American Deserts Research Articles

Contamination désertique du métarécit dans La Disparition de Jim Sullivan de Tanguy Viel

This article examines the eschatological influence of the American desert on the metanarrative structure of Tanguy Viel’s novel La Disparition de Jim Sullivan (2013). Dwayne, the character en abyme, fantasizes about desert adventures but as he progresses towards the arid place, the boundaries between the two diegetic levels vanish. The notion of hyperreality, pervading the novel, reflects Dwayne’s ethnocentric posture. He is absorbed in his fantasies and unable to contemplate his environment without artifice. Bearing on the notion of desertification, I demonstrate that the desert, long considered an empty space to be filled, reclaims its rights over humanity with agency. In the last chapter, Dwayne commits suicide in the desert, and the arid place absorbs the character in its turn. The desert is no longer perceived as an archaic space of un-culture, but as the new place where anxieties about the future of humankind crystallize.

Effect of water stress on locomotor performance in Pleurodema nebulosum (Anura: Leptodactylidae) a native frog from the Argentina Monte desert

Locomotion is a fundamental aspect in the life cycle of any organism, and plays a crucial role in survival, feeding, escaping from predators, territoriality, and reproduction. Locomotion in amphibian anurans includes swimming, walking, jumping, climbing, and gliding. Amphibians living in arid regions face a constant compromise between hydration balance and locomotor performance. We studied the effects of water stress on the locomotion of the frog Pleurodema nebulosum, a specialist from the Monte Desert. Locomotor performance was measured through different physical variables during the jump. The locomotor performance of P. nebulosum showed a significant decrease in the magnitudes associated with a decrease in body hydration. Our study demonstrated how a desert-adapted frog (P. nebulosum) showed changes in locomotion related to the loss of body water. Additionally, we observed an abrupt drop in locomotion with 15% desiccation, followed by a plateau where the evaluated parameters remained stable. Pleuroderma nebulosum showed a clear adaptation to extreme desiccation. The frogs are rarely found in optimal hydration conditions as the environment in which they develop is extremely stressful from a water perspective. The data evaluated here are the beginning of a deeper exploration of the desert adaptations of South American desert frogs.

Theatre for Sentient Beings: a performative practice of apprenticing gestures and transformation with the southwestern American desert high plateaux

Theatre for Sentient Beings: a performative practice of apprenticing gestures and transformation with the southwestern American desert high plateaux

The benefits of woody plant stem photosynthesis extend to hydraulic function and drought survival in Parkinsonia florida.

As climate change exacerbates drought stress in many parts of the world, understanding plant physiological mechanisms for drought survival is critical to predicting ecosystem responses. Stem net photosynthesis, which is common in arid environments, may be a drought survival trait, but whether the additional carbon fixed by stems contributes to plant hydraulic function and drought survival in arid land plants is untested. We conducted a stem light-exclusion experiment on saplings of a widespread North American desert tree species, Parkinsonia florida L., and after shading acclimation, we then subjected half of the plants to a drought treatment to test the interaction between light exclusion and water limitation on growth, leaf and stem photosynthetic gas exchange, xylem embolism assessed with micro-computed tomography and gravimetric techniques, and survival. Growth, stem photosynthetic gas exchange, hydraulic function and survival all showed expected reductions in response to light exclusion. However, stem photosynthesis mitigated the drought-induced reductions in gas exchange, xylem embolism (percent loss of conductivity, PLC) and mortality. The highest mortality was in the combined light exclusion and drought treatment, and was related to stem PLC and native sapwood-specific hydraulic conductivity. This research highlights the integration of carbon economy and water transport. Our results show that additional carbon income by photosynthetic stems has an important role in the growth and survival of a widespread desert tree species during drought. This shift in function under conditions of increasing stress underscores the importance of considering stem photosynthesis for predicting drought-induced mortality not only for the additional supply of carbon, but also for its extended benefits for hydraulic function.

Strengths and weaknesses of acoustic pipe microphone systems in ephemeral, sandy, gravel‐bed rivers

AbstractWe calibrated an acoustic pipe microphone system to monitor bedload flux in a sandy, gravel‐bed ephemeral channel. Ours is a first attempt to test the limit of an acoustic surrogate bedload system in a channel with a high content of sand. Calibrations varied in quality; significant data subsetting was required to achieve R2 values >0.75. Several data quality issues had to be addressed: (1) apparent pulses, which occur when a sensor records an impulse from sediment impacting the surrounding substrate rather than directly impacting the sensor, were frequent, especially at higher signal amplifications. (2) The impact sensors were frequently covered by gravel sheets. This prompted the development of a cover detection protocol that rejected part of the impact sensor record when at least one sensor was partially or fully covered. (3) Because of the lack of sensor sensitivity to impacts of sand‐sized particles, which was anticipated, and the considerable sand component of bedload in this channel, a grain size‐limited bedload flux was estimated. This was accomplished by sampling the bedload captured by slot samplers and evaluating the variation of grain size with increasing flow strength. This considerably improved the results when compared to attempts at estimating the flux of the entire distribution of grain sizes. This calibration is a successful first attempt, though the impact sensors required several site‐specific calibration steps. A universal set of equations using impact sensors to estimate bedload transport of fine‐gravel with a large content of sand remains elusive. Notwithstanding, our study demonstrates the utility of impact sensor data, producing relatively low root mean square errors that are independent of measurements of flow strength (i.e. discharge). These tools will be particularly useful in settings that would benefit from new methodologies for estimating bedload transport in sand‐rich gravel‐bed rivers, such as the American desert Southwest.

Spatial Distribution of Ammonia Concentrations and Modeled Dry Deposition in an Intensive Dairy Production Region.

Agriculture generates ~83% of total US ammonia (NH3) emissions, potentially adversely impacting sensitive ecosystems through wet and dry deposition. Regions with intense livestock production, such as the dairy region of south-central Idaho, generate hotspots of NH3 emissions. Our objective was to measure the spatial and temporal variability of NH3 across this region and estimate its dry deposition. Ambient NH3 was measured using diffusive passive samplers at 8 sites in two transects across the region from 2018-2020. NH3 fluxes were estimated using the Surface Tiled Aerosol and Gaseous Exchange (STAGE) model. Peak NH3 concentrations were 4-5 times greater at a high-density dairy site compared to mixed agriculture/dairy or agricultural sites, and 26 times greater than non-agricultural sites with prominent seasonal trends driven by temperature. Annual estimated dry deposition rates in areas of intensive dairy production can approach 45 kg N ha-1 y-1, compared to <1 kg N ha-1 y-1 in natural landscapes. Our results suggest that the natural sagebrush steppe landscapes interspersed within and surrounding agricultural areas in southern Idaho receive NH3 dry deposition rates within and above the range of nitrogen critical loads for North American deserts. Finally, our results highlight a need for improved understanding of the role of soil processes in NH3 dry deposition to arid and sparsely vegetated natural ecosystems across the western US.

America’s Deserter: Forms of Racialised Mistreatment and Escaping the Need to Escape in Percival Everett’s American Desert

In this article, I consider the protagonist of Percival Everett’s American Desert (2004) – Theodore “Ted” Street – and his treatment as a short-lived cultural phenomenon after inexplicably coming back from the dead. I read Ted’s experiences alongside Saidiya Hartman and Fred Moten’s ideas on the impacts of racial inequality on Black experience and writing. I discuss Hartman’s work on the “afterlife of slavery” in “The Belly of the World: A Note on Black Women’s Labors” (2016), and Moten’s Black and Blur: consent not to be a single being (2017), where he discusses the “predication of blackness” as “immersion” in the aftereffects of the slave trade.American Desert’s episodic narrative problematises Ted’s efforts to escape mistreatment by persistently placing obstacles in front of them. Ted’s afterlife leads to different forms of mistreatment, including unwanted media attention, harassment towards him and his family, and being held captive in two different settings, which are all intensified because Everett invites us to read his character as AfricanAmerican. In line with Hartman and Moten’s work, as the novel progresses Ted realises that to end his cycle of futile escapes he must escape the need to escape, which is a necessary response to the racialised mistreatment he is subjected to.

Climate-driven past and present interspecies gene flow may have contributed to shape microscale adaptation capacity in Tillandsia lomas in hyperarid south American desert systems

Epiarenic (sand-growing) Tillandsia vegetation in the hyperarid and arid region of the Chilean-Peruvian Atacama Desert represents an extreme case of adaptation in plant species-poor ecosystems. The involved species exist at the limit of terrestrial life and form mono/oligo-specific and very characteristic structures within the landscape. Covering thousands of square kilometers they represent the major carbon sink in the hyperarid Atacama core. The various Tillandsia species and respective vegetation may have evolved and adapted independently to this extreme environment. The most abundant vicariant diploid species are T. landbeckii in Chile and T. purpurea in Peru. Spatio-temporally varying distribution range overlaps may have caused potentially adaptive gene flow between different species leading to present day gene pools. Using species distribution modelling we explored the idea that from Last Glacial Maximum (LGM) onwards both species shifted their distribution ranges, which resulted in the formation of varying suture zones from Peru towards northern Chile. We further explored genetic data from a Tillandsia loma vegetation in Southern Peru with three sympatrically growing species exemplifying inter-species gene flow crossing even ploidy levels. This mechanism highlights a strategy to evolve and adapt more rapidly to environmental changes in extreme arid and hyperarid habitats and provides an opportunity for Tillandsia populations to efficiently conserve new genotypes via subsequent clonal propagation.

Reading the “Slash” in Percival Everett’s American Desert

This article explores Percival Everett’s multi-dimensional use of a concept he has termed the “slash” (i.e., the line that both separates and conjoins signifier/signified) in his novel American Desert. In effect, this slash is a trope Everett deploys to compel readers not to align themselves with what might otherwise be perceived as the author’s message but rather to explore a wide range of the possible ideas and provisional meanings his fiction might generate, challenge these perceived meanings, constructively play with his text, and eventually tease out some (inevitably contingent) concepts that may, upon further consideration, morph into newer, richer sets of understanding. Although Everett’s use of the slash is not unique to American Desert, it is arguably the novel in which he uses the trope most pervasively.

Geostatistical analysis of the relationship among geomorphology, land cover, and AOD at the local scale in a South American desert region

This work aims to assess the particle matter distribution in Tulum Valley, San Juan, Argentina, during 2019, in relation to geomorphology. Random forest supervised classifications were performed to obtain customized annual landform and seasonal land cover maps using Landsat 8 Surface Reflectance (OLI); Sentinel-1 SAR, SRTM digital elevation images, and a set of spectral indices. Geostatistical analyses, including Linear Mixed Models, were performed considering the ln of the mean, the ln of the standard deviation, and the Angstrom Exponent of the MAIAC Aerosol Optical Depth product as response variables, and landforms, landforms + land cover, Land Surface Temperature, and Moisture Stress Index as explanatory variables. The models allowed statistically significant differentiation of the Aerosol Optical Depth means of the landform and landform + land cover classes. The percentage of residual standard error for the means obtained from the model was up to 4.02%. The Angstrom Exponent values below 0.0858, along with the spatial distribution of the three response variables, indicate that the primary aerosol source in the study area is wind-driven soil/sediment erosion, which shows a strong relationship with emission areas. No long-distance transport of aerosols was observed.

Effects of vegetation rehabilitation on soil inorganic carbon in deserts: A meta-analysis

Over past decades, vast areas of shifting sand lands have been controlled and restored by vegetation rehabilitation. However, a quantitative and comprehensive understanding of the variation in soil inorganic carbon (SIC) following vegetation rehabilitation is lacking. Based on 422 observations derived from 31 studies in the deserts of Asia and North America, we carried out a meta-analysis to quantify the changes in SIC following vegetation rehabilitation on shifting sand lands and analyzed the relationships of the variation in SIC with environmental factors. Overall, vegetation rehabilitation on shifting sand lands significantly increased the SIC content by 43.4% in Asian and North American deserts. The conversions of shifting sand lands to forestlands, shrublands, grasslands and croplands increased the SIC contents by 77.0%, 36.2%, 54.1% and 18.9%, respectively. The response ratio of SIC (RR-SIC) to vegetation rehabilitation was significantly and positively correlated with the rehabilitation age, the response ratio of soil organic carbon and the soil pH, respectively. A quadratic relationship was observed between the RR-SIC and the mean annual precipitation. The results of meta-analysis for the changes in SIC demonstrated that vegetation rehabilitation on shifting sand lands has a high potential to sequester SIC. The relationships of RR-SIC with the environmental factors suggested that the formation of pedogenic inorganic carbon plays an important role in SIC sequestration following vegetation rehabilitation on shifting sand lands. Our findings highlight the importance of SIC in regional carbon budget, and neglecting SIC could underestimate the carbon sequestration capacity of vegetation rehabilitation in deserts.

Once upon a time in Mexico: Holocene biogeography of the spotted bat (Euderma maculatum).

Holocene-era range expansions are relevant to understanding how a species might respond to the warming and drying climates of today. The harsh conditions of North American deserts have phylogenetically structured desert bat communities but differences in flight capabilities are expected to affect their ability to compete, locate, and use habitat in the face of modern climate change. A highly vagile but data-deficient bat species, the spotted bat (Euderma maculatum), is thought to have expanded its range from central Mexico to western Canada during the Holocene. With specimens spanning this latitudinal extent, we examined historical demography, and used ecological niche modeling (ENM) and phylogeography (mitochondrial DNA), to investigate historic biogeography from the rear to leading edges of the species' range. The ENM supported the notion that Mexico was largely the Pleistocene-era range, whereas haplotype pattern and Skyline plots indicated that populations expanded from the southwestern US throughout the Holocene. This era provided substantial gains in suitable climate space and likely facilitated access to roosting habitat throughout the US Intermountain West. Incongruent phylogenies among different methods prevented a precise understanding of colonization history. However, isolation at the southern-most margin of the range suggests a population was left behind in Mexico as climate space contracted and are currently of unknown status. The species appears historically suited to follow shifts in climate space but differences in flight behaviors between leading edge and core-range haplogroups suggest range expansions could be influenced by differences in habitat quality or climate (e.g., drought). Although its vagility could facilitate response to environmental change and thereby avoid extinction, anthropogenic pressures at the core range could still threaten the ability for beneficial alleles to expand into the leading edge.

Population dynamics and life history of the endangered ciénega endemic Eryngium sparganophyllum in Arizona

Eryngium sparganophyllum is a perennial endemic to ciénegas in warm North American deserts. Only four populations remain, yet little scientific knowledge exists to guide its conservation. Based on a spatially balanced sampling design, we quantified plant density, individual size, and reproductive potential of two populations in the U.S. We also assessed conditions influencing germination in the lab. The population in a warmer climate had a larger population size, higher short-term population growth rate, hosted larger individuals, and showed a negative correlation between plant size and plant density. In both populations, plant density was positively correlated with shallow soil moisture and probability of flowering was positively correlated with plant size. Seeds only germinated in the spring, and responded to interactions between temperature, light exposure and population location. We hypothesize that 1) recruitment of E. sparganophyllum may be episodic, relying on a rare niche opportunity of reliable shallow soil moisture and low competition; and 2) adult survival of the species may be limited by interspecific density dependence and climatic extremes. The conservation of this species depends on ensuring high adult survival and promoting recruitment, which can be accomplished through actively protecting extant populations and exploring restoration and introduction possibilities.

Phylogenomics of One of the World’s Most Intriguing Groups of CAM Plants, the Opuntioids (Opuntioideae: Cactaceae): Adaptation to Tropical Dry Forests Helped Drive Prominent Morphological Features in the Clade

Opuntioideae, composed of roughly 370 species, occur in almost every biome in the Americas, from seasonally dry tropical forests (SDTF) to high-elevation Andean grasslands, American deserts and temperate zones. The interrelationships among the three major clades of Opuntioideae (Cylindropuntieae, Opuntieae and Tephrocacteae) are not well resolved, and thus, the ancestral habitat, biogeographic history and evolution of morphological characters, such as large photosynthetic leaves and flattened stems, are poorly understood. To test their geographic origin and evolution of key morphological characters, we built the largest phylogenomic dataset for Cactaceae to date using 103 plastid genes of 107 taxa of Opuntioideae. The subfamily Opuntioideae likely evolved in South America in a combination of seasonally dry tropical forest (SDTF)/desert habitats. Opuntieae most likely evolved in South America in SDTF and, from there, moved into desert regions, Chaco and temperate/subtropical zones, while Tephrocacteae and Cylindropuntieae evolved in South America in desert regions and moved into SDTF, Chaco and temperate/subtropical zones. Analyses of morphological evolution suggest that, although large leaves are plesiomorphic in Opuntioideae, long-lived, photosynthetically active leaves in Cylindropuntieae and Tephrocacteae are homoplasious and do not represent retained plesiomorphy, as is often assumed. Flattened stems are synapomorphic for Opuntieae, possibly representing adaptation to competition for light resources in SDTF, their most likely ancestral area.

The Family Fortuna by Lindsay Eagar (review)

Reviewed by: The Family Fortuna by Lindsay Eagar Wesley Jacques Eagar, Lindsay The Family Fortuna. Candlewick, 2023 [400p] Trade ed. ISBN 9780763692353 $19.99 Reviewed from digital galleys R* Gr. 9-12 Arturo Fortuna is one of the greatest showmen alive, and the Family Fortuna traveling circus has wowed audiences from "Texas to Tacoma" by way of his charisma and the labor of his children: a singularly beautiful daughter showcased to gawkers in the kootchie tent, a dwarf son with a knack for bookkeeping, and Avita, the show-stopping Bird Girl, whose feathered strangeness is, according to her often persuasively callous father, "worth a thousand whores." When the Fortunas return to Peculiar, a late nineteenth-century American desert town, a rival circus and longstanding riffs in the family's exploitation and spectacle-focused dynamic present a turning point for the maturing daughters, frustrated son, pious mom, and deeply [End Page 255] flawed father alike. Narrator Avita falling for a traveling artist brings about a particular shift of the status quo in a richly compelling story about sympathetic, queer, and remarkable carny folks that consistently delivers earnest and heartfelt camp. Eager's punchy, funny prose never falters, and Avita's relatable development—sexual and otherwise—alongside her siblings' pursuit of some semblance of independence from the large, looming figure of their father cleverly reshapes concepts of beauty, seduction, and coming-of-age. Readers will want to grab tickets to this thoughtful, provocative read. Copyright © 2023 The Board of Trustees of the University of Illinois

Long‐term relationships between seed bank communities and wildfire across four North American desert sites

AbstractIt is well documented that the recovery of dryland plant communities following wildfire can be variable, and that legacies of fire can have long‐lasting effects on aboveground plant communities. However, our understanding of the degree to which dryland soil seed banks, or the viable seeds in situ, are impacted by fire and their subsequent postfire succession remains extremely poor. To address this important knowledge gap, we used a time‐since‐fire approach to investigate soil seed bank community changes approximately 15 and 30 years after wildfire and to determine the influence of microsites (e.g., shrub vs. interspace) on seed bank composition. We assessed soil seed bank metrics across four North American deserts, including two cold desert sites (Colorado Plateau and Great Basin) and two warm desert sites (Chihuahuan and Sonoran). In greenhouse emergence trials, we found that seed bank characteristics diverged between warm and cold desert sites, such that warm desert sites had seed banks dominated by annual plants while our cold desert sites had seed banks with greater proportions of perennial species, regardless of fire history. In cold desert sites, fire significantly altered seed bank species composition even 30 years after fire. Shrub versus interspace microsites had no observed influence on seed bank composition in any desert. However, seed bank species richness was greater under shrubs in both warm deserts. Non‐native species were present in the seed banks of all deserts and some were particularly abundant in the burned sites. Despite the presence of native species in both burned and unburned seed banks, the presence of non‐native species suggests some degree of vulnerability to future disturbances because fire can create amplifying feedback with many non‐native plants. Our results highlight strong differences in fires' relationship with seed banks for warm and cold desert sites and lend insight into how fire relates to the composition and diversity of the seeds that play a fundamental role in future plant communities.

Edaphic specialization onto bare, rocky outcrops as a factor in the evolution of desert angiosperms

Understanding the processes that enable organisms to shift into more arid environments as they emerge is critical for gauging resilience to climate change, yet these forces remain poorly known. In a comprehensive clade-based study, we investigate recent shifts into North American deserts in the rock daisies (tribe Perityleae), a diverse tribe of desert sunflowers (Compositae). We sample rock daisies across two separate contact zones between tropical deciduous forest and desert biomes in western North America and infer a time-calibrated phylogeny based on target capture sequence data. We infer biome shifts using Bayesian inference with paleobiome-informed models and find evidence for seven independent shifts into desert habitats since the onset of aridification in the late Miocene. The earliest shift occurred out of tropical deciduous forests and led to an extensive radiation throughout North American deserts that accounts for the majority of extant desert rock daisies. Estimates of life history and micro-habitat in the rock daisies reveal a correlation between a suffrutescent perennial life history and edaphic endemism onto rocky outcrops, an ecological specialization that evolved prior to establishment and diversification in deserts. That the insular radiation of desert rock daisies stemmed from ancestors preadapted for dry conditions as edaphic endemics in otherwise densely vegetated tropical deciduous forests in northwest Mexico underscores the crucial role of exaptation and dispersal for shifts into arid environments.

Utah History Textbooks and Utah History

Utah History Textbooks and Utah History

Flora y vegetación de los trópicos estacionalmente secos en México: origen e implicaciones biogeográficas

Entre las diversas ideas que se han propuesto para explicar la gran diversidad biológica de México está la que afirma que ésta es el resultado del contacto de las biotas neotropical y neártica; sin embargo, esta explicación relacionada con el gran contacto biótico de las Américas no es completamente satisfactoria y necesita ser revisada a la luz de la biogeografía histórica. En este artículo ofrecemos nuevas perspectivas sobre este asunto por medio de una revisión de la historia de la flora y la heterogeneidad vegetacional del trópico estacionalmente seco de este país. Se han usado varios criterios ambientales para definir las regiones tropicales estacionalmente secas, pero ubicar con precisión sus límites geográficos no es siempre fácil. Esto se debe en gran medida a la gran heterogeneidad de la vegetación presente en esta región, entre la que predomina el bosque tropical caducifolio (BTC). El origen de la flora del BTC se remonta, por lo menos, unos 20 millones de años antes del presente y parece estar asociada con la flora del Terciario de Norteamérica. La evidencia disponible no apoya un origen sudamericano para el BTC. Asimismo, no hay razones que justifiquen de forma convincente la separación de la flora del BTC y la de los desiertos calientes de Norteamérica en dos reinos biogeográficos diferentes. La historia de la flora del trópico estacionalmente seco de México sugiere fuertemente que esta dicotomía biogeográfica debería ser reemplazada por el reconocimiento de la existencia de un Reino Panamericano.

Dispersal limitations increase vulnerability under climate change for reptiles and amphibians in the southwestern United States

AbstractSpecies conservation plans frequently rely on information that spans political and administrative boundaries, especially when predictions are needed of future habitat under climate change; however, most species conservation plans and their requisite predictions of future habitat are often limited in geographical scope. Moreover, dispersal constraints for species of concern are not often incorporated into distribution models, which can result in overly optimistic predictions of future habitat. We used a standard modeling approach across a suite of 23 taxa of amphibians and reptiles in the North American deserts (560,024 km2 across 13 ecoregions) to assess impacts of climate change on habitat and combined landscape population dispersal simulations with species distribution modeling to reduce the risk of predicting future habitat in areas that are not available to species given their dispersal abilities. We used 3 general circulation models and 2 representative concentration pathways (RCPs) to represent multiple scenarios of future habitat potential and assess which study species may be most vulnerable to changes forecasted under each climate scenario. Amphibians were the most vulnerable taxa, but the most vulnerable species tended to be those with the lowest dispersal ability rather than those with the most specialized niches. Under the most optimistic climate scenario considered (RCP 2.6; a stringent scenario requiring declining emissions from 2020 to near zero emissions by 2100), 76% of the study area may experience a loss of &gt;20% of the species examined, while up to 87% of the species currently present may be lost in some areas under the most pessimistic climate scenario (RCP 8.5; a scenario wherein greenhouse gases continue to increase through 2100 based on trajectories from the mid‐century). Most areas with high losses were concentrated in the Arizona and New Mexico Plateau ecoregion, the Edwards Plateau in Texas, and the Southwestern Tablelands in New Mexico and Texas, USA. Under the most pessimistic climate scenario, all species are predicted to lose some existing habitat, with an average of 34% loss of extant habitat across all species. Even under the most optimistic scenario, we detected an average loss of 24% of extant habitat across all species, suggesting that changing climates may influence the ranges of reptiles and amphibians in the Southwest.