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Sensitivity of bats to land use change depends on their foraging ecology, which varies among species based on ecomorphological traits. Additionally, because prey availability, vegetative clutter, and temperature change throughout the year, some species may display seasonal shifts in their nocturnal habitat use. In the Coastal Plain of South Carolina, USA, the northern long-eared bat (Myotis septentrionalis), southeastern myotis (Myotis austroriparius), tri-colored bat (Perimyotis subflavus), and northern yellow bat (Lasiurus intermedius) are species of conservation concern that are threatened by habitat loss. Our objective was to identify characteristics of habitat used by these species during their nightly active period and compare use between summer and winter. We conducted acoustic surveys at 125 sites during May–August and at 121 of the same 125 sites December–March 2018 and 2019 in upland forests, bottomland forests, fields, ponds, and salt marsh and used occupancy models to assess habitat use. The northern long-eared bat and southeastern myotis (i.e., myotis bats) used sites that were closer to hardwood stands, pine stands, and fresh water year-round. We did not identify any strong predictors of tri-colored bat habitat use in summer, but during winter they used bottomland forests, fields, and ponds more than salt marsh and upland forests. During summer and winter, northern yellow bats used sites close to fresh water and salt marsh. Additionally, during summer they used fields, ponds, and salt marsh more than upland and bottomland forests, but in winter they used bottomland forests, fields, and ponds more than upland forest and salt marsh. Our results highlight important land cover types for bats in this area (e.g., bottomland forests, ponds, and salt marsh), and that habitat use changes between seasons. Accounting for and understanding how habitat use changes throughout the year will inform managers about how critical habitat features may vary in their importance to bats throughout the year.

Northern yellow bats (Dasypterus intermedius) are tree-roosting bats in the family Vespertilionidae comprised of two subspecies: D. intermedius intermedius and D. intermedius floridanus. The two subspecies are thought to be geographically separated. Due to their cryptic morphology, this hypothesis has never been tested and can benefit from being examined within a molecular framework. In this study, mitochondrial sequence data from 38 D. intermedius and nuclear sequence data from 14 D. intermedius from across their range were used to test the hypothesis that genetically defined groups correspond geographically with the two morphologically defined subspecies. Although high levels of divergence of the mitochondrial sequence (11.6%) suggest genetically distinct clusters sympatric in southern Texas, no genetic structure was recovered with the nuclear marker. Moreover, the mitochondrial sequence data recovered a paraphyletic relationship between the two subspecies of D. intermedius with the Cuban yellow bat (D. insularis), whereas no such paraphyly was recovered from analysis of the nuclear marker. Divergence time based on analyses of mitochondrial sequence for the two subspecies was approximately 5.5 Ma. The patterns observed are hypothesized to be the result of past isolation of lineages and secondary contact that is currently contributing to gene flow.

Knowledge of roost selection by northern yellow bats (Lasiurus intermedius) is limited to a small number of known roost locations. Yet knowledge of basic life history is fundamental to understanding past response to anthropogenic change and to predict how species will respond to future environmental change. Therefore, we examined male northern yellow bat roost selection on 2 Georgia, USA, barrier islands with different disturbance histories. Sapelo Island has a history of extensive disturbance and is dominated by pine (Pinus spp.) forests; Little Saint Simons Island has a limited disturbance history with maritime oak (Quercus spp.) forest as the dominant cover type. From March–July 2012 and 2013, we radio-tracked 35 adult male northern yellow bats to diurnal roosts and modeled roost characteristics at the plot and landscape scales. We located 387 roosts, of which 95% were in Spanish moss (Tillandsia usneoides) hanging in hardwood trees. On both islands, bats selected roost trees with larger diameters than surrounding trees and selected roost locations with greater open flight space (i.e., low midstory clutter) underneath. Roosts were located farther from open areas on Sapelo and closer to fresh water on Little Saint Simons compared to random locations. Lower availability of hardwood forest on Sapelo may have resulted in small-scale roost site selection (i.e., plot level) despite potential increased costs of commuting to water and open areas for foraging. In contrast, greater availability of hardwood forest on Little Saint Simons likely allowed selection of roosts closer to fresh water, which provides foraging and drinking opportunities. Our results indicate that mature hardwood trees in areas with low midstory clutter are important in male northern yellow bat roost selection, but landscape-level features have varying influences on roost selection, likely as a result of differences in disturbance history. Therefore, management will differ depending on the landscape context. Further research is needed to examine roost selection by females, which may have different habitat requirements.

Lasiurus intermedius (Northern Yellow Bat) and Perimyotis subflavus (Tricolored Bat) are species of conservation concern in South Carolina and are threatened by loss of roosting habitat. To better understand summer roost selection, we radio-tracked individuals to roost trees during May through August of 2018 and 2019. We characterized roost trees, sites surrounding roost trees, and unused but available trees for each roost occasion. We used discrete-choice models to test hypotheses of factors influencing roost-site selection. Tri-colored Bats used foliage and Tillandsia usneoides (Spanish Moss) in hardwood trees and selected trees with high densities of Spanish Moss. Northern Yellow Bats used dead palm fronds in Sabal palmetto (Cabbage Palm Trees) or Spanish Moss in trees with high densities of Spanish Moss. Our results suggest that conservation of maritime and bottomland forests with trees that have high densities of important roost structures like Spanish Moss and dead palm fronds would benefit these species.

There are increasing concerns regarding bat mortality at wind energy facilities, especially as installed capacity continues to grow. In North America, wind energy development has recently expanded into the Lower Rio Grande Valley in south Texas where bat species had not previously been exposed to wind turbines. Our study sought to characterize genetic diversity, population structure, and effective population size in Dasypterus ega and D. intermedius , two tree-roosting yellow bats native to this region and for which little is known about their population biology and seasonal movements. There was no evidence of population substructure in either species. Genetic diversity at mitochondrial and microsatellite loci was lower in these yellow bat taxa than in previously studied migratory tree bat species in North America, which may be due to the non-migratory nature of these species at our study site, the fact that our study site is located at a geographic range end for both taxa, and possibly weak ascertainment bias at microsatellite loci. Historical effective population size (N EF ) was large for both species, while current estimates of Ne had upper 95% confidence limits that encompassed infinity. We found evidence of strong mitochondrial differentiation between the two putative subspecies of D. intermedius ( D. i. floridanus and D. i. intermedius ) which are sympatric in this region of Texas, yet little differentiation using microsatellite loci. We suggest this pattern is due to secondary contact and hybridization and possibly incomplete lineage sorting at microsatellite loci. We also found evidence of some hybridization between D. ega and D. intermedius in this region of Texas. We recommend that our data serve as a starting point for the long-term genetic monitoring of these species in order to better understand the impacts of wind-related mortality on these populations over time.

Little is known about the reproductive habits of the 4 species of bat in the genus Lasiurus that live in Louisiana. We examined reproductive notes from specimen records for the eastern red bat (L. borealis), the Seminole bat (L. seminolus), the northern yellow bat (L. intermedius), and the hoary bat (L. cinereus). We found that gestation and partuition happen between May and June for all species. Lactating and postlactating individuals and juveniles were mostly captured in late June or July. Typically, litter sizes range from 3 to 4 pups for both L. borealis and L. intermedius and from 1 to 3 pups for L. seminolus. Males for all species became scrotal in early fall between August and October, suggesting that fertilization is delayed till the spring. However, we do provide evidence that copulation may also occur in early spring for L. intermedius.