Bats represent roughly one-fifth of all mammalian diversity on Earth, yet they remain among the least understood of mammals, and the spotted bat may be the most mysterious of the lot. With its striking black fur, oversized pink ears, and bold white spots, Euderma maculatum is unmistakable when seen, but seeing one is a rare privilege. The species is nocturnal and an agile, high-flying hunter, and unlike many of its relatives it roosts solitarily, often in cliff crevices far from human observation. That combination of solitary habits and remote roosts means conventional ecological monitoring, such as colony counts or roost surveys, yields frustratingly little data. Population trends that would be obvious in a colonial species like the little brown bat remain essentially invisible for the spotted bat, which is precisely why the research team turned to genetics as an alternative lens.

The design of the study was ambitious in its temporal reach. The researchers obtained samples from 121 individual bats spanning three separate timeframes across the species’ range in western North America. The modern component came from live bats captured in the field, while contemporary specimens collected between 1994 and 2025 supplemented the picture. Historical material was drawn from museum collections, with specimens gathered between 1904 and 1991, providing a bridge to the early twentieth century. Most remarkably, the team recovered ancient remains from a cave in northern Arizona, radiocarbon dated to between 120 and 2,100 years before present. By sequencing genetic material across this continuum, the researchers could compare past and present populations directly, testing whether the genetic architecture of the species has shifted as the American West was transformed by settlement, land use change, and a warming climate.

The analytical framework behind such temporal comparisons is grounded in conservation genetics, a discipline that treats variation in DNA as a record of a population’s demographic history. When a population is large and well connected, individuals carry many different variants at the genetic markers being surveyed, and those variants are distributed relatively evenly across the landscape. When a population shrinks or becomes fragmented, two signatures typically appear: genetic diversity declines because rare variants are lost in each generation, and genetic structure increases because populations that no longer exchange migrants begin to drift apart. Relatedness among individuals also rises in isolated groups, as mates become increasingly likely to share recent ancestors. By measuring these quantities in samples from different eras, researchers can distinguish long-standing patterns from recent deterioration, something a snapshot of modern samples alone cannot achieve.

Applying this framework to the spotted bat, Walker and colleagues were able to describe the species’ genetic structure, genetic variation, and patterns of relatedness in unprecedented detail, and to identify clear genetic differences between northern and southern populations. One of the most consequential findings concerns geography: spotted bats in the southwestern United States harbor the greatest genetic diversity found anywhere across the species’ range. As Walker explains, this makes the Southwest a critical reservoir of evolutionary potential for the species, the region where the raw material for adaptation to future environmental change is most abundant. In contrast, the northern populations appear to carry lower genetic diversity, a pattern that may reflect postglacial colonization history, smaller effective population sizes, or reduced connectivity, and that could leave these animals more vulnerable as conditions shift.

The temporal dimension of the data adds a layer of interpretation that purely contemporary studies lack. Ancient remains spanning two millennia establish a baseline from before industrial-scale land transformation, allowing the researchers to ask whether the diversity observed today is a recent casualty of human activity or a persistent feature of the species’ biology. The authors report that their integrative approach across temporal scales highlights the conservation importance of preserving genetically diverse core populations, vulnerable leading-edge populations, and isolated relict lineages. In practical terms, this means the Southwest’s diverse populations deserve protection not merely because they are numerous but because they anchor the species’ adaptive capacity, while northern edge populations and any relict lineages may represent unique evolutionary histories that, once lost, cannot be recovered from elsewhere in the range.

Walker emphasizes the broader methodological lesson for conservation science. Rare and elusive species, she notes, can be extremely difficult to study using conventional methods, and genetics allows researchers to see patterns of connectivity, isolation, and long-term persistence that would otherwise remain hidden, providing information that can directly inform conservation planning. The spotted bat study demonstrates the point vividly: from 121 individuals, most of them represented only by a small tissue sample or a fragment of bone, the team reconstructed population structure across an entire continental range and across more than two thousand years of history. For species where every field sighting is a small event, genetic sampling effectively multiplies the value of each encounter.

The project also illustrates the underappreciated scientific value of natural history collections. Walker describes one of the most rewarding aspects of the work as bringing together samples collected over more than a century, from museum specimens and ancient cave remains to bats captured in the field today, with each sample representing a small piece of the species’ history that, combined with the others, allowed a much broader picture of population change through time. Museum specimens collected by collectors who could not have imagined DNA sequencing have become an irreplaceable genomic archive, and ancient subfossil material extends that archive deep into the pre-industrial past. As sequencing technology improves and costs fall, the marginal value of well-curated collections only grows, a strong argument for their continued funding and protection.

The authors are candid about the study’s limitations, which matter for how the results should be applied. Many of the modern specimens originated from a single cave, introducing a sampling bias that could skew estimates of contemporary diversity and structure if that cave’s residents are not representative of the wider region. The team notes that future studies are needed to better understand the impacts of specific anthropogenic disturbances, such as habitat alteration, climate shifts, and disease, on population dispersal and dynamics. Refining the geographic coverage of modern sampling, and extending the ancient record to additional caves and time periods, would sharpen the inferences and help attribute observed changes to particular causes rather than to general environmental change.

For now, the study offers both a warning and a roadmap. By combining DNA from ancient, historical, and modern specimens, the researchers traced the spotted bat’s evolutionary history across space and time and identified the populations that may be most important to conserve for the future, as Walker puts it. Further knowledge of population structure and genetic diversity across the species’ range, the authors write, will promote conservation and management actions for spotted bats. As emerging threats intensify across North America, the ability to read a species’ demographic past directly from its DNA may prove to be one of conservation biology’s most powerful tools, and the spotted bat, long a ghost of the desert night, has now contributed one of the clearest demonstrations of that power.

Subject of Research: Conservation genetics of the spotted bat using ancient, historical, and modern DNA samples

Article Title: Ancient spotted bat samples help researchers understand present-day population dynamics

Article References: Ancient spotted bat samples help researchers understand present-day population dynamics. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: spotted bat, Euderma maculatum, ancient DNA, conservation genetics, population structure, genetic diversity, museum specimens, PLOS One, white-nose syndrome, North America, wildlife conservation, temporal genomics

The threats are mounting on multiple fronts. White-nose syndrome, the fungal disease caused by Pseudogymnoascus destructans, has devastated hibernating bat populations across eastern North America and is now pressing into the Plains. Wind energy development is concentrated here at the highest capacity of any land-based region on the continent, and wind turbines are a well-documented source of mortality, particularly for migratory species. Climate change, drought, pesticide bioaccumulation in insect prey, and ongoing conversion of native grassland to intensive agriculture all compound the pressure. Because no comprehensive synthesis of grassland bat research existed until now, conservation managers have been working largely without a map. The new review set out to change that by systematically cataloguing what has been studied, where, how, and, crucially, what has been missed.

The methodology was deliberately rigorous. The team defined the Great Plains using United States Environmental Protection Agency ecoregion boundaries, encompassing the Canadian provinces of Alberta, Saskatchewan, and Manitoba; thirteen US states from Montana and North Dakota down to Texas; and three Mexican provinces. They searched the Web of Science database using combinations of bat and grassland-related terms, added state and province names in a second round, and finally combed the publication records of 23 bat biologists known to work in the region to catch studies in smaller journals. Only primary field research published in English between 1995 and 2024 qualified; grey literature, reviews, and purely museum-based or modeling studies were excluded. After removing duplicates and irrelevant records, the three search rounds yielded the 94 publications that formed the basis of the synthesis.

The topical breakdown of those publications is revealing. Twenty-six reported simple distributional records in a natural-history style, making that the most common category. Roosting biology came second with 24 publications, followed by 20 studies of winter ecology, 12 quantitative habitat-association studies, and just 10 on foraging behavior or diet. Only two studies addressed migration movements, a striking gap given the region’s wind energy boom. Chronologically, winter ecology research was essentially absent until 2006, and habitat-association studies did not appear until 2011. Geographically, publications came from all three Canadian provinces and every US state in the region except Wyoming and Minnesota, while no English-language publications emerged from the Mexican portion of the ecoregion, a gap the authors acknowledge reflects language barriers rather than an absence of research.

One of the clearest findings concerns water. Ten of the habitat studies examined water sources, and all found them to be important components of bat habitat in this semi-arid landscape. Species including the big brown bat (Eptesicus fuscus), the hoary bat (Lasiurus cinereus), the silver-haired bat (Lasionycteris noctivagans), and the little brown bat (Myotis lucifugus) were all positively associated with water. One study even documented temporal niche partitioning, with different species drinking and foraging at different hours of the night. But the picture is complicated by the fact that in the Great Plains, water and trees tend to co-occur in riparian zones, making it difficult to disentangle which feature bats are actually responding to. Notably, two species showed negative associations with herbaceous wetlands, which offer water but lack the vertical structure bats seem to require.

That vertical structure, especially trees, emerged as the most studied biotic habitat feature. Eleven publications included vegetation variables, and most found that bat activity, abundance, or occupancy increased with proximity to trees and forest patches or with greater canopy cover. The northern long-eared myotis (Myotis septentrionalis) consistently showed positive associations with closed canopy and cluttered vegetation. Some results were contradictory, however, likely because studies measured vegetation at different spatial scales and quantified bats in different ways. Intriguingly, one study found acoustic activity of five bat species was significantly higher inside black-tailed prairie dog colonies than outside them, hinting that an umbrella species approach to conservation might benefit bats. Urban studies in Calgary, Alberta, showed that city zones hosted the highest bat abundance but the lowest diversity, dominated by little brown bats in poorer body condition, a possible ecological trap created by urbanization.

Roosting biology, the second most studied topic, highlights how bats cope with a landscape that historically offered few roosting opportunities. Ten species were documented roosting in trees, others in rock crevices and caves, and many in anthropogenic structures such as buildings, bridges, cabins, and culverts. Thermal microclimate was the most intensively studied factor in roost selection, with researchers using dataloggers and temperature-sensitive transmitters to show that stable internal conditions matter most, particularly for reproductive females. Findings on anthropogenic roosts varied with latitude: in central Texas, male Brazilian free-tailed bats (Tadarida brasiliensis) favored buildings, while at higher latitudes female big brown bats preferred buildings and enjoyed greater reproductive success than those in rock crevices. Long-term studies documented interannual fidelity to individual roost trees in several species, and big brown bats were observed relocating entire maternity colonies when roost trees were lost naturally.

Winter ecology may be the most ecologically surprising chapter of the review. Although the southern Plains stay warm enough for year-round bat activity, researchers documented bats overwintering far north in caves, rocky crevices, mines, and even road culverts. In the Badlands of North Dakota, six species were found overwintering, and in Alberta, big brown bats hibernate in rock crevices exposed to temperatures as low as minus 10.4 degrees Celsius. Winter flight activity, bats leaving hibernacula to fly during cold months, was recorded in at least eight species, typically peaking shortly after sunset and correlating with warmer ambient temperatures and calmer winds. Why bats fly in winter remains unresolved: foraging is unlikely because insects are absent, and an artificial water source experiment found no evidence bats used it for drinking. Proposed explanations include dehydration, muscle maintenance, waste elimination, and hibernacula switching, all of which matter for managing white-nose syndrome, which kills bats during the winter season.

The review’s authors are candid about why grassland bat research lags so far behind forest bat research. Logistically, the northern Plains have low human population density, few universities, and resource managers responsible for enormous tracts of land, leaving the North American Bat Monitoring Program (NABat) database conspicuously sparse for the region. Methodologically, mist-netting, the traditional capture tool, performs poorly in open grassland, and most capture-based studies were actually conducted in remnant forest patches. Biologically, Plains bats often sit at the periphery of their ranges, occurring at low densities where ecological processes may differ fundamentally from those in core populations. The authors call for multi-scale research leveraging NABat’s standardized monitoring, adoption of emerging technologies such as automated acoustic detection, radar, LiDAR, Motus tracking, and environmental DNA sampling, and urgent attention to migration, fire effects, and woody encroachment, a genuine conservation dilemma since encroaching trees may provide roosts and corridors even as they degrade native grassland. As wind farms expand and white-nose syndrome advances, the message of this synthesis is clear: the bats of the Great Plains have been flying under the scientific radar for thirty years, and closing that knowledge gap is now a conservation imperative.

Subject of Research: Ecology and conservation of bat populations in the North American Great Plains grassland ecosystem

Article Title: Bat ecology and conservation in the Great Plains: a systematic review of research in the past 30 years and future directions

Article References: Bat ecology and conservation in the Great Plains: a systematic review of research in the past 30 years and future directions. (n.d.). https://doi.org/10.1007/s44353-026-00082-2

Image Credits: AI Generated

DOI: 10.1007/s44353-026-00082-2

Keywords: bats, Great Plains, grasslands, white-nose syndrome, wind energy, roosting ecology, winter ecology, habitat association, foraging behavior, NABat, conservation, systematic review