California Desert Research Articles

‘A Dead Sea of Solar Panels:’ solar enclosure, extractivism and the progressive degradation of the California desert

ABSTRACT Based on conversations with 38 interview respondents, four focus groups and participant observation, this article examines intensive solar energy development in east Riverside County, California. Focusing on the Desert Center area, it argues that environmental policy, expressed through market-imperatives and bureaucratically-centered modeling science, severely threatens ecosystems, meanwhile failing to accomplish climate change mitigation. Critical Agrarian Studies (CAS) and Environmental Justice (EJ) are brought into dialogue to explore solar extractivism in Desert Center through the Four-Es (4Es) framework: Enclosure, Exclusion, Encroachment and Entrenchment. A scientific-bureaucratic approach to sustainable development, we find, structurally disregards rural residents, desert habitats and releases more carbon into the atmosphere.

An Analysis of the Lepidoptera of the San Joaquin Desert of California, with Notes on their Herbivory and Host Plant Relationships

An Analysis of the Lepidoptera of the San Joaquin Desert of California, with Notes on their Herbivory and Host Plant Relationships

Nope

Abstract Jordan Peele's Nope (2022) features a shape-shifting and Cthulhu-esque alien that feeds off settlers and other arrivants in the California desert. Focusing in particular on the Haywoods, a family of Hollywood horse wranglers descended from the otherwise anonymous Black rider on the horse of Eadweard Muybridge's famous Animal Locomotion Plate 626, Nope can be read as suggesting the ubiquitous nature of anti-Black violence. Furthermore, this essay will suggest that the informe nature of the alien, referred to in the film as Jean Jacket, and which eventually reveals itself to be something like a giant jellyfish, also mirrors the way in which Blackness has historically been—and continues to be—treated likewise as informe, or what Zakiyyah Iman Jackson refers to as “plastic.” In other words, Nope suggests that Blackness is linked in the white Western imagination to plasticity and animality, as made clear by the restaging in Peele's film of the Muybridge sequence, but now featuring Jean Jacket and OJ Haywood (Daniel Kaluuya). Finally, by exploring Blackness as effectively “alien” to white hegemony, Nope suggests a Black cinema that appropriates that “alienness” and one that becomes a vernacular/informal countercinema that resists white supremacy.

Non-Native Plant Viruses Prevalent in Remnant Natural Plant Communities Harm Native Perennial Hosts

Plant viruses are ubiquitous throughout plant communities, but research on viral impacts largely focuses on crops. Little is known about how viruses influence wild plants in their native habitats. To address this gap, we examined virus interactions with wild drought-tolerant perennials in California desert natural areas encroached upon by agriculture. We used metagenomics, targeted diagnostics, and phylogenetics to assess virus diversity and clade relationships, and experiments to investigate viral influence on hosts. We focused on three herbaceous perennials ( Cucurbita foetidissima, C. palmata, and Datura wrightii) and tested the hypothesis that these wild species accumulate virus infections typically found in crops and transmitted by polyphagous insects. We predicted that such infections might be retained across seasons and potentially impair plant performance. Virome profiling revealed a rich community of previously characterized virus species (12 total), with virus community structure varying by site and host species. The dominant viruses in the wild hosts were non-native crop pathogens, including cucurbit aphid-borne yellows virus (CABYV) and cucurbit yellow stunting disorder virus (CYSDV). Targeted testing revealed that CABYV infected as many as 88% of sampled wild Cucurbita individuals, with dual CABYV–CYSDV infections common in natural areas adjacent to desert agriculture. CABYV infections reduced shoot and root production in greenhouse experiments with the two wild Cucurbita species. Phylogenetic analyses suggest that CABYV was introduced to California multiple times from other continents. Our findings provide concerning evidence of ways in which human activities can alter virus pressure on wild plants and potentially contribute to plant decline.

High inter-population connectivity and occasional gene flow between subspecies improves recovery potential for the endangered Least Bell’s Vireo

Abstract Increasingly, genomic data are being used to supplement field-based ecological studies to help evaluate recovery status and trends in endangered species. We collected genomic data to address 2 related questions regarding the Least Bell’s Vireo (Vireo bellii), an endangered migratory songbird restricted to southern California riparian habitat for breeding. First, we sought to delineate the range limits and potential overlap between Least Bell’s Vireo and its sister subspecies, the Arizona Bell’s Vireo, by analyzing samples from the deserts of eastern California, southwestern Nevada, Utah, and Arizona. Second, we evaluated genetic structure among Least Bell’s Vireo populations in coastal California and estimated effective population size. Clustering analyses based on 10,571 single-nucleotide polymorphisms (SNPs) from 317 samples supported 2 major groups that aligned closely to the previously defined subspecies ranges. The first cluster included birds in the Central Valley, all coastal drainages, and westernmost deserts of California, with no further sub-structuring among coastal drainages. Almost all birds from the Amargosa River in eastern California and eastward assigned to the second cluster; however, low levels of gene flow were detected across the subspecies groups, with greater rates of gene flow from Arizona Bell’s Vireo to Least Bell’s Vireo than the reverse. Admixed individuals occurred in the California deserts; and although smaller than coastal populations, desert populations may be important for maintaining and replenishing genetic diversity and facilitating the movement of potentially adaptive genes between subspecies. Within Least Bell’s Vireo, local populations in coastal drainages comprised a single genetic population, with some evidence of close relatives distributed across drainages, suggesting that these could function as a well-connected metapopulation. These results are consistent with previous Least Bell’s Vireo banding studies that reported high rates of dispersal among drainages. Effective population size for both subspecies was high, suggesting that adaptive potential has been maintained despite previous declines.

Impossible evidence: The legal dismal cycle of regulating off-roading in the California desert

A forty-year battle over off-road vehicle use in the California desert hinges on a deceptively simple question: how many miles of roads and trails were present in 1980? The only problem is that the answer to this question is impossible. This article seeks to understand the history and effects of this impossible regulatory demand through the concept of “impossible evidence,” which describes evidence that is legally demanded but cannot or does not exist. I detail the rise of impossible evidence through the history of off-road vehicles in California, showing how an unregulated activity slowly comes under the purview of a growing environmental administrative state. I then track the 2009 CBD v. BLM decision to show how evidence becomes impossible. Finally, I discuss the implications of impossible evidence for the future of the California desert, revealing how the demand for impossible evidence creates an unworkable legal “dismal cycle,” while allowing for the continuation of the same problem of off-road vehicle route proliferation.

Mafic Alkaline Magmatism and Rare Earth Element Mineralization in the Mojave Desert, California: The Bobcat Hills Connection to Mountain Pass

AbstractOccurrences of alkaline and carbonatite rocks with high concentrations of rare earth elements (REE) are a defining feature of Precambrian geology in the Mojave Desert of southeastern California. The most economically important occurrence is the carbonatite stock at Mountain Pass, which constitutes the largest REE deposit in the United States. A central scientific goal is to understand the genesis of the carbonatite ore body in the context of widespread REE‐rich igneous activity. A swarm of mafic alkaline (shonkinite) dikes has been mapped and sampled at Bobcat Hills, 65 km southeast of the Mountain Pass mine. Whole‐rock geochemistry and zircon geochronology demonstrate a clear affinity to the ca. 1.4 Ga Mountain Pass intrusive system. Bobcat Hills dikes have comparably high REE concentrations (La ∼1,000× chondritic) and an error‐weighted mean 207Pb/206Pb zircon crystallization age of 1,426 ± 2 Ma (2σ). Unlike the alkaline intrusions at Mountain Pass, which have abundant inherited zircon from Paleoproterozoic basement rocks and crustally influenced oxygen isotope compositions (δ18Ozircon = 6.5–7.5‰), the Bobcat Hills dikes lack any evidence of crustal assimilation and have oxygen isotope values that overlap a mantle range (Bobcat Hills average δ18Ozircon = 5.6 ± 0.3‰). The dikes were a high‐temperature, early center of mafic alkaline magmatism in the Mojave Desert that serve as a snapshot of melt generation from a spatially extensive, metasomatized mantle source. We propose that modification of the crust over many tens of Myr at Mountain Pass created an environment that favored crustal assimilation and enabled ascent of late‐stage, REE‐rich carbonatite magmas.

Bacterial denitrification drives elevated N2O emissions in arid southern California drylands.

Soils are the largest source of atmospheric nitrous oxide (N2O), a powerful greenhouse gas. Dry soils rarely harbor anoxic conditions to favor denitrification, the predominant N2O-producing process, yet, among the largest N2O emissions have been measured after wetting summer-dry desert soils, raising the question: Can denitrifiers endure extreme drought and produce N2O immediately after rainfall? Using isotopic and molecular approaches in a California desert, we found that denitrifiers produced N2O within 15 minutes of wetting dry soils (site preference = 12.8 ± 3.92 per mil, δ15Nbulk = 18.6 ± 11.1 per mil). Consistent with this finding, we detected nitrate-reducing transcripts in dry soils and found that inhibiting microbial activity decreased N2O emissions by 59%. Our results suggest that despite extreme environmental conditions-months without precipitation, soil temperatures of ≥40°C, and gravimetric soil water content of <1%-bacterial denitrifiers can account for most of the N2O emitted when dry soils are wetted.

A new species of alkali-sink Paruroctonus Werner, 1934 (Scorpiones, Vaejovidae) from California’s San Joaquin Valley

Herein a new species of Paruroctonus Werner, 1934 is described from alkali-sink habitats in the San Joaquin Desert of central California, Paruroctonus tularesp. nov. It can be differentiated from other Paruroctonus by a combination of morphological features including scalloped pedipalp fingers in males, specific setal counts and morphometric ratios, and specific patterns of fuscous pigmentation. It also inhabits a unique distribution allopatric with all other Paruroctonus species except P. variabilis Hjelle, 1982. Photographs of a large series of live P. tularesp. nov. from across their range and detailed images of several morphological features are provided, their distribution is modeled, a haplotype network is presented, and details about their habitat, ecology, and conservation are discussed.

Evapotranspiration and Yield Impact Tools for More Water-Use Efficient Alfalfa Production in Desert Environments

Drought and climate change have decreased water availability for agriculture, especially in the desert of southwestern USA. Efficiency enhancements in irrigation management aimed at conserving water are key to adjust to limits in water supply, improve profitability and sustainability of alfalfa production in arid and semiarid areas. This study intended to conduct a field-scale analysis to develop yield and ET estimation tools for the effective use of irrigation water in a desert alfalfa production system. Extensive data collection and trials were carried out over three years in nine fully irrigated commercial alfalfa fields in the low deserts of California. The seasonal crop water consumption measured using the residual of energy balance method varied from 1381 mm to 1596 mm across the experimental sites and crop seasons. Variable seasonal dry mater (DM) yields ranged from 23.01 Mg ha−1 to 29.90 Mg ha−1. The results indicated that the first five cuttings each year were the most productive cuttings with a mean DM value ranged between 3.29 (cut 1) and 4.21 (cut 4) Mg ha−1 but declined in later cuttings. An average annual water productivity (WP) value of 17.0 kg ha−1 mm−1 was determined across the sites varying from 15.5 to 18.9 kg ha−1 mm−1. The findings suggested that one may lose up to 1.44 Mg ha−1 alfalfa yields with moderate summer deficit irrigation strategies, using 40% less water applied than full irrigation practices over the summer period of July–September. A more severe summer water deficit, with no irrigation event over the summer period of July–September may result in a potential water savings of 0.234–0.246 (ha·m) ha−1 and 19–21% seasonal yield losses in the desert environment. This study describes the seasonal yield pattern, the crop water use-production function, and the crop coefficient values for various harvest cycles over the crop season. These tools may assist farmers to quantify water savings and estimate yield losses for more accurate and effective irrigation management strategies to meet water conservation objectives and for the resiliency of alfalfa production in the desert region.

Effects of Fire on Kangaroo Rats in the San Joaquin Desert of California

Effects of Fire on Kangaroo Rats in the San Joaquin Desert of California

Linear and landscape disturbances alter Mojave desert tortoise movement behavior

IntroductionAnimal movements are influenced by landscape features; disturbances to the landscape can alter movements, dispersal, and ultimately connectivity among populations. Faster or longer movements adjacent to a localized disturbance or within disturbed areas could indicate reduced habitat quality whereas slower or shorter movements and reduced movements may indicate greater availability of resources. The Mojave desert tortoise (Gopherus agassizii) is a threatened species that is challenged by anthropogenic disturbances.MethodsWe studied tortoise movements using Global Positioning System (GPS) loggers at multiple sites in the Mojave Desert of Nevada and California. Tortoises at our sites encountered localized, linear human infrastructure, including paved roads, dirt roads, and fences, as well as landscape-scale disturbances [wildfire, off highway vehicle use (OHV), livestock grazing area]. We fit two-state (moving and encamped) Hidden Markov models to GPS logger data to infer how tortoise movement behavior relates to anthropogenic and natural features.ResultsWe found that temporal covariates, individual-level random effects (intercepts), and sex best explained state transition probability in all sites. We compared relationships between tortoise movement and linear disturbances, which varied depending on site and context. Tortoises made longer movements within the OHV recreation area, near most dirt roads, and near a low-traffic paved road, indicating that tortoises avoid these habitat disturbances. Conversely, tortoises made shorter movements in areas of higher slope and near highways, suggesting that these features may restrict movement or provide resources that result in prolonged use (e.g., forage or drinking locations). Tortoises that encountered fences around utility-scale solar installations were more active and made longer movements near fences, indicative of pacing behavior.DiscussionThese results provide insight into how different disturbances alter tortoise movement behavior and modify tortoise habitat use, providing information that can be used to manage tortoise habitat.

Of Mojave milkweed and mirrors: The population genomic structure of a species impacted by solar energy development

AbstractA rapid renewable energy transition has facilitated the development of large, ground‐mounted solar energy facilities worldwide. Deserts, and other sensitive aridland ecosystems, are the second most common land‐cover type for solar energy development globally. Thus, it is necessary to understand existing diversity within environmentally sensitive desert plant populations to understand spatiotemporal effects of solar energy siting and design. Overall, few population genomic studies of desert plants exist, and much of their biology is unknown. To help fill this knowledge gap, we sampled Mojave milkweed (Asclepias nyctaginifolia) in and around the Ivanpah Solar Electric Generating Station (ISEGS) in the Mojave Desert of California to understand the species' population structure, standing genetic variation, and how that intersects with solar development. We performed Restriction‐site Associated Sequencing (RADseq) and discovered 9942 single nucleotide polymorphisms (SNPs). Using these data, we found clear population structure over small spatial scales, suggesting each site sampled comprised a genetically distinct population of Mojave milkweed. While mowing, in lieu of blading, the vegetation across the solar energy facility's footprint prevented the immediate loss of the ISEGS Mojave milkweed population, we show that the effects of land‐cover change, especially those impacting desert washes, may impact long‐term genetic diversity and persistence. Potential implications of this include a risk of overall loss of genetic diversity, or even hastened extirpation. These findings highlight the need to consider the genetic diversity of impacted species when predicting the impact and necessary conservation measures of large‐scale land‐cover changes on species with small population sizes.

Species delimitation, biogeography, and natural history of dwarf funnel web spiders (Mygalomorphae, Hexurellidae, Hexurella) from the United States / Mexico borderlands.

The rarely encountered spider genus Hexurella Gertsch & Platnick, 1979 includes some of the smallest mygalomorph spiders in the world, with four poorly known taxa from central and southeastern montane Arizona, southern California, and northern Baja California Norte. At time of description the genus was known from fewer than 20 individuals, with sparse natural history information suggesting a vagrant, web-building, litter-dwelling natural history. Here the first published taxonomic and natural history information for this taxon is provided in more than 50 years, working from extensive new geographic sampling, consideration of male and female morphology, and sequence capture-based nuclear phylogenomics and mitogenomics. Several new species are easily diagnosed based on distinctive male morphologies, while a complex of populations from central and northern Arizona required an integrative combination of genomic algorithmic species delimitation analyses and morphological study. Four new species are described, including H.ephedrasp. nov., H.uwiiltilsp. nov., H.xericasp. nov., and H.zassp. nov. Females of H.encina Gertsch & Platnick, 1979 are also described for the first time. It is predicted that additional new species will ultimately be found in the mountains of central and northwestern Arizona, northern mainland Mexico, and the Mojave Desert of California.

Latinx and Indigenous Mexican Caregivers' Perspectives of the Salton Sea Environment on Children's Asthma, Respiratory Health, and Co-Presenting Health Conditions.

This research investigated Latinx and Indigenous Mexican caregivers' perspectives of the Salton Sea's environment (e.g., dust concentrations and other toxins) on child health conditions. The Salton Sea is a highly saline drying lakebed located in the Inland Southern California desert borderland region and is surrounded by agricultural fields. Children of Latinx and Indigenous Mexican immigrant families are especially vulnerable to the Salton Sea's environmental impact on chronic health conditions due to their proximity to the Salton Sea and structural vulnerability. From September 2020 to February 2021, we conducted semi-structured interviews and focus groups with a total of 36 Latinx and Indigenous Mexican caregivers of children with asthma or respiratory distress living along the Salton Sea. A community investigator trained in qualitative research conducted interviews in Spanish or Purépecha, an indigenous language spoken by immigrants from Michoacán, Mexico. Template and matrix analysis was used to identify themes and patterns across interviews and focus groups. Participants characterized the Salton Sea's environment as toxic, marked by exposure to sulfuric smells, dust storms, chemicals, and fires, all of which contribute to children's chronic health conditions (e.g., respiratory illnesses such as asthma, bronchitis, and pneumonia, co-presenting with allergies and nosebleeds). The findings have important environmental public health significance for structurally vulnerable child populations in the United States and globally.

Direct-to-Video (On Demand): New Industrial and Cultural Valuations of Nontheatrical Film Releases

Direct-to-Video (On Demand): New Industrial and Cultural Valuations of Nontheatrical Film Releases

Regulatory Alchemy: How the Water Cycle Becomes Capital in the California Desert

AbstractA proposed project will take water from an aquifer in the California desert to the coast. Lacking final approvals more than 30 years after it started, the project remains a plan despite sizeable opposition. What is its secret? In this paper, I examine the imaginaries of the underground aquifer underneath the lands of Cadiz Inc, the project proponent. While local theories insist the company is at the centre of a Chinatown conspiracy, I argue that the company stays alive through regulatory alchemy, a term that reveals the magic at the heart of scientific and regulatory approval processes. I examine narratives of the aquifer in environmental compliance and financial reporting in order to reveal how regulatory processes become the conditions of profit‐making, building on debates in critical legal geography and political ecology.

Petrography, mineralogy, and geochemistry of nitrogenous shale in the Western Desert of Egypt: implications for paleoenvironment

Besides nitrate deposits located in the Atacama Desert of Chile and the Mojave Desert of California, the present work documents, for the first time, the occurrence of potassium nitrate as oval-suboval-shaped aggregations associated with the Late Maastrichtian-Early Paleocene Dakhla Shale and the Paleocene-Early Eocene Esna Shale encountered in the northeastern part of the Kharga Oasis, particularly at G. Um El-Ghanayem and G. Ghaneima. Consequently, integrated petrographic, mineralogical, and geochemical investigations were carried out for shale deposits and nitrate salts to reconstruct the paleoenvironmental conditions of shale, reveal the extent to which nitrate salts are genetically related to the paleoenvironment of shale deposits, and build up a complete scenario about the source and the formation mechanism of nitrate salts. The overall results showed that the studied shale deposits were sourced from mafic igneous and quartzose sedimentary provenances where humid climatic conditions were dominant; the transported detrital particles were then settled down under oxidizing bottom water and shallow depositional conditions. Moreover, the nitrate salts are of an epigenetic origin and sourced from the microbial nitrification of organic matter and the wet atmospheric deposition that is believed to be triggered by the active volcanic eruptions during the Late Eocene/Early Oligocene transition where warm climatic conditions prevailed.

Floristic Patterns and Conservation Values of Mojave and Sonoran Desert Springs in California

In the face of a rapidly changing climate, spring-fed habitats are increasingly vulnerable to numerous threats. Botanical inventories provide valuable information to assess the conservation value of desert springs, and can serve as indicators to document changing conditions, including the proportion of native vs. nonnative taxa, diversity of life forms present that influence structure and function of ecosystems, species persistence and longevity, and the proportion of taxa that are rare and sensitive to land use change. Here we evaluate plant species composition and richness within and between springs, and evaluate botanical diversity with respect to physical parameters including hydrology and geography. We find that desert springs collectively support a large proportion of plant diversity, or nearly 22% of the total vascular plant diversity known within the California desert in only 0.000005% of the total land area. The springs we sampled are highly dissimilar in plant species composition, thus, restoration and management activities likely need to be highly individualized and site specific. Monitoring and inventory programs can increase opportunities for restoration and protection by providing information to assess warning signs of habitat degradation, such as changing species composition and local extirpation of wetland-dependent species.

Salton Sea Environmental Work and the Importance of Community Science

In the Southern California desert, the Salton Sea is the cause of a local socioenvironmental crisis reflective of various environmental injustices. Today’s Salton Sea is fed primarily through agricultural water run-off and effluent discharge. Over 23% of the Latinx and Torres Martinez Desert Cahuilla Indian identifying residents live below the poverty line in the two zip codes north of the sea (US Census Bureau, 2021). Persistent droughts and inequitable policies have accelerated the sea’s evaporation, exacerbating environmental health problems such as poor air quality and respiratory illnesses like asthma (Farzan et al., 2019). Since 2010, nonprofit organizations such as Alianza Coachella Valley (hereafter referred to as Alianza) have been addressing these issues and campaigning for economic and environmental justice in the Eastern Coachella Valley (ECV). Prior to this work, no reliable and continuous source of water quality information was easily accessible to local communities. Most recently, Alianza championed a community science initiative with the goal of establishing ongoing environmental monitoring, research, and advocacy. Through this initiative, community members formed the Salton Sea Environmental Time Series (SSET) in 2021 with support from the American Geophysical Union’s (AGU’s) Thriving Earth Exchange program. This collaboration, along with a variety of other institutions, has fostered diversity, equity, and inclusion (DEI) within scientific academia for underrepresented ECV scholars and can serve as a blueprint for future initiatives.