were required to sample a bat community with eight species in homogenous habitat) to accurately census the bat community. As in our batblitz, proper pre-exposure rabies vaccinations for biologists handling bats is required, increasing costs to implement mist net surveys. Thus, using acoustic surveys in conjunction with trapping efforts over adequate timeframes, allows for a more complete understanding of the bat community (O'Farrell and Gannon 1999), especially in rapid assessment approaches.

Here, we report results of the August 2016 Nevada batblitz in northern Washoe County, Nevada. Through this intensive effort, we expanded knowledge about species–habitat relationships, relative bat abundance, bat diversity “hotspots,” and bat species assemblages in the Black Rock Plateau in the northwestern Great Basin Desert. We describe our inventory of bat populations in this region, typified by its extensive sagebrush, woodland, and cliff habitat, and we describe species diversity relative to habitats sampled and detection methods used.

Study Site

We conducted surveys at 19 sites in and proximate to the High Rock region in the Black Rock Plateau in northern Washoe County, Nevada, from August 8 to 11 (Figure 1). The survey region is arid with few perennial streams, although springs are common and sometimes associated with large meadow complexes that are frequently dry by midsummer. Grazing by livestock and feral horses is common across the study area, and flows from many springs have been diverted to provide water for livestock in stock tanks, troughs, and dugouts throughout the region (Figure 2). Within the 19 study sites, average annual precipitation is 324 mm/y (range: 271–315 mm; PRISM 1981–2010 normals; Daly et al. 2008). Typical of the Great Basin, the region receives much of its precipitation in the form of winter snowfall from November to February, and its overall climate is characterized by cool, wet winters followed by hot, dry summers. Mean elevation of study sites is 1,732 m (range: 1,529–1,868 m). Most of the land in the study area is managed by the Bureau of Land Management, although there are substantial private agricultural areas in the western portions of the study area.

Figure 1.

Map of the biodiversity sampling area in northwestern Nevada, including the major vegetation and habitat types, and locations of the August 2016 mist net and acoustic sampling sites.

Figure 1.

Map of the biodiversity sampling area in northwestern Nevada, including the major vegetation and habitat types, and locations of the August 2016 mist net and acoustic sampling sites.

Figure 2.

Representative photos of survey sites and water conditions at the time of the August 2016 biodiversity sampling in northwestern Nevada: (a) stock tanks (survey site 15), (b) dugouts (survey site 19), and (c) natural springs and pools at road crossings (survey site 7).

Figure 2.

Representative photos of survey sites and water conditions at the time of the August 2016 biodiversity sampling in northwestern Nevada: (a) stock tanks (survey site 15), (b) dugouts (survey site 19), and (c) natural springs and pools at road crossings (survey site 7).

Survey sites (Data S1, Supplemental Material) were in the High Rock Creek, Massacre Lake, Fortynine Lake, Alkali Lake, Coleman Creek, and Badger Creek-Rye Creek watersheds. Salt desert scrub and seasonally inundated playas characterize the lowest elevations in the valley, whereas sagebrush steppe dominated by sagebrush Artemisia tridentate subsp. is the primary vegetation community throughout the survey region. Mountain brush characterized by snowberry Symphoricarpos oreophilus, mountain sagebrush Artemisia tridentate subsp. vaseyana, low sagebrush Artemisia arbuscula, and bitterbrush Purshia tridentate dominate in higher elevations. Western juniper woodlands Juniperus occidentalis var. occidentalis are common across mountain slopes and benches, with smaller patches of mountain mahogany Cercocarpus ledifolius var. intermontanus at higher elevation and aspen Populus tremuloides and willow Salix spp. in more mesic areas throughout the region. Cliffs and canyons are ubiquitous across the region, from sheer canyon walls dominating the High Rock Canyon to extensive rimrock and talus slopes across the eastern sides of the Massacre Rim wilderness areas. Ash-flow tuff and basalt flows characterize the area's geology (D. Charlet, unpublished data, 2015). Numerous canyons and large rock outcroppings dot the High Rock region, with small aspen- or willow-dominated riparian areas existing in canyon bottoms.

Methods

Thirty-four participants from nonprofit, university, and state wildlife and federal land management and research agencies participated in a four-night survey of regional bat populations from August 8 to 11, 2016. Over the survey period, we conducted surveys at 19 sites by using passive acoustic monitoring, hand capture using mist net arrays, or both. We conducted mist net surveys at 17 sites. Of those 17 sites, we surveyed 10 with acoustic methods in conjunction with active trapping. We surveyed two sites only with acoustic detectors. Whether by passive or active methods, we sampled survey sites for only one night, with one exception where a mist net survey occurred on the first night and a corresponding acoustic survey occurred on the second night.

Participants conducted surveys at suitable water sources in the area, including dugouts, tanks, and troughs for livestock management or large pools of water from irrigated meadows and flowing streams typically found at road crossings (Figure 2). During planning efforts before the blitz, we used handheld acoustic detectors to understand relative bat activity at a suite of potential sites and used logistical constraints (e.g., access, personnel, and equipment) to narrow our selection to a final site list distributed across habitat types. Several bat species in the region are migratory, notably, hoary bat Lasiurus cinereus, silver-haired bat Lasionycteris noctivagans, and Mexican free-tailed bat Tadarida brasiliensis, whereas others are presumed to overwinter in the area, although hibernacula potential and resources are not well understood in the region. To understand regional species diversity of resident bats, we sampled before migration across a diversity of habitat types by using a majority of the available and suitable water sources within the project area.

Number and length of mist nets varied by size of water source, with a minimum of two nets set over water tanks and a maximum of five mist nets and a triple-high mist net over a larger dugout. We opened nets 30 min before sunset and left them open for an average of 220 min (range: 150–255 min). On average, surveyors checked mist nets every 5 min, and identified bats to species by using morphometric characteristics as described in diagnostic keys from the Western Bat Working Group. Western small-footed myotis Myotis ciliolabrum (MYCI) and California myotis Myotis californicus (MYCA) are extremely difficult to distinguish, with overlapping morphological characteristics and measurements. Genetic methods to discriminate these two species are not available (O'Shea et al. 2016). When we identified an individual as either species, we collapsed the species identification to “MYCICA” due to the high uncertainty in discriminating between the two species. Little brown bat and Yuma myotis Myotis yumanensis can also be cryptic due to overlapping size, absence of calcar, and overlapping forearm length (Weller et al. 2007). Rodhouse et al. (2008) recommend that morphological characteristics be used only to support species identification by echolocation or by genetic methods. However, we did not collapse these species to a MYYULU M. yumanensis or M. lucifigus designation because discrimination between the two species appears feasible in this survey region based on forehead slope, mask darkness, ear color, and dorsal pelage sheen. As necessitated in all mist netting surveys, bat handling and equipment decontamination followed most recent protocols (USFWS 2016).

We usually deployed acoustic monitors, when placed in conjunction with mist nets, over the same time frame (at one survey location, we did not collect a detector until late morning of the following day). For stationary monitoring, we used D500X ultrasound detectors (Pettersson Elektronik, http://www.batsound.com/) for a total of 12 sampling nights. We recorded each sample site for one survey, accounting for approximately 69 total hours over the survey period. The D500X detector directly records in full spectrum to compact flash data cards. We made all recordings using the default user profile settings (sample frequency = 500 kHz, pretrigger time = off, recording length = 3 s, high-pass filter = no, auto-record mode = yes, trigger sensitivity = high) and recording settings (input gain = 60, trigger level = 120, interval between recordings = 0 s). We programmed the detectors to initiate recording 15 min before sunset, and when left out all night, to stop recording 15 min after sunrise, adjusted appropriately for geographic locations.

At each site, a participant experienced in acoustic monitoring deployed a D500X detector with a weather-resistant external microphone with the directional horn provided by the manufacturer elevated on a vertical extending painter's pole to a height ranging from 2.25 to 3.50 m above the ground, depending on clutter and habitat of the site (Figure 3). We oriented the directional microphones roughly parallel to ground surface. Direction and placement of microphones was made to 1) minimize extraneous clutter that may create echoes and refractions in the recordings; 2) record bats in a foraging flyway, increasing the probability of recording diagnostic search-phase echolocation calls; and 3) maximize detection of an individual bat at an appropriate distance from the microphone.

Figure 3.

Representative photo of acoustic detector deployment at survey site 2 during the August 2016 sampling effort in the High Rock region of Nevada.

Figure 3.

Representative photo of acoustic detector deployment at survey site 2 during the August 2016 sampling effort in the High Rock region of Nevada.

We processed all recordings with SonoBat v.4.2 computer software (Data S2, Supplemental Material; Szewczak 2015). Surveyors made qualitative and categorical observations (e.g., habitat description, level of clutter, proximity to water, insect activity) and noted environmental conditions (e.g., temperature, windspeed, cloud cover) and microphone orientation at the time of deployment and collection. We recorded these variables into metadata files imbedded into individual call files by using the SonoBat D500x File Attributer v.2.6 utility program along with a time stamp. We removed excessive environmental noise from files by using the SonoBat Batch Scrubber v.5.4 utility, with the “medium” setting and including signals from 5 to 20 kHz. We classified the calls with SonoBat and the Great Basin Suite auto-classifier package by using default settings (max number of calls to consider per file = 8, acceptable call quality = 0.80, acceptable quality to tally passes = 0.20, decision threshold = 0.90). We manually vetted species identifications of 146 acoustic calls in SonoBat for each species per site by three of the authors independently. We only accepted species that were confirmed by a majority consensus of the authors and were considered present for a given site.

We generated species accumulation curves in R software using the vegan package (Oksanen et al. 2016; R Core Team 2016). We generated species accumulation curves with 200 iterations of sampling without replacement for each site, and boxplots of species totals are represented with 95% confidence intervals. We generated two types of accumulation curves: one set of curves using all data from the 19 sites and another set of curves showing variations between sample completeness by either acoustic or mist net data for the 10 sites where both detection methods were used.

Results

In total, we made 542 bat captures at 17 mist net sites over the four-night survey period (Data S3, Supplemental Material). Long-eared myotis Myotis evotis was the most abundant species over the survey area and was the most abundant species at 13 of the sites. The canyon bat was the most abundant species at both of the High Rock Canyon sites where talus, rock, and cliff formations are extensive. At all survey sites with water tanks and troughs, long-eared myotis was dominant, except for site 16 where MYCICA was dominant.

We detected 14 species during the 2016 batblitz (Table 1). Using only the 10 sites that we sampled with both acoustic and mist netting methods, we captured spotted bat, silver-haired bat, hoary bat, and Mexican free-tailed bat only with acoustic detection. We detected pallid bat Antrozous pallidus only via capture in mist nets. Long-eared myotis was ubiquitous across the survey area and present at all sites surveyed acoustically, with the exception of site 7 in High Rock Canyon. Mexican free-tailed bat was found in only one site, in the sagebrush and juniper woodlands at site 19 proximate to the cliff and canyon area of Coleman Rim. The spotted bat detection was unique to the High Rock Canyon sites, likely due to the extensive rocky outcroppings and sheer canyon walls in this area. We detected pallid bats and canyon bats only in this area as well. We found hoary bats only in two sites: a relatively xeric site surrounded by sagebrush and juniper woodlands and a site in the willow-dominated riparian communities of High Rock Canyon. We found silver-haired bats in three sites: two sites near western juniper woodlands and a third site near an aspen-dominated canyon. We also commonly detected long-legged myotis Myotis volans and Townsend's big-eared bat Corynorhinus townsendii at acoustically monitored sites and captured in mist nets. Little brown bat and Yuma myotis were relative rare, each captured at 5 of the 19 sites. Although we detected both western small-footed myotis and California myotis acoustically, the preponderance of calls (273:18) were autoclassified as western small-footed myotis. We recommend that biologists continue to document morphological characteristics that could be used to distinguish the western small-footed myotis from California myotis and little brown bat from Yuma myotis in hand. However, because identifications can be ambiguous, species can always be collapsed into MYCICA or MYYULU categories post hoc. We recommend using hand releases and acoustic recordings in conjunction with genetic sampling to confirm identifications.

Table 1.

Bat species detection by site and by method over the 19 sites surveyed during the 2016 sampling in northwestern Nevada.

Bat species detection by site and by method over the 19 sites surveyed during the 2016 sampling in northwestern Nevada.
Bat species detection by site and by method over the 19 sites surveyed during the 2016 sampling in northwestern Nevada.

We captured most of species predicted to occur in northern Nevada, with two notable exceptions. We did not capture the western red bat Lasiurus blossevillii that has been found in deciduous and coniferous forest and woodland areas across the Intermountain West and has recently been detected on the Sheldon National Wildlife Refuge, east of our study region (Hayes 2003; Barnett and Collins 2019). We captured all Myotis species, except for fringed myotis Myotis thysanodes whose potential distribution in this region is unknown (Bradley et al. 2006; Barnett and Collins 2019). Our inventory effort documented tree-roosting bats likely using either aspen-dominated or western juniper–dominated habitats such as the long-legged myotis, long-eared myotis, silver-haired bat, and hoary bat as well as those tied to the distinctive and ubiquitous regional rocky habitats (e.g., rock outcrops, cliffs, talus) such as the spotted bat, canyon bat, and pallid bats.

In 8 of the 10 sites, we detected one or two more species by acoustic methods compared with mist net surveys (Figure 4). In one site, both methods captured the same number of species; in another site, the mist net survey detected three more species than the paired acoustic survey. In 9 of 10 sites, each method revealed one to three additional species not detected by the other method. With both acoustic and mist net data combined over all 19 sites, the species accumulation curve suggests that the asymptote of species richness was reached after sampling 10 sites (Figure 5; Moreno and Halffter 2000). We detected 14 species after sampling 12 sites. Using only the 10 sites surveyed with both acoustic and mist net measures, we noted that species richness was higher with acoustic methods (14) than with mist net methods (9) (Figure 6).

Figure 4.

Total number of bat species detected acoustically and mist netted at each of the 10 biodiversity sampling sites where both methods were conducted concurrently in northwestern Nevada in August 2018. Total cumulative number of species is also indicated for each of these sites.

Figure 4.

Total number of bat species detected acoustically and mist netted at each of the 10 biodiversity sampling sites where both methods were conducted concurrently in northwestern Nevada in August 2018. Total cumulative number of species is also indicated for each of these sites.

Figure 5.

Species accumulation curve over all 19 sites surveyed during the August 2016 biodiversity sampling effort in northwestern Nevada. Two sites were surveyed with acoustic methods only, and seven sites where surveyed by mist net only. Ten sites received paired sampling using mist net and acoustic methods. The species accumulation curve is generated with 200 permutations of resampling without replacement. Bat species detected include pallid bat Antrozous pallidus, Townsend's big-eared bat Corynorhinus townsendii, big brown bat Eptesicus fuscus, spotted bat Euderma maculatum, silver-haired bat Lasionycteris noctivagans, western small-footed myotis Myotis ciliolabrum, California myotis Myotis californicus, , long-eared myotis Myotis evotis, little brown bat Myotis lucifigus, long-legged myotis Myotis volans, Yuma myotis Myotis yumanensis, canyon bat Parastrellus hesperus, and Mexican free-tailed bat Tadarida brasiliensis.

Figure 5.

Species accumulation curve over all 19 sites surveyed during the August 2016 biodiversity sampling effort in northwestern Nevada. Two sites were surveyed with acoustic methods only, and seven sites where surveyed by mist net only. Ten sites received paired sampling using mist net and acoustic methods. The species accumulation curve is generated with 200 permutations of resampling without replacement. Bat species detected include pallid bat Antrozous pallidus, Townsend's big-eared bat Corynorhinus townsendii, big brown bat Eptesicus fuscus, spotted bat Euderma maculatum, silver-haired bat Lasionycteris noctivagans, western small-footed myotis Myotis ciliolabrum, California myotis Myotis californicus, , long-eared myotis Myotis evotis, little brown bat Myotis lucifigus, long-legged myotis Myotis volans, Yuma myotis Myotis yumanensis, canyon bat Parastrellus hesperus, and Mexican free-tailed bat Tadarida brasiliensis.

Figure 6.

Species accumulation curves for only the 10 sites sampled with paired mist net and acoustic surveys during August 2016 survey effort. Curve on left shows only species presence generated from mist net surveys, and curve on right shows only species generated from acoustic surveys. Bat species detected include pallid bat Antrozous pallidus, Townsend's big-eared bat Corynorhinus townsendii, big brown bat Eptesicus fuscus, spotted bat Euderma maculatum, silver-haired bat Lasionycteris noctivagans, western small-footed myotis Myotis ciliolabrums, California myotis Myotis californicus , long-eared myotis Myotis evotis, little brown bat Myotis lucifigus, long-legged myotis Myotis volans, Yuma myotis Myotis yumanensis, canyon bat Parastrellus hesperus, and Mexican free-tailed bat Tadarida brasiliensis.

Figure 6.

Species accumulation curves for only the 10 sites sampled with paired mist net and acoustic surveys during August 2016 survey effort. Curve on left shows only species presence generated from mist net surveys, and curve on right shows only species generated from acoustic surveys. Bat species detected include pallid bat Antrozous pallidus, Townsend's big-eared bat Corynorhinus townsendii, big brown bat Eptesicus fuscus, spotted bat Euderma maculatum, silver-haired bat Lasionycteris noctivagans, western small-footed myotis Myotis ciliolabrums, California myotis Myotis californicus , long-eared myotis Myotis evotis, little brown bat Myotis lucifigus, long-legged myotis Myotis volans, Yuma myotis Myotis yumanensis, canyon bat Parastrellus hesperus, and Mexican free-tailed bat Tadarida brasiliensis.

Discussion

We designed our rapid inventory approach to capture a snapshot of regional biodiversity, and we used two methods, acoustic and mist net sampling, to achieve this goal. From the 10 sites surveyed by both methods, the species accumulation curves reveal that acoustic survey results rather than mist net results yielded higher species diversity. However, at the site level, combining mist net surveys with acoustic surveys provided a more complete understanding of local species diversity. Bat detection by using both methods in areas with greater habitat diversity, such as in the aspen-dominated Hanging Rock Canyon with extensive talus and cliff structures or the cliff- and talus-dominated High Rock Canyon with a primary willow-lined drainage, provided a greater understanding of local species diversity. The species accumulation curve using both methodologies indicated that we needed to survey at least 10 sites to understand landscape-level species richness. Environmental conditions on the last night of surveys underscored a common problem with a rapid assessment approach and compromised our understanding of species richness. Those sites surveyed on the last night of our inventory yielded few captures, possibly due to a high degree of moon illumination, thus underestimating our understanding of species' distribution and diversity in these habitats. Repeat sampling becomes doubly important when trapping occurs during less-than-ideal environmental conditions.

BioBlitzes are valuable for 1) understanding local and regional species dynamics; 2) education, outreach, and training by using both passive and active methods; and 3) collaboration among agencies and stakeholders (Parker et al. 2018). In our batblitz, some sites were extremely active but had few species, whereas other sites had greater biodiversity but fewer numbers of bats. Both of these types of sites are valuable in the batblitz construct: the former sites allow for training opportunities or for WNS surveillance if potential affected species are present, and the latter sites allow for a more accurate description of biodiversity. We recommend preplanning efforts using acoustic detection to identify these types of sites and maximize blitz outcomes. We recommend planning efforts also include identification of regional habitat types, with an emphasis on sampling unique habitat types or sites with greater habitat complexity. Continued sampling with acoustic measures at these sites may offer further insights into diversity.

Results presented here showcase the diversity of bat species in the Black Rock Plateau (Barnett and Collins 2019). Although historic species records do not exist for the survey area, the Arctos database (https://arctos.database.museum/) shows specimens collected from 1920 to 1978 for the surrounding area. Specimens from five species were collected in 1920 in Little High Rock Canyon to the south of our study area: one long-eared myotis was collected to the east on the Sheldon National Wildlife Refuge in 1978 and one western small-footed myotis was collected in 1941 in California to the northwest of the survey region. For this survey effort, discriminatory acoustic calls for 13 of the species and a photo voucher for pallid bat, which was captured only by mist net, can be found at the iNaturalist website (https://www.inaturalist.org/observations/; 6839967, 6839899, 6839406, 6838142, 6838129, 6838120, 6838098, 6838072, 6837943, 6837869, 6837840).

Our work highlights the bat communities in or near western juniper habitats in the Intermountain West. Studies in analogous pinyon Pinus monophylla or Pinus edulis–juniper Juniperus osteosperma or Juniperus scopulorum arid woodland habitats in California, Nevada, Colorado, and New Mexico have documented the importance of these areas to bats, both for foraging and as roost and maternity colony sites (Szewczak et al. 1998; Chung-MacCoubrey 2003, 2005; Snider et al. 2013). Western juniper habitats may provide similar values for bat fauna, and this inventory provides a platform for further investigation. Rich species diversity in some sites, especially throughout the High Rock Canyon area, was likely due to the site's unique rocky habitats, from talus and rock outcroppings to sheer canyon walls and the proximity of limited water sources to those habitats. These sites, some in wilderness areas, provide insight into the bat fauna existing in an arid region of Nevada and provide ideal sites for continued monitoring and inventory. Population-level changes to multiple species can be detected at some of these more diverse sites, allowing for powerful early warning systems should WNS occur in Nevada.

Our results underscore the importance of safeguarding water sources is an arid region. We captured high numbers of bats at many stock tank sites. Properly placed appropriate escape ramps and removal of obstructions from the top of stock tanks ensure these locations provide benefits to bats. Elsewhere, water sources, especially those with relatively larger surface area and proximate to good roosting habitat in trees or rocky environments, provide an otherwise limiting resource in an arid environment (Rabe and Rosenstock 2005; O'Shea at al. 2016). Degraded springs, riparian areas, and streams were noticeable throughout the project area, in wilderness study areas, and across many parts of the Black Rock-High Rock National Conservation Area, indicating a need for better awareness and protection of these critical areas. Restoration at many of these mesic resources is needed before water sources and associated vegetation communities are irreparably damaged or lost. Other threatened habitats include aspen-dominated systems that appear to be hosting a unique bat community, despite their relatively small patch size in this region. Aspen mortality across the Intermountain West, including in Nevada, is prevalent in some regions and time periods (Kulakowski et al. 2013). Monitoring the health of biodiversity hotspots in aspen and other mesic ecosystems and applying restoration prescriptions as appropriate will help to support bat populations and other wildlife here and throughout the Great Basin (Campbell and Bartos 2001).

Supplemental Material

Please note: The Journal of Fish and Wildlife Management is not responsible for the content or functionality of any supplemental material. Queries should be directed to the corresponding author for the article.

Data S1. Site location, proximate habitat type, water source description, and survey method(s) used for the 19 sites surveyed during the 2016 batblitz effort in the High Rock region of northern Washoe County, Nevada.

Found at DOI: https://doi.org/10.3996/022019-JFWM-009.S1 (19 KB DOCX).

Data S2. Summary of Sonobat v.4.2 autoclassification results for all files with bat calls generated from the 2016 batblitz in northern Washoe County, Nevada. Species classification is recorded in the “SppAccp” column (x = unknown bat; ANPA = pallid bat Antrozous pallidus; COTO = Townsend's big-eared bat Corynorhinus townsendii; EPFU = big brown bat Eptesicus fuscus; EUMA = spotted bat Euderma maculatum; LANO = silver-haired bat Lasionycteris noctivagans; MYCA = western small-footed myotis Myotis californicus; MYCI = California myotis Myotis ciliolabrum; MYCICA = western small-footed myotis or California myotis; MYEV = long-eared myotis Myotis evotis; MYLU = little brown bat Myotis lucifigus; MYVO = long-legged myotis Myotis volans; MYYU = Yuma myotis Myotis yumanensis; PAHE = canyon bat Parastrellus hesperus; TABR = Mexican free-tailed bat Tadarida brasiliensis). SiteNumber (column Y) reflects specific site in project area.

Found at DOI: https://doi.org/10.3996/022019-JFWM-009.S2 (371 KB XLSX).

Data S3. Bat capture data from 17 sites sampled by mist net during the August 2016 batblitz in northern Washoe County, Nevada. Individuals are recorded to species with sex (male or female), toothwear (1 = no wear; 2 = rounded, three-fourths length; 3 = one-half length; and 4 = near gum line), age (A = adult, J = juvenile, young of the year), forearm length, weight, reproductive status (NR = nonreproductive, L = lactating, R = reproductive, PL = postlactating), and capture status (new capture vs. recapture) taken opportunistically. Species codes are as follows: ANPA = pallid bat Antrozous pallidus; COTO = Townsend's big-eared bat Corynorhinus townsendii; EPFU = big brown bat Eptesicus fuscus; EUMA = spotted bat Euderma maculatum; LANO = silver-haired bat Lasionycteris noctivagans; MYCA = western small-footed myotis Myotis californicus; MYCI = California myotis Myotis ciliolabrum; MYCICA = western small-footed myotis or California myotis; MYEV = long-eared myotis Myotis evotis; MYLU = little brown bat Myotis lucifigus; MYVO = long-legged myotis Myotis volans; MYYU = Yuma myotis Myotis yumanensis; PAHE = canyon bat Parastrellus hesperus; TABR = Mexican free-tailed bat Tadarida brasiliensis.

Found at DOI: https://doi.org/10.3996/022019-JFWM-009.S3 (50 KB XLSX).

Figure S1. U.S. Fish and Wildlife Service. 2019. WNS map update.

Found at DOI: https://doi.org/10.3996/022019-JFWM-009.S4 (2.04 MB JPG); also available at https://www.whitenosesyndrome.org/where-is-wns.

Reference S1. [USFWS] U.S. Fish and Wildlife Service. 2012. North American bat death toll exceeds 5.5 million from white-nose syndrome. Arlington, VA: U.S. Fish and Wildlife Service.

Found at DOI: https://doi.org/10.3996/022019-JFWM-009.S5 (109 KB PDF); also available at https://www.whitenosesyndrome.org/static-page/news.

Reference S2. Loeb SC, Rodhouse TJ, Ellison LE, Lausen CL, Reichard JD, Irvine KM, Ingersoll TE, Coleman JT, Thogmartin WE, Sauer JR, Francis CM, Bayless ML, Stanley TR, Johnson DH. 2015. A plan for the North American bat monitoring program (NABat). Asheville, North Carolina: U.S. Department of Agriculture Forest Service, Southern Research Station, General Technical Report SRS-208.

Found at DOI: https://doi.org/10.3996/022019-JFWM-009.S6 (21.53 MB PDF); also available at https://www.srs.fs.usda.gov/pubs/gtr/gtr_srs208.pdf.

Reference S3. [USFWS] U.S. Fish and Wildlife Service. 2016. National White-Nose Syndrome Decontamination Protocol - Version 04.12.2016. Protocol used during mist-net sampling in the 2016 batblitz in the High Rock region of northern Washoe County, Nevada. Washington, DC: USFWS.

Found at DOI: https://doi.org/10.3996/022019-JFWM-009.S7 (321 KB PDF).

Reference S4. Campbell RB, Bartos DL. 2001. Aspen ecosystems: objectives for sustaining biodiversity. Pages 299–307 in Shepperd WD, Binkley D, Bartos DL, Stohlgren TJ, Eskew LG, compilers. Sustaining aspen in western landscapes: symposium proceedings. Fort Collins, Colorado: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. RMRS-P-18.

Found at DOI: https://doi.org/10.3996/022019-JFWM-009.S8 (135 KB PDF); also available at https://www.fs.usda.gov/treesearch/pubs/35836.

Acknowledgments

We thank all those who participated and helped to plan this survey event: T. Bowden, E. Flores, J. Mueller, M. Peterfreund, S. Stevens (Bureau of Land Management–Applegate Field Office); M. Cota (Bureau of Land Management–Carson City District); K. Reitch, A. Rutledge (Bureau of Land Management–Las Vegas Field Office), K. Lunn, T. Smith (Great Basin Institute); K. Hargreaves, A. Jimenez (Humboldt State University); J. Ewanyk, S. Peterson (Institute for Wildlife Studies); R. Haley (National Park Service, Lake Mead National Recreation Area); M. Horner, J. Long, S. Schratz (National Park Service, Great Basin National Park); Kelly Hunt, Jenni Jeffers, Rory Lamp, Jen Newmark, T. Slatauski, J. Williams, L. Williams (Nevada Department of Wildlife); K. Szabo (Nevada Natural Heritage Program); B. Schnelle (Point Blue Conservation–Natural Resource Conservation Service); G. Rios-Sotelo, K. Shoemaker (University of Nevada, Reno); and T. Torrell. In particular, we thank T. Bowden and E. Flores from the Bureau of Land Management–Applegate Field Office for helping to coordinate this effort and providing equipment. We also thank M. Myers formerly from Friends of the Black Rock-High Rock for providing equipment and logistical support. We thank staff at Bureau of Land Management–Winnemucca District for assisting with wilderness permits. We thank reviewers and Associate Editor for improving this article. Project coordination, technical assistance, and survey time for biologists from Nevada Department of Wildlife was funded through the USFWS State Wildlife Grants program.

Any use of trade, product, website, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

References

References
Adams
AM,
Jantzen
MK,
Hamilton
RM,
Brockett-Fenton
M.
2012
.
Do you hear what I hear? Implications of detector selection for acoustic monitoring of bats
.
Methods in Ecology and Evolution
3
:
992
998
.
Alves
DMCC,
Terribile
LC,
Brito
D.
2014
.
The potential impact of white-nose syndrome on the conservation status of North American bats
.
PLoS ONE
9
:
e107395
.
Barnett
JK,
Collins
GH.
2019
.
Species richness and seasonality of bat occupancy on northwestern national wildlife refuges
.
Journal of Fish and Wildlife Management
10
:
468
479
.
Bradley
PV,
O'Farrell
MJ,
Williams
JA,
Newmark
JE.
2006
.
The revised Nevada bat conservation plan
.
Nevada Bat Working Group
,
Reno, Nevada
.
Britzke
ER,
Gillam
EH,
Murray
KL.
2013
.
Current state of understanding of ultrasonic detectors for the study of bat ecology
.
Acta Theriologica
58
:
109
117
.
Campbell
RB,
Bartos
DL.
2001
.
Aspen ecosystems: objectives for sustaining biodiversity
.
Pages
299
307
in
Shepperd WD, Binkley D, Bartos DL, Stohlgren TJ, Eskew LG, compilers.
Sustaining aspen in western landscapes: symposium proceedings
.
Fort Collins, Colorado: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. RMRS-P-18
(see Supplemental Material, Reference S4).
Charlet,
D.
2015
.
Nevada physiography: a sketch.
252
p.
Chung-MacCoubrey
AL.
2003
.
Monitoring long-term reuse of trees by bats in pinyon-juniper woodlands of New Mexico
.
Wildlife Society Bulletin
31
:
73
79
.
Chung-MacCoubrey
AL.
2005
.
Use of pinyon-juniper woodlands by bats in New Mexico
.
Forest Ecology and Management
204
:
209
220
.
D'Antonio
CM,
Vitousek
PM.
1992
.
Biological invasions by exotic grasses, the grass/fire cycle and global change
.
Annual Review of Ecology and Systematics
23
:
63
87
.
Daly
C,
Halbieb
M,
Smith
JI,
Gibson
WP,
Dogett
MK,
Taylor
GH,
Curtis
J,
Pasteris
PP.
2008
.
Physiographically sensitive mapping of climatological temperature and precipitation across the conterminous United States
.
International Journal of Climatology
28
:
2031
2064
.
Dobkin
DD,
Rich
AC,
Pyle
WH.
1998
.
Habitat and avifaunal recovery from livestock grazing in a riparian meadow system of the northwestern Great Basin
.
Conservation Biology
12
:
209
221
.
Duchamp
JE,
Yates
M,
Muzika
R,
Swihart
RK.
2006
.
Estimating probabilities of detection for bat echolocation calls: an application of the double-observer method
.
Wildlife Society Bulletin
34
:
408
412
.
Flaquer
C,
Torre
I,
Arrizabalaga
A.
2007
.
Comparison of sampling methods for inventory of bat communities
.
Journal of Mammalogy
88
:
526
533
.
Foster
MA,
Mueller
LI,
Dykes
SA,
Pete Wyatt
RL,
Gray
MJ
.
2013
.
Efficacy of bioblitz surveys with implications for sampling nongame species
.
Journal of the Tennessee Academy of Science
88
:
56
62
.
Hayes
JP.
2003
.
Habitat ecology and conservation of bats in western coniferous forest
.
Pages
81
119
in
Zabel
CJ,
Anthony
RG,
editors.
Mammal community dynamics: management and conservation in the coniferous forests of western North America
.
Cambridge University Press
,
UK
.
Jachowski
DS,
Dobony
CA,
Coleman
LS,
Ford
WM,
Britzke
ER,
Rodrigue
JL.
2014
.
Disease and community structure: white-nose syndrome alters spatial and temporal niche partitioning in sympatric bat species
.
Diversity and Distributions
20
:
1002
1015
.
Kuenzi
AJ,
Morrison
ML.
1998
.
Detection of bats by mist-nets and ultrasonic sensors
.
Wildlife Society Bulletin
26
:
307
311
.
Kulakowski
D,
Kaye
MW,
Kashian
DM.
2013
.
Long-term aspen cover change in the western US
.
Forest Ecology and Management
299
:
52
59
.
Larsen
RJ,
Boegler
KA,
Genoways
HH,
Masefield
WP,
Kirsch
RA,
Pedersen
SC.
2007
.
Mist netting bias, species accumulation curves, and the rediscovery of two bats on Montserrat (Lesser Antilles)
.
Acta Chiropterologica
9
:
423
435
.
Loeb
SC,
Rodhouse
TJ,
Ellison
LE,
Lausen
CL,
Reichard
JD,
Irvine
KM,
Ingersoll
TE,
Coleman
JT,
Thogmartin
WE,
Sauer
JR,
Francis
CM,
Bayless,
ML,
Stanley
TR,
Johnson
DH.
2015
.
A plan for the North American bat monitoring program (NABat)
.
Asheville, North Carolina
:
U.S. Department of Agriculture Forest Service, Southern Research Station, General Technical Report SRS-208 (see Supplemental Material, Reference S2)
.
MacSwiney Gonzalez MC, Clarke FM, Racey PA
.
2008
.
What you see is not what you get: the role of ultrasonic detectors in increasing inventory completeness in Neotropical bat assemblages
.
Journal of Applied Ecology
45
:
1364
1371
.
Maine
JJ,
Boyles
JG.
2015
.
Bats initiate vital agroecological interactions in corn
.
Proceedings of the National Academy of Sciences of the United States of America
112
:
12438
12443
.
Meyer
CFJ.
2015
.
Methodological challenges in monitoring bat population-and assemblage-level changes for anthropogenic impact assessment
.
Mammalian Biology
80
:
159
169
.
Moreno
CE,
Halffter
G.
2000
.
Assessing the completeness of bat biodiversity inventories using species accumulation curves
.
Journal of Applied Ecology
37
:
149
158
.
Oksanen
J,
Blanchet
FG,
Friendly
M,
Kindt
R,
Legendre
P,
McGlinn
D,
Minchin
PR,
O'Hara
RB,
Simpson
GL,
Solymos
P,
Stevens
MHH,
Szoecs
E,
Wagner
H.
2016
.
vegan: community ecology package. R package version 2.4-1
.
Available: https://CRAN.R-project.org/package=vegan (December 2019).
O'Farrell
MJ,
Gannon
WL.
1999
.
A comparison of acoustic versus capture techniques for the inventory of bats
.
Journal of Mammalogy
80
:
24
30
.
O'Shea
TJ,
Cryan
PM,
Hayman
DTS,
Plowright
RK,
Streicker
DG.
2016
.
Multiple mortality events in bats: a global review
.
Mammal Review
46
:
175
190
.
O'Shea
TJ,
Klinger
C,
Smythe
LA,
Wilkinson
L,
Dumbacher
JP.
2016
.
Survey of the bat fauna, Desert National Wildlife Refuge, Nevada
.
Western North American Naturalist
76
:
501
508
.
Parker
SS,
Pauly
GB,
Moore
J,
Fraga
NS,
Knapp
JJ,
Principe
Z,
Brown
BV,
Randall
JM,
Cohen
BS,
Wake
TA.
2018
.
Adapting the bioblitz to meet conservation needs
.
Conservation Biology
32
:
1007
1019
.
Rabe
MJ,
Rosenstock
SS.
2005
.
Influence of water size and type on bat captures in the lower Sonoran Desert
.
Western North American Naturalist
65
:
87
90
.
R Core Team
.
2016
.
R: a language and environment for statistical computing
.
R Foundation for Statistical Computing
,
Vienna
.
Available: https://www.R-project.org/ (December 2019).
Rodhouse
TJ,
Scott
SA,
Ormsbee
PC,
Zinck
JM.
2008
.
Field identification of Myotis yumanensis and Myotis lucifugus: a morphological evaluation
.
Western North American Naturalist
68
:
437
443
.
Sada
DW,
Lutz
AK.
2016
.
Environmental characteristics of Great Basin and Mojave desert spring systems
.
Smallwood
KS.
2013
.
Comparing bird and bat fatality-rate estimates among North American wind-energy projects
.
Wildlife Society Bulletin
37
:
19
33
.
Snider
EA,
Cryan
PM,
Wilson
KR.
2013
.
Roost selection by western long-eared myotis (Myotis evotis) in burned and unburned piñon-juniper woodlands of southwestern Colorado
.
Journal of Mammalogy
94
:
640
649
.
Szewczak
JM.
2015
.
SonoBat v. 4.2. 2015. Available: www. sonobat.com (December 2019).
Szewczak
JM,
Szewczak
SM,
Morrison
ML,
Hall
LS.
1998
.
Bats of the White and Inyo mountains of California-Nevada
.
Great Basin Naturalist
58
:
66
75
.
Thalken
MM,
Lack
MJ,
Johnson
JJ.
2018
.
Shifts in assemblage of foraging bats at Mammoth Cave National Park following arrival of white-nose syndrome
.
Northeastern Naturalist
25
:
202
214
.
[USFWS] U.S. Fish and Wildlife Service
.
2012
.
North American bat death toll exceeds 5.5 million from white nose syndrome
.
Washington, DC
:
USFWS (see Supplemental Material, Reference S1)
.
[USFWS] U.S. Fish and Wildlife Service
.
2016
.
National white-nose syndrome decontamination protocol v 04.12.2016
(see Supplemental Material, Reference S3).
Weller
TJ,
Cryan
PM,
O'Shea
TJ.
2009
.
Broadening the focus of bat conservation and research in the USA for the 21st century
.
Endangered Species Research
8
:
129
145
.
Weller
TJ,
Lee
DC.
2007
.
Mist net effort required to inventory a forest bat species assemblage
.
Journal of Wildlife Management
71
:
251
257
.
Weller
TJ,
Scott
SA,
Rodhouse
TJ,
Ormsbee
PC,
Zinck
JM.
2007
.
Field identification of the cryptic vespertilionid bats, Myotis lucifugus and M. yumanensis
.
Acta Chiropterologica
9
:
133
147
.

Author notes

Citation: Van Gunst KJ, Klinger C, Hamilton B, Slocum K, Rhea-Fournier DJ. 2020. Rapid biodiversity sampling for bat assemblages in northwestern Nevada. Journal of Fish and Wildlife Management 11(1):300-310; e1944-687X. https://doi.org/10.3996/022019-JFWM-009

Competing Interests

The findings and conclusions in this article are those of the author(s) and do not necessarily represent the views of the U.S. Fish and Wildlife Service.