Species of biscuitroot (Lomatium: Apiaceae) are endemic to western North America, where multiple species can be common members of perennial wildflower communities from basin sagebrush-steppe and juniper woodlands up to alpine meadows. Despite Lomatium being the largest genus of Apiaceae in North America, little is known about its pollination needs or pollinators. Manual pollinations of the tiny flowers of one species, desert parsley (L. dissectum), showed it to be a self-compatible species, akin to other genera of Apiaceae. Seed production, however, largely requires pollinators to move pollen within and between the andromonoecious umbels. Regional sampling of floral visitors to L. andrusianum, L. dissectum, L. triternatum, and several other species revealed a sometimes abundant and exceptionally rich diversity of mostly Andrena bees. These 21 Andrena species together composed 94% of the individuals methodically sampled at Lomatium plants; this number is at odds with claims of taxonomic promiscuity for pollinator faunas of the Apiaceae. But for several Lomatium specialists, these Andrena species all seem to be floral generalists with apparent pollination value for Lomatium. These ground-nesting bees, as well as their Lomatium hosts, should survive the increasingly frequent and extensive wildfire events burning the sagebrush-steppe and juniper woodlands that they inhabit, owing to their springtime seasonalities and the insulative protection of overlying soil.

We compared the movement patterns of foraging Colorado Checkered Whiptails (Aspidoscelis neotesselata) in 2 different habitat types: shrub-grassland and pinyon pine–juniper woodland. We characterized movement by (1) segmenting movement paths into step lengths and turn angles and (2) determining first-passage times (FPTs). Lizards differed in their pattern of movement in the 2 habitats. FPTs were shorter in the pinyon pine–juniper woodland habitat and were positively correlated with ground cover. Lizards also moved more frequently, had longer step lengths, and traveled greater total distances in the pinyon pine–juniper woodland. There were no habitat differences in turn angles, net displacement, or movement path straightness. Habitat-based differences in movement might reflect differences in prey availability and predation risk.

A comprehensive understanding of foraging choices within an optimal framework requires a basic understanding of the differential nutritive concentrations and availability of prey items. Herein we present both nutritional data (e.g., the macronutrient, gross energy, and mineral concentrations) and temporal abundance of wild-caught arthropods from Nebraska prairies. Additionally, we report the size-mediated nutritional concentrations of 2 Orthoptera families: Acrididae and Tettigoniidae. Crude fat concentrations were 56%, 63%, and 53% higher in small, medium, and large Tettigoniidae than in Acrididae, respectively. Crude protein concentration varied minimally among arthropod groups (range 60.32%–76.00%), while caloric densities (gross energy) were similar among the majority of arthropod groups that were analyzed (range 16.54–23.36 kJ/g). In addition, small (early instar) orthropterans peaked synchronous to the mean first clutch hatch date for 2 species of grassland birds at the study site. Our results suggest that size and insect taxonomy influence crude fat and protein concentrations but do not appear to influence gross energy concentrations. Peak fat and protein concentration occurred during the early nestling phase for both avian species, implying synchrony between food availability and the nestling provisioning period for grassland nesting birds.

Shrubs create heterogeneity in resource availability, yet the influences of shrub age and size on these conditions in semiarid ecosystems is largely unknown. In order to inform restoration and conservation efforts in global shrub-steppe ecosystems that are currently imperiled, we assessed plant age-size relationships within an Artemisia tridentata stand in southern Idaho, USA, and examined the dependence of 2 resources, soil water content (SWC) and light at the soil surface (photosynthetically active radiation [PAR]), on size of individual plants in understory and interspace microsites. Results included a positive relationship between shrub age and size, a median shrub age of 19 years old, and shrub sizes that varied by more than 3 orders of magnitude (i.e., 0.001 m³ to 1 m³). Across this broad range in stand structure, PAR was significantly lower in understory than in interspace microsites, and it declined slightly with increasing shrub volume. Similarly, SWC declined faintly with shrub volume, but understory and interspace microsites did not differ. These findings indicate that resource heterogeneity created by shrubs is potentially dependent on shrub size within this ecosystem, and that variation in stand structure directly influenced resource heterogeneity between understory and interspace microsites. We suggest that routine monitoring of heterogeneity in stand structure could serve as a valuable indicator to assess site suitability for restoration activities and to make quantitative comparisons among sites to prioritize conservation efforts.

Grassland birds are one of the most rapidly declining bird guilds in North America, likely as a result of the loss and degradation of native grasslands. The Grasshopper Sparrow (Ammodramus savannarum), a migratory grassland bird of North America, relies on dense, relatively tall grasses with low shrub densities. In Mexico, 4 subspecies of A. savannarum have been reported; however, the distribution of the species in the summer is poorly known, with only 2 records from northern Mexico within the states of Zacatecas and Chihuahua. Here, we report on the presence and nesting activity of A. savannarum in the Cuchillas de la Zarca Grassland Priority Conservation Area in northern Durango, Mexico. We describe the morphometric characteristics of the birds captured, speculate on subspecies designation, and report on characteristics within the territories of singing males and habitat at the nest site. The Cuchillas de la Zarca region is one of the most important sites for wintering grassland birds, particularly A. savannarum, but faces threats such as shrub encroachment caused by poor grazing management. Here we present evidence that this region also provides breeding habitat for the Grasshopper Sparrow, further highlighting its value as a priority area for the conservation of grassland birds.

Range contractions in the Great Basin over the last century suggest that American pikas (Ochotona princeps) might be highly sensitive to climate change. However, documentation of pikas residing at relatively warm, low-elevation sites has recently shed new light on the possible resilience of pika populations to warmer ambient conditions when they have access to cooler microhabitats for thermoregulation. To provide insight into the possible behavioral mechanisms of adaptation to warmer habitats, we investigated activity patterns, foraging behavior, and space use of a population of pikas living in an atypical, warmer habitat at Craters of the Moon National Monument and Preserve, an extensive lava flow surrounded by high desert grassland and sagebrush communities in southern Idaho. We compared pika behavior at this site to that of a population in a more typical alpine habitat at Grays Peak in the nearby Pioneer Mountains in Idaho. Specifically, we evaluated and compared activity patterns and foraging behavior of pikas in relation to temperature, time of day, and month. Pikas at Craters of the Moon were less active aboveground during all times of the day from late May until mid-August, compared to those at Grays Peak. Surface temperatures were warmer across the entire season at Craters of the Moon than at Grays Peak, and pikas exhibited a crepuscular activity pattern that coincided with variations in surface temperature at Craters of the Moon. Pikas were the least active during the midday, when the surface temperatures were highest and the insulating effect of the lava tubes (i.e., the difference between surface and crevice temperatures) was most pronounced. Pikas at Craters of the Moon spent less time haying and displayed fewer territorial behaviors than pikas at Grays Peak, but both groups filled a similar number of hay piles. The vegetation community was less diverse and sparser at Craters of the Moon than at Grays Peak, and consequently, the vegetation that was consumed and cached reflected these differences. Our results expand the body of literature about American pikas at their environmental limits, and this study is the first step in identifying the unique suite of behaviors that pikas use to persist in a seemingly inhospitable environment at Craters of the Moon.

Despite extensive range overlap between Great Basin gopher snakes (Pituophis catenifer deserticola) and Greater Sage-Grouse (Centrocercus urophasianus) within sagebrush ecosystems, there are few documented predator–prey interactions between these species. Although gopher snakes have been observed preying on nests of other prairie grouse, studies that used video-monitoring at sage-grouse nests found gopher snakes unable to consume sage-grouse eggs and reported just a single instance of a snake consuming a <1-day-old chick in a nest bowl. On the morning of 4 June 2018 at 04:55, we observed a Great Basin gopher snake killing, constricting, and attempting to consume a 19-day-old sage-grouse chick in the foothills of the Owyhee Mountains, southwestern Idaho. This observation is the first record of a gopher snake killing a sage-grouse chick during the late brood-rearing period and highlights the likelihood that large gopher snakes are a cause of chick mortality from hatch day to at least 19 days post-hatch.

Forests of northern California provide important breeding and wintering habitat for the Northern Saw-whet Owl (Aegolius acadicus) (Zeiner et al. 1990). This study examined 77 pellets collected over 2 fall-winter seasons in order to better understand the dietary needs of this species.

We collected quantitative data on small mammal activity during the 2017 solar eclipse at a locality in south-central Idaho, at the center of the path of totality where the eclipse reached totality near midday. The day before the eclipse, temperature and light intensity approached daily maximum values during the 3-h period that would encompass the solar eclipse, and only diurnal squirrels were active during this interval. During the eclipse, changes in temperature and light were similar to those that normally occur before dusk and following dawn. Results suggest that diurnal species may have curtailed their activity during the eclipse, and species with facultative activity responded as they would with the approach of dusk. Despite their numerical dominance, nocturnal species were not detected during the eclipse, perhaps due to the brevity of the event or the stronger influence of endogenous activity cycles.

We report results from a 3-year field investigation to limit hybridization between native and nonnative suckers in 2 small tributaries of the Gunnison River basin, Delta County, Colorado. Upstream movement to spawning habitat was selectively impeded by picket weir in intermittent Cottonwood Creek. There, native suckers were identified based on morphological characters in the field and were transferred upstream of the weir, whereas nonnative fishes were excluded from upstream movement. Another stream, Potter Creek, was not impeded by weir. Genetic identification of adult fishes in both streams was consistent with morphological identification in the field. Larval genetic identification was consistent with probable spawning species in Potter Creek. However, in Cottonwood Creek, larval fish proportions differed significantly from likely spawners. Proportions of nonnative suckers were high in Cottonwood Creek because exclusion structures were compromised by flooding during the spawning season. Yet, instream control of spawning by nonnative fishes has potential for reducing the incidence of hybridization, but practical challenges remain for implementation in the field.

The known distributions of eastern red bats and western red bats in western North America have changed greatly over the past 2 decades, resulting in inaccurate range maps and uncertainty regarding the presence or probable absence of these species within states and provinces. We obtained capture and specimen records from the western United States and Canada for 276 eastern red bats and for 863 western red bats. We documented the expansion of the range of eastern red bats in northwestern Canada and clarified the northern and eastern limits of western red bat distribution in the United States. We found that the eastern red bat and western red bat exhibit a mostly allopatric distribution, with western red bats mainly inhabiting warmer, drier forested ecoregions at lower latitudes than those inhabited by eastern red bats. A small zone of overlap between the species was identified only in far western Texas, although it is possible that sympatry may be more widespread due to errors on museum specimen labels and misidentification of captured red bats.

The function of the nuchal hump on adult humpback chub (Gila cypha) has been the subject of longtime conjecture. Hypotheses about the purpose of the hump range from it being a feature that confers hydrodynamic advantages in swift water to speculation about how the hump may have reduced predation vulnerability to Colorado pikeminnows (Ptychocheilus lucius). We used comparative histology of the head region of captive-reared and wild specimens of humpback chub to evaluate whether histological examination could give insight into the function of the hump. Tissues were sectioned, stained, and photographed under a microscope at 2×, 4×, and 40× magnification. The hump is composed almost entirely of skeletal muscle, with little nervous system innervation or fatty tissue. Hump muscle and dorsal muscle appear very similar in terms of muscle cell size, fat content, and connective tissue content. No apparent differences exist between the hump tissues of wild-caught and captive-reared individuals. Histological analysis and study of the anatomical structure of the head through dissection, along with evidence from other species, suggest that the hump evolved to reduce predation vulnerability. Although the reason for the evolution of the hump in humpback chub remains uncertain, additional information about the composition of the hump can help to support or refute hypotheses related to its function.

Mountain pine beetle (MPB; Dendroctonus ponderosae Hopkins) outbreaks are an important component in forest succession for Pinus (pine) forests in the western United States. The research presented here is the first attempt to use pollen data from lake sediment cores to identify MPB disturbance over the past 1600 years within a pine-dominated forest. With evidence of both current and presettlement MPB outbreaks in the surrounding forest, Fishstick Lake, a small subalpine lake in the Sawtooth Mountains of Idaho, is located in a Pinus contorta (lodgepole pine)–dominated forest. Previous work by Morris et al. (2010) and Morris and Brunelle (2012) used pollen data from lake sediment cores to identify Dendroctonus rufipennis (spruce beetle) outbreaks in a Picea engelmannii (Engelmann spruce) forest by identifying the tradeoff between host (P. engelmannii) and nonhost (Abies lasiocarpa [subalpine fir]) conifers following an outbreak. This research tested the hypothesis that pollen data can be used to identify disturbance events that affect Pinus within a Pinus-dominated forest. Because the abundance of non-pine taxa is low in pine-dominated systems, it was uncertain whether the response of non-pine, nonhost taxa would be detectable. This study used a normalized difference pollen index (NDPI) to test this hypothesis. The results indicate that proxy data (pollen) can be used to identify MPB disturbance in a pine-dominated forest.

We used a combination of acoustic detectors, thermal imaging cameras, and mist netting to confirm the use of a rock crevice by northern long-eared myotis (Myotis septentrionalis) in winter in northeastern Nebraska. Bats roosted in a large crevice in a rock face along the Missouri River, and 5 individuals were captured emerging from the opening of the crevice in March 2017. Our study is the first to confirm the use of a rock-crevice hibernaculum by M. septentrionalis and adds to the growing literature on the winter use of rock crevices by hibernating bats in North America. As white-nose syndrome (WNS) continues to spread across North America and decimate populations of M. septentrionalis, more knowledge of hibernation requirements is necessary to develop an effective recovery plan and to monitor this threatened species.

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.

Nolina microcarpa S. Watson (Asparagaceae) shrubs in northwest Arizona were covered with insect-emergence traps to determine whether Triarius trivittatus Horn (Coleoptera: Chrysomelidae), a beetle species that carries pollen from male to female flowers, undergoes larval development on the plant. The 3 traps covered different clumps of leaf rosettes and caught 39 beetles, 15 males and 24 females, during 27 May–24 June 2019. Larvae of T. trivittatus likely develop on roots, similar to other beetles in the same tribe, or on underground stems that connect leaf rosettes. Development of larvae on the plant, as well as pollen transport to female flowers by the adult beetles, suggests that N. microcarpa and T. trivittatus have a mutualistic relationship.