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Soil desertification poses a critical ecological challenge in arid and semiarid climates worldwide, leading to decreased soil productivity due to the disruption of essential microbial community processes. Fungi, as one of the most important soil microbial communities, play a crucial role in enhancing nutrient and water uptake by plants through mycorrhizal associations. However, the impact of overgrazing-induced desertification on fungal community structure, particularly in the Caatinga biome of semiarid regions, remains unclear. In this study, we assessed the changes in both the total fungal community and the arbuscular mycorrhizal fungal community (AMF) across 1. Natural vegetation (native), 2. Grazing exclusion (20 years) (restored), and 3. affected by overgrazing-induced degradation (degraded) scenarios. Our assessment, conducted during both the dry and rainy seasons in Irauçuba, Ceará, utilized Internal Transcribed Spacer (ITS) gene sequencing via Illumina® platform. Our findings highlighted the significant roles of the AMF families Glomeraceae (∼71% of the total sequences) and Acaulosporaceae (∼14% of the total sequences) as potential key taxa in mitigating climate change within dryland areas. Moreover, we identified the orders Pleosporales (∼35% of the total sequences) and Capnodiales (∼21% of the total sequences) as the most abundant soil fungal communities in the Caatinga biome. The structure of the total fungal community differed when comparing native and restored areas to degraded areas. Total fungal communities from native and restored areas clustered together, suggesting that grazing exclusion has the potential to improve soil properties and recover fungal community structure amid global climate change challenges.

Introduction: Mapping soil organic carbon (SOC) with high precision is useful for controlling soil fertility and comprehending the global carbon cycle. Low-relief locations are characterized by minimal variability in traditional soil-forming elements, such as terrain and climatic conditions, which make it difficult to reflect the spatial variation of soil properties. In the meantime, vegetation cover makes it more difficult to obtain direct knowledge about agricultural soil. Crop growth and biomass are reflected by the normalized difference vegetation index (NDVI), a significant indicator. Rather than using conventional soil-forming variables. Methods: In this study, a novel model for predicting SOC was developed using Landsat-8 Operational Land Imager (OLI) band data (Blue (B), Green (G), Red (R), and Near Infrared (NIR), NDVI data as the supporting variables, and Artificial Neural Networks (ANNs). A total of 120 surface soil samples were collected at a depth of 25 cm in the northeastern Nile Delta near Damietta City. Of these, 80% (96 samples) were randomly selected for model training, while the remaining 24 samples were used for testing and validation. Additionally, Gaussian Process Regression (GPR) models were trained to estimate SOC levels using the Matern 5/ 2 kernel within the Regression Learner framework. Results and discussion: The results demonstrate that both the ANN with a multilayer feedforward network and the GPR model offer effective frameworks for SOC prediction. The ANN achieved an R² value of 0.84, while the GPR model with the Matern 5/2 kernel achieved a higher R² value of 0.89. These findings, supported by visual and statistical evaluations through crossvalidation, confirm the reliability and accuracy of the models. Conclusion: The systematic application of GPR within the Regression Learner framework provides a robust tool for SOC prediction, contributing to sustainable soil management and agricultural practices. [ABSTRACT FROM AUTHOR]

Fog is an important water source that alleviates vegetation water stress, especially for dryland ecosystems. Comprehensive knowledge of fog and rainfall effects can help us better understand dryland vegetation responses to current and future climates. However, the differences between fog and rainfall effects on vegetation are poorly understood. This study compared the effects of fog and rainfall on vegetation greenness changes based on the ground‐level meteorological observations in the Namib Desert and the satellite vegetation index. The vegetation index and its first derivative were utilized to indicate vegetation greenness and its change rate, respectively. Results showed that fog played a more significant role than rainfall in explaining vegetation greenness change rates, while accumulated rainfall was more important than fog in determining vegetation greenness. Soil temperature was an important factor in explaining vegetation greenness changes. These findings offer key insights into how fog and rainfall differentially contribute to vegetation greenness changes. Plain Language Summary: Dryland plant significantly impacts the global carbon budget, making up about 40% of global net primary productivity. The importance of fog on dryland productivity is highlighted since plant growth in dry areas is strongly constrained by water resources. This study showed that fog consistently appeared among the top five most critical factors in explaining variations in plant greenness and its change rates for both herbaceous and woody areas. Notably, it was found that plant greenness change rates were more influenced by fog than rainfall, although plant greenness was more sensitive to accumulated rainfall than fog. Soil temperature consistently showed large effects on plant greenness changes, potentially limiting plant growth in the context of future global warming. Key Points: The first study to simultaneously quantify the effects of fog and rainfall on vegetation greenness changes in a dryland ecosystemFog was more important than rainfall in explaining vegetation greenness change ratesSoil temperature played an important role in vegetation greenness changes with a negative effect [ABSTRACT FROM AUTHOR]

Drylands are susceptible to erosion by wind and water. Thus, the reestablishment of vegetation is a crucial focus of watershed restoration in order to stabilize soils and improve water infiltration. Currently, limited research exists quantifying vegetation responses to rock detention structures (RDS) in the Chihuahuan Desert, and no studies have quantified the effects of RDS paired with seed introduction. Our study area in the Rincon Arroyo Watershed, in southern New Mexico, tested the hypotheses that two types of RDS, micro‐catchments and stone‐lines paired with seeding, support increases in seedling recruitment and vegetation cover compared to untreated controls. This study also tested whether the application of seed to RDS alters plant communities in comparison to controls. One season after seeded RDS were applied, seedling recruitment, cover, and plant community responses were evaluated at treatment and control areas. Seeded stone‐lines showed significantly greater seedling recruitment (2×) and cover (0.3×) than controls (p < 0.05), whereas seeded micro‐catchments showed significantly greater cover (0.3×) than controls (p < 0.05) but did not exhibit significant differences in seedling recruitment compared to controls (p > 0.05). The lack of a significant difference between plant communities at treatment and control areas (p > 0.05) suggests that the addition of seed had little to no effect on plant communities or positive responses in seedling recruitment and cover. These results suggest that stone‐lines and micro‐catchments, alone, can support vegetation establishment in degraded dryland watersheds without the addition of seed. [ABSTRACT FROM AUTHOR]

This study provides a comprehensive overview of Phase I of the deforestation dryland alert system. It focuses on its operation and outcomes from 2020 to 2022 in the Caatinga biome, a unique Brazilian dryland ecosystem. The primary objectives were to analyze deforestation dynamics, identify areas with highest deforestation rates, and determine regions that require prioritization for anti-deforestation efforts and conservation actions. The research methodology involved utilizing remote sensing data, including Landsat imagery, processed through the Google Earth Engine platform. The data were analyzed using spectral unmixing, adjusted Normalized Difference Fraction Index, and harmonic time series models to generate monthly deforestation alerts. The findings reveal a significant increase in deforestation alerts and deforested areas over the study period, with a 148% rise in alerts from 2020 to 2022. The Caatinga biome was identified as the second highest in detected deforestation alerts in Brazil in 2022, accounting for 18.4% of total alerts. Hexagonal assessments illustrate diverse vegetation cover and alert distribution, enabling targeted conservation efforts. The Bivariate Choropleth Map demonstrates the nuanced relationship between alert and vegetation cover, guiding prioritization for deforestation control and native vegetation restoration. The analysis also highlighted the spatial heterogeneity of deforestation, with most deforestation events occurring in small patches, averaging 10.9 ha. The study concludes that while the dryland alert system (SAD-Caatinga—Phase I) has effectively detected deforestation, ongoing challenges such as cloud cover, seasonality, and more frequent and precise monitoring persist. The implementation of DDAS plays a critical role in sustainable forestry by enabling the prompt detection of deforestation, which supports targeted interventions, helps contain the process, and provides decision makers with early insights to distinguish between legal and illegal practices. These capabilities inform decision-making processes and promote sustainable forest management in dryland ecosystems. Future improvements, including using higher-resolution imagery and artificial intelligence for validation, are essential to detect smaller deforestation alerts, reduce manual efforts, and support sustainable dryland management in the Caatinga biome. [ABSTRACT FROM AUTHOR]

This article explores the recent history of early warning systems in Kenya, determining key features of the entangled political, technical and conceptual processes that prefigure contemporary drought management there. In doing so, it draws out wider implications regarding drought and anticipatory action across Africa's drylands, considering the friction between the dynamics of disaster risk management that structure formal early warning systems and those that shape pastoralist engagements with the volatile and uncertain worlds they inhabit. Surveying recent literature on pastoralism's unique relationship with uncertainty, and associated forms of networked, relational resilience, it reflects on some of the inherent limitations of current approaches to "local knowledge" in the humanitarian sphere. In doing so, it emphasises the need for new, creative approaches to early warning and anticipatory action, which are not merely established via the external synthesis of data but are rather oriented around local pastoralist drought preparation and mitigation strategies and comprise enough flexibility to adapt to a fast-shifting terrain of challenges and possibilities. [ABSTRACT FROM AUTHOR]

Zones of alluviation at tributary – trunk confluences can act as sediment storage/transfer switches. Evaluating the temporal variation in tributary – trunk connectivity is key to understanding the origin, dynamics and residence time of tributary alluvial fill sequences, and determining relative and interacting effects of different drivers of landscape development. This paper evaluates processes and timescales of tributary (Prins River) – trunk (Touws River) connectivity at a site in the Little Karoo, as context for discussing sediment dispersal dynamics and implications for interpreting the landscape response to environmental change. An alluvial terrace in the tributary valley preserves a chronology (optically stimulated luminescence) of tributary valley alluviation that is regionally synchronous with valley alluviation in the upper Huis River and floodplain alluviation in the lower Touws and Groot rivers. A climatic shift within the Little Karoo at ~1000 years BP from relative aridity to relative humidity (and higher-energy rain-bearing circulation types) may have initiated widespread re-working of alluvial fills and the breaching of geomorphological buffers. Alternatively, there may be an intrinsic limit to sediment preservation potential associated with a regional floodplain cycling time of one to two thousand years. Longer archives are needed to contextualize fluvial responses to climatic variability in the region. [ABSTRACT FROM AUTHOR]

Due to the considerable uncertainties inherent in the datasets describing the spatiotemporal distributions of precipitation in the drylands of China, this study presents a new merged monthly precipitation product with a spatial resolution of approximately 0.2° × 0.2° during 1980–2019. The newly developed precipitation product was validated at different temporal scales (e.g., monthly, seasonally, and annually). The results show that the new product consistently aligns with the spatiotemporal distributions reported by the Chinese Meteorological Administration Land Data Assimilation System (CLDAS) product and Multi-Source Weighted Ensemble Precipitation (MSWEP). The merged product exhibits exceptional quality in describing the drylands of China, with a bias of −2.19 mm month−1 relative to MSWEP. In addition, the annual trend of the merged product (0.09 mm month−1 yr−1) also closely aligns with that of the MSWEP (0.11 mm month−1 yr−1) during 1980–2019. The increasing trend indicates that the water cycle and wetting process intensified in the drylands of China during this period. In particular, there was an increase in wetting during the period from 2001–2019. Generally, the merged product exhibits potential value for improving our understanding of the climate and water cycle in the drylands of China. [ABSTRACT FROM AUTHOR]

Heatwaves represent a significant and growing threat to natural ecosystems and socio‐economic structures, making heatwave risk mitigation and prevention an important area of research. In exploring heatwave frequency and intensity from 1901 to 2020, the present study finds a sharp increase in both. The study also finds that the spatial distribution of heatwaves is unequal, the volatility of intensity characteristics has become more prominent over time, and the Gini coefficients of four key heatwave indictors have become larger due to increasing dryness. Although heatwaves occur more frequently in drylands, there is greater cumulative heat in humid areas, resulting in a higher heatwave risk in those areas. The global heatwave risk over the past three decades (1991–2020) has increased nearly five‐fold compared to the early 20th century (1901–1930). Furthermore, GeoDetector analysis indicates that the Palmer drought severity index (PDSI) and downward surface shortwave radiation (Srad) contributing the most in drylands and humid areas (0.29 and 0.41, respectively). The contribution of relative humidity (RH), wind speed (WS), soil moisture (SM), and the normalized difference vegetation index (NDVI) is also significant in humid areas, but is much smaller in drylands. Composite analysis shows that the years with anomalously high heatwave risk correspond to positive anomalies of 500hPa geopotential height and surface pressure. The inhibition of cloud formation due to sinking air and the resulting increase in temperature in the atmosphere may be increasing the risk of heatwave occurrence. This study emphasizes the urgent need to address worsening climate change impacts. Plain Language Summary: Heatwaves are high‐impact extreme events, and their monitoring, risk assessment, and countermeasure development are critically important. This study focuses on the evolution of heatwaves, including their risk assessment and driving mechanisms, based on Gini coefficients, GeoDetector, and composite analysis. It is found that heatwaves have become more frequent and intense over the past 120 years (1901–2020), and their occurrence rate has increased five‐fold. After 1980, heatwave characteristics (frequency, intensity, duration, and severity) increased in volatility and their spatial distribution showed an increase in inequality. Interestingly, while drylands experience more heatwaves, humid areas accumulate more heat, leading to a higher risk of heatwaves in humid areas. In fact, the intensity of heatwave risk is 7.7% higher in humid areas than in drylands, with factors such as relative humidity, wind speed, soil moisture, and the normalized difference vegetation index contributing more in humid areas than in drylands. The study also relates these changes to atmospheric circulation, which is typically characterized by higher upper atmospheric pressure and surface pressure, leading to reduced cloud formation and higher temperatures. Our study of heatwave risk highlights the increasing impacts of climate change and the need for urgent action, especially in humid areas. Key Points: Heatwaves are more frequent in drylands, but cumulative heat is greater in humid areasHeatwave risk has quintupled over one century and is higher in humid areas than in drylandsHigh heatwave risk is usually accompanied by anticyclonic anomalies [ABSTRACT FROM AUTHOR]

As a key region supplementing China's limited croplands, Northwest China has undergone rapid cropland expansion over the past decades to satisfy rising food demand from population growth and socio‐economic development. Although cropland expansion may overconsume local water resources in general, in Northwest China, increased precipitation and enhanced glacier melt have increased the water available for croplands. Counterintuitively, the enhanced evapotranspiration (ET) resulting from this cropland expansion could benefit remote ecologically vulnerable natural vegetation through atmospheric moisture recycling. In this study, we used a moisture tracking model to quantify contributions of croplands and cropland expansion to local precipitation and the consequent precipitation supply to natural vegetation in Northwest China. We found that the croplands contributed 27.69 billion m3/year (2.13%) of regional total precipitation and supplied 17.30 billion m3/year (2.39%) of precipitation over natural vegetation, and the cropland expansion resulted in a net increase of 80.25 million m3/year (1.07% of the total increase) in regional precipitation and 36.23 million m3/year (4.56% of the total increase) in precipitation supply for natural vegetation. Among different types of natural vegetation, grasslands received the most precipitation supply due to its vast area, followed by forests and shrublands. The more arid regions experienced not only faster rates of cropland expansion but also obtained a greater increase in regional precipitation and precipitation supply to natural vegetation. Our study quantifies the ecological impacts of cropland expansion through moisture recycling in Northwest China. This shows the complexities of water competition between agricultural development and ecological conservation in drylands and elsewhere. Plain Language Summary: As an important agricultural region, Northwest China has undergone rapid cropland expansion over the past decades to satisfy rising food demand from population growth. While necessary for feeding the population, this expansion has led to environmental concerns like soil degradation and increased irrigation needs. However, our study introduces a new perspective on this issue. We focused on how the expanded croplands affect atmospheric moisture recycling—a process where water evaporates from the land and returns as rainfall. This cycle is vital for ecosystems, crop production, and water security. The expansion of croplands, especially in dry areas like Northwest China, has intensified this cycle. It increases evapotranspiration, which is then returned as increased rainfall, helping local vegetation. Our findings highlight the complex balance between agricultural expansion and environmental sustainability, showing that while cropland growth poses challenges, it also contributes in some ways to the local hydrological cycle, helping to mitigate some of the environmental impacts in this ecologically fragile region. Key Points: A novel method for quantifying the precipitation contributions from croplands and cropland‐expansionWater resources consumed by croplands can contribute to precipitation over distant natural vegetation through moisture transportInvestigating the complexities of water competition between agricultural development and ecological conservation [ABSTRACT FROM AUTHOR]

Plant respiration and photosynthesis are the two main processes influencing carbon (C) flux balance at leaf‐to‐ecosystem scales. The ratio of respiration to photosynthesis (R:A) or carbon use efficiency (CUE) is considered an important trait for determining global carbon storage in the near future. One school of thought assumes that R:A is constant in terrestrial productivity models, irrespective of biomass, climate, and species. Others believe it is variable, although within a limited range. Semiarid systems dominated by woody vegetation, such as sagebrush steppe, have been recognized as potentially important C sinks on regional to global scales in the context of future climate scenarios. Therefore, there is a critical need to study R:A over different organizational scales (i.e., at the leaf, whole plant, and ecosystem scales) to use this approach for future C flux predictions under climate change scenarios. The objective of this study was to compare leaf‐, shrub‐, and ecosystem‐scale R:A among three sagebrush (Artemisia spp.) communities, and to determine how R:A varies throughout the growing season (i.e., early, mid‐, and late summer) among these communities. We measured photosynthesis and respiration monthly in three sagebrush communities spanning a 685‐m elevation gradient at the Reynolds Creek Experimental Watershed and Critical Zone Observatory in southwestern Idaho. Consistent with our expectations, we found large seasonal variations in R and A at all scales, but with differences in A among the three sagebrush communities significant only at the leaf scale. The R:A ratio was not significantly different among the three species at all organizational scales. However, the R:A ratio did vary among months at the leaf level and there was a statistical interaction between species and month at both leaf and shrub levels. Our study indicates that the R:A ratio is generally conservative, although not tightly constrained (range: 0.12–0.77) among three sagebrush species. Therefore, approaches that assume conservative R:A ratios in terrestrial productivity models need to be considered carefully to evaluate the impact of projected climatic changes on future C cycling in shrub‐dominated rangeland ecosystems. [ABSTRACT FROM AUTHOR]

Land surface phenology (LSP) is useful to understand patterns of terrestrial ecosystems. Detecting LSP in drylands is more challenging when compared to agricultural and mesic environments due to vegetation heterogeneity, the presence of evergreen and seasonal species, and the dominant role of water (which is often received episodically with variable timing) in determining vegetation growth. In this study, LiDAR‐derived vegetation classes are defined to guide and improve the interpretation of LSP metrics extracted using temporally decomposed Landsat fPAR time series. This method was applied to waterholes within the Cooper Creek floodplain, in dryland Australia, which are important for ecological conservation. Results showed that phenology is mostly associated with the recurrent vegetation (approximately 80% of all identified phenological events) in all waterholes. However, during high streamflow periods, the number of phenological events associated with the persistent vegetation greatly increased (up to 40% of the identified events). Non‐annual phenology was also identified, with more than one phenological event occurring across a water year during high streamflow periods. The duration of the phenological events of the persistent vegetation exceeded one water year during periods of high streamflow. Phenological differences of the LiDAR‐derived vegetation classes occupying the riparian zone of the waterholes were also identified. Streamflow movement across the floodplain exerts an important influence on the vegetation phenology, as suggested by a lag in the phenology when comparing southern and northern waterholes. The method developed herein can be applied to other highly spatially heterogeneous ecosystems where vegetation species simultaneously present permanent and seasonal patterns. Plain Language Summary: Knowing the vegetation life cycle is useful to understand terrestrial ecosystems. However, understanding these cycles in drylands is more complex when compared to agricultural and mesic environments due to heterogeneity and presence of evergreen and seasonal vegetation. In this study, vegetation structure is characterized to guide and improve the interpretation of the vegetation cycles identified using the temporally decomposed time series of a vegetation index. This method was applied at the Cooper Creek floodplain, in dryland Australia. Results showed vegetation cycles are mostly associated with the seasonal vegetation (approximately 80% of all identified cycles). However, during high streamflow periods, the number of cycles associated with the evergreen vegetation greatly increased (up to 40% of the identified events). Multiple cycles were also identified within one water year during high streamflow periods. The duration of the cycles of the evergreen vegetation exceeded one water year during periods of high streamflow. Differences on the life cycle of the different vegetation types were also identified. Streamflow exerts an important influence on the vegetation life cycles by creating a north‐to‐south gradient. The method developed herein can be applied to other highly spatially heterogeneous ecosystems where vegetation species simultaneously present permanent and seasonal patterns. Key Points: Vegetation phenology in riparian zones of waterholes in central Australia is studied by integrating LiDAR data and Landsat time seriesLiDAR‐derived vegetation classes assisted in interpreting temporally decomposed Landsat fPAR time series providing ecohydrological insightsReflective satellite mixed pixel problem commonly found in drylands was addressed by extracting the phenology of each vegetation component [ABSTRACT FROM AUTHOR]

We studied the causal link between forage condition and food security in northern Kenya and southern Ethiopia and probed the mechanisms through which the effects occur. The study utilized weekly panel survey data collected over a period of 94 weeks (March 2021–December 2022) from drought-prone pastoral regions and estimated two-stage least squares instrumental variables regression to assess causal impacts. We found that an increase in the normalized difference vegetation index (NDVI) – our proxy for forage condition – by 10% significantly reduced the likelihood of a household experiencing food insecurity by 12 percentage points. The main mechanisms through which improved forage condition increased food security were livestock productivity enhancement, reduced prices of basic food commodities (cereals, legumes, and vegetables), and utilization of better coping strategies by households. These findings suggest the need for interventions and initiatives aimed at boosting livestock productivity and reducing vulnerability to drought-induced poor forage conditions. Efforts focused on the monitoring of forage conditions and supporting market development for livestock feed are important for addressing the adverse impacts of drought and deteriorating forage conditions in the horn of Africa. Furthermore, the monitoring of drought conditions and shocks using high-frequency data has the potential for providing early warning and informing anticipatory action. [ABSTRACT FROM AUTHOR]

Key message: We have identified poplar clones suitable for dryland forestry, which stand out for their resistance to cavitation, level of anisohydrism, adjustment of cellular water relations and high water use efficiency. In drylands, such as the arid western region of Argentina, poplar afforestation depends on intermittent furrow irrigation, subjecting the plantations to variable water availability both in time and space. Our objective was to study stem biomass production and drought resistance responses of eight poplar clones, to explore whether there are more suitable varieties for forestry in drylands than those currently cultivated, i.e. the hybrid Populus × canadensis clones 'Conti' 12 and 'Guardi'. We conducted a pot experiment with three levels of water availability (control, moderate stress and severe stress), studying four clones of P. × canadensis, 'Conti 12', 'Guardi', 'I-214' and 'I45/51', as well as four clones of the Populus deltoides species, 'Stoneville 67', 'Catfish 2', 'Dvina' and 'Australiano 129/60'. We found that the clones that were more productive under water stress, 'I-214' and 'I45/51', were also the most resistant to cavitation. However, these clones were not very productive under high water availability. The 'Guardi' and 'Australiano 129/60' clones performed best in this situation, showing moderately high productivity under water stress. These clones exhibited the highest degree of anisohydrism, high water use efficiency and 'Australiano 129/60' stood out for its low water potential at the point of wilting due to osmotic adjustment. The currently most cultivated variety in Cuyo region, 'Conti 12', was less productive, did not make cellular adjustments and had low water use efficiency. These results suggest that other available clones may be more suitable for poplar forestry in drylands and should be evaluated in field trials. [ABSTRACT FROM AUTHOR]

Dryland precipitation depends on upwind and local moisture sources via moisture recycling. How upwind moisture variations affect interannual variations of downwind precipitation and vegetation in China's drylands remains unclear. We used high‐resolution moisture tracking data sets and found terrestrial moisture (93%) was the dominant moisture source for China's drylands, especially from drylands themselves (46%). In most dryland grids, we observed strong correlations between precipitation and upwind moisture sources from 2003 to 2022 (median r = 0.55), with a more significant effect in drier areas. These demonstrated the upwind moisture control on interannual variations of dryland precipitation, in which internal moisture from drylands exceeds the influence of external terrestrial sources. The upwind moisture variations, especially the recycled moisture of drylands, propagate to influence downwind vegetation greenness in precipitation‐sensitive dryland areas. Our findings revealed that upwind moisture variations induced by climate or land‐cover changes have important implications for water and food security in China's drylands. Plain Language Summary: Moisture recycling refers to the hydrological cycling in which winds transport evapotranspiration water from upwind source regions and generate precipitation in downwind regions. Precipitation in China's drylands depends on moisture from their upwind source regions, mainly Eurasia and the drylands themselves. Therefore, variations in evaporated water from upwind source regions may affect precipitation in China's drylands and vegetation activities that require water. This study used moisture tracking data sets and found the crucial influence of upwind moisture on dryland precipitation across years. The year‐by‐year changes in upwind moisture, especially from drylands themselves, influence precipitation and vegetation activities in dryland areas where vegetation growth is sensitive to water. The moisture changes due to climate or land cover changes in the upwind source regions could affect water and food security in China's drylands. Key Points: Upwind moisture source regions and downwind China's drylands are tele‐connected through moisture recyclingUpwind moisture variations induce interannual variations in dryland precipitation and vegetation greennessUpwind moisture variations have implications for water and food security in China's drylands [ABSTRACT FROM AUTHOR]

Smallholder farmers, who mostly engage in low-value agriculture in the drylands of Northern Africa, were the first to have felt the effects of climate change, with threats to their livelihoods and food security. The increasing costs of agricultural production, poor water and energy infrastructure, loss of agricultural land due to urban expansion, fragmented resource management, and unsustainable management practices all contribute to this vulnerability to climate change. This highlights the urgent need for innovative practices in farming systems. Within the framework of the water–energy–food–ecosystem nexus, this paper explores innovative practices in dryland farming systems, by assessing their impact on water, energy, food, and ecosystem through stakeholder perception. In this work, we aim to present a systems approach for assessing the resilience of the water–energy–food–ecosystem nexus in arid and semiarid regions. By using a multi-criteria analysis (MCA) approach, the study—which focuses on the Fès–Meknès region in Morocco—involves local actors to help researchers identify the key variables in order to assist farmers in their adaptation to climate change. The findings revealed different priorities between farmers and other stakeholders regarding the adoption of agricultural innovations. Farmers prioritize innovations that guarantee higher profitability and more market opportunities, such as integrating olive trees with cereal crops, by highlighting the importance of sustainable income sources. Meanwhile, stakeholders, such as researchers, engineers, government officials, and agribusiness entrepreneurs, prioritize innovations that emphasize high water use efficiency, which is crucial for the resilience of dryland farming areas: for instance, rainwater harvesting or the use of drought-resistant crop varieties that directly address the need for water conservation. But in doing so they are overlooking broader aspects within the water–energy–food–ecosystem nexus. [ABSTRACT FROM AUTHOR]

For many drylands, both long‐ and short‐term drought conditions can accentuate landscape heterogeneity at both temporal (e.g., role of seasonal patterns) and spatial (e.g., patchy plant cover) scales. Furthermore, short‐term drought conditions occurring over one season can exacerbate long‐term, multidecadal droughts or aridification, by limiting soil water recharge, decreasing plant growth, and altering biogeochemical cycles. Here, we examine how experimentally altered seasonal precipitation regimes in a mixed shrub grassland on the Colorado Plateau impact soil moisture, vegetation, and carbon and nitrogen cycling. The experiment was conducted from 2015 to 2019, during a regional multidecadal drought event, and consisted of three precipitation treatments, which were implemented with removable drought shelters intercepting ~66% of incoming precipitation including: control (ambient precipitation conditions, no shelter), warm season drought (sheltered April–October), and cool season drought (sheltered November–March). To track changes in vegetation, we measured biomass of the dominant shrub, Ephedra viridis, and estimated perennial plant and ground cover in the spring and the fall. Soil moisture dynamics suggested that warm season experimental drought had longer and more consistent drought legacy effects (occurring two out of the four drought cycles) than either cool season drought or ambient conditions, even during the driest years. We also found that E. viridis biomass remained consistent across treatments, while bunchgrass cover declined by 25% by 2019 across all treatments, with the earliest declines noticeable in the warm season drought plots. Extractable dissolved inorganic nitrogen and microbial biomass nitrogen concentrations appeared sensitive to seasonal drought conditions, with dissolved inorganic nitrogen increasing and microbial biomass nitrogen decreasing with reduced soil volumetric water content. Carbon stocks were not sensitive to drought but were greater under E. viridis patches. Additionally, we found that under E. viridis, there was a negative relationship between dissolved inorganic nitrogen and microbial biomass nitrogen, suggesting that drought‐induced increases in dissolved inorganic nitrogen may be due to declines in nitrogen uptake from microbes and plants alike. This work suggests that perennial grass plant–soil feedbacks are more vulnerable to both short‐term (seasonal) and long‐term (multiyear) drought events than shrubs, which can impact the future trajectory of dryland mixed shrub grassland ecosystems as drought frequency and intensity will likely continue to increase with ongoing climate change. [ABSTRACT FROM AUTHOR]

Dryland ecosystems cover 40% of our planet's land surface, support billions of people, and are responding rapidly to climate and land use change. These expansive systems also dominate core aspects of Earth's climate, storing and exchanging vast amounts of water, carbon, and energy with the atmosphere. Despite their indispensable ecosystem services and high vulnerability to change, drylands are one of the least understood ecosystem types, partly due to challenges studying their heterogeneous landscapes and misconceptions that drylands are unproductive "wastelands." Consequently, inadequate understanding of dryland processes has resulted in poor model representation and forecasting capacity, hindering decision making for these at‐risk ecosystems. NASA satellite resources are increasingly available at the higher resolutions needed to enhance understanding of drylands' heterogeneous spatiotemporal dynamics. NASA's Terrestrial Ecology Program solicited proposals for scoping a multi‐year field campaign, of which Adaptation and Response in Drylands (ARID) was one of two scoping studies selected. A primary goal of the scoping study is to gather input from the scientific and data end‐user communities on dryland research gaps and data user needs. Here, we provide an overview of the ARID team's community engagement and how it has guided development of our framework. This includes an ARID kickoff meeting with over 300 participants held in October 2023 at the University of Arizona to gather input from data end‐users and scientists. We also summarize insights gained from hundreds of follow‐up activities, including from a tribal‐engagement focused workshop in New Mexico, conference town halls, intensive roundtables, and international engagements. Plain Language Summary: Drylands are landscapes with limited water availability, which cover 40% of Earth's land surfaces, support billions of humans, and play a substantial role in Earth's weather and climate systems. However, these ecosystems are under threat from droughts and heatwaves. They are also poorly understood because of challenges measuring their highly diverse vegetation types and interspersed vegetation cover and because of incorrect perceptions that they are unimportant "wastelands." These limitations make it challenging to manage their landscapes and quantify how drylands are driving Earth's weather and climate. NASA solicited proposals for a multi‐year field campaign, of which Adaptation and Response in Drylands (ARID) was one of two scoping studies selected. The ARID scoping study aims to design a plan for how NASA satellite, aircraft, and field instruments can be used to better understand dryland ecosystems and their response to change. A primary scoping goal is to engage with scientists and data‐users, especially those who manage land, to understand research and management priorities in drylands. Here, we discuss details of our meeting with over 300 scientists and data‐users in Tucson, AZ in October 2023. We also highlight feedback from our tribal‐focused workshop in New Mexico, conference town halls, and international meetings. Key Points: Adaptation and Response in Drylands (ARID) is a 1‐year scoping study for a multi‐year NASA Terrestrial Ecology dryland field campaignAn ARID workshop was held in Tucson, Arizona in October 2023 with more than 30 data end‐users and 300 scientists in attendanceFurther input from hundreds of researchers and end‐users was obtained through workshops, conference townhalls, and tribal engagement [ABSTRACT FROM AUTHOR]

Drylands cover more than 40% of global land surface and will continue to expand by 10% at the end of this century. Understanding the resistance mechanisms of native species is of particular importance for vegetation restoration and management in drylands. In the present study, metabolome of a dominant shrub Campylotropis polyantha in a dry-hot valley were investigated. Compared to plants grown at the wetter site, C. polyantha tended to slow down carbon (C) assimilation to prevent water loss concurrent with low foliar reactive oxygen species and sugar concentrations at the drier and hotter site. Nitrogen (N) assimilation and turn over were stimulated under stressful conditions and higher leaf N content was kept at the expense of root N pools. At the drier site, roots contained more water but less N compounds derived from the citric acid cycle. The site had little effect on metabolites partitioning between leaves and roots. Generally, roots contained more C but less N. Aromatic compounds were differently impacted by site conditions. The present study, for the first time, uncovers the apparent metabolic adaptations of C. polyantha to hostile dryland conditions. However, due to the limited number of samples, we are cautious about drawing general conclusions regarding the resistance mechanisms. Further studies with a broader spatial range and larger time scale are therefore recommended to provide more robust information for vegetation restoration and management in dryland areas under a changing climate. [ABSTRACT FROM AUTHOR]

Abstract Smallholder farmers, who mostly engage in low-value agriculture in the drylands of Northern Africa, were the first to have felt the effects of climate change, with threats to their livelihoods and food security. The increasing costs of agricultural production, poor water and energy infrastructure, loss of agricultural land due to urban expansion, fragmented resource management, and unsustainable management practices all contribute to this vulnerability to climate change. This highlights the urgent need for innovative practices in farming systems. Within the framework of the water–energy–food–ecosystem nexus, this paper explores innovative practices in dryland farming systems, by assessing their impact on water, energy, food, and ecosystem through stakeholder perception. In this work, we aim to present a systems approach for assessing the resilience of the water–energy–food–ecosystem nexus in arid and semiarid regions. By using a multi-criteria analysis (MCA) approach, the study—which focuses on the Fès–Meknès region in Morocco—involves local actors to help researchers identify the key variables in order to assist farmers in their adaptation to climate change. The findings revealed different priorities between farmers and other stakeholders regarding the adoption of agricultural innovations. Farmers prioritize innovations that guarantee higher profitability and more market opportunities, such as integrating olive trees with cereal crops, by highlighting the importance of sustainable income sources. Meanwhile, stakeholders, such as researchers, engineers, government officials, and agribusiness entrepreneurs, prioritize innovations that emphasize high water use efficiency, which is crucial for the resilience of dryland farming areas: for instance, rainwater harvesting or the use of drought-resistant crop varieties that directly address the need for water conservation. But in doing so they are overlooking broader aspects within the water–energy–food–ecosystem nexus.

Large‐scale topographies affect global extreme weather and climate though dynamic and thermal forcing. However, the impacts of typical topographies on heat waves in different drylands globally remain unclear. In this study, we find that heat waves are mainly occurred in global drylands during 1940–2022. The frequencies and intensities of heat waves in global drylands have significantly increased after 1980s. Multiple numerical model simulations reveal that the impact range of Asian topography on heat waves in global drylands is widest, not only in East Asia, Central, and west Asia locally, but also can reach as far as North Africa and North America. While the impact ranges of topographies in Africa, Arabian Peninsula, North America, and South America on heat waves in drylands are relatively narrow, which are concentrated in localized and their surroundings. These conclusions could provide clues to understand the influence of topography on global weather and climate extremes. Plain Language Summary: Topographies have important impacts on heat waves in global drylands. Through numerical model simulations, this study reveals that Asian topography contributes significantly to heat waves in global drylands, with the widest impact ranges which can cover drylands of East Asia, Central and west Asia, North Africa, even North America. The impacts of the East African Plateau, the Arabian Plateau, the Sierra Madre in North America and the Andes in South America on heat waves are mainly in the local and surrounding regions. Key Points: Heat waves are mainly occurred in global drylands and experience significant increases after 1980sThe impact range of Asian topography on heat waves in global drylands is widest, which can reach as far as North Africa and North AmericaThe topographies in Africa, Arabian Peninsula, North America, and South America can only affect heat waves in localized and surroundings [ABSTRACT FROM AUTHOR]

Sand and dust storms (SDS) pose a wide range of hazards to human society, affecting people in drylands and beyond. This paper, based on a wide-ranging review of the scientific and grey literature, presents, for the first time, a comprehensive synthesis of mitigation and adaptation interventions designed to manage the risks involved and thus build resilience to these SDS hazards in line with the Sendai Framework for Disaster Risk Reduction 2015–2030 (Sendai Framework) and the Sustainable Development Goals. It highlights case studies and good practice examples of measures available to reduce the risks and impacts associated with SDS beyond SDS source areas. These measures, which are interrelated and complementary, are summarized under education initiatives (for schools, specific sectors and vulnerable groups), risk/impact assessments (involving information on hazard, exposure and vulnerability), vulnerability assessment/mapping, integrated monitoring and early warning (using the World Meteorological Organization's Sand and Dust Storm Warning Advisory and Assessment System, or SDS-WAS) and emergency response and risk reduction plans (including contingency planning). Many of these measures are developed for other hazards, but not for SDS. Data availability is an important issue in this regard, and the example of Kuwait illustrates that even with a relatively good understanding of SDS, many aspects of impact mitigation remain poorly understood. Developing appropriate responses to SDS hazards is a matter of some urgency given climate change projections that indicate more frequent and intense SDS emissions due to increased aridity and worsening drought conditions (frequency, severity and duration). [ABSTRACT FROM AUTHOR]

Cation exchange capacity is a crucial metric for managing soil fertility and promoting agricultural sustainability. An alternative technique for the non-destructive assessment of important soil parameters is reflectance spectroscopy. The main focus of this paper is on how to analyze and predict the content of various soil cation exchange capacities (CEC) in arid conditions (Sohag governorate, Egypt) at a low cost using laboratory analysis of CEC, visible near-infrared and shortwave infrared (Vis-NIR) spectroscopy, partial least-squares regression (PLSR), and Ordinary Kriging (OK). Utilizing reflectance spectroscopy with a spectral resolution of 10 nm and laboratory studies with a spectral range of 350 to 2500 nm, 104 surface soil samples were collected to a depth of 30 cm in the Sohag governorate, Egypt (which is part of the dry region of North Africa), in order to accomplish this goal. The association between the spectroradiometer and CEC averaged values was modeled using PLSR in order to map the predicted value using Ordinary Kriging (OK). Thirty-one soil samples were selected for validation. The predictive validity of the cross-validated models was evaluated using the coefficient of determination (R2), root mean square error (RMSE), residual prediction deviation (RPD), and ratio of performance to interquartile distance (RPIQ). The results indicate that ten transformation methods yielded calibration models that met the study's requirements, with R2 > 0.6, RPQ > 2.5, and RIQP > 4.05. For evaluating CEC in Vis-NIR spectra, the most efficient transformation and calibration model was the reciprocal of Log R transformation (R2 = 0.98, RMSE = 0.40, RPD = 6.99, and RIQP = 9.22). This implies that combining the reciprocal of Log R with PLSR yields the optimal model for predicting CEC values. The CEC values were best fitted by four models: spherical, exponential, Gaussian, and circular. The methodology used here does offer a "quick", inexpensive tool that can be broadly and quickly used, and it can be readily implemented again in comparable conditions in arid regions. [ABSTRACT FROM AUTHOR]

Aim: Drylands cover about 41% of Earth's land surface and are home to fragile biota with high levels of endemism. Two hypothetical models, i.e., cradle and museum, have been proposed to account for present‐day species diversity in an ecoregion or biome. We investigated macroevolutionary patterns to test these two different models in Nitrariaceae, a characteristic component of the Eurasian dryland ecosystem. We also used this family to explore the intercontinental disjunct distribution pattern between the deserts of Eurasia and western North America, known as the Madrean–Tethyan disjunction. Location: Drylands in the Northern Hemisphere. Taxon: Nitrariaceae (Sapindales, Angiosperms). Method: We sampled all 16 of the currently recognized extant species of Nitrariaceae and 59 species from the eight other families of Sapindales. A fossil‐calibrated phylogeny was generated using 12 fossil constraints. The ancestral range and climate niche of Nitrariaceae were reconstructed, and diversification rates were estimated. Results: The most recent common ancestor of Nitrariaceae likely inhabited arid habitats with low rainfall in the temperate zone in the Late Cretaceous, which geographically corresponds to present‐day Central Asia. The western North American Peganum mexicanum split from its Central Asian sister group at approximately 39 Ma. Net diversification rates of Nitrariaceae experienced a significant increase around 11 Ma. Within Sapindales, at least seven arid species originated markedly prior to the Miocene. Main Conclusions: The North Atlantic land bridge and global cooling climate in the Late Eocene might have driven the formation of the present‐day disjunct distribution of Nitrariaceae between arid Central Asia and western North America. Nitrariaceae originated in the Late Cretaceous and exhibited long‐term climate niche conservatism, but experienced a rapid diversification in the late Miocene of Eurasia in response to orogenetic and climatic changes. These findings suggest that Eurasian drylands serve as both evolutionary cradles and museums for the diversity of Nitrariaceae and likely for other arid‐adapted lineages. [ABSTRACT FROM AUTHOR]

Within communities, species are wrapped in a set of feedbacks with each other and with their environment. When such feedbacks are strong enough they can generate alternative stable states. So far, research on alternative stable states has mostly focused on systems with a small number of species and a limited diversity of interaction types. Here, we analyze a spatial model of plant community dynamics in stressed ecosystems such as drylands, where each species is characterized by a strategy, and the different species interact through facilitation and competition for space and resources, such as water. We identify three different types of multistability emerging from the interplay of competition and facilitation. Under low‐stress levels, plant communities organize in small groups of coexisting species, maintained by space, competition and facilitation ("cliques"). Under higher stress levels, positive feedback from facilitation lead to the dominance of a single facilitating species ("mutual exclusion states"). At the highest stress levels, the single facilitating species left in the system coexists with the desert state. By linking community ecology and alternative stable states theory using a spatial plant community model for stressed ecosystems, our study contributes to highlight the importance of positive feedback loops for the stability of ecological communities. [ABSTRACT FROM AUTHOR]

Restoring biological crust (biocrust) in disturbed drylands is challenging due to the difficult environmental conditions, such as limited soil moisture, low soil nutrients, and extreme temperatures, that impede growth. Understanding how the key components of biocrust—mosses, lichens, and cyanobacteria—react to different environmental factors informs the optimal timing, locations, and species composition for biocrust reintroduction, thereby increasing the likelihood of establishment. Here, we inoculated soils with a diverse range of biocrust organisms, analogous to seeding an area with diverse vascular plant seeds, and varied environmental conditions to observe how these changes influenced the development and functions of reintroduced biocrust. We found that by manipulating soil texture and time spent wet, we can change the proportional cover of biocrust within a restoration‐like setting. Specifically, we found that 4 months after inoculation, finer textured soils that received more water become dominated by moss cover, while coarser textured soils with less water remained dominated by cyanobacteria cover, and the interactions between texture and time spent wet strongly influenced cover. We found biocrust morphological group cover had a small, but detectable, effect on ecosystem functions (soil stability and nitrogenase activity, a proxy for nitrogen fixation), but that environmental conditions had a stronger impact on the functions we measured. Manipulative experiments in controlled environments, like this one, can help elucidate the mechanisms underlying the establishment rate and patterns of biocrusts post‐inoculation, and inform implementation of inoculations in the field. [ABSTRACT FROM AUTHOR]

Purpose: Drylands occupy 41% of the Earth's surface and 31% of South America. In these environments, anthropogenic climate changes may contribute to the intensification of droughts and increase the susceptibility of lands to desertification. In this study, the evolution, current topics, and the research trends in climate change in four dry environments in South America (Caatinga, Patagonia, Gran Chaco, and the Atacama Desert) were analyzed. Methods: The database was obtained from the Core Collection of Web of Science. A total of 1,386 scientific papers (1993–2022) were analyzed. Results: Patagonia accounted for 37.4% of research on climate change in the four studied environments, while the Gran Chaco accounted for only 6.9%. Overall, the research trends indicate the need for the understanding in the increasing severity of drought in the Caatinga and the intensification of fire frequency in the Gran Chaco on soil properties, animals, and plants. The implementation of more sustainable animal production systems, aiming at soil conservation and reducing greenhouse gases (GHG) emissions should be a priority in Patagonia. In Atacama Desert, the relationship between climate change and soil microbiome, as well as plant-microorganism interactions under hyper-arid conditions, represent important research trends in this ecosystem. Across all biomes, quantification of GHG emissions, the development of strategies to promote C sequestration by biomass and in soils and studies to understand the effects of climate change on people's lives have been scarce and urgently need implementation. Conclusion: There is an urgent need to implement public policies aimed at mitigating and adapting to climate change in the dry climate environments of South America with emphasis on the Gran Chaco, where climate-environmental research is limited, and ecosystem degradation is pronounced. [ABSTRACT FROM AUTHOR]

One of the key goals of ecology is to understand how communities are assembled. The species co‐existence theory suggests that community β‐diversity is influenced by species pool and community assembly processes, such as environmental filtering, dispersal events, ecological drift and biotic interactions. However, it remains unclear whether there are similar β‐diversity patterns among different soil microbial groups and whether all these mechanisms play significant roles in mediating β‐diversity patterns. By conducting a broad survey across Chinese deserts, we aimed to address these questions by investing biological soil crusts (biocrusts). Through amplicon‐sequencing, we acquired β‐diversity data for multiple microbial groups, that is, soil total bacteria, diazotrophs, phoD‐harbouring taxa, and fungi. Our results have shown varying distance decay rates of β‐diversity across microbial groups, with soil total bacteria showing a weaker distance‐decay relationship than other groups. The impact of the species pool on community β‐diversity varied across microbial groups, with soil total bacteria and diazotrophs being significantly influenced. While the contributions of specific assembly processes to community β‐diversity patterns varied among different microbial groups, significant effects of local community assembly processes on β‐diversity patterns were consistently observed across all groups. Homogenous selection and dispersal limitation emerged as crucial processes for all groups. Precipitation and soil C:P were the key factors mediating β‐diversity for all groups. This study has substantially advanced our understanding of how the communities of multiple microbial groups are structured in desert biocrust systems. [ABSTRACT FROM AUTHOR]

Ephemeral alluvial streams pose globally significant flood hazards to human habitation in drylands, but sparse data for these regions limit understanding of the character and impacts of extreme flooding. In this study, we document decadal changes in dryland ephemeral channel patterns at two sites in the lower Colorado River Basin (southwestern United States) that were ravaged by extraordinary flash floods in the 1970s: Bronco Creek, Arizona (1971), and Eldorado Canyon, Nevada (1974). We refer to these two floods as 'fluviomorphic erasure events', because they produced blank slates for the channels that were gradually moulded by more frequent but much smaller flood events. We studied georectified aerial photos that span ~60 years at each site to show that both study sites recovered to their pre‐flood condition after ~25 years. We employ channel network metrics: stream‐link area (SLA), geometric braiding index and junction‐node density. Each metric decreased during the short‐duration extreme flood erasure events. Subsequently, a fluviomorphic trajectory at a decadal tempo returned the channels to pre‐flood values. The SLA decreased at rates of 3.6%–4.1% per year in the decade following the floods. The extreme flood events decreased the pre‐flood geometric braiding index at the two sites by 56%–68%, and it took 15–24 years for this index to recover to pre‐flood values. In contrast, it took 30–35 years for the channels to recover to a uniform pre‐flood channel form, as indicated by the spatial distribution of bars and junction nodes. Our results document baseline examples of ephemeral stream channel evolution trajectories, as future climatic change will likely accelerate increases in the magnitudes and frequencies of extreme floods and geomorphic erasure events. [ABSTRACT FROM AUTHOR]

The sustainability of dry regions has become a key issue for global development. Their natural and cultural landscapes are facing threats resulting from ongoing global changes. This paper presents an overview of geomorphological, climatic-environmental, and archaeological studies in the hyper-arid eastern Tarim Basin (Lop Nur), northwest China, a world-renowned crossroad for early east-west communications, to provide a scientific foundation for sustaining its nature-culture heritage. The late Quaternary landscape changes in the Lop Nur region are characterised by cycles between oases and yardang deserts, shaping the extensive aeolian landform. Archaeological evidence suggests humans' adaptation and resilience to today what are viewed as inhospitable environments since the late Pleistocene by exploiting the diverse range of oasis resources, movement, and encouraging adjacent populations to diversify their subsistence base. Settlement- and regional-scale deterioration of available water resources, affected by environmental and climatic dynamics, caused the eventual abandonment. Periodic occupation and abandonment in the Lop Nur region accompanying oasis-desert/yardang environment cycles provide important lessons for present-day policymakers to contextualise the relationship between human communities and fragile ecosystems. The open-air sites in the Lop Nur region represent the best-preserved oasis-desert civilisation, suffering cultural history losses. We propose the urgent necessity to establish a transdisciplinary database, construct a master chronological framework of settlement, and integrate the culture-nature heritage within the network of the Silk Roads. The scientific management of river networks is also critical for protecting those riverine cultural relics. The site- and group-level management of heritage needs to be adapted to the projected changes in climate and environment. [ABSTRACT FROM AUTHOR]

The honeybee, Apis mellifera, stands out for its positive image due to its contribution to crop pollination and honey production, which facilitated its widespread distribution. However, large apiaries resulting in high honeybee densities could increase pollination frequency while increasing competition for floral resources, ultimately affecting native plant fitness.We studied the impact of managed honeybee hives on pollination and reproductive success of native plants in Villavicencio Nature Reserve, Mendoza, Argentina. During the flowering peak, we studied pollination and reproduction of three native plant species (Larrea divaricata, L. cuneifolia and Zuccagnia punctata) near and far from the hives. We estimated pollen deposition on flower stigmas, pollen tubes developed in flower pistils, fruit set, seed set and seed viability.We found that the honeybee hives had a positive effect on the reproduction of the self‐compatible species, L. divaricata. For the self‐incompatible species, results differed among species: Hives had positive effects on the pollination and negative effects on the reproduction of L. cuneifolia, while they had negative effects on the reproduction of Z. punctata.Synthesis and applications. Beekeeping is increasingly turning to natural areas in search of better quality honey; however, increased honeybee abundance in the field could influence the reproduction of native plants. Our results show that the introduction of managed hives negatively affected the reproduction of self‐incompatible native plants. This result allows us to make several recommendations for conservation and management actions concerning beekeeping in natural areas, regarding the among‐year rotation of the location of hives, the number of hives per site, and the need to monitor the reproduction of self‐incompatible species. [ABSTRACT FROM AUTHOR]

Soil health and conservation agriculture are two pivotal components of soil security that link agricultural and soil science to policy by integrating stakeholders, scales, functions, and assessment tools, going beyond crop production or other human profits (e.g., human health). The study employed the Analytical Hierarchy Process to integrate the perspectives of two key stakeholders, namely farmers and experts, in order to identify soil health indicators that could guide the selection of conservation tillage systems. The primary objective was to determine the priority assigned to different soil health indicators by these stakeholders. The results showed that farmers prioritized and assigned a higher weight to soil mineral nitrogen, soil organic carbon, and soil water content to enhance the soil health by means of the conservation tillage systems. Conversely, agricultural experts assigned the highest weight to soil organic carbon, soil water content, soil respiration, and soil microbial biomass when choosing the proper tillage systems to improve soil health. Further, the results indicated that farmers and agricultural experts prefer no-tillage and reduced tillage systems to enhance soil health. More so, farmers and experts together indicated that these criteria accounted for 59% of the selection of no-tillage, 34% for reduced tillage, and 19% for conventional tillage systems. The results showed the usefulness of our work as an analysis framework to inform policy makers for supporting No-Tillage crop management programs and other agroecological engineering practices. Our findings could be broadly used to offer insights into crafting soil health policy and soil security for transitions toward sustainable and healthy ecosystem. [ABSTRACT FROM AUTHOR]

Abstract As a key region supplementing China's limited croplands, Northwest China has undergone rapid cropland expansion over the past decades to satisfy rising food demand from population growth and socio‐economic development. Although cropland expansion may overconsume local water resources in general, in Northwest China, increased precipitation and enhanced glacier melt have increased the water available for croplands. Counterintuitively, the enhanced evapotranspiration (ET) resulting from this cropland expansion could benefit remote ecologically vulnerable natural vegetation through atmospheric moisture recycling. In this study, we used a moisture tracking model to quantify contributions of croplands and cropland expansion to local precipitation and the consequent precipitation supply to natural vegetation in Northwest China. We found that the croplands contributed 27.69 billion m3/year (2.13%) of regional total precipitation and supplied 17.30 billion m3/year (2.39%) of precipitation over natural vegetation, and the cropland expansion resulted in a net increase of 80.25 million m3/year (1.07% of the total increase) in regional precipitation and 36.23 million m3/year (4.56% of the total increase) in precipitation supply for natural vegetation. Among different types of natural vegetation, grasslands received the most precipitation supply due to its vast area, followed by forests and shrublands. The more arid regions experienced not only faster rates of cropland expansion but also obtained a greater increase in regional precipitation and precipitation supply to natural vegetation. Our study quantifies the ecological impacts of cropland expansion through moisture recycling in Northwest China. This shows the complexities of water competition between agricultural development and ecological conservation in drylands and elsewhere.

Abstract Heatwaves represent a significant and growing threat to natural ecosystems and socio‐economic structures, making heatwave risk mitigation and prevention an important area of research. In exploring heatwave frequency and intensity from 1901 to 2020, the present study finds a sharp increase in both. The study also finds that the spatial distribution of heatwaves is unequal, the volatility of intensity characteristics has become more prominent over time, and the Gini coefficients of four key heatwave indictors have become larger due to increasing dryness. Although heatwaves occur more frequently in drylands, there is greater cumulative heat in humid areas, resulting in a higher heatwave risk in those areas. The global heatwave risk over the past three decades (1991–2020) has increased nearly five‐fold compared to the early 20th century (1901–1930). Furthermore, GeoDetector analysis indicates that the Palmer drought severity index (PDSI) and downward surface shortwave radiation (Srad) contributing the most in drylands and humid areas (0.29 and 0.41, respectively). The contribution of relative humidity (RH), wind speed (WS), soil moisture (SM), and the normalized difference vegetation index (NDVI) is also significant in humid areas, but is much smaller in drylands. Composite analysis shows that the years with anomalously high heatwave risk correspond to positive anomalies of 500hPa geopotential height and surface pressure. The inhibition of cloud formation due to sinking air and the resulting increase in temperature in the atmosphere may be increasing the risk of heatwave occurrence. This study emphasizes the urgent need to address worsening climate change impacts.

Abstract Fog is an important water source that alleviates vegetation water stress, especially for dryland ecosystems. Comprehensive knowledge of fog and rainfall effects can help us better understand dryland vegetation responses to current and future climates. However, the differences between fog and rainfall effects on vegetation are poorly understood. This study compared the effects of fog and rainfall on vegetation greenness changes based on the ground‐level meteorological observations in the Namib Desert and the satellite vegetation index. The vegetation index and its first derivative were utilized to indicate vegetation greenness and its change rate, respectively. Results showed that fog played a more significant role than rainfall in explaining vegetation greenness change rates, while accumulated rainfall was more important than fog in determining vegetation greenness. Soil temperature was an important factor in explaining vegetation greenness changes. These findings offer key insights into how fog and rainfall differentially contribute to vegetation greenness changes.

Abstract Plant respiration and photosynthesis are the two main processes influencing carbon (C) flux balance at leaf‐to‐ecosystem scales. The ratio of respiration to photosynthesis (R:A) or carbon use efficiency (CUE) is considered an important trait for determining global carbon storage in the near future. One school of thought assumes that R:A is constant in terrestrial productivity models, irrespective of biomass, climate, and species. Others believe it is variable, although within a limited range. Semiarid systems dominated by woody vegetation, such as sagebrush steppe, have been recognized as potentially important C sinks on regional to global scales in the context of future climate scenarios. Therefore, there is a critical need to study R:A over different organizational scales (i.e., at the leaf, whole plant, and ecosystem scales) to use this approach for future C flux predictions under climate change scenarios. The objective of this study was to compare leaf‐, shrub‐, and ecosystem‐scale R:A among three sagebrush (Artemisia spp.) communities, and to determine how R:A varies throughout the growing season (i.e., early, mid‐, and late summer) among these communities. We measured photosynthesis and respiration monthly in three sagebrush communities spanning a 685‐m elevation gradient at the Reynolds Creek Experimental Watershed and Critical Zone Observatory in southwestern Idaho. Consistent with our expectations, we found large seasonal variations in R and A at all scales, but with differences in A among the three sagebrush communities significant only at the leaf scale. The R:A ratio was not significantly different among the three species at all organizational scales. However, the R:A ratio did vary among months at the leaf level and there was a statistical interaction between species and month at both leaf and shrub levels. Our study indicates that the R:A ratio is generally conservative, although not tightly constrained (range: 0.12–0.77) among three sagebrush species. Therefore, approaches that assume conservative R:A ratios in terrestrial productivity models need to be considered carefully to evaluate the impact of projected climatic changes on future C cycling in shrub‐dominated rangeland ecosystems.

Abstract Dryland ecosystems cover 40% of our planet's land surface, support billions of people, and are responding rapidly to climate and land use change. These expansive systems also dominate core aspects of Earth's climate, storing and exchanging vast amounts of water, carbon, and energy with the atmosphere. Despite their indispensable ecosystem services and high vulnerability to change, drylands are one of the least understood ecosystem types, partly due to challenges studying their heterogeneous landscapes and misconceptions that drylands are unproductive “wastelands.” Consequently, inadequate understanding of dryland processes has resulted in poor model representation and forecasting capacity, hindering decision making for these at‐risk ecosystems. NASA satellite resources are increasingly available at the higher resolutions needed to enhance understanding of drylands' heterogeneous spatiotemporal dynamics. NASA's Terrestrial Ecology Program solicited proposals for scoping a multi‐year field campaign, of which Adaptation and Response in Drylands (ARID) was one of two scoping studies selected. A primary goal of the scoping study is to gather input from the scientific and data end‐user communities on dryland research gaps and data user needs. Here, we provide an overview of the ARID team's community engagement and how it has guided development of our framework. This includes an ARID kickoff meeting with over 300 participants held in October 2023 at the University of Arizona to gather input from data end‐users and scientists. We also summarize insights gained from hundreds of follow‐up activities, including from a tribal‐engagement focused workshop in New Mexico, conference town halls, intensive roundtables, and international engagements.

IntroductionMapping soil organic carbon (SOC) with high precision is useful for controlling soil fertility and comprehending the global carbon cycle. Low-relief locations are characterized by minimal variability in traditional soil-forming elements, such as terrain and climatic conditions, which make it difficult to reflect the spatial variation of soil properties. In the meantime, vegetation cover makes it more difficult to obtain direct knowledge about agricultural soil. Crop growth and biomass are reflected by the normalized difference vegetation index (NDVI), a significant indicator. Rather than using conventional soil-forming variables.MethodsIn this study, a novel model for predicting SOC was developed using Landsat-8 Operational Land Imager (OLI) band data (Blue (B), Green (G), Red (R), and Near Infrared (NIR), NDVI data as the supporting variables, and Artificial Neural Networks (ANNs). A total of 120 surface soil samples were collected at a depth of 25 cm in the northeastern Nile Delta near Damietta City. Of these, 80% (96 samples) were randomly selected for model training, while the remaining 24 samples were used for testing and validation. Additionally, Gaussian Process Regression (GPR) models were trained to estimate SOC levels using the Matern 5/2 kernel within the Regression Learner framework.Results and discussionThe results demonstrate that both the ANN with a multilayer feedforward network and the GPR model offer effective frameworks for SOC prediction. The ANN achieved an R2 value of 0.84, while the GPR model with the Matern 5/2 kernel achieved a higher R2 value of 0.89. These findings, supported by visual and statistical evaluations through cross-validation, confirm the reliability and accuracy of the models.ConclusionThe systematic application of GPR within the Regression Learner framework provides a robust tool for SOC prediction, contributing to sustainable soil management and agricultural practices.

Climate change is reshaping the seasonal distribution of precipitation patterns across Central Asia, affecting not only the total accumulation but also the timing of precipitation events. However, how seasonal precipitation timing (i.e., precipitation seasonality) shift and may influence dryland ecosystem responses have rarely been considered. Here we utilized gross primary productivity (GPP) data derived from satellite observations over 2001–2022 and a proxy of precipitation timing (precipitation center time index, PCT) to elucidate changes in precipitation timing and assess its impact on vegetation productivity along bioclimate gradients in Central Asia. Our findings revealed that, from southwest to northeast, the precipitation season gradually extended from spring (PCT ≤ 5.0) to summer (PCT ≥ 6.0). Notably, approximately 74.4 % of the study area exhibited a trend of advanced precipitation, particularly evident in regions characterized by earlier precipitation onset. Changes in precipitation timing were found to induce variations in vegetation productivity, albeit with spatial heterogeneity. About 82.0 % of the vegetated areas showed positive GPP anomalies with advanced precipitation, especially in the eastern drylands, while delayed precipitation depressed productivity, leading to negative GPP anomalies in nearly 65.9 % of the vegetation zones. Vegetation in arid regions demonstrated heightened susceptibility to altered precipitation timing, whereas this sensitivity diminished in humid regions characterized by greater moisture availability. More precipitation distributed in early growing season would be more favorable to increase GPP, especially in xeric sparse vegetation, grassland, rained cropland, and shrubland. Our study highlight that it is necessary to pay more attention to the effects of altered precipitation timing on changes in terrestrial ecosystem productivity related to carbon cycle, especially in dryland.

This article is an editorial published in Frontiers in Environmental Science that focuses on the impact of climate change, land surface processes, and critical zone processes in endorheic basins. Endorheic basins are land-locked drainage systems that do not drain into rivers leading to the ocean. These basins are highly sensitive to climate change and human activities, but our understanding of the processes and fluxes in these areas is limited. The editorial highlights several studies that investigate the hydrological impacts of climate change, the movement of sediments, the unique hydrochemistry of these basins, and the effects of drought and vegetation changes. The authors emphasize the need for precise water resource management and climate adaptation strategies in these regions. [Extracted from the article]

Dry subtropical (DST) regions that share similar climatic and topographic conditions exhibit today significant disparities in population density, agricultural intensity, wealth and cultural values. In addition, they are also facing increasing pressures on their natural resources. These attributes collectively shape individuals' varying dependence on natural resources and may influence their perception of ecosystem services (ES). In this study, we conducted a systematic literature review, focusing on the DST regions, to address two main questions: 1) What is the current state, temporal trends and regional variability in scientific research on ES and 2) What are the potential drivers of the variability in ES research? Amongst the 471 publications found in our review, 53% focused on provisioning services, followed nearly equally by cultural (33%) and regulating (30%) services. Only 13% addressed more than one ES category and approximately 33% mentioned economic valuation. Our study reveals that research on ES in the dry subtropics experienced a significant increase from 2005 onwards. Approximately 45% of the publications included the term 'ecosystem service' and its frequency has risen substantially over time. Most publications primarily focus on African dry subtropics (over 60%), followed by South and North American ones. Publications from southern Asia and NE Australia were more scarce. Importantly, we found no clear relationship between the number of publications, publication density or representativeness and the variables used as indicators of human pressure (e.g. population density). Consequently, research efforts in the DST regions appear to be influenced by a diverse range of financial and institutional constraints, international research agendas, as well as the personal interests of researchers, contributing to the idiosyncratic nature of this field.