Desert Systems Research Articles

Hot, dry, and salty: The present and future of an Extremophile model lizard from Argentina

Global warming poses a threat to lizard populations by raising ambient temperatures above historical norms and reducing thermoregulation opportunities. Whereas the reptile fauna of desert systems is relatively well studied, the lizard fauna of saline environments has not received much attention and—to our knowledge—thermal ecology and the effects of global warming on lizards from saline environments have not been yet addressed. This pioneer study investigates the thermal ecology, locomotor performance and potential effects of climate warming on Liolaemus ditadai, a lizard endemic to one of the largest salt flats on Earth. We sampled L. ditadai using traps and active searches along its known distribution, as well as in other areas within Salinas Grandes and Salinas de Ambargasta, where the species had not been previously recorded. Using ensemble models (GAM, MARS, RandomForest), we modeled climatically suitable habitats for L. ditadai in the present and under a pessimistic future scenario (SSP585, 2070). L. ditadai emerges as an efficient thermoregulator, tolerating temperatures near its upper thermal limits. Our ecophysiological model suggests that available activity hours predict its distribution, and the projected temperature increase due to global climate change should minimally impact its persistence or may even have a positive effect on suitable thermal habitat. However, this theoretical increase in habitat could be linked to the distribution of halophilous scrub in the future. Our surveys reveal widespread distribution along the borders of Salinas Grandes and Salinas de Ambargasta, suggesting a potential presence along the entire border of both salt plains wherever halophytic vegetation exists. Optimistic model results, extended distribution, and no evidence of flood-related adverse effects offer insights into assessing the conservation status of L. ditadai, making it and the Salinas Grandes system suitable models for studying lizard ecophysiology in largely unknown saline environments.

Exploring Ecological Management Plans for Typical Systems in Arid Areas from the Perspective of Ecosystem Service Value Evolution

Ecological management zoning plays a significant role in optimizing resource utilization, improving ecosystem service function, and promoting coordinated regional development. Taking Hexi Corridor as a representative region of the Mountain–Oasis–Desert composite system in arid regions of Asia, this study analyzed the spatial and temporal evolution of ecosystem service values and explored the influencing mechanism based on the optimal parameters-based geographical detector model. We have comprehensively divided ecological management zones and proposed corresponding control strategies. The results show that (1) the Hexi Corridor is characterized by regional differentiation, which is composed of three systems: The southern mountain system, central oasis system, and northern desert system. The mountain system is mainly composed of forestland and grassland, the oasis system is mainly composed of cropland, and the desert system is mainly composed of unused land. The conversion of land use mainly involves the conversion of unused land to cropland and grassland, while grassland is mainly converted to cropland. (2) The ecosystem service value of the Hexi Corridor increased significantly and demonstrated agglomeration characteristics in space. The highest value areas are mainly distributed in the southern mountain, with higher value and medium areas mainly distributed in the central oasis, and the lowest value areas are mainly located in the northern desert. (3) Socio-economic factors greatly influence the spatial differentiation of ecosystem service values in the Hexi Corridor, with natural environmental factors having less impact. Additionally, the internal interaction of natural environmental factors is the most significant. (4) The Hexi Corridor is divided into three ecological management zones: Ecological function protection zone, ecological and agricultural coordinated development zone, and ecological and urbanization coordinated development zone. This research has important reference value for global ecological management in arid regions.

Relict Plants Are Better Able to Adapt to Climate Change: Evidence from Desert Shrub Communities

Shrubs are the main dominant plants in arid desert systems and play an important role in maintaining the biodiversity, ecosystem services and stability of desert ecosystems. Studies have shown that the survival of a large number of shrub species in desert areas under the influence of climate change is significantly threatened, with different species showing different response strategies. To test the tolerance of different shrub species to climate change, this study selected 10 dominant shrub species (ancient relict shrub species and regional endemic shrub species) in the Alashan desert area as the research object. Based on a field survey of species distribution, a species distribution model was developed to simulate the suitable distribution area of shrub species under current conditions and under future climate change scenarios. The distribution changes of ancient relict and regional endemic shrub species under the climate change scenarios were tested, and the tolerance of the two types of shrub to climate change was analyzed. The results showed that under different climate change scenarios, except for Ammopiptanthus mongolicus, the total suitable area of four out of the five relict plants was relatively stable, the potential distribution area of Tetraena mongolica increased, and the future distribution pattern was basically consistent with the current distribution. However, the suitable area of typical desert plants was unstable under different climate change scenarios. Except for Kalidium foliatum, the suitable distribution areas of four out of the five shrubs showed different degrees of reduction, and the distribution location showed significant migration. Based on the research results, climate change will lead to the reduction and displacement of the distribution area of typical desert shrubs, while relict shrubs will be less affected by climate change. This is because, compared to desert species, relict plants have a longer evolutionary history and have developed a wider range of adaptations after experiencing dramatic environmental changes. This study provides a scientific basis for actively responding to the impacts of climate change on desert ecosystems.

A dataset of energy, water vapor, and carbon exchange observations in oasis–desert areas from 2012 to 2021 in a typical endorheic basin

Abstract. Oases and deserts generally act as a landscape matrix and mosaic in arid and semiarid regions. The significant difference in thermal and dynamic characteristics between an oasis and desert surface will result in oasis–desert interaction. Specifically, this refers to the interaction between an oasis and desert system via the exchange of momentum, energy, water, and carbon, which can lead to a series of microclimate effects that affect the structure of the atmospheric boundary layer, changes in carbon sources and sinks in an oasis, and the local ecological environment. Therefore, studying water, heat, and carbon exchange is significant to achieve the goals of carbon peaking and carbon neutrality in oasis–desert areas and support the ecological security and sustainable development of oases. To monitor energy, water vapor, and carbon exchange between the land surface and atmosphere, a land surface process integrated observatory network was established in the oasis–desert area in the middle and lower reaches of the Heihe River basin, the second largest endorheic basin in China. In this study, we present a suite of observational datasets from artificial and natural oasis–desert systems that consist of long-term energy, water vapor, carbon and methane fluxes as well as auxiliary data involving hydrometeorology, vegetation, and soil parameters from 2012 to 2021. Half-hourly turbulent flux data were acquired by an eddy covariance system and scintillometer. The hydrometeorological data (including radiation, soil heat flux, and soil temperature profiles; gradients of air temperature and humidity and of wind speed and direction; and air pressure, precipitation, and soil moisture profiles) were observed from automatic weather stations with a 10 min average period as well as the groundwater table data. Moreover, vegetation and soil parameters were also supplemented in the datasets. Careful data processing and quality control were implemented during data production, including data collection, processing, archiving, and sharing. The current datasets can be used to explore the water–heat–carbon process and its mechanism of influence; to calibrate and validate related remote-sensing products; to simulate energy, water vapor, and carbon exchange in oasis and desert areas; and to provide references and representatives for other similar artificial and natural oases along the “Silk Road”. The data are available from the National Tibetan Plateau Third Pole Environment: https://doi.org/10.11888/Terre.tpdc.300441 (Liu et al., 2023).

Precipitation pattern changed the content of non-structural carbohydrates components in different organs of Artemisia ordosica

BackgroundNon-structural carbohydrates (NSC) play a significant role in plant growth and defense and are an important component of carbon cycling in desert ecosystems. However, regarding global change scenarios, it remains unclear how NSCs in desert plants respond to changing precipitation patterns. [Methods] Three precipitation levels (natural precipitation, a 30% reduction in precipitation, and a 30% increase in precipitation) and two precipitation intervals levels (5 and 15 d) were simulated to study NSC (soluble sugar and starch) responses in the dominant shrub Artemisia ordosica.ResultsPrecipitation level and interval interact to affect the NSC (both soluble sugar and starch components) content of A. ordosica. The effect of precipitation on NSC content and its components depended on extended precipitation interval. With lower precipitation and extended interval, soluble sugar content in roots increased and starch content decreased, indicating that A. ordosica adapts to external environmental changes by hydrolyzing root starch into soluble sugars. At 5 d interval, lower precipitation increased the NSC content of stems and especially roots.ConclusionsA. ordosica follows the “preferential allocation principle” to preferentially transport NSC to growing organs, which is an adaptive strategy to maintain a healthy physiological metabolism under drought conditions. The findings help understand the adaptation and survival mechanisms of desert vegetation under the changing precipitation patterns and are important in exploring the impact of carbon cycling in desert systems under global environmental change.

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.

Remotely sensed localised primary production anomalies predict the burden and community structure of infection in long-term rodent datasets.

The increasing frequency and cost of zoonotic disease emergence due to global change have led to calls for the primary surveillance of wildlife. This should be facilitated by the ready availability of remotely sensed environmental data, given the importance of the environment in determining infectious disease dynamics. However, there has been little evaluation of the temporal predictiveness of remotely sensed environmental data for infection reservoirs in vertebrate hosts due to a deficit of corresponding high-quality long-term infection datasets. Here we employ two unique decade-spanning datasets for assemblages of infectious agents, including zoonotic agents, in rodents in stable habitats. Such stable habitats are important, as they provide the baseline sets of pathogens for the interactions within degrading habitats that have been identified as hotspots for zoonotic emergence. We focus on the enhanced vegetation index (EVI), a measure of vegetation greening that equates to primary productivity, reasoning that this would modulate infectious agent populations via trophic cascades determining host population density or immunocompetence. We found that EVI, in analyses with data standardised by site, inversely predicted more than one-third of the variation in an index of infectious agent total abundance. Moreover, in bipartite host occupancy networks, weighted network statistics (connectance and modularity) were linked to total abundance and were also predicted by EVI. Infectious agent abundance and, perhaps, community structure are likely to influence infection risk and, in turn, the probability of transboundary emergence. Thus, the present results, which were consistent in disparate forest and desert systems, provide proof-of-principle that within-site fluctuations in satellite-derived greenness indices can furnish useful forecasting that could focus primary surveillance. In relation to the well-documented global greening trend of recent decades, the present results predict declining infection burden in wild vertebrates in stable habitats; but if greening trends were to be reversed, this might magnify the already upwards trend in zoonotic emergence.

The sedimentological characteristics of the intermontane desert system in the Jurong Basin, South China and its relationship with the Late Cretaceous hot climate

As a typical greenhouse period, the Late Cretaceous was characterized by an extremely warm and arid climate. In this period, intermontane deserts were widely distributed in South China, which can be used to inform the evolution of the palaeogeography and palaeo-wind patterns during the hot climate of the Late Cretaceous. The Jurong Basin is located at the eastern margin of South China and close to the palaeo-Pacific Ocean; it has typical aeolian deposits but is hitherto less studied. In this study, four sedimentary facies (aeolian dune, dry/damp/wet interdune, sandsheet, and desert lake facies) and three forms of aeolian dunes (simple, compound, and complex) are identified in the Upper Cretaceous Chishan Formation, confirming the development of an intermontane desert in the Jurong Basin. The dynamic evolution models show that the intermontane desert transitioned from a lacustrine-dominated to an aeolian-dominated system, which indicates a gradual drying trend. We suggest that the development of the Chishan intermontane desert was controlled by the Late Cretaceous greenhouse climate, the accelerated aridification of the subtropical high, and the rainshadow effect of the coastal mountains. Palaeo-wind directions in the Chishan desert show westerlies and possible palaeo-monsoon wind patterns. The input of palaeo-monsoon moisture led to the development of desert lake and damp/wet interdune deposits in the Chishan desert, which indicates that the Jurong Basin might have been on the windward side of the coastal mountains during the Late Cretaceous. Our study extends the eastern boundary of the South China intermontane desert system during the Late Cretaceous.

Groundwater Quality Assessment Using Multi-Criteria GIS Modeling in Drylands: A Case Study at El-Farafra Oasis, Egyptian Western Desert

The most critical issue that was the main research interest is its groundwater quality which is vital for public health concerns. Groundwater is a significant worldwide water supply for diverse communities, especially in dryland regions. Groundwater quality assessment in desert systems is largely hindered by the lack of hydrological data and the remote location of desert Oases. This study provides a preliminary understanding of the influences of climate, land usage, and population growth on the groundwater quality in El-Farafra Oasis in the Western Desert in Egypt from 2000 to now. Therefore, the study’s main objective was to determine the extent of change in temporal water quality and the factors causing it. The present study integrates chemical analyses and geospatial modeling better to assess groundwater quality in the study area. A chemical analysis of thirty-one groundwater samples from wells representing each study area was carried out during three time periods (2000, 2010, and 2022). Several chemical properties of groundwater samples gathered from wells in the research area were analyzed. Furthermore, the groundwater quality trend from 2000 to the present was identified using three approaches: Wilcox and Schoeller Diagram in Aq.QA software, interpolation in the ArcGIS software, and Ground Water Quality Index (GWQI). Moreover, the influence of changing land usage on groundwater quality was studied, and it was found that the increase in agriculture and urbanization areas is linked to groundwater quality degradation. The findings revealed that the barren area in 2000, 2010, and 2022 was 371.7, 362.0, and 343.2 km2, respectively, which indicates a substantial decrease of 6.2% within this research timeframe. In contrast, agriculture and human-made structures have expanded by 1.8%. Also, population growth has led to an increase in water consumption as the population has grown at a rate of 7.52% annually from 2000 to 2020. As the climatic condition increases from 2000 to 2022, these changes could extend to the water quality in shallow aquifers with increasing evaporation. Based on the water quality spatial model, it is found that, despite a declining tendency in the rate of precipitation and an expansion in agricultural areas and population growth, the water quality was still appropriate for human and farming consumption in large areas of the study area. The presented approach is applicable to the assessment of groundwater in desert regions in the Middle East area.

An Introduction to the Ecology of Desert Systems

An Introduction to the Ecology of Desert Systems

Biodiversity of ecosystems in an arid setting: The late Albian plant communities and associated biota from eastern Iberia.

Deserts are stressful environments where the living beings must acquire different strategies to survive due to the water stress conditions. From the late Albian to the early Cenomanian, the northern and eastern parts of Iberia were the location of the desert system represented by deposits assigned to the Utrillas Group, which bear abundant amber with numerous bioinclusions, including diverse arthropods and vertebrate remains. In the Maestrazgo Basin (E Spain), the late Albian to early Cenomanian sedimentary succession represents the most distal part of the desert system (fore-erg) that was characterised by an alternation of aeolian and shallow marine sedimentary environments in the proximity of the Western Tethys palaeo-coast, with rare to frequent dinoflagellate cysts. The terrestrial ecosystems from this area were biodiverse, and comprised plant communities whose fossils are associated with sedimentological indicators of aridity. The palynoflora dominated by wind-transported conifer pollen is interpreted to reflect various types of xerophytic woodlands from the hinterlands and the coastal settings. Therefore, fern and angiosperm communities abundantly grew in wet interdunes and coastal wetlands (temporary to semi-permanent freshwater/salt marshes and water bodies). In addition, the occurrence of low-diversity megafloral assemblages reflects the existence of coastal salt-influenced settings. The palaeobotanical study carried out in this paper which is an integrative work on palynology and palaeobotany, does not only allow the reconstruction of the vegetation that developed in the mid-Cretaceous fore-erg from the eastern Iberia, in addition, provides new biostratigraphic and palaeogeographic data considering the context of angiosperm radiation as well as the biota inferred in the amber-bearing outcrops of San Just, Arroyo de la Pascueta and La Hoya (within Cortes de Arenoso succesion). Importantly, the studied assemblages include Afropollis, Dichastopollenites, Cretacaeiporites together with pollen produced by Ephedraceae (known for its tolerance to arid conditions). The presence of these pollen grains, typical for northern Gondwana, associates the Iberian ecosystems with those characterising the mentioned region.

Lake dynamics in an Early Jurassic desert: Evidence from the Clarens Formation in southern Africa

ABSTRACTInterdune deposits are sensitive to climatic fluctuations and ancient interdune lacustrine systems can reveal the drivers of erg dynamics through time and space. This southern African study details the dynamics of interdune deposition in a vast ancient desert system that was active over Pangaea in the Middle Mesozoic and formed part of one of the largest known sand seas in Earth's history. Focusing on the Sinemurian to Pliensbachian Clarens Formation in the main Karoo Basin (south‐west Gondwana), three facies associations were identified that formed in meso‐scale and macro‐scale lakes amongst aeolian dunes and sand sheets of the Clarens erg system. The northern facies association is restricted to interdune hollows within an actively climbing dune system. High‐sediment availability and high‐wind speeds limited the space available for these meso‐scale lakes to expand. Here, migrating dunes outpaced the water table rise promoting the formation of discontinuous lenses of lake deposits, as is typical in erg centres. The southern facies associations developed both in spatially isolated meso‐scale lakes, where flooding was controlled by groundwater inundation (water table rise), as well as in macro‐scale lakes, where flooding was related to groundwater inundation and floods (surface runoff) that induced terminal splays. Relative to the north, the southern facies associations, with their more significant thickness and lateral extent, show that, here, the basin was characterized by a higher rate of relative subsidence. Moreover, the southern lake systems were established along the erg's margin, where the interdunes expanded during pluvial phases. Ultimately, the facies associations in the Clarens Formation show that the widespread arid conditions in the Early Jurassic of south‐west Gondwana were subjected to prolonged and repeated pluvial phases in an otherwise harsh environment. Given the prominence of Jurassic aeolianites across Pangea, this study provides a southern African perspective on global palaeo‐erg dynamics and Early Jurassic climatic shifts.

Plateau archives of lithosphere dynamics, cryosphere and paleoclimate: The formation of Cretaceous desert basins in east Asia

Southeastern Eurasia is a global window to the Cretaceous paleoclimate and lithosphere coupling. China contains one of the most complete and complex sedimentary records of Mesozoic desert basins on planet Earth. In this study, we perform the spatio-temporal tracking of 96 Cretaceous palaeoclimate indicators during 79 Myr which reveal that the plateau paleoclimate archives from East Asia resulted from an Early to Mid-Cretaceous ocean–atmosphere coupling and a shift to a preponderant role of Late Cretaceous lithosphere dynamics and tectonic forcing on high-altitude depositional systems linked to the subduction margins of the Tethys and Paleo-Pacific realms beneath the Eurasian plate. The crustal response to tectonic processes linked with the spatio-temporal evolution of the Tethyan and Paleo-Pacific margins defined the configuration of major sedimentary basins on this region. The significant increase and decrease in the number of active sedimentary basins that occur during the Cretaceous, from 16 in the Early Cretaceous, to 28 in the Mid-Cretaceous, and a decreasing to 20 sedimentary basins in the Late Cretaceous, is a direct response of lithospheric dynamics associated with the two main subduction zones (Tethys and Pacific domains). A shift in subduction style from an Early Cretaceous Paleo-Pacific Plate slab roll back to a Late Cretaceous flat-slab mode might have triggered regional plateau uplift, blocked intraplate volcanism, thus enhancing the denudation and sediment availability, and created wind corridors that led to the construction and accumulation of extensive Late Cretaceous aeolian sandy deserts (ergs) that covered Mid-Cretaceous plateau salars. At the same time, plateau uplift associated with crustal thickening following terrane assembly in the Tethyan margin triggered altitudinal cryospheric processes in sandy desert systems. Evidence of an active Cretaceous cryosphere in China include Valanginian-Hauterivian glacial debris flows, Early Aptian geochemical signature of melt waters from extensive ice sheets, and Cenomanian–Turonian ice-rafted debris (IRD). These cryospheric indicators suggest an already uplifted plateau in southeastern Eurasia during the Cretaceous, and the marked correlation between cold plateau paleoclimate archives and marine records suggests a strong ocean-atmosphere coupling during Early and Mid-Cretaceous cold snaps. We thus conclude that lithospheric tectonics during Cretaceous played a fundamental role in triggering high-altitude basin desertification and spatio-temporal plateau paleohydrology variability in the Cretaceous of south-eastern Eurasia.

Contributions of Solar Photovoltaic Systems to Environmental and Socioeconomic Aspects of National Development—A Review

Presently, the world is undergoing exciting haste to install photovoltaic (PV) systems in industry, residential/commercial buildings, transportation, deserts, street lights, and many other applications. Solar photovoltaic energy systems are clean and reliable energy sources that are unlimited, unlike their fossil fuel counterparts. The energy market is rapidly growing globally with newly and cumulative installed capacities of about 37.6 GW and 139.6 GW, accounting for 53% and 55%, respectively, in 2017, making it one of the fastest-growing industries. The cumulative photovoltaic installations are projected to have reached 600 GW worldwide and are projected to reach 4500 GW by 2050 because of the strategies and policies of many countries. In 2021, more than three-quarters of the developed countries are now home to one solar installation. This article evaluates a critical and extensive review of the contributions of solar photovoltaic systems to national development. The approach follows all steps, starting with capturing photovoltaics on the Earth’s surface, then price reduction, load management, and socioeconomic impact of solar photovoltaic systems. From the study, it is found that the policies and strategies adopted by the leading countries, such as tax credits, capital subsidies, net-metering, VAT reduction, feed-in tariffs (FiTs), and renewable portfolio standards (RPS), have significantly helped in more installations. Additionally, the significant drop in photovoltaic module prices from 4731 $/W in 2010 to 883 $/W in 2020 has boosted the move for more installations. Based on the findings, approximately 10 million permanent employments would be put in place by advancing solar power across the globe annually.

Range expansion and contraction of Tillandsia landbeckii lomas in the hyperarid Chilean Atacama Desert indicates ancient introgression and geneflow

Among the fascinating and highly specialized vascular plants in the hyperarid core of the Chilean and Peruvian Atacama Desert there are few Tillandsia species from the bromeliad family (Bromeliaceae). These grow epiarenically on bare sand without a functional root system, and in some rare cases they build up a monospecific and often the only landscape characterizing vegetation type, which is called Tillandsiales or Tillandsia loma. Tillandsia landbeckii is the dominating epiarenic species in Chile totally dependent on fog serving as the only water resource. Herein we elaborate on the hypothesis that migration and multiple colonization in concert with putative introgression from other Tillandsia species build up the present day phylogeographic distribution pattern and may contribute to the evolutionary dynamics and long-term success in hyperarid desert systems. Genomic analyses using GBS (genotyping-by-sequencing) data from the nuclear and plastid genome were conducted at the population level. A genome skimming approach was used to generate reference plastome data. The results indicate that both, multiple colonization and secondary contact of old gene pools and interspecies geneflow, contribute to present-day population genetic structure. Local-scale analysis also indicates that these past footprints of evolutionary history do contribute to present-day local adaptive potential of the species.

Water inputs across the Namib Desert: implications for dryland edaphic microbiology

Microbes have a dominant role in nutrient cycling processes in the world’s deserts, where growth and activity are limited by the availability of water. In order to understand the dynamics of water availability in a desert system and how it may affect the soil microbiome, we analysed soil temperature and relative humidity fluctuations recorded between April 2018 and April 2020 across a precipitation gradient in the Namib Desert and compared them with recorded data from satellites and nearby weather stations. This allowed us to assess the possible impact of fog and rain events in terms of biologically-available water. Using published literature on the water activity limits for various physiological processes in microorganisms, we were able to infer the annual ‘metabolic windows’ for desert microbial communities across the longitudinal precipitation gradient. Specifically, soil surface microbial communities were estimated to have the capacity for active growth for an average of 184- 363 hours per year with the duration heavily dependent on intermittent rainfall events. During the relatively wet period of April 2018 - March 2019, the maximum growth window was found in the hyper-arid central region of the transect (approximately 100 km from the coast). During the dryer 2019- 2020 period, there was almost no predicted growth capacity in the hyper-arid region but substantial metabolic windows both near the coast and for the eastern inland areas, where water input comes in the form of fog and moist coastal air, and higher rainfall, respectively. As the first detailed study of the temperature and relative humidity characteristics of Namib Desert near-surface soils, this study provides valuable insights into the biogeography of microbial communities. In addition, the estimates for organismal functionality calculated in this study offer a baseline for future quantitation of the impacts of climate change on the functional capacity of desert soil microbiomes.

Shaping effects of sand flow channels on aeolian geomorphology – a case study of the Badain Jaran, Tengger, and Ulan Buh Deserts, northern China

Based on the interactions between mountains, we identified three sand flow channels in the Badain Jaran, Tengger, and Ulan Buh Deserts, northern China. We found that the height difference of the terrain in these areas provided favorable conditions for the transportation of sand. Owing to the venturi effect of their geomorphologies, airflow was compressed in these channels, and their wind regimes were strong and unimodal. Compared with the interior of the desert, the sand transport potential was relatively large in these areas, and westerly and northwest winds prevailed. We found that the wind accelerated in the sand flow channels, resulting in faster-moving dunes. The dune types that developed in these channels were relatively simple owing to the unimodal wind regimes; they mainly comprised barchan and transverse dunes. We also identified a transition landscape from barchan dunes to transverse, or complex dunes. Based on their sediment characteristics and the prevailing wind directions, we found that the sand flow channels provided a direct sand supply between the three deserts. The sand flow channels connected these independent deserts to an entire desert system. Similar sand flow channels can also be found in other deserts globally. Collectively, these sand flow channels reflect interactions between deserts.

Biochar Addition Alters C: N: P Stoichiometry in Moss Crust-Soil Continuum in Gurbantünggüt Desert.

The biogeochemical cycling of soil elements in ecosystems has changed under global changes, including nutrients essential for plant growth. The application of biochar can improve the utilization of soil nutrients by plants and change the stoichiometry of carbon (C), nitrogen (N), and phosphorus (P) in plants and soil. However, the response of ecological stoichiometry in a moss crust-soil continuum to local plant biochar addition in a desert ecosystem has not been comprehensively explored. Here, we conducted a four-level Seriphidium terrae-albae biochar addition experiment (CK, 0 t ha−1; T1, 3.185 t ha−1; T2, 6.37 t ha−1; T3, 12.74 t ha−1) to elucidate the influence of biochar input on C: N: P stoichiometry in moss crusts (surface) and their underlying soil (subsurface). The results showed that biochar addition significantly affected the C, N, and P both of moss crusts and their underlying soil (p < 0.001). Biochar addition increased soil C, N, and P concentrations, and the soil N content showed a monthly trend in T3. The C, N, and P concentrations of moss crusts increased with the addition levels of biochar, and the moss crust P concentrations showed an overall increasing trend by the month. Moreover, the soil and moss crust C: P and N: P ratios both increased. There was a significant correlation between moss crust C, N, and P and soil C and N. Additionally, nitrate nitrogen (NO3−N), N: P, C: P, EC, pH, soil moisture content (SMC), and N have significant effects on the C, N, and P of moss crusts in turn. This study revealed the contribution of biochar to the nutrient cycle of desert system plants and their underlying soil from the perspective of stoichiometric characteristics, which is a supplement to the theory of plant soil nutrition in desert ecosystems.

Movement Patterns of Resident and Translocated Beavers at Multiple Spatiotemporal Scales in Desert Rivers

Wildlife translocations alter animal movement behavior, so identifying common movement patterns post-translocation will help set expectations about animal behavior in subsequent efforts. American and Eurasian beavers (Castor canadensis; Castor fiber) are frequently translocated for reintroductions, to mitigate human-wildlife conflict, and as an ecosystem restoration tool. However, little is known about movement behavior of translocated beavers post-release, especially in desert rivers with patchy and dynamic resources. We identified space-use patterns of beaver movement behavior after translocation. We translocated and monitored nuisance American beavers in desert river restoration sites on the Price and San Rafael Rivers, Utah, USA, and compared their space use to resident beavers after tracking both across 2 years. Resident adult (RA) beavers were detected at a mean maximum distance of 0.86 ± 0.21 river kilometers (km; ±1 SE), while resident subadult (RS) (11.00 ± 4.24 km), translocated adult (TA) (19.69 ± 3.76 km), and translocated subadult (TS) (21.09 ± 5.54 km) beavers were detected at substantially greater maximum distances. Based on coarse-scale movement models, translocated and RS beavers moved substantially farther from release sites and faster than RA beavers up to 6 months post-release. In contrast, fine-scale movement models using 5-min location intervals showed similar median distance traveled between RA and translocated beavers. Our findings suggest day-to-day activities, such as foraging and resting, were largely unaltered by translocation, but translocated beavers exhibited coarse-scale movement behavior most similar to dispersal by RSs. Coarse-scale movement rates decreased with time since release, suggesting that translocated beavers adjusted to the novel environment over time and eventually settled into a home range similar to RA beavers. Understanding translocated beaver movement behavior in response to a novel desert system can help future beaver-assisted restoration efforts to identify appropriate release sites and strategies.

Abstract WP55: Stroke Center Accessibility Study In The U.s. Using Geospatial Analysis And Machine Learning

Background: Several accrediting bodies certify the level of stroke care hospitals provide. The Joint Commission on Hospital Accreditation (JC) is the largest accrediting body in the United States. There is no open source Geographic Information Systems (GIS) dataset showing the distribution of JC accredited centers by ZIP code. Objective: to create a stroke center accessibility and stroke center desert system using geospatial analysis and machine learning which provides real-time assessment of stroke center availability, distribution and access to care. Method: Geospatial data layers of JC accredited stroke centers were compiled using data sources including U.S. Census Bureau and CDC. Map layers corresponding to the levels of JC accredited stroke hospitals geolocated using ZIP code were created as follows: 1) Acute Stroke Ready 2) Primary 3) Thrombectomy Capable 4) Comprehensive Stroke Center. A GIS dataset displaying stroke mortality by region was obtained from the ArcGIS Living Atlas. Stroke center deserts are analyzed using a 4.5 hour drive map along with population and diversity. Machine learning models were implemented to estimate stroke mortality as a function of distance to care centers and capability levels of the stroke centers. Results: Stroke centers are highly concentrated within large urban centers. There are geographic regions that have poor access to stroke centers. Such regions include the Gulf Coast States of Louisiana, Mississippi, and Alabama that have large areas with poor stroke center acces while having some of the highest stroke mortality in the country. (Figure 1) Conclusion: There are regional variations in stroke center availability. There are certain regions with high stroke mortality with very little stroke center access. Geospatial AI tools can be utilized to improve stroke systems of care.