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We report the first radiocarbon ages on vertebrate fossils from Labor-of-Love Cave, White Pine County, Nevada, based on purified collagen in teeth and bone, as well as a description of the cave's vertebrate paleontology. This cave was discovered in 1982 with the recovery of an associated partial skeleton of the extinct giant short-faced bear (Arctodus simus). Subsequent excavations in 1985 recovered additional fossil material of birds and mammals from stream deposits in the cave. These fossils, along with fossils collected from the surface during surveys in 2018, are reported here. Radiocarbon ages indicate that most fossil material was deposited in the cave before and during the Last Glacial Maximum (LGM; 21,441–27,774 cal yr BP) and eroded from stream deposits inside the cave following the LGM, presumably from increased precipitation and stream flow. The vertebrate assemblage includes 4 other extinct taxa including 1 carnivore (Panthera atrox) and 3 ungulates (Equus sp., Oreamnos harringtoni, Euceratherium collinum) and the first record of Canada lynx (Lynx canadensis) from the Great Basin. If contemporaneous, the assemblage as a whole indicates an open grassland/sagebrush/tundra environment in Spring Valley during the late Pleistocene, with coniferous forest on mountain slopes facing this valley and where the cave is situated. Although the entrance to the cave is now blocked by slumped talus and breakdown, in the Pleistocene it was likely a large accessible opening at the base of a limestone cliff, with stream flow emerging and flowing into the valley below during the late Pleistocene, when bears and other species possibly used the cave as a shelter or den.
From 2002 to 2018, we conducted 525 events to survey bats (nights of mist-netting and visits to bridges, mines, caves, etc.) and captured or observed 6119 bats, including all 9 species that regularly reside in Iowa. Our captures include a total of 142 new county records, and we located an additional 11 county records in specimens deposited in museums; we present at least 8 county records for each species in the state. Since the geographic distributions of most species span the entire state, many of these county records simply fill in gaps within hypothesized distributions. Records for Lasionycteris noctivagans, Lasiurus borealis, Myotis lucifugus, Myotis septentrionalis, Myotis sodalis, Nycticeius humeralis, and Perimyotis subflavus, however, extend the known range for these species or fill large gaps in their suspected distribution. Additionally, our captures provide evidence of reproduction occurring across the state for most species. Previously, little information had been published on the geographic extent of reproduction for bats in Iowa. Lastly, we report new information regarding timing of seasonal activities for bats in Iowa. For most species, we present new early and/or late records for lactation, postlactation, appearance of flying young, and flight activity outside of hibernation. Collectively, these records expand our knowledge of the biology of bats in Iowa.
As regional climates continue to warm, climate-sensitive species might increasingly depend on microclimates to maintain normal activities. The American pika (Ochotona princeps) has been suggested as a sentinel of montane climate change, largely due to its sensitivity to warm temperatures and high exposure to changing climatic conditions. Pikas use talus to thermoregulate and have been shown to persist more often in talus slopes that create stable microclimates. However, many studies of pika behavior and persistence use metrics of climate measured above the talus surface, outside of the proposed microclimates that pikas can access. We paired fine-scale microclimate measurements with behavioral observations of uniquely tagged pikas in the Colorado Rocky Mountains to model how pikas might use talus subsurface habitat as a microrefuge. Our findings suggest that pikas spend more time on the surface of the talus when there is a stronger gradient in temperatures between “shallow” (0.1 m below the surface) and “deep” (1 m below the surface) regions of the talus, especially during the middle of the day when shallow temperatures are warmer. These results underscore the importance of pairing fine-scale data on microclimate with behavioral observations of tagged individuals to more accurately evaluate how animals might use climate refugia to persist in changing conditions.
Patterns in body mass and molt provide useful information about how birds interact with their environment and act as potential explanatory variables in behavioral and demographic differences among sex and age classes. We collected population data for Greater Sage-Grouse (Centrocercus urophasianus) in Jackson and Moffat counties, Colorado, from 1973 to 1993 prior to consideration of federal listing of the species under the Endangered Species Act. Using spotlights and long-handled nets, we located and captured Greater Sage-Grouse while they roosted (primarily at night). Each captured bird was banded and released near the site of capture. We recorded the molt status of the primary flight feathers (1–10) and measured body mass. Most birds were captured prior to and during breeding (March–May) and during the brood-rearing period (July–September). Replacement of primary (P) flight feathers was initiated in May, starting with the first primary (P1), and was completed at the last primary (P10) by late September for adult (ASY) and subadult (SY) males, and by October for hatch-year males (young of the year, HY). Adult and subadult females did not replace primary flight feathers until after nesting was completed, starting in June. Primaries 1–3 were replaced within a week of the hen leaving the nest site, with or without chicks. Primary replacement then was similar to that of adult and subadult males and was completed before early October. A few late-nesting hens retained P10 and P9 into early October. Young of the year rarely replaced juvenal P9 and P10 in the year of hatching. Body mass of males peaked (x̄ = 3000 g for adults, and 2200 g for yearlings) in March–April when birds were primarily feeding on sagebrush and then decreased to late May and reached seasonal lows (x̄ = 2200 g) in July–August. Mass of females peaked in April (x̄ = 1640 g) and decreased to 1250 g in August.
In this paper, we share data collected during implementation of a vegetation management project on the Fishlake National Forest in central Utah. This project—designed to remove encroaching pinyon and juniper trees from sage-steppe and grassland communities—has been ongoing since 2017. While cutting and lopping the targeted woodland species, Fishlake employees counted and measured both cut and leave trees. The resulting data indicate that on sites like this one, the primary postsettlement encroacher is pinyon pine (Pinus edulis), and that due to slow growth rates, trees of just 25 cm in diameter at root collar may have been established prior to Euro-American settlement. For managers, it is important to recognize that some proposed pinyon-juniper removal projects will remove primarily pinyon, not juniper. Whether such pinyon eradication is either necessary or desirable should be carefully considered by land managers.
Predation affects the demography and population dynamics of prey species. Because predators commonly stalk prey from concealed routes, attack quickly, and frequently avoid areas with human observers, documenting predation under natural conditions is often difficult. An adult female American badger (Taxidea taxus) with offspring moved into a colony of Gunnison's prairie dogs (Cynomys gunnisoni) living under natural conditions at Valles Caldera National Preserve in New Mexico, United States, and provided an excellent opportunity to record predations over a period of 33 consecutive days in June–July 2018. Badgers are commonly nocturnal, but the badger at our study area captured a total of 100 Gunnison's prairie dogs during daylight hours. Sixty-two of the victims were adults (≥1 year old), 32 were juveniles (≤3 months since birth), and 6 were of unknown age. Most predations occurred in mid-morning and early afternoon. Our results, which do not account for nighttime predations and therefore underestimate numbers of successful attacks, suggest that a single predatory individual can have a sudden, devastating effect on a prey species.
Noninvasive survey methods may be necessary when studying rare species or when site conditions are likely to result in unintended mortalities during conventional live trapping. Traditional noninvasive methods based on visual and auditory observations, such as stationary point and roaming, time-constrained area surveys, may be prone to error. Remote cameras are primarily used with large mammals but have increasingly been applied to small mammals. We compared survey methods for a rare subspecies of the Colorado chipmunk (Neotamias quadrivittatus oscuraensis) occurring in a remote mountain range in New Mexico using stationary point surveys; roaming, time-constrained area surveys; and remote-camera survey methods. We detected chipmunks at substantially more locations using remote cameras (13%–23%) versus surveys using visual and auditory cues at stationary points (2.6%) or roaming within 2.7-ha plots (5.6%). In addition, remote cameras have additional strengths, such as reducing the risk of false positive and false negative results as well as providing verifiable and archivable evidence that can be used to corroborate study results.
Lycium cooperi (Solanaceae) is a woody shrub found along the eastern, northern, and western edges of the Mojave Desert in Arizona, Nevada, and California and along the western edge of the Sonoran Desert in California and Mexico. The plant produces funnel-shaped flowers during spring with stamens and a pistil that extend to near the top of a greenish-white corolla. I investigated the pollination of L. cooperi in southern Nevada during 30 March–21 April 2019 by aspirating insects from flowers, determining where they carried pollen on their bodies, and estimating the proportions of conspecific pollen in their pollen loads. Flowers were mostly visited at night by 8 species of moths (Lepidoptera) in Noctuidae and Geometridae and less frequently during the day by 3 species of flies (Diptera) in Syrphidae. The most frequent visitor to flowers was Euxoa serricornis (Noctuidae), followed by Digrammia colorata (Geometridae) and Peridroma saucia (Noctuidae), a widespread agricultural pest. Most flies at flowers were 2 large species of Copestylum. Flowers were also visited by the migratory butterfly Vanessa cardui (Lepidoptera: Nymphalidae). Pollen was carried mainly on the proboscis of moths and butterflies and on the anterior thorax of flies. Lycium cooperi pollen grains in brightfield microscopy are trilobed in polar view, elliptic in equatorial view, and grainy in appearance. A higher mean proportion of L. cooperi pollen was carried by moths and butterflies (0.50) compared with flies (0.21), and moths in Noctuidae carried a higher proportion of conspecific pollen (0.59) compared with moths in Geometridae (0.25). Insects pollinated only 19.8% of the profuse flowers produced by shrubs. Pollination of L. cooperi primarily by moths corresponds with the shrub's partially white and tubular flowers. Similar flowers on most other Lycium species in the Mojave and Sonoran Deserts indicate a likelihood of similar pollination by moths.
Phlox pungens is a rare taxon restricted to cold deserts in the Wyoming Basins Ecoregion of west-central Wyoming, with occurrences in both the Wind River Basin (from which it was originally described) and the Green River Basin (populations that have been characterized as a different “morph”). The population genetics of P. pungens was investigated using microsatellite markers developed for the genus. Four microsatellite loci were genotyped from a total of 200 individuals of P. pungens from 10 sites. Ploidy levels were also assessed using flow cytometry. Most sampled populations of P. pungens were tetraploid, but 2 populations in the Green River Basin were diploid, and one high-ploidy population was discovered in the Wind River Basin. Mitotic chromosome counts were conducted for the high-ploidy site and documented the presence of 10x individuals (2n = approximately 70). Microsatellite data analysis revealed moderate genetic differentiation between populations of P. pungens, notably structured by geography with the Wind River Basin versus the Green River Basin (i.e., the 2 morphs) corresponding closely to different genetic groups. Cytotypic variation generally did not impact genetic patterns, with the exception of the high-ploidy population, which constituted a third genetic group with a high number of alleles per locus and many private alleles. The genetic differences between the 2 morphs were driven more by different allele frequencies than by fixation for different alleles at these microsatellite loci. The results of this study highlight the genetic differentiation between populations of P. pungens in the Wind River versus the Green River Basins. Moreover, P. pungens is part of a taxonomically challenging set of glandular cespitose Phlox taxa distributed in western North America, and our findings on population genetic variation in this rare taxon contribute to ongoing work on taxonomy and diversity in the Phlox study system.
The Gila robusta complex includes 3 large cyprinid species native to the Colorado River drainage. All 3 members of this complex, Humpback Chub G. cypha, Bonytail Chub G. elegans, and Roundtail Chub G. robusta, historically occurred in the Yampa River Canyon of Colorado and Utah. Both Humpback Chub and Bonytail Chub are federally listed as endangered, and the Roundtail Chub is now considered either imperiled or vulnerable to extinction by all state management agencies in the Colorado River basin. In late June or early July of 1998, 1999, 2001, and 2002, we collected Roundtail Chub from the Yampa River in Dinosaur National Monument. Our objectives were to determine the efficacy of scales, opercular bones, and otoliths as aging structures, and to describe age, mortality, growth, and tuberculation patterns relative to reproductive stages. We obtained interpretable annuli for 111 fish by using otoliths, 91 fish by using opercles, and 111 fish by using scales. Otolith annuli showed the least measurement error; scale annuli generally agreed with otolith annuli up to approximately 7–8 years, after which scale annuli consistently underestimated otolith annuli. Opercular annuli closely agreed with otolith annuli up to 10–12 years before underestimating otolith annuli. Based on otoliths, the oldest fish was aged at 22 years, with 7 fish exceeding 15 years. Using a linearized catch-curve, Roundtail Chub had an instantaneous mortality rate of –0.158, corresponding to 85% survivorship. Growth in length was initially high and then declined at older ages. Slopes of mass versus length differed between sexes, and females had a slightly greater body mass per unit length than males for lengths above 398 mm TL. Both sexes have similar ages at first reproduction (5–6 years), and both develop tubercles. The greatest tubercle development occurred in males with maturing or running ripe testes, and in females with maturing ovaries.
Near-term extirpations of macroinvertebrates are predicted for mountain streams worldwide as a warming climate drives the recession of high-elevation ice and snow. However, hydrological sources likely vary in their resistance to climate change, and thus streams fed by more resistant sources could persist as climate refugia for imperiled biota. In 2015–2016, we measured habitat characteristics and quantified macroinvertebrate community structure along 6 alpine streams in the Teton Range, Wyoming, USA. Strong differences in habitat characteristics (e.g., temperature, bed stability, conductivity) confirmed 3 major stream sources: surface glaciers, perennial snowfields, and subterranean ice. Subterranean ice-fed streams—termed “icy seeps”—appear common in the Teton Range and elsewhere, yet are globally understudied. Midges in the family Chironomidae dominated our study sites, representing 78.6% of all specimens sampled, with nematodes, caddisflies (Neothremma), and mayflies (Epeorus) also common. At the community scale, glacier- and snowmelt-fed streams differed significantly in multivariate space, with icy-seep communities intermediate between them, incorporating components of both assemblages. Because the thermal environment of subterranean ice, including rock glaciers, is decoupled from large-scale climatic conditions, we predict that icy seeps will remain intact longer than streams fed by surface ice and snow. Furthermore, our results suggest that icy seeps are suitable habitat for many macroinvertebrates occupying streams fed by vulnerable hydrological sources. Thus, icy seeps may act as key climate refugia for mountain stream biodiversity, an idea in need of further investigation.
While borophagine canids are known from numerous Tertiary faunas across North America, they have not been well documented from the Tertiary faunas of Idaho. Five species represented by 2 genera are now known from Idaho faunas ranging from the latest Clarendonian / earliest Hemphillian to the late Blancan. The earliest records of borophagines in Idaho are Epicyon haydeni from the early Hemphillian Star Valley fauna and Borophagus pugnator from the late Clarendonian / early Hemphillian Poison Creek Formation. Borophagus secundus is present in the late Hemphillian Chalk Hills Formation, and 2 species are present in the Blancan Glenns Ferry Formation: (1) B. hilli in the early Blancan Hagerman local fauna and (2) the terminal taxon of the subfamily, B. diversidens, in the late Blancan Grand View local fauna.
The Mexican Hermit (Phaethornis mexicanus) is endemic to west-central Mexico, with 2 recognized subspecies, P. mexicanus mexicanus and P. mexicanus griseoventer. This hummingbird forms leks, where males are territory holders and females visit them to choose a mate. Only the female provides parental care to the progeny. We observed P. mexicanus griseoventer leks over different breeding seasons at 3 sites in the understory of tropical dry forest and subtropical moist lowland forests. The displays of males consisted of monosyllabic calls from perched individuals and, when a female appeared nearby, slow-speed tail movements and hover flying in front of that female. The females visited the leks and moved around, perching in the territories of different males. In addition, we monitored one nest from egg-laying to fledging of the young in Hacienda Las Tres Carmelitas. We also characterized the nest site and the materials used in nest construction. For 20 d in July and August, the female incubated 2 eggs and hatched 2 chicks. The young left the nest 31 d after hatching. We inferred that the Mexican Hermit moves between the cloud forest (790 m asl) and the pine-oak forest (1080 m asl) to obtain nest material and food. Our observations of lekking and nesting behavior suggest that breeding in P. m. griseoventer extends from February (leks) to at least mid-October (nesting).
The Crested Guan (Penelope purpurascens) is globally decreasing and endangered in Mexico. Here we report new records (8 adults and 2 juveniles) from a protected relict maple forest (critically endangered Acer binzayedii) in Parque Estatal Bosque de Arce (PEBA), Talpa de Allende, Jalisco, Mexico. Our results confirm the continuous presence of the Crested Guan over the last 2 years and the existence of reproductive activity in the study area. Our results also highlight the relevance of the species in this fragile, imperiled habitat.