Small Mammals of Winter Wheat and Grain Sorghum Croplands in West-Central Kansas

Populations of small mammals were studied in the wheat/grain sorghum rotation agro- system in west-central Kansas. Two areas, each representing a different phase of the crop rotation cycle, were live-trapped. Diversity, evenness, richness, and relative densities of small mammals in the crop fields and in two uncultivated habitats were compared. Croplands had the lowest diversity and overall relative densities although the wheat field supported the greatest relative density of P. maniculatus. The grain sorghum field exhibited high diversity and evenness but had the lowest relative density. Community similarity coefficients indicated that croplands were least similar in their small mammal compositions, whereas the wheat field and adjoining edge habitat were most similar. Peromyscus maniculatus was the only species that was a common resident in croplands throughout the year, and ecological characteristics of this species were evaluated. Populations of deer mice peaked in spring during the period of rapid growth of wheat. Occasional disruptions in the wheat field did not have a detrimental effect on the population of deer mice, whereas the more frequent cultivations in the grain sorghum field might have contributed to the low population densities of small mammals found therein

Intraspecific Comparison of Population Structure, Genetic Diversity, and Dispersal Among Three Subspecies of Townsend’s Big-Eared Bats, \u3ci\u3eCorynorhinus townsendii townsendii, C. t. pallescens\u3c/i\u3e, and the Endangered \u3ci\u3eC. t. birginianus\u3c/i\u3e

Townsend’s big-eared bat, Corynorhinus townsendii, is distributed broadly across western North America and in two isolated, endangered populations in central and eastern United States. There are five subspecies of C. townsendii; C. t. pallescens, C. t. australis, C. t. townsendii, C. t. ingens, and C. t. virginianus with varying degrees of concern over the conservation status of each. The aim of this study was to use mitochondrial and microsatellite DNA data to examine genetic diversity, population differentiation, and dispersal of three C. townsendii subspecies. C. t. virginianus is found in isolated populations in the eastern United States and was listed as endangered under the Endangered Species Act in 1979. Concern also exists about declining populations of two western subspecies, C. t. pallescens and C. t. townsendii. Using a comparative approach, estimates of the genetic diversity within populations of the endangered subspecies, C. t. virginianus, were found to be significantly lower than within populations of the two western subspecies. Further, both classes of molecular markers revealed significant differentiation among regional populations of C. t. virginianus with most genetic diversity distributed among populations. Genetic diversity was not significantly different between C. t. townsendii and C. t. pallescens. Some populations of C. t. townsendii are not genetically differentiated from populations of C. t. pallescens in areas of sympatry. For the western subspecies gene flow appears to occur primarily through male dispersal. Finally, geographic regions representing significantly differentiated and genetically unique populations of C. townsendii virginianus are recognized as distinct evolutionary significant units

Guidelines for Defining Biologically Important Bat Roosts: A Case Study from Colorado

Conservation of roosts is regularly recommended as a strategy to decrease the risk of threats to local bat populations (e.g., white-nose syndrome). Determining whether a roost site plays a meaningful role in maintaining a local bat population can be difficult given the variability found in roost structure type, and use by season, duration, and sex. Here we provide land managers and biologists with guidelines to aid in the decision process for determining which roosts are biologically important in maintaining healthy bat populations at a local scale. We define methods for determining biologically important roost sites and provide a case study of their use on bat roosts in Colorado. To be considered biologically important, we suggest that a roost meet two primary criteria: 1) it is considered a hibernaculum, maternity roost, transient roost, colonial bachelor roost, or fall swarming site used by bat species that are gregarious roosters, hibernators, or are known to swarm, and 2) if the site is disturbed or lost, it could affect 5% or more of the local population of the species, as defined by the investigator. Additive measures to further evaluate the importance of the roost and assign higher conservation value include: 1) a roost used by a special status species and 2) large aggregations of bats where an estimated 20% or more of the local population is roosting or swarming at the site. We also provide definitions for the seasonality of roost types, examples of several real-life scenarios where management decisions have been made for roosts, and a worksheet that helps guide users through the process

A review of bat hibernacula across the western United States: Implications for white-nose syndrome surveillance and management

Efforts to conserve bats in the western United States have long been impeded by a lack of information on their winter whereabouts, particularly bats in the genus Myotis. The recent arrival of white-nose syndrome in western North America has increased the urgency to characterize winter roost habitats in this region. We compiled 4,549 winter bat survey records from 2,888 unique structures across 11 western states. Myotis bats were reported from 18.5% of structures with 95% of aggregations composed of ≤10 individuals. Only 11 structures contained ≥100 Myotis individuals and 6 contained ≥500 individuals. Townsend’s big-eared bat (Corynorhinus townsendii) were reported from 38% of structures, with 72% of aggregations composed of ≤10 individuals. Aggregations of ≥100 Townsend’s big-eared bats were observed at 41 different caves or mines across 9 states. We used zero-inflated negative binomial regression to explore biogeographic patterns of winter roost counts. Myotis counts were greater in caves than mines, in more recent years, and in more easterly longitudes, northerly latitudes, higher elevations, and in areas with higher surface temperatures and lower precipitation. Townsend’s big-eared bat counts were greater in caves, during more recent years, and in more westerly longitudes. Karst topography was associated with higher Townsend’s big-eared bat counts but did not appear to influence Myotis counts. We found stable or slightly-increasing trends over time in counts for both Myotis and Townsend’s big-eared bats from 82 hibernacula surveyed ≥5 winters since 1990. Highly-dispersed winter roosting of Myotis in the western USA complicates efforts to monitor population trends and impacts of disease. However, our results reveal opportunities to monitor winter population status of Townsend’s big-eared bats across this region