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This study investigates the effectiveness of passive design in low-rise residential buildings located in arid desert climates, using the Dubai Solar Decathlon Middle East (SDME) competition as a case study. This full-scale experiment offers a unique opportunity to evaluate design solutions under controlled, realistic conditions; prescriptive, modeled performance; and monitored performance assessments. The prescriptive assessment reviews geometry, orientation, envelope thermal properties, and shading. Most houses adopt compact forms, with envelope-to-volume and envelope-to-floor area ratios averaging 1 and 3.7, respectively, and window-to-wall ratios of approximately 17%, favoring north-facing openings to optimize daylight while reducing heat gain. Shading is strategically applied, horizontal on south façades and vertical on east and west. The thermal properties significantly exceed the local code requirements, with wall performance up to 80% better than that mandated. The modeled assessment uses Building Energy Models (BEMs) to simulate the impact of prescriptive measures on energy performance. Three variations are applied: assigning minimum local code requirements to all the houses to isolate the geometry (baseline); removing shading; and applying actual envelope properties. Geometry alone accounts for up to 60% of the variation in cooling intensity; shading reduces loads by 6.5%, and enhanced envelopes lower demand by 14%. The monitored assessment uses contest-period data. Indoor temperatures remain stable (22–25 °C) despite outdoor fluctuations. Energy use confirms that houses with good designs and airtightness have lower cooling loads. Airtightness varies widely (avg. 14.5 m3/h/m2), with some well-designed houses underperforming due to construction flaws. These findings highlight the critical role of passive design as the first layer for improving the energy performance of the built environment and advancing toward net-zero targets, specifically in arid desert climates.

The Lop sheep (LOP), a unique local breed from Xinjiang, exhibits remarkable resilience to the harsh conditions of a desert arid climate and frequent sandstorms, alongside notable fecundity characteristics. This study aims to investigate the adaptability of LOP within this challenging environment by collecting whole blood samples from 110 LOP individuals in the Lop Nur region of Xinjiang for genome resequencing. The resulting data will be compared with whole genome resequencing information from 22 local sheep breeds worldwide to analyze the origin and evolution of LOP. Additionally, comparisons will be made with HUS sheep from warm and humid regions to identify genomic differences through selection signal analysis, thereby assessing the impact of a desert arid climate on the extreme living conditions of LOP. Finally, qPCR was used to preliminarily analyse the impact of the desert arid climate on the genome of the Bactrian sheep. Genetic diversity results indicate that LOP exhibits a relatively stable genetic structure alongside high genetic diversity. The results of population structure analysis and gene flow indicate that we can tentatively posit that LOP is a breed that originated from the Middle East, subsequently mixing with MGS upon its arrival in Xinjiang. Chinese local sheep breeds trace their origins to AMS, with the gene flow evolving from west to east, progressing through mountainous hills (BSBS), basins (LOP, HTS, CLHS, DLS), plains (MGS, TANS), and coastal areas (HUS). LOP is associated with ALTS, BSBS, HTS, CLHS, and DLS, as well as with MGS, HUS, TANS, WDS, and SSSP, in a context of gene exchange, with the degree of exchange diminishing in that order. Selection signal analysis revealed that the candidate genes identified are closely related to adaptation to desert arid climates and disease resistance (PDGFD, NDUFS3, ATP1B2, ITGB8, and CD79A), using HUS as the reference group. qPCR results demonstrated that LOP was significantly upregulated in cardiac, splenic, and lung tissues compared to HUS, suggesting that LOP plays a crucial role in cardiac function, immune response, and respiratory capacity.

This study introduces a refined techno-economic, demand-oriented methodology to assessment and optimization of solar water pumping systems in line with the needs of sustainable agriculture in arid, water-limited regions. For Baghdad, Iraq, winter wheat, we balanced technical performance versus economic viability. System performance for three fixed-tilt angle strategies was analyzed using PVsyst software: summer-tuned (17°), winter-tuned (47°), and annual-tuned (28°). The analysis revealed the most efficient to be the summer-optimized tilt angle of 17°. This approach not only boasts the highest high-performance ratio but also yields the highest average volume of pumped water (298.8 m³/day) precisely when it is most critical: during the plant’s crucial growth stage. Moreover, the 17° tilt angle has the highest overall system and pump performance coupled with the lowest percentage of missing water. The approach is also the most cost-effective, with the lowest water cost at 0.4 $/m³. These findings unequivocally prove that a peak-demand-optimized, demand-based design is technically superior and less expensive than conventional annually optimized solutions. This research offers an adaptable and reliable framework for the formulation and implementation of effective solar water pumping systems; hence, it greatly enhances food and water security in desert areas.

Relationships between biodiversity and multiple ecosystem functions (that is, ecosystem multifunctionality) are context-dependent. Both plant and soil microbial diversity have been reported to regulate ecosystem multifunctionality, but how their relative importance varies along environmental gradients remains poorly understood. Here, we relate plant and microbial diversity to soil multifunctionality across 130 dryland sites along a 4,000 km aridity gradient in northern China. Our results show a strong positive association between plant species richness and soil multifunctionality in less arid regions, whereas microbial diversity, in particular of fungi, is positively associated with multifunctionality in more arid regions. This shift in the relationships between plant or microbial diversity and soil multifunctionality occur at an aridity level of ∼0.8, the boundary between semiarid and arid climates, which is predicted to advance geographically ∼28% by the end of the current century. Our study highlights that biodiversity loss of plants and soil microorganisms may have especially strong consequences under low and high aridity conditions, respectively, which calls for climate-specific biodiversity conservation strategies to mitigate the effects of aridification. Biodiversity-ecosystem functioning relationships may vary with climate. Here, the authors study relationships of plant and soil microbial diversity with soil nutrient multifunctionality in 130 dryland sites in China, finding a shift towards greater importance of soil microbial diversity in arid conditions.

This study analyzes areal changes and regional climate variations in global semi-arid regions over 61 years (1948–2008) and investigates the dynamics of global semi-arid climate change. The results reveal that the largest expansion of drylands has occurred in semi-arid regions since the early 1960s. This expansion of semi-arid regions accounts for more than half of the total dryland expansion. The area of semi-arid regions in the most recent 15 years studied (1990–2004) is 7 % larger than that during the first 15 years (1948–1962) of the study period; this expansion totaled 0.4 × 10⁶ and 1.2 × 10⁶ km² within the American continents and in the Eastern Hemisphere, respectively. Although semi-arid expansion occurred in both regions, the shifting patterns of the expansion are different. Across the American continents, the newly formed semi-arid regions developed from arid regions, in which the climate became wetter. Conversely, in the continental Eastern Hemisphere, semi-arid regions replaced sub-humid/humid regions, in which the climate became drier. The climate change in drying semi-arid regions over East Asia is primarily dominated by a weakened East Asian summer monsoon, while the wetting of semi-arid regions over North America is primarily controlled by enhanced westerlies.

A large proportion of dryland trees and shrubs (hereafter referred to collectively as trees) grow in isolation, without canopy closure. These non-forest trees have a crucial role in biodiversity, and provide ecosystem services such as carbon storage, food resources and shelter for humans and animals 1 , 2 . However, most public interest relating to trees is devoted to forests, and trees outside of forests are not well-documented 3 . Here we map the crown size of each tree more than 3 m 2 in size over a land area that spans 1.3 million km 2 in the West African Sahara, Sahel and sub-humid zone, using submetre-resolution satellite imagery and deep learning 4 . We detected over 1.8 billion individual trees (13.4 trees per hectare), with a median crown size of 12 m 2 , along a rainfall gradient from 0 to 1,000 mm per year. The canopy cover increases from 0.1% (0.7 trees per hectare) in hyper-arid areas, through 1.6% (9.9 trees per hectare) in arid and 5.6% (30.1 trees per hectare) in semi-arid zones, to 13.3% (47 trees per hectare) in sub-humid areas. Although the overall canopy cover is low, the relatively high density of isolated trees challenges prevailing narratives about dryland desertification 5 – 7 , and even the desert shows a surprisingly high tree density. Our assessment suggests a way to monitor trees outside of forests globally, and to explore their role in mitigating degradation, climate change and poverty. Deep learning was used to map the crown sizes of each tree in the West African Sahara, Sahel and sub-humid zone using submetre-resolution satellite imagery, revealing a relatively high density of trees in arid areas.

Harvesting water vapor from desert, arid environments by metal-organic framework (MOF) based devices to deliver clean liquid water is critically dependent on environment and climate conditions. However, reported devices have yet been developed to adapt in real-time to such conditions during their operation, which severely limits water production efficiency and unnecessarily increases power consumption. Herein, we report and detail a mode of water harvesting operation, termed ‘adaptive water harvesting’, from which a MOF-based device is proven capable of adapting the adsorption and desorption phases of its water harvesting cycle to weather fluctuations throughout a given day, week, and month such that its water production efficiency is continuously optimized. In performance evaluation experiments in a desert, arid climate (17–32% relative humidity), the adaptive water harvesting device achieves a 169% increase in water production (3.5 L H2O kg MOF −1 d −1 ) when compared to the best-performing, reported active device (0.7–1.3 L H2O kg MOF −1 d −1 at 10–32% relative humidity), a lower power consumption (1.67–5.25 kWh L H2O −1 ), and saves time by requiring nearly 1.5 cycles less than a counterpart active device. Furthermore, the produced water meets the national drinking standards of a potential technology-adopting country. Atmospheric water harvesting by MOF-based devices is critically dependent on weather conditions. Here, the authors report a MOF-based adaptive water harvesting system capable of adapting its cycles to temperature and relative humidity fluctuations throughout the day, continuously optimizing water production.

Deserts are important landscapes on the earth and their variations have impacts on global climate through feedback processes. However, there is a limited understanding of the climatic controls on the spatial and temporal variations of global deserts. Here, we use climate reanalysis datasets, global land use/land cover (LULC) products and the CMIP6 (Coupled Model Intercomparison Project) model outputs to calculate the changing of global deserts during 1982–2020, and estimate future spatial trends of global deserts. Our results show that mean annual global desert area over this period is 17.64×10 6 km 2 , accounting for 12% of the terrestrial land. Desert areas decreased rapidly from the end of the 1980s to the 1990s in North Africa and Australia, followed by a slow expansion in the early 21st century globally. Spatio-temporal variations of areas of arid climate are characterized by interdecadal fluctuations, and there are clear regional differences in dynamics of the aridity index (AI, used here as a proxy for the area of drylands) and desert areas. Statistical analyses reveal that increased vegetation cover is directly related to the reduction of desert area, while potential evaporation, surface temperature and humidity are also significantly correlated with the desert area. The relationship between wind speed and desert dynamics varies regionally. The results of the CMIP6 simulations suggest that global deserts will expand in the 21st century, albeit at different rates under the ssp245 and ssp585 scenarios. Desert expansions are modelled to be greatest in Asia, Africa and Australia, while those of southern North Africa may reduce as their southern borders migrate northwards.

Aim: Growing attention has been focused on the changes in the structure and diversity of microbial communities under altered precipitation pattern, but little is known about how this factor impacts microbial interactions. Our aim was to elucidate the variations of microbial interactions in semi-arid grassland soils and determine the key factor in regulating microbial assemblies in water–limited areas. Location: A c. 3,700 km transect across three habitats (desert, desert grassland and typical grassland) in Northern China. Time period: July and August 2012. Major taxa studied: Total bacteria and archaea. Method: The random matrix theory (RMT)-based network inference approach was used to construct species interaction networks. The relationships between microbial network topology and environmental variables were examined by Mantel and partial Mantel tests. Results: At the regional scale (across habitats), mean annual precipitation was the most important factor constraining the network structure, whereas at the local scale (within a habitat), soil conditions and plant parameters became more important, but their relative effects differed among habitats. In particular, no correlation was detected between the desert network and any environmental factors. The number of central species increased substantially in desert grassland and typical grassland networks in comparison to those in the desert network. Inter- and intra-module connections, particularly negative connections, also increased in the two grassland habitats. Main conclusions: Microbial networks become more complex as precipitation increases. A simple network structure (no connectors between modules, more sparsely distributed species and lower competitive links) and less association with environmental factors in the desert network indicate that microbial communities in extremely dry ecosystems are unstable and vulnerable; that is future climate change will greatly influence microbial interactions in these extremely dry areas. Overall, our findings provide new insight into the way in which microbes respond to changing precipitation patterns by regulating their interactions in water-limited ecosystems.

Background Plants accomplish multiple functions by the interrelationships between functional traits. Clarifying the complex relationships between plant traits would enable us to better understand how plants employ different strategies to adapt to the environment. Although increasing attention is being paid to plant traits, few studies focused on the adaptation to aridity through the relationship among multiple traits. We established plant trait networks (PTNs) to explore the interdependence of sixteen plant traits across drylands. Results Our results revealed significant differences in PTNs among different plant life-forms and different levels of aridity. Trait relationships for woody plants were weaker, but were more modularized than for herbs. Woody plants were more connected in economic traits, whereas herbs were more connected in structural traits to reduce damage caused by drought. Furthermore, the correlations between traits were tighter with higher edge density in semi-arid than in arid regions, suggesting that resource sharing and trait coordination are more advantageous under low drought conditions. Importantly, our results demonstrated that stem phosphorus concentration (SPC) was a hub trait correlated with other traits across drylands. Conclusions The results demonstrate that plants exhibited adaptations to the arid environment by adjusting trait modules through alternative strategies. PTNs provide a new insight into understanding the adaptation strategies of plants to drought stress based on the interdependence among plant functional traits.