Death Valley National Research Articles

The Great Death Valley National Monument Mission 66 Conspiracy (That Never Was)

In 1956 the U.S. National Park Service (NPS) launched Mission 66, a ten-year program to rebuild and improve infrastructure within hundreds of units of the National Park System, among them Death Valley National Monument in California. As elsewhere, plans in this unit centered on a visitor center, new employee housing, administrative and maintenance facilities, and campgrounds. The original plans developed for Death Valley were abruptly changed, leading to allegations that the NPS was involved in a deal with a resort in the park, in which the NPS would receive a land donation in exchange for overlooking illegal use of monument water by the resort. This Great Death Valley Mission 66 Conspiracy reached the ears of Congress, and in 1962 Congressional hearings were held to investigate these matters. The NPS director and many others were called to give testimony. This story gives a fascinating glimpse into the development of Mission 66 facilities in a large park, and how the plans for these facilities depended on an underlying geography of land ownership, water rights, dubious surveys, and expectations by faraway bureaucrats; these in turn reveal much about possibilities and limitations on opportunities for park development. The Mission 66 facilities in Death Valley have stood the test of time and remain central to visitation in the park to this day.

Complete Blood Count and Biochemistry Reference Intervals for Healthy Adult Donkeys in the United States.

Previous hematologic and serum biochemistry reference interval (RI) values have been established for donkeys in various geographic regions, life-stages, or for specific donkey breeds. The last extensive investigation establishing RIs for adult donkeys in the United States (U.S.) was published over three decades ago. We aimed to establish updated robust RIs using a reference population of apparently healthy adult donkeys from across the U.S. Standard sized (n = 102), miniature (n = 17), and mammoth (n = 1) donkeys from four different states were enrolled, with 20% of the study population including donkeys captured directly from the wild in Death Valley National Park, CA. RIs were established in accordance with the American Society for Veterinary Clinical Pathology and Clinical Laboratory Standards Institute guidelines. The findings will assist practitioners with the interpretation of their complete blood count and biochemistry panel results in U.S. donkeys. This study also highlights a comparison of results for some important analytes in U.S. donkeys compared to U.S. horses and previously established donkey RIs.

Meteorological data from Badwater, Death Valley National Park 1998 to 2019

AbstractWe installed a meteorological recording system at Badwater (elev. −75 m), the lowest point in Death Valley, California and recorded data over the period 1998–2019. A second station (the Outhouse Station) was established nearby from 2014 to 2019. Here, we report on and publicly archive the data from these two stations. Of interest was the comparison between two air temperature measurements at the Badwater Station, the first with an aspirated platinum resistance temperature device and the second with a thermistor probe in a passive sun shield. During the hottest periods of the summer when temperatures were typically between 30°C at night and 50°C daily peak, the passively shielded sensor indicated up to 0.5°C warmer than the aspirated temperature sensor due to radiative effects. The data suggest a correction for radiative heating of (T–35)/30, for T > 35°C, where, T, is the uncorrected temperature reading of a passively shielded sensor subtracted after any calibration at lower temperatures. Our station was the first precision temperature measurements at Badwater. A longer record exists for the reporting station near the visitor's centre at the Furnace Creek. The summer temperature maxima at the Badwater site correlate well with the values the same day from the Furnace Creek site. The daily maximum temperatures in winter at the Badwater site appear to be about 1°C lower than at the Furnace Creek site. The largest differences are in the minimum temperatures for which the Badwater site averages about 2–3°C warmer than the Furnace Creek site.

A new species of Corethrella Coquillett (Diptera: Corethrellidae) from Death Valley, California, United States of America

Abstract A new species of frog-biting midge in the genus Corethrella Coquillett from Death Valley National Park, California, United States of America, is described, based on a single female. The species belongs to the rotunda species group, which are otherwise known to have hyporheic larvae. The species is placed phylogenetically within the group, and a modified portion of a Nearctic key is presented. The rotunda species group now contains 13 species, three of which are in the Nearctic, and the remaining 10 of which are in the Neotropical region.

Funeralaspis n. gen.: a new odontopleurine trilobite from the early Middle Ordovician (Dapingian) of Death Valley, eastern California, USA, and the classification of Ordovician odontopleurines.

Funeralaspis n. gen. (type species F. deathvalleyensis n. sp.) is the oldest known formally named odontopleurine trilobite species, described on the basis of abundant secondarily silicified sclerites of all sclerite types except the rostral plate, from the Dapingian of the Antelope Valley Formation, west flank of the Funeral Range, Death Valley National Park, Inyo County, California. Many Ordovician odontopleurines have been assigned to Diacanthaspis, to the point that it has become something of a taxon of convenience. All of the potential species are listed along with their provenance, preservation, and represented sclerite types. A core group of Diacanthaspis, termed Diacanthaspis (sensu stricto or s.s.) possibly represents a Laurentian clade, consisting of the type species, D. cooperi, and D. lepidus, D. orandensis, D. scitulus, D. secretus, and possibly D. elapsa and D. parvula. This group is characterized by extreme dorsal spinosity, dorsal accessory spines on the base of the genal spine, pygidial spines with lateral fringes of tiny spines, and thoracic and pygidial ring furrows with fringes of tiny spines. Funeralaspis deathvalleyensis has none of the features characteristic of Diacanthaspis and in general scarcely resembles members of this Upper Ordovician group. Remaining species that have been assigned to Diacanthaspis, some of which are very poorly known, should be reclassified as knowledge of Ordovician odontopleurines advances, but for the present are treated as Diacanthaspis (sensu lato or s.l.). A heretofore nearly unknown species described as Ceratocephala maquoketensis from the early Katian of Howard County, Iowa, has not been commented upon in the literature since it was proposed. It is an odontopleurine which in the current state of knowledge should be assigned to the Diacanthaspis (s.l.) group.

Microbial Motility at the Bottom of North America: Digital Holographic Microscopy and Genomic Motility Signatures in Badwater Spring, Death Valley National Park.

Motility is widely distributed across the tree of life and can be recognized by microscopy regardless of phylogenetic affiliation, biochemical composition, or mechanism. Microscopy has thus been proposed as a potential tool for detection of biosignatures for extraterrestrial life; however, traditional light microscopy is poorly suited for this purpose, as it requires sample preparation, involves fragile moving parts, and has a limited volume of view. In this study, we deployed a field-portable digital holographic microscope (DHM) to explore microbial motility in Badwater Spring, a saline spring in Death Valley National Park, and complemented DHM imaging with 16S rRNA gene amplicon sequencing and shotgun metagenomics. The DHM identified diverse morphologies and distinguished run-reverse-flick and run-reverse types of flagellar motility. PICRUSt2- and literature-based predictions based on 16S rRNA gene amplicons were used to predict motility genotypes/phenotypes for 36.0-60.1% of identified taxa, with the predicted motile taxa being dominated by members of Burkholderiaceae and Spirochaetota. A shotgun metagenome confirmed the abundance of genes encoding flagellar motility, and a Ralstonia metagenome-assembled genome encoded a full flagellar gene cluster. This study demonstrates the potential of DHM for planetary life detection, presents the first microbial census of Badwater Spring and brine pool, and confirms the abundance of mobile microbial taxa in an extreme environment.

How cougars and feral donkeys change desert wetlands: Novel interactions between native predators and non-native megaherbivores shape trophic cascades in the Anthropocene.

Research Highlight: Lundgren, E. J., Ramp, D., Middleton, O. S., Wooster, E. I. F., Kusch, E., Balisi, M., Ripple, W. J., Hasselerharm, C. D., Sanchez, J. N., Mills, M. & Wallach, A. D. (2022) A novel trophic cascade between cougars and feral donkeys shapes desert wetlands. Journal of Animal Ecology, (91, 2010-2022). https://doi.org/10.1111/1365-2656.13766. Despite being absent from most regions of the contemporary world, megafauna species dominated the dynamics of ecological communities until the late Pleistocene. Trophic rewilding is a promising approach to restoring megafauna interactions, their functional roles and the consequent trophic cascades. Unintentional rewilding with large non-native herbivores, such as equids, offers outstanding opportunities for ecologists to understand the outcomes of using replacement species to restore the ecological functions of extinct native megafauna. In this context, it is relevant to understand the extent to which extant native predators can impose top-down control on non-native megaherbivores and how trophic cascades arising from novel predator-prey interactions influences biodiversity and ecosystem functions. In Death Valley National Park (United States), Lundgren et al. depict a natural experiment showing compelling evidence of native cougars overcoming ecological naïveté-that is, the mismatches between predator and prey species that do not share a common evolutionary history-and are now successfully preying on younger individuals of feral donkeys. These non-native donkeys, whose growing wild populations threaten the native biota, became cougars' most frequent dietary item in that region. In areas with cougars, donkeys changed their spatiotemporal foraging patterns, becoming diurnal and less active. On the other hand, donkeys remain more active and forage throughout the day and night in areas without cougars. The cougar-donkey interaction triggered a behaviourally mediated trophic cascade emerging from a 'landscape of fear', that is, from the perception of spatial heterogeneity in predation risk by donkeys. Areas with cougars have less trampled ground, fewer donkey trails, and much more canopy cover and vegetation around water. Donkeys concentrate their activity mostly in topologically plain terrains lacking proper sites for the ambush behaviour of cougars and with more intense human presence, likely acting as a shield against the predators. Lundgren et al. present a promising model system for studying the effects of fearful grazers on community structure in the context of novel ecological interactions being established in the Anthropocene. Whether the emerging cascade is transient or persistent, the relative roles of consumptive and non-consumptive effects as underlying mechanisms, and their consequences for food web structure, functioning and stability, are questions of general interest. Addressing them can help us to elucidate the costs and benefits of using non-native megaherbivores in the functional restoration of permanently invaded ecosystems.

A novel trophic cascade between cougars and feral donkeys shapes desert wetlands.

Introduced large herbivores have partly filled ecological gaps formed in the late Pleistocene, when many of the Earth's megafauna were driven extinct. However, extant predators are generally considered incapable of exerting top-down influences on introduced megafauna, leading to unusually strong disturbance and herbivory relative to native herbivores. We report on the first documented predation of juvenile feral donkeys Equus africanus asinus by cougars Puma concolor in the Mojave and Sonoran Deserts of North America. We then investigated how cougar predation corresponds with differences in feral donkey behaviour and associated effects on desert wetlands. Focusing on a feral donkey population in the Death Valley National Park, we used camera traps and vegetation surveys to compare donkey activity patterns and impacts between wetlands with and without cougar predation. Donkeys were primarily diurnal at wetlands with cougar predation, thereby avoiding cougars. However, donkeys were active throughout the day and night at sites without predation. Donkeys were ~87% less active (measured as hours of activity a day) at wetlands with predation (p < 0.0001). Sites with predation had reduced donkey disturbance and herbivory, including ~46% fewer access trails, 43% less trampled bare ground and 192% more canopy cover (PERMANOVA, R2 =0.22, p=0.0003). Our study is the first to reveal a trophic cascade involving cougars, feral equids and vegetation. Cougar predation appears to rewire an ancient food web, with diverse implications for modern ecosystems. Our results suggest that protecting apex predators could have important implications for the ecological effects of introduced megafauna.

Hydroclimate response of spring ecosystems to a two-stage Younger Dryas event in western North America

The Younger Dryas (YD) climate event is the preeminent example of abrupt climate change in the recent geologic past. Climate conditions during the YD were spatially complex, and high-resolution sediment cores in the North Atlantic, western Europe, and East Asia have revealed it unfolded in two distinct stages, including an initial stable climatic period between ~ 12.9 and 12.2 ka associated with a weakened Atlantic Meridional Overturning Circulation (AMOC) and a second phase characterized by variable conditions until 11.7 ka as the AMOC recovered. Decades of investigations into the climate of western North America during the YD have failed to identify this stepped phenomenon. Here we present hydroclimate data from paleospring deposits in Death Valley National Park (California, USA) that demonstrate unequivocal evidence of two-stage partitioning within the YD event. High groundwater levels supported persistent and long-lived spring ecosystems between ~ 13.0 and 12.2 ka, which were immediately replaced by alternating wet and dry environments until ~ 11.8 ka. These results establish the mid-YD climate transition extended into western North America at approximately the same time it was recorded by hydrologic systems elsewhere in the Northern Hemisphere and show that even short-lived changes in the AMOC can have profound consequences for ecosystems worldwide.

Balancing quietness and freedom: Support for reducing road noise among park visitors

The importance of natural soundscapes and natural quiet to the recreational experience in protected areas is well established. While a growing body of research examines how recreationists are impacted by anthropogenic noise that inhibits their experience of natural soundscapes, a very limited amount of research examines recreationists’ preferences for soundscape management. In fact, sparse research examines park visitors’ preferences concerning the management of road noise—perhaps the greatest source of noise pollution in protected areas. It is therefore the purpose of this study to bridge a significant gap in the protected area soundscape literature by examining how varying road noise management actions—including quiet pavement—impact recreationist utility. In this research, the results of a field-based choice experiment in Death Valley National Park (USA) are used to analyze how visitors navigate the tradeoff between natural quiet and freedom and how varying management actions impact recreationist utility. Results show that recreationists require substantial gains in quietness to relinquish freedom; and quiet pavement and reduced speed limits have the least negative impact on recreationist utility. Implications of these results include improved management of road noise in protected areas and considerations for future research of park soundscapes. This research highlights the important roles natural quiet and freedom play in hikers’ experiences in parks and protected areas. In this case of road noise mitigation, quiet pavement and reduced speed limits represent management actions that can achieve reduced road noise while remaining relatively unobtrusive to the recreationist experience and not leading to substantial losses in freedom. However, park managers must also consider the demographics and noise sensitivity of their visitors when assessing their soundscape management options, as the impacts of management actions and noise dispersion vary across nationality and noise sensitivities.

Moving across the Terrain: Perceiving and performing the landscape

This research brings into focus a rich cross-disciplinary dialogue between performance studies and landscape architecture. As a research and pedagogical investigation, it reveals possibilities for advancing how designers might integrate performative methodologies into site research. Typical site research methods are predicated upon the use of media remote from the physical terrain, such as maps, drawings and three-dimensional models. These modes of representation are necessary for landscape architects because they enable the scale of landscape, which generally far exceeds that of the human body, to be made physically accessible to the designer. Performative strategies can be used to develop navigational tools for sharpening the body’s perceptive capacity within vast landscapes. These strategies are unpacked across the article’s three sections. Un-distancing discusses questions of representation and suggests that embodied modes of drawing can connect the designer more directly and deeply with the land as their medium; Measuring as Performance explores the act of measuring the land itself as a performance; and Figured Ground considers the body as an active agent in the shaping of the ground. These performative strategies were tested in the context of a landscape architecture design studio at California State Polytechnic University, Pomona. Students were taken on a field trip to Death Valley National Park and surrounding areas located near the border of California and Nevada in the Western United States. In this region the raw beauty of texture, colour and light illuminates the vastness of this landscape as it is perceived through the tactile, visual, auditory and kinaesthetic senses. Immersing themselves in a series of embodied exercises under the theme of Moving Across the Terrain the students’ moving bodies became perceptive instruments that enabled them, both individually and collectively, to ‘measure’ the landscape and experience scale, topography and time in visceral ways.

Vascular Plants of Northern Death Valley National Park (Death Valley, Last Chance Range, and Eureka Valley), Inyo County, California

The northern portion of Death Valley National Park closely (but not entirely) corresponds to the northernmost portion of the Mojave Desert in California. From 2014 through 2019 we surveyed the vascular plants in the Eureka Valley, northern Last Chance Range, and northern Death Valley. This study area covers 1735 sq km and ranges in elevation from 810 to 2577 m; it contains the tallest sand dunes in California, a calcium-rich mountain range, and alkaline seeps. These features provide specialized habitats for narrowly and regionally endemic plants. Fossil data from packrat middens suggest that the local climate has become warmer and drier during the Holocene and the assemblage of plants currently observed has only been in place for a few thousand years. During six years of fieldwork, we documented 542 specimens of minimum-rank taxa, including 51 special concern taxa and 25 non-natives. We were unable to relocate 45 taxa known from historic collections. Fifty-one collections were the first for the study area; these include 24 range extensions. Observations from our collections are combined with those from historic collections and other collectors in an annotated checklist.

List of Bryophytes Collected in the Northern Last Chance Range and Eureka Valley, Death Valley National Park

A list of bryophytes occurring naturally in northern Death Valley National Park is presented. So far, 41 taxa have been documented, representing seven families and 24 genera. One species, Jaffueliobryum wrightii, is considered rare by the California Native Plant Society.

Mapping metamorphic hydration fronts with field-based near-infrared spectroscopy: Teakettle Junction contact aureole, Death Valley National Park (California, USA)

Abstract Mineral distribution in a previously undescribed contact aureole in siliceous dolomite at Teakettle Junction, Death Valley National Park (California, USA), was mapped with a handheld visible and near-infrared (Vis-NIR, 0.35–2.5 μm) spectrometer. With increasing distance from a small Jurassic(?) pluton, the following mineral zones occur: periclase (hydrated to brucite), forsterite (variably hydrated to serpentine and typically accompanied by clinohumite), tremolite, and talc. Airborne Vis-NIR imaging spectrometer data with 5 m ground resolution shows serpentine and tremolite distribution in close agreement with the field data. Field measurements show dolomite and calcite throughout the study area, along with minor amounts of phlogopite and illite. Hydrous minerals were detected in field measurements at levels on the order of 1 vol%. Phlogopite, talc, and illite crystals in many samples are &amp;lt;20 μm in size and difficult to identify without scanning electron microscopy examination. Sensitivity of Vis-NIR spectroscopy to hydrous minerals is especially important in the context of metamorphic fluid flow. Significant hydration of wall rocks is limited to samples between the pluton contact and the serpentine (forsterite) isograd as shown by mineral distribution and variation in the depth of the OH absorption feature near 1.4 μm. This boundary is interpreted to represent a metamorphic hydration front beyond which there was minimal infiltration of wall rocks by H2O-rich fluid. Within this zone of hydration, however, the extent of hydration is highly variable, even at individual sample sites with samples spaced on the order of 1 m or less. Heterogeneity of fluid-rock interaction at this scale must be considered in models of heat and mass transfer accompanying contact metamorphism.

Pavement treatment type influences visitor experiences related to vehicular road sound in Death Valley National Park

ABSTRACT In many parks and protected areas around the globe, reducing human-caused sounds is a critical component to providing quality visitor experiences. However, very little research examines the effect of vehicular road sounds on visitor experiences. Additionally, emerging pavement treatments have the potential to provide a new management tool for reducing impacts from vehicular road sounds. In this research, intercept surveys of visitors in Death Valley National Park and dose-response methods are used to identify the impacts of vehicular road sounds using normative concepts. The effects of different pavement treatments on visitor experiences are also evaluated. Results show that increasing vehicular road sounds have a negative impact on visitor experiences. Furthermore, Type II microsurfacing pavement treatments have a larger negative impact on visitor experiences than other pavement treatments. From this, managers of parks and protected areas can better understand the impacts of vehicle road sounds on visitor experiences, and possibly further reduce impacts through the use of pavement treatments.

The Eureka Valley Landslide: Evidence of a Dual Failure Mechanism for a Long-Runout Landslide

Abstract Long-runout landslides are well-known and notorious geologic hazards in many mountainous parts of the world. Commonly encompassing enormous volumes of debris, these rapid mass movements place populations at risk through both direct impacts and indirect hazards, such as downstream flooding. Despite their evident risks, the mechanics of these large-scale landslides remain both enigmatic and controversial. In this work, we illuminate the inner workings of one exceptionally well-exposed and well-preserved long-runout landslide of late Pleistocene age located in Eureka Valley, east-central California, Death Valley National Park. The landslide originated in the detachment of more than 5 million m3 of Cambrian bedrock from a rugged northwest-facing outcrop in the northern Last Chance Range. Its relatively compact scale, well-preserved morphology, varied lithologic composition, and strategic dissection by erosional processes render it an exceptional laboratory for the study of the long-runout phenomenon in a dry environment. The landslide in Eureka Valley resembles, in miniature, morphologically similar “Blackhawk-like” landslides on Earth, Mars, and minor planet Ceres, including the well-known but much larger Blackhawk landslide of southern California. Like these other landslides, the landslide in Eureka Valley consists of a lobate, distally raised main lobe bounded by raised lateral levees. Like other terrestrial examples, it is principally composed of pervasively fractured, clast-supported breccia. Based on the geologic characteristics of the landslide and its inferred kinematics, a two-part emplacement mechanism is advanced: (1) a clast-breakage mechanism (cataclasis) active in the bedrock canyon areas and (2) sliding on a substrate of saturated sediments encountered and liquefied by the main lobe of the landslide as it exited the main source canyon. Mechanisms previously hypothesized to explain the high-speed runout and morphology of the landslide and its Blackhawk-like analogs are demonstrably inconsistent with the geology, geomorphology, and mineralogy of the subject deposit and its depositional environment.

Groundwater forensics approach for differentiating local and regional springs in arid Eastern California, USA

While water sources that sustain many of the springs in the Mojave Desert have been poorly understood, desert wildlife and ecosystems can be highly dependent on such resources. With ever expanding use of desert groundwater, the effect of groundwater extraction on groundwater-dependent ecosystems in the Sonoran and Mojave Deserts is an ongoing concern. Springs that are more susceptible to impacts from groundwater withdrawals are typically those in hydraulic connection with surrounding basin-fill aquifer systems. Since spatial and/or temporal data gaps prevent a detailed model of the groundwater system, this evaluation of groundwater forensic approaches identifies a range of characteristics and parameters that demonstrate key indicators of spring-aquifer connectivity using data collected during a California Mojave Desert-wide spring survey conducted during 2015–2016, and subsequent monitoring and sampling events in both the California Mojave and Sonoran Deserts. In total, monitoring and sampling took place at nearly 400 springs primarily in lands managed by the U.S. Bureau of Land Management (BLM), and scattered private lands where accessible. Springs in National Park Service units such as Joshua Tree National Park, Mojave National Preserve and Death Valley National Park and in military bases were not included in the investigation scope. The multiple lines of evidence described regarding spring-aquifer connectivity include field parameters for water, such as temperature, pH, and conductivity, as well as geochemical characteristics of water, such as stable isotope and radiocarbon analyses. While other information about the setting, such as spring-site geology, are important in evaluating flow-path characteristics, simple field reconnaissance of these springs may be inconclusive as to provenance, and they are ultimately of lesser importance than the actual water characteristics in identifying spring provenance and potential hydraulic linkage to basin-fill aquifer systems that are, or may in the future, be utilized for regional groundwater development.

Early Permian tectonic evolution of the Last Chance thrust system: An example of induced subduction initiation along a plate boundary transform

AbstractThe late Paleozoic is an important precursor stage in the development of the Mesozoic Cordilleran subduction system along the western margin of North America, but the tectonic history remains ambiguous due to complex overprinting deformation and magmatism. Determining the driving mechanism of large magnitude Permian shortening in southwest Laurentia is critical to understanding the late Paleozoic transition from transform margin to subduction zone. We investigated the driving mechanism of the Permian Last Chance thrust system in east-central California to understand this transition prior to the development of the Mesozoic Cordilleran arc. Here, we present the results of new geological mapping, detrital zircon U-Pb geochronology, and a synthesis of regional tectonics to inform a kinematic model of the Last Chance thrust system and outline the Permian–Triassic tectonic evolution of the plate boundary during induced subduction initiation. The record of subduction initiation along an inferred late Paleozoic transform fault (the California-Coahuila transform) is preserved by (1) Permian arc magmatism, (2) the onset of volcaniclastic sedimentation, and (3) the development of a regional transpressional system in present-day east-central California. The evolution of this transpressional system and subduction zone is recorded by development of the Last Chance thrust system of the Death Valley region. Geological mapping in the Last Chance Range, northern Death Valley National Park, and the Inyo Mountains reveals the east-directed Last Chance thrust system was constructed by repetitive out-of-sequence deformation consistent with transpressional strain. The Last Chance thrust system accommodated a minimum of &amp;gt;75 km (60%) shortening, based on cross-section restorations guided by regional stratigraphic relationships and restoration of subsequent Mesozoic deformation. Our revised model of Jurassic extensional exhumation of the Snow Lake terrane argues the Last chance thrust was not reactivated during the Mesozoic. Large-magnitude shortening along the California-Coahuila transform accommodated a significant component of the convergent plate motion as the Panthalassan crust was thrust below the continental margin before initial slab sinking. Numerical models show the forces resisting subduction are greatest before initial slab sinking takes place, and compression is transmitted in board from the plate boundary. We argue the Last Chance thrust system developed in response to this compression. Early-middle Permian plutons and late Permian detrital zircons in coeval basins suggest subduction was well established by the early Permian. Collectively, the preservation of a thrust system, early arc magmatism, and syntectonic sedimentary basins, which are features typically destroyed by subduction magmatism and deformation, allow for the evaluation of subduction initiation mechanisms based on field observations.

A Pilot Serosurvey for Selected Pathogens in Feral Donkeys (Equus asinus).

Simple SummaryThis study aimed to assess the pathogen exposure status of recently captured feral donkeys from Death Valley National Park, California. Assays to detect the presence of antibodies to equine herpesvirus 1, equine influenza virus, West Nile virus, and Borrelia burgdorferi (the causative agent of Lyme disease) were performed on serum samples from these feral donkeys. The results indicate that this population is mostly naïve and likely susceptible to these common equid pathogens upon removal from the wild. Recent removal and relocation of feral donkeys from vast public lands to more concentrated holding pens, training facilities, and offsite adoption locations raises several health and welfare concerns. Very little is known regarding the common equid pathogens that are circulating within the feral donkey population in and around Death Valley National Park, California, USA. The aim of this study was to utilize serologic assays to assess previous exposure of these donkeys to equine herpesvirus 1 (EHV-1), equine influenza (EIV), West Nile virus (WNV), and Borrelia burgdorferi (the causative agent of Lyme disease). The results of this study indicate that this feral equid population is mostly naïve and likely susceptible to these common equid pathogens upon removal from the wild.

Survey of Serum Amyloid A and Bacterial and Viral Frequency Using qPCR Levels in Recently Captured Feral Donkeys from Death Valley National Park (California).

Simple SummaryThis study aimed to measure the inflammatory marker (Serum Amyloid A; SAA) derived from such pathogenic processes specifically bacterial and virus found in recently captured feral donkeys. Quantitative Real-Time PCR (qPCR) was performed to detect and quantify RNA and DNA viruses and bacterial DNA. Behavior, body condition score, nasal discharge, and coughing were found to be related in cases of Asinine Herpesvirus 2 (AHV-2) and Streptococcus equi subspecies zooepidemicus DNA. SAA concentrations descended with age, with foals presenting higher concentrations. Positive tests differed for AHV-2 and Streptococcus equi spp. zooepidemicus between sampling moments. In conclusion, donkeys caught in the wild may not be a source of disease for domestic horses. However, the transmission of some pathogens, such as Streptococcus equi subspecies zooepidemicus, and/or AHV-2, may occur.Feral donkey removal from state land has raised concerns in terms of disease transmission between equine species. Disease outbreaks may occur as a result of the relocation of animals to new environments. Virus and bacteria DNA load and serum amyloid A derived from the pathogenic processes that they involve were measured in recently captured donkeys. Blood and nasal swabs were collected from 85 donkeys (Death Valley National Park, Shoshone, California); 24 were retested after 30/60 days in the Scenic (Arizona) long-term holding facility co-mingled with feral donkeys from Arizona and Utah. Quantitative Real-Time PCR (qPCR) was performed to detect viral and bacterial genomic material (equine influenza A [EIV], equine rhinitis A and B viruses, AHV-2, AHV-3, AHV-5 and EHV-1, EHV-4, Streptococcus equi subspecies equi and zooepidemicus,). Significant relations between behavior, body condition score, nasal discharge, and coughing were found in donkeys for which AHV-2 and Streptococcus zooepidemicus DNA was detected. Higher SAA concentrations were found in foals. AHV-2 and Streptococcus zooepidemicus DNA concentrations significantly differed between sampling moments (p < 0.05). In conclusion, donkeys do not appear to be a substantial risk for disease transmission to horses but could be if they carried strangles or other processes in which AHV-2 and Streptococcus zooepidemicus were involved.