Southern California Desert Research Articles

The relative effects of artificial shrubs on animal community assembly

Facilitative associations between the foundational shrub species Ephedra californica and local vertebrate species can drive positive interactions within desert ecosystems that influence diversity and assembly processes. These foundational shrubs can contribute to the structural heterogeneity of ecosystems for plants and animals including variation in temperature profiles, refuge from predation, and habitat for foraging. Artificial structures can also influence fine‐scale ecological and micro‐environmental dynamics. We tested the hypothesis that artificial shrubs (mimics) positively influence desert vertebrate association through facilitative interactions, similar to foundational shrub species. Mimics were deployed at four distinct sites within the central deserts of Southern California. A combination of camera traps and temperature pendants were utilized to measure the association patterns of vertebrate species and the microclimatic variation at mimic, open, and shrubs. A total of 21 species were observed in this study. Mimics had a significantly higher vertebrate abundance and richness than open microsites and functioned similarly to shrubs. These findings suggest that mimics can be utilized as a stop‐gap replacement for foundational shrub species as they can act as a novel fine‐scale habitat for many desert vertebrate species.

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.

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.

Comparison of Trap Efficiency Using Suction Traps Baited With Either UV or CO2 for the Capture of Culicoides (Diptera: Ceratopogonidae) Species in the Southern California Desert, United States.

Culicoides Latreille (Diptera: Ceratopogonidae) biting midges are hematophagous flies that can transmit several disease-causing pathogens to animals. Surveillance of Culicoides is important for understanding pathogen transmission risk. The most commonly used traps for midge surveillance are suction traps baited with UV light or CO2. Culicoides species are understudied in the southern California desert region and trapping methods for these desert midges remain largely unexplored. In this study, capture rates of different Culicoides species were compared using suction traps baited with either UV or CO2 placed at two locations at a southern California desert site where a narrow canyon (Deep Canyon) drains the adjacent peninsular mountain range and leads to an expansive floodplain. Over all trap nights and locations, UV-baited traps outperformed CO2-baited traps for most Culicoides species captured at the study site, except for Culicoides sonorensis Wirth and Jones and C. mohave Wirth. Capture rates varied for each species by trap location, with desert Culicoides species captured in greater numbers at the canyon mouth while C. sonorensis and C. mohave were captured in greater numbers on the floodplain nearer to urban development including a golf course and small zoo. An interaction of trap type with trapping location on the capture rate was noted for some Culicoides species, especially for C. mohave which was captured in greater numbers using UV traps at the canyon mouth but captured in greater numbers using CO2 traps in the floodplain. This trap efficiency study will facilitate future research targeting Culicoides species in the southern California desert.

PSXIV-1 Effect of Ambient Temperature on Respiration Rate and Ruminal Temperature for Growing-Finishing Calf-fed Holstein Steers in the Feedlot During Summer in Southern California

Abstract Objectives were to evaluate the relationships between ambient temperature (AT) and respiration rate (RR) and ruminal temperature (RT) of calf-fed Holstein steers during the extreme heat characteristic of the months of August and September in the Southern California desert region. Holstein steers (n = 21; one steer per pen; initial BW = 422 ±15 kg) were utilized in 28-d experiment (August 17 – September 14, 2021). Steers were blocked by initial shrunk weight (220 d before the initiation of the experiment) and randomly assigned to 21 pens (5 steers per pen). Pens were 62 m2 with 25 m2 overhead shade, automatic waterers and 2.4 m fence-line feed bunks. All steers were fed a steam-flaked corn-based growing-finishing diet. A bolus measuring temperature activity (smaXtec Basic, Smaxtec Animal Care GmbH, Austria) was placed in the rumen of each steer 55 d before the initiation of the experiment (June 22, 2021). During the experimental period, the respiration rate of one calf per pen was collected weekly. Respiration rate was obtained at 1100 h by counting the number of flank movements per minute. Ambient temperature at 1100 h averaged 37.6 ± 2.3° C for the experimental period. Temperature-humidity-index (THI) at 1100 h averaged 83.5 ± 1.7 (steers experienced “danger” or “emergency” THI categories through the entire 28 d trial). As AT increased from the minimum of 22.9° C to a maximum of 39.8° C, RR increased from 58.6 ± 12.9 breaths/min to 103.9 ± 16.9 breaths/min (RR = -54.9 + 4.13 AT, P < 0.01, r2 = 0.65). Likewise, RR increased with increasing RT (RR = -1259 + 33.7 RT, P < 0.01, r2 = 0.92) as RT increased. As ambient temperature increased, ruminal temperature increased (RT = 35.9 + 0.117 AT, P< 0.01, r2 = 0.65), though never exceeding 40.6° C.

PSXIV-3 Effect of pen mud Accumulation on the Growth Performance Growing-Finishing Calf-fed Holstein Steers in the Feedlot During Summer in Southern California

Abstract Objectives were to evaluate the relationship between pen mud accumulation and growth performance of calf-fed Holstein steers during the extreme heat characteristic of the months of August and September in the Southern California desert region. Holstein steers (n = 105; initial BW = 443 ±17 kg) were utilized in 28-d experiment (August 17 – September 14, 2021). Steers were blocked by initial shrunk weight (220 d before the initiation of the experiment) and randomly assigned to 21 pens (5 steers per pen). Pens were 62 m2 with 25 m2 overhead shade, automatic waterers and 2.4 m fence-line feed bunks. All steers were fed a steam-flaked corn-based growing-finishing diet. A bolus measuring temperature activity (smaXtec Basic, Smaxtec Animal Care GmbH, Austria) was placed in the rumen of each steer 55 d before the initiation of the experiment (June 22, 2021). Mud scores were recorded weekly by visual inspection. Mud score was determined as the percentage of pens surface area covered with mud. Scores were determined as follows: 1 – 0 to 20% of pen covered by mud; 2 – 21 to 40% of pen covered by mud; 3 – 41 to 60% of pen covered by mud; 4 – 61 to 80% of pen covered by mud; 5 – 81 to 100% of pen covered by mud. Ambient temperature averaged 33.2 ±2.3° C for the experimental period. Temperature of dry pen surfaces was greater than that of muddy surfaces (50.3 vs 20.4° C, respectively, P < 0.01). The relationship between ruminal temperature and pen mud score was not appreciable (P = 0.56). However, ADG was greater with a pen mud score of 2. Average daily gain decreased as pen mud score increased (r2 = 0.55). Similarly, feed efficiency was greatest in pens with a pen mud score of 2. Greater pen mud scores resulted in decreased feed efficiency (r2 = 0.56).

Morphological and Molecular Identification of Culicoides (Diptera: Ceratopogonidae) Species of the Southern California Desert.

Culicoides Latreille (Diptera: Ceratopogonidae) biting midges are vectors of important animal pathogens including bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV). While some Culicoides species present in the southern California desert are implicated in the transmission of these viruses to ruminant animals, these species have not been extensively studied due in part to the challenge of identifying Culicoides to species and to the lack of published gene sequences for these species to support their molecular identification. In this study, Culicoides were captured using suction traps baited with either carbon dioxide or UV light from transitional habitat between the southern California peninsular mountain ranges and the Colorado desert of southeastern California. Captured midges were initially identified using traditional morphological methods, with species identification subsequently confirmed by sequence analysis of COI and 28S rDNA genes. Phylogenetic analyses support that some Culicoides subgenera are not monophyletic. Two recognized species (C. sitiens Wirth and Hubert and C. bakeri Vargas) shared the same COI and 28S sequences. An additional cryptic species may be present within C. sitiens. Two additional recognized species (C. cacticola Wirth and Hubert and C. torridus Wirth and Hubert) may be conspecific or cryptic to each other. In total, 19 Culicoides species (or species aggregate) were collected in this study, with genetic sequences published for the first time for 16 of them. Published genetic sequences will support future research on these species, including studies on the ecology and habits of their immature stages which are often tedious to identify using morphology.

Perceptions of the Coronavirus and COVID-19 testing and vaccination in Latinx and Indigenous Mexican immigrant communities in the Eastern Coachella Valley

BackgroundA novel coronavirus, SARS-CoV-2 (known as COVID-19), spread rapidly around the world, affecting all and creating an ongoing global pandemic. Across the United States, Latinx and Indigenous populations have been disproportionately affected by COVID-19 cases and death rates. An examination of the perceptions and beliefs about the spread of the virus, COVID-19 testing, and vaccination amongst racial-ethnic minority groups, specifically Latinx and Indigenous Latin American immigrant communities, is needed to alleviate the widespread disparity in new cases and deaths.MethodsThis study was carried out from August 2020 to January 2021 and used community-based participatory research to engage community partners and build the capacity of community health workers (i.e., promotores de salud) and pre-medical and medical students in conducting qualitative research. The objective of the study was to examine the structural and social determinants of health on perceptions of the coronavirus, its spread, and decisions around COVID-19 testing and vaccination. Data collection included ethnography involving observations in public settings and focus groups with members of Latinx and Indigenous Mexican farm-working communities in the Eastern Coachella Valley, located in the Inland Southern California desert region. A total of seven focus groups, six in Spanish and one in Purépecha, with a total of 55 participants were conducted. Topics covered include perceptions of the coronavirus and its spread, as well as COVID-19 testing and vaccination.ResultsUsing theme identification techniques, the findings identify structural and social factors that underly perceptions held by Latinx and Indigenous Mexican immigrants about the virus and COVID-19, which, in turn, shape attitudes and behaviors related to COVID-19 testing and vaccination. Common themes that emerged across focus groups include misinformation, lack of trust in institutions, and insecurity around employment and residency.ConclusionsThis immigrant population is structurally vulnerable to historical and present-day inequalities that put them at increased risk of COVID-19 exposure, morbidity, and mortality. Study findings indicate a significant need for interventions that decrease structural vulnerabilities by addressing issues of (dis)trust in government and public health among this population.

PSVIII-18 Effect of rumen temperature on the average daily gain of growing-finishing calf-fed Holstein steers in the feedlot

Abstract Objectives were to evaluate the relationship between ruminal temperature and average daily gain of calf-fed Holstein steers during the extreme summer months characteristic of the Southern California desert region. Thirty-eight calf-fed Holstein steers (395 ±25 kg) were utilized in the 84-d experiment (June 30 – September 20, 2020). Steers were blocked by initial shrunk weight (168 d before the initiation of the experiment) and randomly assigned to 38 pens with 4 other steers (5 steers per pen). Pens were 62 m2 with 25 m2 overhead shade, automatic waterers and 2.4 m fence-line feed bunks. All steers were fed a steam-flaked corn-based growing-finishing diet. A bolus measuring temperature and activity at ten-minute intervals (smaXtec Basic, SmaXtec Animal Care GmbH, Austria) was placed in the rumen of each steer 112 d before the initiation of the experiment (March 10, 2020). Air temperature for the trial averaged 34.90 ± 3.03°C (maximum = 43.8 ± 2.97° C; minimum 24.72 ± 4.00°C). Average temperature-humidity-index (THI) was 80.1 ±5.4. Maximum THI during the 84-d period averaged 89.29 ± 7.85 (steers experience “emergency” THI category for all 84 days of the trial). Maximum (RTmax) and mean (RTm) daily ruminal temperature averaged 40.93 ±0.24 and 40.21 ±0.23°C, respectively. Average daily gain (mean = 1.18 kg/d; maximum = 1.54 kg/d; minimum = 0.88 kg/d) increased (P < 0.01) as RTm decreased (ADG, kg = 19.13 – 0.45 RTm; r2 = 0.28). There was a close association between RTmax and RTm (RTm = 4.57 + 0.87 RTmax; r2 = 0.84). While there are numerous factors that influence ADG of feedlot cattle, differences in ruminal temperature during periods of elevated ambient conditions (ie. temperature, humidity, ration) accounts for an important portion of that variation.

DELAYED DIAGNOSIS OF COCCIDIODES IMMITIS INFECTION WITH PULMONARY ABSCESS AND ARDS DIAGNOSED IN CHICAGO

TOPIC: Chest Infections TYPE: Fellow Case Reports INTRODUCTION: Coccidiodes immitis is a highly pathogenic fungus that is found in western and southern California's desert's regions. It frequently presents as a pneumonia that does not get better after anti-biotic therapy. With less than 5% of immunocompetent patient's progressing to have disseminated or severe infections (1). A disseminated Coccididiodes infection can be treated with liposomal amphotericin B, fluconazole, and steroids when there is Acute Respiratory Distress Syndrome (ARDS) (1,2). CASE PRESENTATION: In this case, a relatively healthy 80-year-old male with a past medical history of gastroesophageal reflux disease, hypertension, and hyperlipidemia who comes in shortness of breath, cough, and congestion. He had completed a course of azithromycin without resolution of symptoms. His initial chest x-ray showed a right upper lobe consolidation (Figure 1a). Bronchoscopy with transbronchial biopsies was performed which showed an acute organizing pneumonia (Figure 2). Despite antibiotic therapy and steroids, the patient did not have significant clinical improvement. So liposomal amphotericin B was started. An open lung biopsy was performed on day 14 as his chest X-ray was significantly worse with significant hypoxia (Figure 1b). Open lung biopsy showed a large abscess. A chest tube was placed. The abscess was irrigated with saline containing antibiotics. Pathology reported numerous coccidiodes spores (Figure 3). Antibiotics were discontinued. The patient's hospital course was complicated by a persistent air leak post lung biopsy and ARDS. Adjunctive steroids were added with improvement of his hypoxia. The patient was transitioned to a lower dose of steroids and to high dose fluconazole for long term treatment of his Coccidiodes infection. He was stable for placement of a tracheostomy and discharged to a long term acute care hospital (LTACH) for further care. His chest x-ray showed significant fibrosis (Figure 1c). DISCUSSION: When we re-examined the patient's history, he had a short trip to the southwestern United states for a total of 10 days with his family. This is the source of the patient's exposure. A thorough history may have helped, but urine Coccidiodes antigen testing was negative even after the open lung biopsy was performed. Despite clinical improvement, the patient passed 6 weeks after discharge to long term acute care hospital. CONCLUSIONS: Severe Coccoidiodes pulmonary infections can progress to ARDS. While, it is responsive to liposomal amphotericin B and steroids, it is still associated with a high morbidity and mortality (2). A high index of suspicion for a fungal infection should be maintained in patient's who have pneumonia refractory to antibiotic therapy. Speaking directly with the pathologist will also aide in the diagnosis of fungal infections non-endemic to the area especially like in this case (3). REFERENCE #1: Kirkland TN, Fierer J. Coccidioides immitis and posadasii; A review of their biology, genomics, pathogenesis, and host immunity. Virulence. 2018;9(1):1426-1435. doi:10.1080/21505594.2018.1509667 REFERENCE #2: Shibli M, Ghassibi J, Hajal R, O'Sullivan M. Adjunctive corticosteroids therapy in acute respiratory distress syndrome owing to disseminated coccidioidomycosis. Crit Care Med. 2002 Aug;30(8):1896-8. doi: 10.1097/00003246-200208000-00037. PMID: 12163812. REFERENCE #3: Pitcher JH, Zuckerman JB. Coccidioides Immitis Infection with Involvement of the Airway. Conn Med. 2016 Oct;80(9):539-541. PMID: 29772139 DISCLOSURES: No relevant relationships by Justin Ching, source=Web Response

Plantae Coulterianae: Thomas Coulter’s Californian Exsiccata

An account of the extent, diversity, and importance of the Californian collections of Thomas Coulter in the herbarium (TCD) of Trinity College, Dublin, Ireland, is presented here. It is based on examination of collections in TCD, several other collections available online, and referenced literature. Additional information on historical context, content of herbarium labels and annotations is included. Coulter’s collections in TCD are less well known than partial duplicate sets at other herbaria. He was the first botanist to cross the desert of southern California to the Colorado River. Coulter’s collections in TCD include not only 60 vascular plant specimens previously unidentified as type material but also among the first moss and marine algae specimens known to be collected in California. A list of taxa named for Thomas Coulter is included. Images of the map of his route are presented here as well as comments on some locality errors. Mention is made of works cited in annotations that were, in fact, never published, leading to persistent author citation errors. Coulter’s expansive interests in collecting and natural history included languages of the indigenous tribes he encountered in California.

Landsat Time Series Assessment of Invasive Annual Grasses Following Energy Development

Invasive annual grasses are of concern in much of the western United States because they tolerate resource variability and have high reproductive capacity, with propagules that are readily dispersed in disturbed areas like those created and maintained for energy development. Early season invasive grasses “green up” earlier than most native plants, producing a distinct pulse of greenness in the early spring that can be exploited to identify their location using multi-date imagery. To determine if invasive annual grasses increased around energy developments after the construction phase, we calculated an invasives index using Landsat TM and ETM+ imagery for a 34-year time period (1985–2018) and assessed trends for 1755 wind turbines installed between 1988 and 2013 in the southern California desert. The index uses the maximum Normalized Difference Vegetation Index (NDVI) for early season greenness (January-June), and mean NDVI (July–October) for the later dry season. We estimated the relative cover of invasive annuals each year at turbine locations and control sites and tested for changes before and after each turbine was installed. The time series was also mapped across the region and temporal trends were assessed relative to seasonal precipitation. The results showed an increase in early season invasives at turbine sites after installation, but also an increase in many of the surrounding control areas. Maps of the invasive index show a region-wide increase starting around 1998, and much of the increase occurred in areas surrounding wind development sites. These results suggest that invasions around the energy developments occurred within the context of a larger regional invasion, and while the development did not necessarily initiate the invasion, annual grasses were more prevalent around the developments.

Shifts in Vegetation Cover of Southern California Deserts in Response to Recent Climate Variations

In the deserts of Southern California, air temperatures have been rising and precipitation variability has been increasing over the past several decades. These recent climate shifts may have begun to threaten the survival of certain plant and animal species in these arid ecosystems. This study was designed to quantify and characterize variations in vegetation canopy density using more than 30 consecutive years of Landsat satellite image data across the western Lower Colorado (Sonoran) and southern Mojave Desert region. Mapping of the normalized difference vegetation index (NDVI) from Landsat images (1985 to 2017), which has been closely correlated with percent cover measurements of green vegetation canopies in a variety of arid ecosystems, was used to detect periodic upslope and downslope shifts in plant cover. The change in Landsat NDVI between 1985 and 2017 within the Santa Rosa Mountains Wilderness at four elevation zones between 500 m and 2500 m showed that vegetation green cover dropped notably in below-average precipitation periods, whereas green cover increased sharply in above-average precipitation years. This same temporal pattern of shifting in NDVI was detected along steep elevation gradients in the Anza-Borrego Desert State Park and in the Little San Bernardino Mountains of Joshua Tree National Park. Although the distribution of the dominant plant species along elevation gradients may have increased by more than 60 m over several decades (prior to 2007), we found no evidence that upslope shifts in percent plant cover have yet become a permanent pattern at these mountainous desert sites.

Detection of Vegetation Cover Change in Renewable Energy Development Zones of Southern California Using MODIS NDVI Time Series Analysis, 2000 to 2018

New solar energy facilities on public lands in the deserts of southern California are being monitored long-term to detect environmental impacts. For this purpose, we have developed a framework for detecting changes in vegetation cover region-wide using greenness index data sets from the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite sensor. This study focused on three sites, Joshua Tree National Park (JOTR), Mojave National Preserve (MOJA), and a proximal group of solar energy Development Focus Areas (DFAs). Three MODIS vegetation indices (VIs), the normalized difference (NDVI), enhanced (EVI), and soil-adjusted (SAVI), all at 250-m spatial resolution, were evaluated using the Breaks for Additive Season and Trend (BFAST) methodology to estimate significant time series shifts (“breakpoints”) in green vegetation cover, from February 2000 to May 2018. The sample cross-correlation function with local precipitation records and comparison with timing of wildfires near the study sites for breakpoint density (proportion of area with a breakpoint) showed that NDVI had the strongest response and hence greatest sensitivity to these major disturbances compared to EVI and SAVI, supporting its use over the other VIs for subsequent analysis. Time series of NDVI breakpoint change densities for individual solar energy DFAs did not have a consistent vegetation response following construction. Bootstrap-derived 95% confidence intervals show that the DFAs have significantly larger kurtosis and standard deviation in positive NDVI breakpoint distribution than protected National Park System (NPS) sites, but no significant difference appeared in the negative distribution among all sites. The inconsistent postconstruction NDVI signal and the large number of detected breakpoints across all three sites suggested that the largest shifts in greenness are tied to seasonal and total annual precipitation amounts. Further results indicated that existing site-specific conditions are the main control on vegetation response, mostly driven by the history of human disturbances in DFAs. Although the results do not support persistent breakpoints in solar energy DFAs, future work should seek to establish links between statistical significance and physical significance through ground-based studies to provide a more robust interpretation.

Controls on Land Surface Temperature in Deserts of Southern California Derived from MODIS Satellite Time Series Analysis, 2000 to 2018

The land surface temperature (LST) in arid regions is a primary controller of many ecological processes. Consequently, we have developed a framework for detection of LST change on a regional scale using data sets covering all deserts of southern California from the Moderate-Resolution Imaging Spectroradiometer (MODIS) satellite sensor. The Breaks for Additive Season and Trend (BFAST) methodology was applied to MODIS 1-km monthly LST data from the years 2000 to 2018 to estimate significant time series shifts (breakpoints) and gradual trends. Area-wide results showed five times more positive LST breakpoints (abrupt temperature warming events) than negative (surface cooling) breakpoints. Cross-correlations with high rainfall periods around Mojave dry lake playas, and comparison with timing of wildfire burns for breakpoint patterns, showed that abrupt shifts in LST had the strongest response to these controllers. We detected negative LST (abrupt cooling) breakpoints as consistently associated with the construction of new solar energy facilities. Over the majority of the study area, BFAST results showed warming LST trends between the years 2000 and 2018. The western-most margins of the study area showed consistent widespread warming trends, whereas the eastern portions of the Mojave and Lower Colorado Deserts showed a mix of positive and neutral LST trends. Long-term cooling LST trends were detected only in some of the largest dry lake formations in the Antelope Valley, Death Valley, and Bristol, Cadiz, and Danby playas.

Learning to feel at home in the Anthropocene:

ABSTRACTIn the deserts of Southern California, a series of climate crises has disturbed the form and content of the ordinary. In this context of unfolding change, Californians are experimenting with the spaces, surfaces, objects, and infrastructures of their homes, harnessing the material elements of the house as a site not only of repetition and reproduction but also of reinvention. At times, these experiments in the ecologies of everyday life unleash a range of transformative effects on both self and world, accreting into instances of cosmological reconfiguration. Rather than analyze such experiments as practices of adaptation or recovery, we can better understand them as attempts to cultivate alternative ways of feeling at home in the Anthropocene. Such experiments take up the relations among aesthetics, ethics, and affect as their primary site of improvisation and innovation.

Imaging analysis of biological soil crusts to understand surface heating properties in the Mojave Desert of California

Biological soil crusts (biocrusts) are composed of a combination of cyanobacteria, green algae, lichens, and mosses that can protect arid soil surfaces from erosive forces. The presence of biocrusts in desert regions is influenced by a complex interaction of climatic, edaphic, and topographic variables, but their distribution and coverage densities in southern California deserts are not precisely mapped. Visible satellite bands (red-green-blue; RGB) and infra-red image resolution are generally too coarse to distinguish between biocrusts and their interstitial sand substrates, limiting most remote sensing analysis of these soil biotic assemblages. The purpose of this study was to better understand the relationships between biocrust cover, surface coloration and roughness, and the thermal infra-red (TIR) emission properties of biocrusts to determine if new types of imaging of desert surfaces could be used to more accurately detect biocrust presence. Based on the results from megapixel digital photos and TIR imaging for nearly 130 different, well-developed biocrust surfaces in the Mojave and Lower Colorado Deserts of California, we designed laboratory heating experiments to test the effect of biocrust cover on the heating properties of sandy wash habitats. Biocrust samples collected from the field were subjected to artificial heating and cooling to simulate the Mojave Desert diurnal cycle. We used image segmentation algorithms to separate true-color biocrust images from their sandy substrates, and to map the heating and cooling patterns of these surfaces with different levels of biocrust coloration and roughness. The major findings of this study showed that biocrust patch images in the field had Red texture mean values between digital numbers of 95 and 131 with moderate positive tail shewness levels, indicative of a highly rugose surface of the biocrust cover. Such patches were also well-compacted overall, with moderate skewness toward negative tails. In controlled laboratory temperature experiments to simulate the desert diurnal cycle, surface wetting with a fine mist of water resulted in significantly lower peak surface temperatures of biocrust samples compared to dry biocrust heating results of the same crust and sand samples. The findings of this study can improve future mapping for lichen-dominated biocrust surfaces in the Mojave Desert.

Dancing with hyperobjects: Ecological Body Weather choreographies from Height of Sky to Into the Quarry

Abstract Timothy Morton claims that hyperobjects – things ‘massively distributed in time and space relative to humans’ such as global warming, the total sum of all the nuclear materials on earth, a weather system – have completely altered how we think and experience, forcing us into confronting the fact that we must relate to them as fellow objects. In this article I argue that Body Weather-based dance practices, developed by Japanese dancer Min Tanaka on his Hakushu farm in Japan between 1985 and 2010, attempt to form corporeal and kinaesthetic relationships with hyperobjects through training dancers to sensitize their bodies to their existence as part of what Morton calls the mesh. I discuss two Body Weather-related projects: Morleigh Steinberg’s 2004 film Height of Sky about Oguri’s two-year danced investigation of the Mojave and Colorado Deserts of Southern California, and my own work in North Texas, Into the Quarry. This work, I suggest, provides a model for how to develop a radically different relationship with our environment, one based on the mutual interconnection of interobjectivity.

A Contribution to the Phylogeography and Anatomy of Helminthoglyptid Land Snails (Pulmonata: Helminthoglyptidae) from the Deserts of Southern California

Abstract Land snails in the family Helminthoglyptidae are found sparingly and locally throughout southern California's deserts. They are mostly restricted to rock outcrops and talus in partially shaded canyons where they can gain access to cooler temperatures under the rocks. Several species are known only from their type localities, and were described by shell characters only. We have endeavored to locate known species, document their reproductive anatomy and embryonic shell structure, refine knowledge of their distribution, and incorporate genetic sequencing of two mitochondrial genes (COI and 16S) to investigate evolutionary relationships in these taxa. As a “first pass” molecular study, we have established basic sequence and divergence data for 27 populations of snails in five genera: Helminthoglypta (subgenus Coyote), Eremarionta, Cahuillus, Chamaearionta and Sonorelix. Fifteen of the populations were previously unknown. We confirmed that the Salton Rift/Coachella Valley is a major biogeographic barr...

The Map and the Territory: Documenting David Dunn’s Sky Drift

In 1977, a large group of musicians performed David Dunn’s Sky Drift while moving slowly across a Southern California desert, documenting the concert with four stationary microphones. A year later, Dunn presented the work in New York as a ‘performance/documentation’, playing back the audio recording for a seated audience. This article explores issues of ‘liveness’ in recorded sound, ‘transparency’, ‘aura’ and ‘the work itself’ in order to examine the consequences of this act: what does it mean for a recording of an outdoor performance to be shared at an indoor concert event? Can such a complex and interactive experience – with widely dispersed musicians and mobile audience members – be successfully converted into a fixed document? What does a recording capture and what must it exclude? Because Sky Drift constantly shifts the physical relationships between musicians and audience across a vast outdoor landscape, each listener’s experience represents an equally valid sonic perspective on the piece. As a result, it is unclear how a satisfying recording might be made or what it might even mean to ‘hear the music’ at all. When relocated – away from its original outdoor context – Sky Drift is deprived of much of its potential to communicate meaning.