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.

Mountain pine beetle (MPB) (Dendroctonus ponderosae Hopkins) is a native bark beetle that reproduces in pine (Pinus) species across western North America. High population levels can result in widespread host tree mortality. Over the past 2 decades, MPB has been responsible for pine mortality across millions of forested hectares in the western United States. Although a majority of the pine species found in the western United States are considered hosts to MPB, the host status of Rocky Mountain (RM) bristlecone pine (Pinus aristata) is unclear. We surveyed stands across the range of RM bristlecone pine in Colorado, USA, and quantified MPB-caused mortality within the past 10 years in stands where RM bristlecone and at least one other pine species co-occurred. We also evaluated in the field whether successful MPB brood production occurred in RM bristlecone pine. Our results confirm that RM bristlecone pine is susceptible to MPB attack and suitable for MPB reproduction. In mixed-species stands, pine species availability influenced MPB attack occurrence. The proportion of trees experiencing fatal beetle attack within a particular Pinus species was best predicted by the basal area proportion of that species in the stand prior to the most recent 10 years of mortality. These results indicate that RM bristlecone pine is vulnerable to ongoing climate change–induced contact with MPB.

Glen Canyon National Recreation Area covers large and geographically unique regions of southern Utah and northern Arizona. However, multiple surveys of bats from 1952 to 2017 have not been published. Prior to 2015, most bat surveys in the recreation area were conducted using mist nets only and did not include acoustic monitoring. In this paper we compile records of bats found in Glen Canyon National Recreation Area from 1952 to 2017, including records from our recent surveys using both mist nets and acoustic sampling. During our recent surveys, 2 new species were captured (Nyctinomops macrotis and Lasionycteris noctivagans), and 2 other new species were documented using acoustic detection (Myotis evotis and Eumops perotis), bringing the total documented bat species in Glen Canyon National Recreation Area to 17 species. This paper sheds light on the diverse bat assemblage of Glen Canyon National Recreation Area that will serve as a baseline for future research and conservation efforts.

Wildlife conservationists and managers often need to estimate abundance and demographic parameters to monitor the status of populations, and to ensure that these populations are meeting management goals. DNA capture-recapture surveys have become increasingly common in situations where physical surveys are consistently difficult or counts are small or variable. Desert mule deer (Odocoileus hemionus eremicus) inhabit rugged terrain, occur at low population densities, and demonstrate cryptic behaviors, making monitoring and assessing population status difficult. We assessed the effectiveness of a fecal DNA–based capture-recapture method for estimating abundance and survival of desert mule deer. We designed and implemented a fecal DNA sampling design focused at water sources during the dry season (June–July) of 2015–2017 in the Little Chuckwalla Mountains (study area ∼968 km²) located in the Sonoran Desert of southeastern California. We conducted 6, 5, and 4 surveys in 2015, 2016, and 2017, respectively. We used the capture-recapture data in the POPAN open-population model to estimate abundance and the Cormack–Jolly–Seber model to estimate annual survival. We detected 234, 193, and 211 unique individuals in 2015, 2016, and 2017, respectively. Over the 3-year study, population abundance estimates ranged from 386 in 2015 (95% CI, 264–509) to 301 in 2017 (95% CI, 260–342). Precision (i.e., coefficient of variation [CV]) of male and female abundance estimates ranged from 7% to 16%, and CV for males and females combined ranged from 5% to 15%. Annual apparent survival for females and males was 0.91 (95% CI, 0.59–0.98) and 0.71 (95% CI, 0.51–0.85), respectively. We concluded that fecal DNA–based capture-recapture is an effective method for estimating abundance and survival of desert mule deer. This approach could be expanded to encompass additional areas adjacent to our study site, with the potential to monitor the larger metapopulation of desert mule deer in the Sonoran Desert of California. More generally, DNA mark-recapture may be widely applicable to other species that congregate around water sources (or any required resource) during part of the year. Results from this study will be useful for developing population monitoring plans and for studies evaluating the effects of human development or environmental factors on desert mule deer and other desert ungulates.

How aquatic insects cope with cold temperatures is poorly understood. This is particularly true for high-elevation species, which often experience a seasonal risk of freezing. In the Rocky Mountains, nemourid stoneflies (Plecoptera: Nemouridae) are a major component of mountain stream biodiversity and are typically found in streams fed by glaciers and snowfields, which are rapidly receding due to climate change. Predicting the effects of climate change on mountain stoneflies is difficult because their thermal physiology is largely unknown. We investigated cold tolerance of several alpine stoneflies (Lednia tumana, Lednia tetonica, and Zapada spp.) from the Rocky Mountains, USA. We measured the supercooling point (SCP) and tolerance to ice enclosure of late-instar nymphs collected from a range of thermal regimes. SCPs varied among species and populations, with the lowest SCP measured for nymphs from an alpine pond, which was much more likely to freeze solid in winter than flowing streams. We also show that L. tumana cannot survive being enclosed in ice, even for short periods of time (<3 h) at relatively mild temperatures (–0.5 °C). Our results indicate that high-elevation stoneflies at greater risk of freezing may have correspondingly lower SCPs, and despite their common association with glacial meltwater, these stoneflies appear to be living near their lower thermal limits.

The Snake River Pilose Crayfish, Pacifastacus connectens (Faxon 1914), previously known only from the middle Snake River drainage in south-central Idaho west to the Harney Basin in southeastern Oregon, was discovered in the lower Deschutes River in north-central Oregon co-occurring with Signal Crayfish, Pacifastacus leniusculus (Dana 1852). Two groups of obligate ectosymbionts (i.e., entocytherid ostracods and branchiobdellidans) associated with these 2 Pacifastacus species displayed asymmetrical patterns of host switching, with host exchange primarily occurring from P. leniusculus onto P. connectens. Our results have implications for understanding patterns of host specificity over short ecological timescales but also raise questions about the persistence of these patterns over time.

Riparian areas are an important resource for many wildlife species, especially in the arid Southwest. Understanding species occurrence in areas dominated by nonnative vegetation is important to determine whether management should be implemented. Saltcedar (Tamarix spp.) is one of the most prevalent and invasive nonnative woody species in riparian areas in the southwestern United States, and it can alter vegetation structure. Little is known about how meso (medium) and large carnivores and herbivores use or avoid stands of saltcedar. We investigated mammal activity in 3 riparian forest types along the San Pedro River in southeastern Arizona: nonnative saltcedar, native mesquite (Prosopis spp.) woodland, and native cottonwood (Populus fremontii) and willow (Salix gooddingii) forest. We determined mammal use, diversity, and occupancy across riparian forest types. We sampled mammals along approximately 25 river kilometers between July 2017 and October 2018, using 18 trail cameras (6 per forest type) spaced 1 km apart. We summarized environmental variables around the cameras and reduced the variables to 4 components using a principal component analysis. We observed 14 meso and large mammal species, including bobcat (Lynx rufus), coyote (Canis latrans), and white-nosed coati (Nasua narica) over 7692 trap nights. Occupancy of some species may have been influenced by the environmental components, but models showed high standard errors, making it difficult to draw firm conclusions. Our results do not indicate that nonnative saltcedar was actively avoided. There were no discernible differences in detections of species or taxonomic groups among forest types; however, the highest species diversity was in mesquite woodlands. We did not find evidence of competitively dominant predators (coyotes and mountain lions [Puma concolor]) altering the temporal activity patterns and forest use of subordinate species (gray fox [Urocyon cinereoargenteus] and bobcat), as each pair used the same riparian space at similar times.

Knowledge of the home range size (HRS) of species is critical for their effective management and conservation. We systematically searched the open literature for information on HRS for Bald Eagle (Haliaeetus leucocephalus), Golden Eagle (Aquila chrysaetos), Prairie Falcon (Falco mexicanus), and Ferruginous Hawk (Buteo regalis). We found 24 articles with HRS estimates and accompanying methodology and demographic information on sampled individuals. Most studies focused on Bald Eagles, followed by Golden Eagles, Prairie Falcons, and Ferruginous Hawks. HRS estimates for the Golden Eagle were the largest and had the greatest associated variance (m = 8797 km²; 95% CI, 0–47,284 km²). Estimates for Bald Eagle HRS were smaller, with a mean of 2215 km² (95% CI, 0–12,472 km²). Prairie Falcon and Ferruginous Hawk HRS estimates were much smaller, with means of 156 km² (95% CI, 0–415.22 km²) and 22 km² (95% CI, 0–96.88 km²), respectively. HRS estimates varied substantially across period (breeding/nonbreeding), sex, age class, fix type, and estimation method for all species, and this finding points to the importance of accounting for the context of these estimates. The information can be used to inform other efforts to characterize the spatial use of these 4 raptors.

Ungulate browsing influences the structure and composition of woody plant communities, including species composition and biomass production as well as age distribution, recruitment, and mortality. We evaluated effects of elk and bison herbivory on narrowleaf cottonwood (Populus angustifolia) communities in a semiarid ecosystem in southern Colorado. Cottonwoods in this ecosystem have been aged at ≥300 years old and are among the oldest cottonwood trees in North America. We compared browsing intensity and structural and productivity responses of cottonwood to ungulate herbivory. We compared responses in sites with elk and bison, sites with elk but no bison, and sites where both ungulates were excluded. We found that the majority of browsing on cottonwood occurred during summer in this high desert ecosystem. Areas with both elk and bison had higher browse utilization than areas with only elk, but diet data indicated that elk consumed a much greater proportion of cottonwood than bison. Overall, browse utilization observed in this study was low to moderate compared to other studies, and our results may not be representative of sites experiencing intense year-round herbivory. Removal of all ungulate herbivory led to taller and denser cottonwood suckers; however, other environmental factors, in addition to herbivory, still strongly limit cottonwood growth and recruitment in this ecosystem.

Santa Catalina Island, located ∼35 km off the Southern California coast, is home to the Blue Cavern Onshore State Marine Conservation Area (SMCA). Although the conservation area is recognized as both an area of special biological significance and a marine life refuge, species richness of the nearshore taxa from this location is not known. In this study, we provide a comprehensive inventory of the intertidal and subtidal marine macroalgae, plants, invertebrates, and fishes documented from 5 different reef sites inside Blue Cavern Onshore SMCA. Species richness data were compiled using scuba-based visual surveys conducted in the field, references from the primary and gray literature, research collections maintained by scholarly institutions, and field monitoring programs. The total number of marine taxa documented in this study (765 species from 17 major phylogenetic groups) represents 63% of the estimated species richness in Blue Cavern Onshore SMCA and is indicative of the high biodiversity known from this region. Specifically, the intertidal and subtidal biota reported here represent 34% and 18% of the marine taxa known from Catalina Island and the Southern California Bight, respectively. Incidences of the introduction of exotic and invasive organisms (n = 18), changes in the geographic distributions of species (n = 14), as well as marine taxa listed as species of concern, endangered, or critically endangered (n = 4), were also identified in the current inventory. Research findings presented here offer an important baseline of species richness in the California Channel Islands and will help to improve efforts by resource managers and policy makers to conserve and manage similar habitats in the coastal waters off Southern California.

The tri-colored bat (Perimyotis subflavus) occurs throughout the eastern United States, from Canada to south Florida and westward to eastern New Mexico, central Colorado, and western Texas. In this study, we document the first record of P. subflavus for both Guadalupe Mountains National Park and Culberson County, Texas. Our record extends the range of P. subflavus into the Trans-Pecos region of Texas. We also examined the diet of this individual and observed that it consisted of Lepidoptera, Coleoptera, and Hemiptera. Our observations of the diet of P. subflavus correspond with results of previous studies from more eastern portions of the species' range.

Plains spotted skunks (Spilogale putorius interrupta) were once common over a wide range, but at present they are much less abundant and infrequently captured. Therefore, it can be difficult to assess the efficacies of capture techniques in the field. I gathered data on the baits, lures, and types of trapping locations recommended in trapping manuals and in articles from trapping magazines published in the early 1900s. A total of 43 trap site recommendations, 42 bait recommendations, and 9 lure recommendations were gleaned from 36 historic articles or books. Seven of 43 trap sites (16.3%) were described simply as “dens,” while 29 of 43 (67.4%) were sites that would probably serve as dens for plains spotted skunks, such as burrows, fencerows, and old buildings. Birds (19.1%), rabbits (14.3%), chickens (11.9%), and mice (11.9%) were most frequently mentioned as baits. Lure recommendations were less common and were mostly fish oil (33.3%) or skunk scent (22%). Based on these historic recommendations, trapping for spotted skunks in crop and grassland habitats, including prairies, may be most successful when the effort targets mammal burrows and other potential den sites. Although the use of small animals as bait may be productive, further research will be needed to determine whether this method is more cost efficient or effective than the canned fish now used as bait by most modern researchers.