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Saudi Arabia has no permanent lakes or rivers but has wet meadows, which are desert wetlands temporarily formed due to the seasonal rainfall. This work investigates the environmental variables' impact on the vegetation pattern in the desert-wetland ecosystem in Taif highlands. Forty-one stands were randomly selected representing three main habitats (wet meadows, slopes, and terraces) to study their floristic features and vegetation analysis. A total of 142 species were recorded belonging to 111 genera and 45 families in the desert wetlands of Taif Province. About 64.1% were natural plants, while 25.4% were segetal weeds, 7.7% were aquatic plants, and 2.8% were plants that escaped from cultivation. Therophytes dominated over the other life forms, and mono-regional taxa were the dominant chorotype. Multivariate analysis of the recorded plants produced eight vegetation groups; four of them (A: Potamogeton nodosus-Nasturtium officinale, B: Lemna gibba-Leptochloa fusca, C: Typha domingensis- Xanthium strumarium and D: Conyza stricta- Cyperus longus) represented the wet meadows, while two (E: Acacia gerrardii- Commicarpus plumbagineus and H: Osteospermum vaillantii- Eragrostis Pilosa) for slopes and other two (F: Argemone ochroleuca-Cyperus rotundus and G: Pulicaria undulata- Solanum incanum) for the desert terraces. The vegetation zonation was clear, which started from real aquatic species in the wet meadows passing through mixed vegetation in the slopes and ended with proper xerophytic vegetation in the terraces. Conyza stricta- Cyperus longus community had the highest species diversity, while that of Potamogeton nodosus-Nasturtium officinale had the lowest. The principal component analysis indicated that HCO3, NO3, Mg, Cl, Ca, and pH values were the most effective soil variable. The presence of several segetal weeds suggests the alteration of the natural status of the desert-wetland ecosystem, and thus the conservation of these natural habitats becomes urgent.

Globally, the impacts of anthropogenic climate change can displace species into more favourable climates. Semi‐arid desert specialists, such as the sandhill dunnart, Sminthopsis psammophila, are typically susceptible to rainfall deficits, wildfires and extreme temperatures caused by anthropogenic climate change. We first used maximum entropy (MaxEnt) species distribution models (SDMs) to predict the current distribution of S. psammophila. Between 2016 and 2018, we ground validated the model’s predictions throughout Western Australia, confirming S. psammophila in 18 locations in which it was predicted to occur. The predicted distribution of S. psammophila appears mostly constrained to within its known range. However, S. psammophila was verified 150 km north of its range in Western Australia and connectivity between the South Australian populations was correctly predicted. In 2019, we used updated occurrence data to project SDMs for S. psammophila during the mid‐Holocene, present day and under two future representative concentration pathways (RCPs) of RCP 4.5 (an optimistic emissions scenario) and RCP 8.5 (“business as usual”) for 2050 and 2070. By 2050 (RCP 8.5), almost all Western Australian Great Victoria Desert (WAGVD) habitat is predicted to be unsuitable for S. psammophila. By 2070 (RCP 8.5), the climates of the WAGVD and Yellabinna Regional Reserve populations are predicted to become unsuitable, and the species’ geographical range is predicted to contract in Australia by 80%. However, the 2070 (RCP 4.5) scenario predicts that this contraction could be halved. As a sandy desert specialist, the distribution of S. psammophila is geographically limited at its southern bounds due to the cessation of suitable spinifex (Triodia spp.) habitats, and so further extension of the range southwards is not possible. Sympatric desert species may be similarly affected, and we suggest that SDMs will be a useful tool in helping to predict the effects of climate change on their distributions.

Warming climate and increasing desertification urge the identification of genes involved in heat and dehydration tolerance to better inform and target biodiversity conservation efforts. Comparisons among extant desert-adapted species can highlight parallel or convergent patterns of genome evolution through the identification of shared signatures of selection. We generate a chromosome-level genome assembly for the canyon mouse (Peromyscus crinitus) and test for a signature of parallel evolution by comparing signatures of selective sweeps across population-level genomic resequencing data from another congeneric desert specialist (Peromyscus eremicus) and a widely distributed habitat generalist (Peromyscus maniculatus), that may be locally adapted to arid conditions. We identify few shared candidate loci involved in desert adaptation and do not find support for a shared pattern of parallel evolution. Instead, we hypothesize divergent molecular mechanisms of desert adaptation among deer mice, potentially tied to species-specific historical demography, which may limit or enhance adaptation. We identify a number of candidate loci experiencing selective sweeps in the P. crinitus genome that are implicated in osmoregulation (Trypsin, Prostasin) and metabolic tuning (Kallikrein, eIF2-alpha kinase GCN2, APPL1/2), which may be important for accommodating hot and dry environmental conditions.

Two new species of Dzhanokmenia Kostjukov (Hymenoptera: Eulophidae: Tetrastichinae), D. stefaniolae Li, Wang & Hu, sp. nov. and D. yuxuannis Li, Wang & Hu, sp. nov., are described and illustrated from Xinjiang Uyghur Autonomous Region, China. D. stefaniolae was reared from stem-galls made by Stefaniola sp. (Diptera: Cecidomyiidae) on black saxaul, Haloxylon ammodendron (Chenopodiaceae); D. yuxuannis was collected by sweeping from both black saxaul and white saxaul, H. persicum, in Beishawo Desert near Fukang. A key to females of all known species of Dzhanokmenia is provided.

The Bar-tailed Lark (Ammomanes cinctura) breeds in desert and semi-desert areas of the Saharo-Sindian region, from north-west Africa through the arid plains of the Arabian Peninsula to the Sind. Despite having a wide distribution, little information is available on the breeding ecology of this species. This study was conducted in a desert in the north of Saudi Arabia, where the daytime ambient temperature may exceed 40 °C. In contrast, the night ambient temperature may reach less than 10 °C in late spring and early summer. The objectives of this study were to collect some baseline data on some aspects of the breeding ecology of this species and to record the nest attendance behavior. The study found that Bar-tailed Larks preferred to nest under shrub trunks, which may camouflage both nests and incubating parents against predators and protect eggs, nestlings and incubating parents from hostile weather conditions. Moreover, nest attendance was high, as Bar-tailed Lark parents incubated their eggs 95.97 ± 2.62% over the entire day, and they seemed to maintain the eggs at temperatures around 23–33 °C. In addition, they incubated more at night than during the daytime. Temperatures under the shrubs at night fell below 21 °C, thus parents increased the nest attendance to warm the eggs and prevent the embryos from exposure to lethal temperatures.

Several studies isolated fungal and bacterial species from extreme environments, such as Sabkha and hot deserts, as their natural habitat, some of which are of medicinal importance. Current research aimed investigating the microbial (fungi and bacteria) diversity and abundance in Sabkha and desert areas in Saudi Arabia. Soil samples from nine different geographical areas (Al-Aushazia lake, AlQasab, AlKasar, Tabuk, Al-Kharj, Al-Madina, Jubail, Taif and Abqaiq) were collected and cultured for microbial isolation. Isolated fungi and bacteria were identified by molecular techniques (PCR and sequencing). Based on 18S rDNA sequencing, 203 fungal species belonging to 33 genera were identified. The most common fungal genera were Fusarium, Alternaria, Chaetomium, Aspergillus Cochliobolus and Pencillium, while the most common species were Chaetomium globosum and Fusarium oxysporum. By 16S rDNA sequencing 22 bacterial species belonging to only two genera, Bacillus and Lactobacillus, were identified. The most commonly isolated bacterial species were Bacillus subtilis and Lactobacillus murinus. Some fungal species were confined to specific locations, such as Actinomyces elegans, Fusarium proliferatum, Gymnoascus reesii and Myzostoma spp. that were only isolated from Al-Aushazia soil. AlQasab soil had the highest microbial diversity among other areas with abundances of 23.5% and 4.4% of total fungi, and bacteria, respectively. Findings of this study show a higher degree of fungal diversity than that of bacteria in all studied areas. Further studies needed to investigate the connection between some isolated species and their habitat ecology, as well as to identify those of medicinal importance.

This study assessed the influence of rhizocompartment types (i.e., root, rhizosphere soil, root‐zone soil, and intershrub bulk soil) on the diversity of soil microbial communities under desert leguminous plant shrubs. Moreover, the influence and variations of soil physicochemical factors in interactions among leguminous plants, soil, and microbes were investigated. Both 16S rRNA high‐throughput genome sequencing and conventional soil physicochemical index determination were used to characterize both the bacterial diversity and soil physicochemical properties in the rhizocompartments of two Hedysarum species (Hedysarum mongolicum and Hedysarum scoparium) in the Mu Us Desert of China. All nutrient indices (except total phosphorus and available phosphorus) in rhizosphere soil were uniformly higher than those in both root‐zone soil and intershrub bulk soil (p

In situations of restricted food supply, the trophic niches of closely-related species of animals should be separate. For sit-and-wait hunters, such as shrikes, this is associated with competition for food and hunting sites. In the present study, the foraging behaviour of two shrike species - Red-tailed Shrike Lanius phoenicuroides and Red-backed Shrike Lanius collurio - was studied in a desert habitat in Oman. The fieldwork was carried out in September 2019, during the peak migration of these birds. Their behaviour was recorded in detail during 30-minute observation bouts. A General Linear Mixed Model with logit link function and binomial error variance was used to compare their behaviour. The type of perch and its height did not differ between them, but there were significant differences in their use of look-out posts only in the mean duration of a single perching event, which was more than twice as long in Red-backed Shrike. No differences in prey size were found between the species and hunting success (the ratio of successful attacks to all attacks) was similar in both (RtS-RbS: 46 vs. 61%). Dietary diversity was twice as great in Red-tailed Shrike as in Red-backed Shrike, but in general, their diets did not differ very much. Dietary overlap between the species at this level of prey identification was 92%. This absence of differences in some aspects of behaviour and diet may be due to the similarity of the two species, above all their same body size, and even the possibility of hybridization. If the species compared are so similar due to body size, behaviour and evolutionary relationship their food niches may overlap.

Over 40% of the Earth’s surface has been converted to agricultural use and agroecosystems have become important habitats for wildlife. In arid regions, intensive agriculture creates artificial oasis-like habitats due to their high irrigation inputs. Date production is one of the primary agricultural practices in the deserts of the Middle East and North Africa. Insectivorous bats are known to use agricultural areas, but the role of date plantations as their foraging habits and the importance of insectivorous bats as date bio-pest control agents are still unknown. We assessed the role of date plantations as foraging habitats for local desert bat species by acoustically recording bat activity in conventional and organic date plantations in the southern Arava Valley, Israel. In addition, we captured bats in the plantations and collected feces for DNA metabarcoding analysis to investigate the presence of pest species in their diets. We found that 12 out of the 16 known species of bats in this region frequently used both conventional and organic date plantations as foraging habitats. Species richness was highest in the organic plantation with complex ground vegetation cover. Foraging activity was not affected by plantation type or management. However, bat species richness and activity increased in all plantations during summer date harvesting. Molecular analysis confirmed that bats feed on a variety of important date pests, but the particular pests consumed and the extent of consumption varied among bat species. Our results highlight a win–win situation, whereby date plantations are an important foraging habitat for desert bats, while bats provide bio-pest control services that benefit the date plantations. Therefore, date farmers interested in bio-pest control should manage their plantations to support local desert bat populations.

Soil bacteria have been widely investigated and their roles in terrestrial ecosystems are relatively well understood. The soil bacterial community and potential function are controlled by vegetation and bacteria are factors indicating changes in soil microenvironment. However, there is a knowledge gap regarding microbial influence and their use to predict the change in metabolic function after afforestation in desert ecosystem. Pinus sylvestris var. mongolica is the most important evergreen species in desertified northern China. Therefore, we used the 16S rRNA high-throughput sequencing and PICRUSt platform to identify the soil bacterial community and potential metabolic function across stand ages (HQh: half-mature forest, HQn: nearly-mature forest, HQm: mature forest) and control (CK, natural grassland) in the Horqin Desert. Soil characteristics were determined to clarify edaphic driving factors and reveal the effect of afforestation on bacteria. The results indicated that (1) The dominant soil bacterial community category was stable but potential metabolic function changed across stand ages. The dominant phyla and genera were Proteobacteria and Acidobacteria and Sphingomonas, RB41, respectively; the metabolic functions changed from carbohydrate to amino acid metabolism. (2) P. sylvestris plantations significantly increased soil bacterial diversity (P

Changes in ecosystems resulting from anthropause caused by Covid-19 relate to both abiotic and biotic factors which have both a positive or negative effect on wildlife. The lockdown was manifested by reduced air and water pollution, lower mortality of animals on the roads, an increase in animals' body condition and reproduction success. On the other hand, the closures lead to an increase in the populations of invasive species or poaching. We studied the behavioural reaction of natural, desert-dwelling Nubian ibex (Capra nubiana) on the appearance of a new element in the environment - the facial-masks. We hypothesized that the mask would trigger a response expressed through differences in the vigilance towards a potentially new threat. We applied the flight initiation distance (FID) technique to check the reaction at the approach of a human with a facial-mask and without it. The average FID was 8.8 m and was longer when the observer was wearing a mask (10.7 m) as compared to trials without the mask (6.9 m). Our study indicates that wildlife, even if habituated to human silhouette at a distance, appear to notice unusual accessories when up-close and respond by increased vigilance and what may affect their overall fitness.

Simple Summary Nutrient cycling in terrestrial ecosystems requires moisture. Deserts are characterized by low precipitation and extreme surface temperature that limit biological activity. Attempts to resolve how nutrients recycle despite these constraints were focused primarily on abiotic factors. We suggest that macro-arthropods may play a disproportionally large role in resolving this conundrum. Macro-arthropods are prevalent in deserts and many of them are burrowing detritivores that can remain active during long dry periods. Desert arthropods process and transport plant litter nutrients belowground, where the conditions are favorable for decomposer activity. Consequently, arthropods may accelerate the recycling rate of plant litter nutrients to inorganic nutrients that become available for plant use. This generates a vertical nutrient recycling loop (VRL) that may also assist in explaining how desert plants receive nutrients when the shallow soil is dry. Macro-arthropods may also regulate the spatiotemporal distribution of nutrients by transporting them between patches and across ecosystems. Burrowing activity that alters the desert microtopography and reduces soil salinity may contribute further to creating hotspots of productivity and biological diversity in the otherwise poor desert environment. We conclude that macro-arthropods may play a key role in explaining how desert ecosystems function, and that better understanding of this unique role may assist combating desertification and restoring degraded arid lands. Abstract Nutrient dynamics in most terrestrial ecosystems are regulated by moisture-dependent processes. In drylands, nutrient dynamics are often weakly associated with annual precipitation, suggesting that other factors are involved. In recent years, the majority of research on this topic focused on abiotic factors. We provide an arthropod-centric framework that aims to refocus research attention back on the fundamental role that macro-arthropods may play in regulating dryland nutrient dynamics. Macro-arthropods are prevalent in drylands and include many detritivores and burrowing taxa that remain active during long dry periods. Macro-arthropods consume and process large quantities of plant detritus and transport these nutrients to the decomposer haven within their climatically buffered and nutritionally enriched burrows. Consequently, arthropods may accelerate mineralization rates and generate a vertical nutrient recycling loop (VRL) that may assist in explaining the dryland decomposition conundrum, and how desert plants receive their nutrients when the shallow soil is dry. The burrowing activity of arthropods and the transportation of subterranean soil to the surface may alter the desert microtopography and promote desalinization, reducing resource leakage and enhancing productivity and species diversity. We conclude that these fundamental roles and the arthropods’ contribution to nutrient transportation and nitrogen fixation makes them key regulators of nutrient dynamics in drylands.

Vachellia (formerly Acacia) trees are native to arid environments in Africa and the Arabian Peninsula, where they often support the local animal and plant communities acting as keystone species. The aim of this study was to examine whether oil pollution affected the central metabolism of the native keystone trees Vachellia tortilis (Forssk.) and V. raddiana (Savi), as either adults or seedlings. The study was conducted in the Evrona Nature Reserve, a desert ecosystem in southern Israel where two major oil spills occurred in 1975 and in 2014. Leaf samples were collected to analyze the central metabolite profiles from oil-polluted and unpolluted adult trees and from Vachellia seedlings growing in oil-polluted and unpolluted soils in an outdoor setup. We found that oil pollution had a stronger effect on one-year-old seedlings than on adult trees, reducing the levels of amino acids, sugars, and organic acids. While adult trees are mildly affected by oil pollution, the effects on young seedlings can cause a long-term reduction in the population of these keystone desert trees, ultimately threatening this entire ecosystem. The research was part of a postcontamination monitoring program in the Evrona Nature Reserve, funded by the Israel Nature and Parks Authority (INPA) and managed by the HaMaaragIsrael National Nature Assessment Program. We are grateful for the ongoing support to the ADSSC (Winters G.) by the Israel Ministry for Science and Technology (MOST). M.F. was the recipient of a postdoctoral fellowship from the Jacob Blaustein Center for Scientific Cooperation. info:eu-repo/semantics/publishedVersion

A novel copper, zinc superoxide dismutase (CuZnSOD) was purified to homogeneity from the liver of an animal well adapted to the stressful living conditions of the desert, the camel (Camelus dromedarius). The biochemical properties of camel liver CuZnSOD were examined. The purified enzyme had a native molecular weight of 28 kDa, as judged by gel filtration chromatography, and showed a single band at 27 kDa on SDS-PAGE, indicating that it is a monomeric protein. Optimal activity of the purified enzyme occurred at 43 °C and pH 6.0, and the activation energy was 1.42 kJ/mol. CuZnSOD activity was strongly inhibited by ?-ME, DTT, H 2 O 2 and SDS and slightly inhibited by EDTA, NaN 3 and PMSF. Al 3+ , Ca 2+ , Cd 2+ , Mg 2+ and Zn 2+ stimulated CuZnSOD activity, whereas Ba 2+ , Co 2+ , Fe 2+ and Ni 2+ inhibited it. The purified enzyme contained 0.010 µg of Cu and 0.69 µg of Zn per mg of protein. K m , V max , k cat and k cat /K m values for NBT and riboflavin were 16.27 and 0.16 µM, 20.85 and 21.54 U/mg, 9.65 and 9.97 s ?1 , and 0.59 and 62.33 s -1 µM ?1 , respectively. Camel liver CuZnSOD exhibited unique biochemical properties compared to those of other CuZnSODs, including lower molecular weight with a monomeric structure, higher optimum temperature, very low E a , very low optimum pH, very low contents of Cu and Zn, and higher affinity, turnover number and catalytic efficiency for riboflavin. These unique properties of camel liver CuZnSOD might be related to the ability of this animal to inhabit stressful desert conditions. © 2019 Elsevier Inc.

International audience; The seasonal variations of the diet of the desert Trident leaf-nosed bat, Asellia tridens, were investigated using dropping analyses during the whole year 2015 in the Timimoun region, south-western Algerian Sahara. We identified one order of arachnids (Araneae) and ten orders of insects: Coleoptera, Hymenoptera, Diptera, Orthoptera, Mantodea, Hemiptera, Isoptera, Ephemeroptera, Blattodea and Odonata in a decreasing rank. Coleoptera (31.07%) were Carabidae, Curculionidae, Chrysomelidae, Tenebrionidae, Aphodidae, Scarabaeidae, and Histeridae. Hymenoptera (21.31%) were Formicidae, Myrmicidae and Vespidae, Diptera (13.78%) were Culicidae and Tabanidae, and Orthoptera (11.40%) were Acrididae and Gryllidae. The autumn-winter diet (October to December) included a large amount of Odonata, Scarabaeidae, Blattodea, Acrididae and Myrmicidae. The spring-summer diet (February to August) was characterized mainly by Chrysomelidae, Vespidae, Tenebrionidae, Aphodidae and Araneae. As other desert bat species A. tridens displays a combination of opportunism and selective predation depending on the abundance of insect groups.

The purpose of this research was to investigate the structure of soil bacteria communities present in the Gibson (Australia) and the Sahara (Egypt) deserts, as well as to estimate strain survivability under different environmental factors. It should be noticed that the screening of bacterial resistance to wide spectra of principally different stress conditions was performed for the first time. Experiments were conducted with culturable bacterial communities. Strains were identified using 16S rRNA sequencing, and stress-tolerance was estimated by growing strains in various nutrient media. In order to characterize the community the epifluorescent microscopy and multisubstrate testing were also performed. High bacterial abundance in the desert soils was detected, and there was seen a significant proportion of culturable cells. The close numbers of psychotropic and mesophilic bacteria in arid ecosystems were revealed. The representatives of the Actinobacteria phylum were dominant in the microbial communities, and Firmicutes, Proteobacteria, and Bacteroidetes phyla representatives were also identified. Tolerance of the axenic bacterial cultures, isolated from arid desert ecotopes, to temperature, pH, salts (KCl, NaCl, MgSO4, NaHCO3), strong oxidizers (Mg(ClO4)2), and antibiotics (ampicillin, cephalexin, chloramphenicol, tetracycline, doxycycline, kanamycin, rifampicin) was studied. The bacterial isolates were characterized by polyextremotolerance and by the ability to maintain metabolic activity in vitro while influenced by a wide range of physicochemical and biotic factors.

Background The visual system of desert rodents demonstrates a rather high degree of development and specific features associated with adaptation to arid environment. The aim of this study is to carry out a descriptive investigation into the most relevant features of the sand rat eye. Results Light microscopic observations revealed that the eye of Psammomys obesus diurnal species, appears similar to that of others rodent with characteristic mammalian organization. The eye was formed by the three distinct layers typical in vertebrates: fibrous tunic (sclera and cornea); vascular tunic (Iris, Ciliary body, Choroid); nervous tunic (retina). Three chambers of fluid fundamentals in maintaining the eyeball’s normal size and shape: Anterior chamber (between cornea and iris), Posterior chamber (between iris, zonule fibers and lens) and the Vitreous chamber (between the lens and the retina) The first two chambers are filled with aqueous humor whereas the vitreous chamber is filled with a more viscous fluid, the vitreous humor. These fluids are made up of 99.9% water. However, the main features, related to life style and arid environment, are the egg-shaped lens, the heavy pigmentation of the middle layer and an extensive folding of ciliary processes, thus developing a large surface area, for ultrafiltration and active fluid transport, this being the actual site of aqueous production. The ciliary muscle is poorly developed and the dilator pupillae is not apparent. Conclusions The ocular globe of sand rat demonstrates a high degree of development and several specific features associated with adaptation to life style and arid environment.

Temperature and light are two of the most crucial factors for microalgae production. Variations in these factors alter their growth kinetics, macromolecular composition and physiological properties, including cell membrane permeability and fluidity. The variations define the adaptation mechanisms adopted by the microalgae to withstand changes in these environmental factors. In the Qatar desert the temperature varies widely, typically between 10° and 45 °C There are also wide variations in light intensity, with values of over 1500 μmolhν.m−2s−1 in summer. A study of the effects of these thermal and light fluctuations is therefore essential for large-scale outdoor production systems, especially during the summer when temperature and light fluctuations are at their highest. The aim of this work is to study the impact of temperature and light intensity variations as encountered in summer period on the Nannochloropsis QU130 strain, which was selected for its suitability for outdoor cultivation in the harsh conditions of the Qatar desert. It was carried out using lab-scale photobioreactors enabling simulation of both constant and dynamic temperature and light regimes. Biomass productivity, cell morphology and biochemical compositions were examined first in constant conditions, then in typical outdoor cultivation conditions to elucidate the adjustments in cell function in respect of fluctuations. The dynamic light and temperature were shown to have interactive effects. The application of temperature cycles under constant light led to a 13.6% increase in biomass productivity, while a 45% decrease was observed under light and temperature regimes due to the combined stress. In all cases, the results proved that N. sp. QU130 has a high level of adaptation to the wide fluctuations in light and temperature stress. This was shown through its ability to easily change its physiology (cell size) and metabolic process in response to different cultivation conditions.

The response of microbial communities to continual and prolonged water exposure provides useful insight when facing global climate changes that cause increased and uneven precipitation and extreme rainfall events. In this study, we investigated an in situ manipulative experiment with four levels of water exposure (ambient precipitation +0%, +25%, +50%, and +100% of local annual mean precipitation) in a desert ecosystem of China. After 9 years of water addition, Illumina sequencing was used to analyze taxonomic compositions of the soil bacterial, archaeal, and fungal communities. The results showed significant increases in microbial biomass carbon (MBC) at higher amended precipitation levels, with the highest values reported at 100% precipitation. Furthermore, an increase in the bacterial species richness was observed along the water addition gradient. In addition, the relative abundance of several bacterial phyla, such as Proteobacteria, significantly increased, whereas that of some drought-tolerant taxa, including Actinobacteria, Firmicutes, and Bacteroidetes, decreased. In addition, the phyla Planctomycetes and Nitrospirae, associated with nitrification, positively responded to increased precipitation. Archaeal diversity significantly reduced under 100% treatment, with changes in the relative abundance of Thaumarchaeota and Euryarchaeota being the main contributors to shifts in the archaeal community. The fungal community composition was stable in response to water addition. Results from the Mantel test and structural equation models suggested that bacterial and archaeal communities reacted contrastingly to water addition. Bacterial community composition was directly affected by changing soil moisture and temperature, while archaeal community composition was indirectly affected by changing nitrogen availability. These findings highlight the importance of soil moisture and nitrogen in driving microbial responses to long-term precipitation changes in the desert ecosystem.

Ecology and evolution 11(20), 14146-14161 (2021). doi:10.1002/ece3.8132, Published by John Wiley & Sons, Inc., [S.l.]

espanolLos roedores de la subfamilia Gerbillinae Gray, 1825, representan un importante componente de la fauna de pequeno tamano de regiones aridas y deserticas de Africa y Asia. El jerbo de Sundevall Meriones crassus es una de las especies deserticas mas extendidas de esta subfamilia y esta distribuido desde Marruecos hasta Pakistan. En este estudio secuenciamos el gen citocromo b del ADN mitocondrial de dos especimenes capturados en Marruecos, lo que constituye la primera identificacion genetica de esta especie en el continente africano. La identificacion molecular se complemento y confirmo con evidencia morfologica. Ademas, propusimos la hipotesis de una extension de su distribucion geografica 250 km hacia el norte en Marruecos, quiza indicativa de la creciente desertificacion que afecta al norte de Africa. La confirmacion de dicha hipotesis requerira pruebas adicionales. catalaEls rosegadors de la subfamilia Gerbillinae Gray, 1825, representen un component important de la fauna de mida petita de regions arides i desertiques d’Africa i Asia. El jerbu de Sundevall Meriones crassus es una de les especies desertiques mes esteses d’aquesta subfamilia i esta distribuit des del Marroc fins al Pakistan. En aquest estudi sequenciem el gen citocrom b de l’ADN mitocondrial de dos especimens capturats al Marroc, la qual cosa constitueix la primera identificacio genetica d’aquesta especie al continent africa. La identificacio molecular es va complementar i confirmar amb evidencia morfologica. A mes a mes, vam proposar la hipotesi d’una extensio de la seva distribucio geografica 250 km cap al nord al Marroc, potser indicativa de la creixent desertitzacio que afecta el nord d’Africa. La confirmacio d’aquesta hipotesi requerira proves addicionals. EnglishRodents from the subfamily Gerbillinae Gray, 1825, are an important component of small fauna in arid and desertic regions in Africa and Asia. Among this group of rodents, Sundevall’s jird, Meriones crassus, is one of the most widespread desert species, found in countries ranging from Morocco to Pakistan. In this study, we sequenced the cytochrome b gene of the mitochondrial DNA in two specimens captured in Morocco, constituting the first genetic identification for this species in the African continent. Molecular identification was complemented and supported with morphological evidence. Additionally, we propose the hypothesis of a northward extension of 250 km of the geographic distribution of Sundevall’s jird in Morocco, perhaps indicating the increasing desertification affecting North Africa. Further evidence will be required to test the latter hypothesis.

International audience; Plant architecture strongly influences ecological performance, yet its role in plant evolution has been weakly explored. By testing both phylogenetic and environmental signals, it is possible to separate architectural traits into four categories: development constraints (phylogenetic signal only); convergences (environmental dependency only); key confluences to the environmental driver (both); unknown (neither).We analysed the evolutionary history of the genus Euphorbia, a model clade with both high architectural diversity and a wide environmental range. We conducted comparative analyses of 193 Euphorbia species worldwide using 73 architectural traits, a dated phylogeny, and climate data.We identified 14 architectural types in Euphorbia based on trait combinations. We found 22 traits and three types representing convergences under climate groups; 21 traits and four types showing phylogenetic signal but no relation to climate; and 16 traits and five types with both climate and phylogenetic signals. Major drivers of architectural trait evolution likely include water stress in deserts (selected for succulence, continuous branching), frost disturbance in temperate systems (selected for simple, prostrate, short‐lived shoots) and light competition (selected for arborescence). Simple architectures allowed resilience to disturbance, and frequent transitions into new forms. Complex architectures with functional specialisation developed under stable climates but have low evolvability.

Perennial shrub-annual plant interactions play key roles in desert regions influencing the structure and dynamics of plant communities there. In the present study, carried out in northwestern Saudi Arabia, we examined the effect of Haloxylon salicornicum shrubs on their associated understory annual species across four consecutive growing seasons, along with a record of the seasonal rainfall patterns. We measured density and species richness of all the annual species in permanent quadrats located beneath individual shrubs, as well as in the spaces between shrubs. During wet growing season H. salicornicum shrubs significantly enhanced the density and species richness of sub-canopy species, whereas in the relatively dry seasons they exerted negative effects on the associated species. In all growing seasons, the presence of shrubs was associated with enhanced soil properties, including increased organic carbon content, silt + clay, and levels of nutrients (N, P and K). Shrubs improved soil moisture content beneath their canopies in the wet growing season, while in the dry seasons they had negative effects on water availability. Differences in effects of H. salicornicum on understory plants between growing seasons seem due to the temporal changes in the impact of shrubs on water availability. Our results suggest the facilitative effects of shrubs on sub-canopy annuals in arid ecosystems may switch to negative effects with increasing drought stress. We discuss the study in light of recent refinements of the well-known &ldquo, stress-gradient hypothesis&rdquo

It is commonly thought that bacterial distributions show lower spatial variation than for multicellular organisms. In this article, we present evidence that these inferences are artifacts caused by methodological limitations. Through leveraging innovations in sampling design, sequence processing, and diversity analysis, we provide multifaceted evidence that bacterial communities in fact exhibit strong distribution patterns. This is driven by selection due to factors such as local soil characteristics. Altogether, these findings suggest that the processes underpinning diversity patterns are more unified across all domains of life than previously thought, which has broad implications for the understanding and management of soil biodiversity., Bacteria have been inferred to exhibit relatively weak biogeographic patterns. To what extent such findings reflect true biological phenomena or methodological artifacts remains unclear. Here, we addressed this question by analyzing the turnover of soil bacterial communities from three data sets. We applied three methodological innovations: (i) design of a hierarchical sampling scheme to disentangle environmental from spatial factors driving turnover; (ii) resolution of 16S rRNA gene amplicon sequence variants to enable higher-resolution community profiling; and (iii) application of the new metric zeta diversity to analyze multisite turnover and drivers. At fine taxonomic resolution, rapid compositional turnover was observed across multiple spatial scales. Turnover was overwhelmingly driven by deterministic processes and influenced by the rare biosphere. The communities also exhibited strong distance decay patterns and taxon-area relationships, with z values within the interquartile range reported for macroorganisms. These biogeographical patterns were weakened upon applying two standard approaches to process community sequencing data: clustering sequences at 97% identity threshold and/or filtering the rare biosphere (sequences lower than 0.05% relative abundance). Comparable findings were made across local, regional, and global data sets and when using shotgun metagenomic markers. Altogether, these findings suggest that bacteria exhibit strong biogeographic patterns, but these signals can be obscured by methodological limitations. We advocate various innovations, including using zeta diversity, to advance the study of microbial biogeography. IMPORTANCE It is commonly thought that bacterial distributions show lower spatial variation than for multicellular organisms. In this article, we present evidence that these inferences are artifacts caused by methodological limitations. Through leveraging innovations in sampling design, sequence processing, and diversity analysis, we provide multifaceted evidence that bacterial communities in fact exhibit strong distribution patterns. This is driven by selection due to factors such as local soil characteristics. Altogether, these findings suggest that the processes underpinning diversity patterns are more unified across all domains of life than previously thought, which has broad implications for the understanding and management of soil biodiversity.

Historical population contraction and expansion events associated with Pleistocene climate change are important drivers of intraspecific population structure in Australian arid-zone species. We compared phylogeographic patterns among arid-adapted Dasyuridae (Sminthopsis and Planigale) with close phylogenetic relationships and similar ecological roles to investigate the drivers of phylogeographic structuring and the importance of historical refugia. We generated haplotype networks for two mitochondrial (control region and cytochrome b) and one nuclear (omega-globin) gene from samples distributed across each species range. We used &Phi, ST to test for a genetic population structure associated with the four Pilbara subregions, and we used expansion statistics and Bayesian coalescent skyline analysis to test for signals of historical population expansion and the timing of such events. Significant population structure associated with the Pilbara and subregions was detected in the mitochondrial data for most species, but not with the nuclear data. Evidence of population expansion was detected for all species, and it likely began during the mid-late Pleistocene. The timing of population expansion suggests that these species responded favorably to the increased availability of arid habitats during the mid-late Pleistocene, which is when previously patchy habitats became more widespread. We interpret our results to indicate that the Pilbara region could have acted as a refugium for small dasyurids.

Background and aims Restoration of degraded desert soil with three species of legume trees and the giant cardon cactus was evaluated 11 years after planting in the southern Sonora Desert. Methods The trees in six independent field experiments were grown individually or in combination of a legume tree and cardon cactus and were originally treated with plant growth-promoting bacteria, arbuscular mycorrhizal fungi, or small amounts of cattle compost or a combination of all treatments. Survival and height of trees and cacti and cactus biovolume were measured. Results When data were combined from all experiments and analyzed together, the best survivor was the cardon cacti and, to a lesser extent, the legume tree mesquite amargo. Over a decade later, a combination of a legume tree with cardon cactus, while detrimental to the legume, significantly increased the chances of the cactus to survive and grow in degraded soil. The biotic and compost treatments, while enhancing the initial establishment of the plants in 2004, had only marginal benefit on the growth of cactus 11 years later. Conclusions Long-term desert restoration with native trees is possible. Because this cactus is the native, long term soil stabilizer, a combination cactus-legume tree is recommended for long term desert restorations.

Simple Summary Information on population characteristics of Paraechinusis is valuable for ensuring long term survival of populations, however, studies are currently lacking. Here we investigate the population dynamics of Ethiopian hedgehogs based on a capture study in Qatar by fitting several statistical models. Over the 19 months of the study, we estimate a mean population of 60 hedgehogs, giving a density of 7 hedgehogs per km2 in our 8.5 km2 search area. The monthly abundance of hedgehogs decreased over the study and although survival was constant over the study period, with a mean monthly rate of 75%, there was a decline in the number of new entrants over time. We also studied these parameters over one year, excluding winter, and found that monthly estimates of juvenile and subadult survival decreased over time. We surmise that survival of juveniles may be a factor in the decrease in abundance and there may be implications for the persistence of this population in the future, with human influenced resources playing an important role. We caught between 91.3% and 100% of the estimated population at this site, indicating that our capture methodology was efficient. We conclude that the methodology used here is transferrable to other hedgehog species. Abstract Information on population characteristics of Paraechinusis is valuable for ensuring long term survival of populations, however, studies are currently lacking. Here we investigate the population dynamics of Ethiopian hedgehogs based on a capture-mark-recapture study in Qatar by fitting Jolly-Seber and Cormack-Jolly-Seber models. Over the 19 months of the study, we estimate a mean population of 60 hedgehogs, giving a density of 7 hedgehogs per km2 in our 8.5 km2 search area. The monthly abundance of hedgehogs decreased over the study and although survival was constant over the study period, with a mean monthly rate of 75%, there was a decline in the number of new entrants over time. We also studied these parameters over one year, excluding winter, and found that monthly estimates of juvenile and subadult survival decreased over time. We surmise that survival of juveniles may be a factor in the decrease in abundance and there may be implications for the persistence of this population, with anthropogenic influenced resources playing an important role. We caught between 91.3% and 100% of the estimated population at this site, indicating that our capture methodology was efficient. We conclude that the methodology used here is transferrable to other hedgehog species.

La radiación solar, los vientos y la cobertura vegetal sobre los nidos pueden influir en las decisiones de las aves acerca de cómo construirlos; por ejemplo, en la orientación de la entrada. En este estudio se examinó la orientación de la entrada en nidos de hornero (Furnarius rufus) en un sitio desértico subtropical del norte de la Argentina. Se evaluó si la radiación solar y los vientos influyen en la orientación media de los nidos con abundante cobertura vegetal superior y en los que tienen escasa o nula cobertura vegetal superior. Los nidos con abundante cobertura vegetal superior mostraron una orientación aleatoria de la boca de entrada, lo que sugiere que la radiación solar y los vientos no influyen al momento de la construcción del nido. Los nidos con poca o nula cobertura vegetal superior presentaron una orientación de entrada no aleatoria hacia el sureste, con lo cual reducen la radiación solar directa. Además, estos nidos con escasa cobertura vegetal se orientan hacia los vientos húmedos predominantes del sur, lo que facilitaría la refrigeración dentro del nido.Este trabajo resalta la importancia de incluir la cobertura vegetal de los nidos como variable que puede influir en la orientación de los nidos. Solar radiation, winds and cover vegetation can affect nest construction decisions in birds; for example, the orientation of their entrance. In this study, the nest entrance orientation of rufous hornero (Furnarius rufus) in a subtropical desert site from Northern Argentina was examined. It was evaluated whether solar radiation and winds influence the mean orientation of nests with abundant upper vegetation cover and of those with little or no upper vegetation cover. Nests with abundant upper vegetation cover showed a randomly defined nest entrance orientation, suggesting that solar radiation and winds are not relevant in nest construction. Nests with little or no upper vegetation cover showed a non-random entrance, southeastern oriented, which would avoid direct solar radiation. Thus, nest with little or no upper vegetation cover were oriented towards prevailing southern humid winds as to increase cooling inside the nest. This work emphasizes the importance of including nest vegetation cover as a variable that may affect nest orientation. Fil: Schaaf, Alejandro Alberto. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Studies of microbial biogeography are often convoluted by extremely high diversity and differences in microenvironmental factors such as pH and nutrient availability. Desert endolithic (inside rock) communities are exceptionally simple ecosystems that can serve as a tractable model for investigating long-range biogeographic effects on microbial communities. We conducted a comprehensive survey of endolithic sandstones using high-throughput marker gene sequencing to characterize global patterns of diversity in endolithic microbial communities. We also tested a range of abiotic variables in order to investigate the factors that drive community assembly at various trophic levels. Macroclimate was found to be the primary driver of endolithic community composition, with the most striking difference witnessed between hot and polar deserts. This difference was largely attributable to the specialization of prokaryotic and eukaryotic primary producers to different climate conditions. On a regional scale, microclimate and properties of the rock substrate were found to influence community assembly, although to a lesser degree than global hot versus polar conditions. We found new evidence that the factors driving endolithic community assembly differ between trophic levels. While phototrophic taxa were rigorously selected for among different sites, heterotrophic taxa were more cosmopolitan, suggesting that stochasticity plays a larger role in heterotroph assembly. This study is the first to uncover the global drivers of desert endolithic diversity using high-throughput sequencing. We demonstrate that phototrophs and heterotrophs in the endolithic community assemble under different stochastic and deterministic influences, emphasizing the need for studies of microorganisms in context of their functional niche in the community.

Mangroves are important coastal ecosystems of warm climatic regions that often grow in shallow saline or brackish waters of estuaries and river mouths which are affected by wide tidal intervals and receive abundant nutrient supply. However, mangroves also occur in areas of little tidal influence and devoid of riverine inputs, where they can develop a stunted plant form. Here we report that Avicennia marina trees in the fringe of the Red Sea have maximum heights toward the lower range of that reported elsewhere (average maximum canopy height of 4.95 m), especially in the central region, where mangroves are stunted with an average tree height of 2.7 m. Maximum tree height and chlorophyll a concentration correlated positively with nitrogen concentration in the leaves of A. marina. We conclude that the stunted nature of mangrove trees in the central Red Sea is likely driven by nitrogen limitation., This research was supported by the King Abdullah University of Science and Technology through baseline funding and funds by the Tarek Ahmed Juffali Research Chair in Red Sea Ecology to CD.

Die Wüste Atacama in Chile steht unter speziellen klimatischen Einflüssen, die sehr selten aufunserer Erde zu finden sind. Durch ihre Lage an der Westküste des amerikanischen Südkontinents werden die Niederschäge durch kaltes Auftriebswasser vom Festland ferngehalten und die Atacama stellt somit eine der trockensten Wüsten der Erde dar. In ihrem Zentrum findet sich seit Millionen Jahren ein hyperarides Klima. In der Atacama Wüste soll eine Forschungsstation entstehen, in welcher Themen wie Wüstenbildung, Wasserbildung und die Anpassung von Flora und Fauna an die klimatischen Bedingungen der Wüsten untersucht werden. Zusätzlich wird Wohnraum für die Forscher entstehen, die abgelegen von bestehenden Ansiedlungen die Ökosysteme der Atacama Wüste erforschen wollen. Die Forscher sollen sich autonom an diesem Ort aufhalten können. Auch Touristen sollen das Gebäude besuchen können und dort Zuflucht vor dem harschen Wüstenklima finden. Gleichzeitig soll die Forschungsstation durch ihre ökologisch nachhaltige Bauweise auf zukünftige Entwicklungen und Probleme aufmerksam machen. Das Gebäude, in dem aktiv Forschung betrieben wird, soll auf seine Umwelt reagieren und sich bestehende, traditionelle Wüstenarchitektur zum Vorbild nehmen. Das Projekt soll zudem Teil eines Diskurses der zukünftigen Desertifikation menschlicher Lebensräume sein., The Chilean Atacama desert stands out due to its globally unique climatic conditions. Due to its location on the South American west coast precipitation is kept away by cold, upwelling water. The Atacama is said to be one of the driest deserts of the world. A hyper arid climate has dominated the region for millions of years. In this harsh climate a research station will be created to investigate topics like desertification, hydrology and the adjustment of flora and fauna to the existing climatic conditions. Additionally the architectural proposal will include housing for scientists that want to conduct research on the ecosystems of the Atacama Desert, far from existing settlements. The scientists staying at the station will be able to live autonomously for several weeks. Additionally visitors will have access to the building to escape the harsh desert climate. Simultaneously the ecologically sustainable building is supposed to address current developments and issues in architecture. The building, where research will be conducted, will react to its surroundings and take inspiration from existing, traditional architecture of desert regions around the world. Furthermore the project will contribute to the discourse of the future desertification of human habitats.

Cape gannet Morus capensis chicks depend entirely on fish prey and metabolic water for water requirements during development. Water loss through evaporative cooling due to heat stress is substantial. We measured water flux and field metabolic rates (FMR) of Cape gannet chicks and adults to determine if gannets developed water saving strategies. The water economy index (WEI, gkJ(-1)) decreased with chick age according to the model WEI=0.676 - 0.272xlog(10)(t), indicating that water efficiency increased with age. At fledging, the WEI of chicks was at the level expected of adult desert birds. Desert birds maintain a low WEI by also having a low FMR, whereas Cape gannet chicks have FMR comparable to other seabird species' nestling requirements. We propose that maintaining low WEI is adaptive for Cape gannets because (1) chicks need to balance water loss through evaporative cooling, (2) fledglings need to overcome a period of up to a week when they cannot ingest any water and (3) adults spend extended periods in the breeding colony during which water can become a limiting factor. Understanding the physiological mechanism of maintaining low WEI will become increasingly important with future rising temperatures.

Understanding the impacts of environmental factors on spatial–temporal and large-scale rodent distribution is important for rodent damage prevention. Investigating rat hole density (RHD) is one of the most effective methods to obtain the intensity of rodent damage. However, most of the previous field surveys or UAV-based remote sensing methods can only evaluate small-scale RHD and its influencing factors. However, these studies did not consider large-scale temporal and spatial heterogeneity. Therefore, we collected small-scale and in situ measurement records of RHD on the northern slope of the Tien Shan Mountains in Xinjiang (NTXJ), China, from 1982 to 2015, and then used correlation analysis and Bayesian network (BN) to analyze the environmental impacts on large-scale RHD with satellite remote sensing data such as the GIMMS NDVI product. The results show that the built BN can better quantify causality in the environmental mechanism modeling of RHD. The NDVI and LAI data from satellite remote sensing are important to the spatial–temporal RHD distribution and the mapping in the future. In regions with an elevation higher than 600 m (UPR) and lower than 600 m (LWR) of NTXJ, there are significant differences in the driving mechanism patterns of RHD, which are dependent on the elevation variation. In LWR, vegetation conditions have a weaker impact on RHD than UPR. It is possibly due to the Artemisia eaten by the dominant species Lagurus luteus (LL) in UPR being more sensitive to precipitation and temperature if compared with the Haloxylon ammodendron eaten by the Rhombomys opimus (RO) in LWR. In LWR, grazing intensity is more strongly and positively correlated to RHD than UPR, possibly due to both winter grazing and RO dependency on vegetation distribution; moreover, in UPR, sheep do not feed Artemisia as the main food, and the total vegetation is sufficient for sheep and LL to coexist. Under the different conditions of water availability of LWR and UPR, grazing may affect the ratio of aboveground and underground biomass by photosynthate allocation, thereby affecting the distribution of RHD. In extremely dry years, the RHD of LWR and UPR may have an indirect interactive relation due to changes in grazing systems.

Understanding the effect of nitrogen addition on species trait–abundance relationships is one of the central focuses of community ecology and can offer us insights into the mechanisms of community assembly under atmospheric nitrogen deposition. However, few studies have focused on desert ecosystems. In this study, we measured the abundance and ecological stoichiometric traits, leaf carbon content (LCC), nitrogen content (LNC), and phosphorus content (LPC) for all annual ephemerals in all plots subjected to nitrogen addition in early spring in Gurbantunggut Desert, northern Xinjiang, China. We found a significant relationship between traits (LNC, N:P, and C:N) and abundance, indicating that ecological stoichiometry is a good proxy for explaining and predicting species abundance. We further found that significant trait–abundance relationships still existed under different nitrogen addition levels. The result suggests that trait-based niche-assembly theory plays an important role in determining species abundance under atmospheric nitrogen deposition.

In addition to feeding on animal remains, many scavengers also function as predators. Carcasses may therefore affect local animal communities by attracting facultative scavengers and increasing predation risk for other species in the vicinity of the carcasses. This risk may be elevated in low productivity environments, especially where humans increase carcass production and where facultative scavengers include invasive species. In June and October 2018, we monitored experimentally placed red kangaroo (Osphranter rufus) carcasses and artificial bird nests in two different habitats in the Simpson Desert, Australia, to identify the nest predators attracted to the carcasses, and to determine how carcasses affect overall and predator-specific nest predation. We modelled our nests to approximate those of the ground nesting little buttonquail (Turnix velox) and the endangered night parrot (Pezoporus occidentalis). Native Corvus spp. and then invasive red foxes (Vulpes vulpes) were the top carcass visitors and nest egg predators. Carcass presence and open habitat increased overall nest predation and fewer artificial parrot nest eggs were depredated compared to those of quail. Open habitat and carcass presence only increased predator-specific nest predation by foxes, but corvid nest predation was highest in June 2018, and for the artificial quail nest types. Foxes were the main predator of eggs from night parrot nests. Our study shows that carcass provisioning by humans may have indirect, deleterious effects on ground nesting birds, and indicates that foxes might pose a greater threat to night parrot populations than previously recognised.

The responses of herbaceous species to shrubs are crucial for community succession, but are not fully understood. Three sites experiencing degraded, early positive and late positive successional stages in Laizhou Bay coastal wetland of North China were selected to investigate herbaceous responses to the dominant shrub Tamarix chinensis at both community and species level. The effects of T. chinensis on plant diversity and growth of herbaceous community were negative in the degraded succession but facilitative in the positive succession. Solar irradiance was the only environmental factor investigated that was significant for species' proximity to the shrub in the degraded succession, while both aboveground (solar irradiance) and belowground environmental factors (soil electrical conductivity, water content, nitrogen concentration) played an important role in the positive succession. The performances of dominant herbaceous species in interaction with T. chinensis were both species-specific and traits-specific. Of all investigated factors, both solar irradiance and soil electrical conductivity significantly affected by the shrub and were the key factors for plant growth and leaf nutrient concentration at the species level. Thus, T. chinensis played an important role in the succession processes of the coastal wetland, but mainly in the positive succession stage and less in the degraded succession.

The specific mechanisms that result in the success of any species invasion case are difficult to document. Reproductive strategies are often cited as a primary driver of invasive success, with human activities further facilitating invasions by, for example, acting as seed vectors for dispersal via road, train, air, and marine traffic, and by producing efficient corridors for movement including canals, drainages, and roadways. Sahara mustard (Brassica tournefortii) is a facultative autogamous annual native to Eurasia that has rapidly invaded the southwestern United States within the past century, displacing natives, and altering water‐limited landscapes in the southwest. We used a genotyping‐by‐sequencing approach to study the population structure and spatial geography of Sahara mustard from 744 individuals from 52 sites across the range of the species’ invasion. We also used herbaria records to model range expansion since its initial introduction in the 1920s. We found that Sahara mustard occurs as three populations in the United States unstructured by geography, identified three introduction sites, and combined herbaria records with genomic analyses to map the spread of the species. Low genetic diversity and linkage disequilibrium are consistent with self‐fertilization, which likely promoted rapid invasive spread. Overall, we found that Sahara mustard experienced atypical expansion patterns, with a relatively constant rate of expansion and without the lag phase that is typical of many invasive species.

Desert environments are sensitive to disturbances, and their functions and processes can take many years to recover. Detecting early signs of disturbance is critical, but developing such a capability for expansive remote desert regions is challenging. Using a variogram and 15-cm resolution Visible Atmospherically Resistant Index (VARI) imagery, we examined the usefulness of the spatial structure of desert lands for monitoring early signs of habitat changes using the Riverside East solar energy zone located within Riverside County, California. We tested the method on four habitat types in the region, Parkinsonia florida&ndash, Olneya tesota, Chorizanthe rigida&ndash, Geraea canescens, Larrea tridentata&ndash, Ambrosia dumosa, and Larrea tridentata&ndash, Encelia farinosa alliances. The results showed that the sill, range, form, and partial sill of the variogram generated from VARI strongly correlate with overall vegetation cover, average canopy size, canopy size variation, and spatial structure within a dryland habitat, respectively. Establishing a baseline of variogram parameters for each habitat and comparing to subsequent monitoring parameters would be most effective for detecting internal changes because values of variogram parameters would not match absolute values of landscape properties. When monitoring habitats across varying landscape characteristics, a single appropriate image resolution would likely be the resolution that could adequately characterize the habitat dominated by the smallest vegetation. For the variogram generated from VARI, which correlates to vegetation greenness, the sills may indicate the health of vegetation communities. However, further studies are warranted to determine the effectiveness of variograms for monitoring habitat health. Remotely sensed landscape structure obtained from variograms could provide complementary information to traditional methods for monitoring internal changes in dryland vegetation communities.

A specimen of Masticophis lateralis (Hallowell, 1853) was found and photographed in the outskirts of San Juanico Bay, Baja California Sur, Mexico. This record fills in a gap of the distribution of this species along both coasts of Baja California Sur.

Increasing aridity is one of the most important trends of current climate change. Leaf functional traits suggest a substantial basis for assessing the aridity effects on vegetation. However, since plants possess diverse leaf morphology and anatomy due to different evolutionary history of taxa, the effect of aridity can hardly be revealed in a multi-species analysis. We studied leaf functional traits for 317 samples of 193 plant species in steppe and desert communities along a 1600-km latitudinal gradient in Southern Siberia (Transbaikalia, Russia) and Mongolia. We determined morphological leaf traits, quantitative anatomical parameters, physiological parameters, and photosynthetic pigments content. Different relevance of leaf traits for indication of plant response to climate has been demonstrated. The clearest changes in site-mean values along the aridity gradient were shown for leaf thickness, total chloroplast number per leaf area (Nchl/A) and total surface area of chloroplasts (Achl/A) and cells (Ames/A) per leaf area. Unlike leaf size and leaf mass per area, these quantitative mesophyll parameters related to plant photosynthetic capacity were strongly correlated with climate. We found no evidence for a decrease in sizes of mesophyll cells with aridity, but cell volume as well as chloroplast number per cell were linked with plant functional type (PFT). We revealed an increase in Nchl/A and Achl/A in desert-steppe species in comparison to steppe and forest-steppe vegetation types within each PFT of C3-plants (C3-dicot herbs, C3-dicot shrubs, C3-monocots and C3-succulents). C4-plants were generally characterized by low Achl/A and Ames/A, but had higher rate of CO2-transfer through mesophyll and chloroplast surfaces. C3- and C4-plants differed in response to aridity and showed opposite trends in changes of leaf traits along the aridity gradient. We conclude that leaf mesophyll traits contribute to important mechanism of climatic adaptation in different PFTs along a large latitudinal gradient. © 2018 Elsevier GmbH Russian Foundation for Basic Research, RFBR: АААА-А17-117072810011-1, 17-29-05019, АААА-А17-117011810036-3 The authors are deeply indebted Joint Russian-Mongolian Complex Biological Expedition RAS and MAS, who supported the field observation and data collection used in this study. The analytical part of this research has been partially supported by RFBR grant 17-29-05019 , and partly by project №АААА-А17-117072810011-1 of Russian Federal Budget . The research of O.A. Anenkhonov was carried out using the framework of project № АААА-А17-117011810036-3 supported by the Russian Federal Budget .

Summary Intraspecific competition among parasites should, in theory, increase virulence, but we lack clear evidence of this from nature.1–3 Parasitic plants, which are sessile and acquire carbon-based resources through both autotrophy (photosynthesis) and heterotrophy (obtaining carbon from the host), provide a unique opportunity to experimentally study the role of intraspecific competition for nutrients in shaping the biology of both parasite and host.4–6 Here, we manipulated the spatial position of naturally occurring individuals of desert mistletoe (Phoradendron californicum), a xylem hemiparasite, by removing parasites from co-infected branches of a common nitrogen-fixing host, velvet mesquite (Prosopsis velutina), in the Sonoran Desert. We measured physiological performance of both host and parasite individuals under differing competitive environments—parasite location along the xylem stream—through time. Performance was determined by measuring resource availability and use, given that resource demand changed with competitor removal and monsoon-driven amelioration of seasonal drought. Our principal finding was that intraspecific competition exists for xylem resources between mistletoe individuals, including host carbon. Host performance and seasonal climate variation altered the strength of competition and virulence. Hemiparasitic desert mistletoes demonstrated high heterotrophy, yet experimental removals revealed density- and location-dependent effects on the host through feedbacks that reduced mistletoe autotrophy and improved resource availability for the remaining mistletoe individual. Trophic flexibility tempered intraspecific competition for resources and reduced virulence. Mistletoe co-infections might therefore attenuate virulence to maintain access to resources in particularly stressful ecological environments. In summary, experimental field manipulations revealed evidence for intraspecific competition in a parasite species.

Background: Camel is vital to daily life as a source of food and means of transportation, and just as importantly, its milk and urine have been used as medicine for diverse ailments since ancient times for people living in the desert region.Aim: The current study was planned to investigate the effect of different watering regimes on physiological and hematological parameters of lactating Marecha camels during the summer season.Methods: For this purpose, 12 lactating she-camels of almost similar age (8–13 years) and parity (2–5) were selected in a completely randomized design with four animals per treatment at the Camel Breeding and Research Station Rakh Mahni District Bhakkar. The trial was completed in 60 days, while 7 days were given as an acclimatization period for adaptation. The treatments were as follows: Group-1 (G-1) considered as the control had access to water once in a day; Group-2 (G-2) had access to water once in 4 days, and Group-3 (G-3) had access to water once in 6 days. Animals were housed individually for feeding and watering in an intensive management system. The same feed consisting of green fodder (Lucerne) and gram straw (Cicer arientinum) was offered to all animals. The average ambient temperature and relative humidity were 39°C–41°C and 55%–63%, respectively.Result: The mean values (p < 0.001) of water intake were found to be 82.94 ± 1.34 l in G-3, which was higher than G-1 and G-2. Blood analysis showed that packed cell volume, white blood cells, and hemoglobin were affected significantly (p < 0.001, p < 0.01, and p < 0.05, respectively).Conclusion: No serious changes in complete blood count and physiological parameters were reported in this study. So, this shows that the camel is unique in its physiological adaptation in hot and hostile environments.

Drought is a major constraint in drylands for crop production. Plant associated microbes can help plants in acquisition of soil nutrients to enhance productivity in stressful conditions. The current study was designed to illuminate the effectiveness of desert rhizobacterial strains on growth and net-return of chickpeas grown in pots by using sandy loam soil of Thal Pakistan desert. A total of 125 rhizobacterial strains were isolated, out of which 72 strains were inoculated with chickpeas in the growth chamber for 75 days to screen most efficient isolates. Amongst all, six bacterial strains (two rhizobia and four plant growth promoting rhizobacterial strains) significantly enhanced nodulation and shoot-root length as compared to other treatments. These promising strains were morphologically and biochemically characterized and identified through 16sRNA sequencing. Then, eight consortia of the identified isolates were formulated to evaluate the growth and development of chickpea at three moisture levels (55%, 75% and 95% of field capacity) in a glass house experiment. The trend for best performing consortia in terms of growth and development of chickpea remained T2 at moisture level 1 &gt, T7 at moisture level 2 &gt, T4 at moisture level 3. The present study indicates the vital role of co-inoculated bacterial strains in growth enhancement of chickpea under low moisture availability. It is concluded from the results that the consortium T2 (Mesorhizobium ciceri RZ-11 + Bacillus subtilis RP-01 + Bacillus mojavensis RS-14) can perform best in drought conditions (55% field capacity) and T4 (Mesorhizobium ciceri RZ-11 + Enterobacter Cloacae RP-08 + Providencia vermicola RS-15) can be adopted in irrigated areas (95% field capacity) for maximum productivity of chickpea.

Small insectivorous tree-roosting bats are among the most taxonomically diverse group of mammals in Australia's desert, yet little is known about their thermal physiology, torpor patterns and roosting ecology, especially during summer. We used temperature-telemetry to quantify and compare thermal biology and roost selection by broad-nosed bats Scotorepens greyii (6.3 g; n = 11) and Scotorepens balstoni (9.9 g; n = 5) in Sturt National Park (NSW Australia) over 3 summers (2010–13). Both vespertilionids used torpor often and the total time bats spent torpid was ∼7 h per day. Bats rewarmed using entirely passive rewarming on 44.8% (S. greyii) and 29.4% (S. balstoni) of all torpor arousals. Both bat species roosted in hollow, cracked dead trees relatively close to the ground (∼3 m) in dense tree stands. Our study shows that torpor and passive rewarming are 2 common and likely crucial survival traits of S. greyii and S. balstoni.

Geophytes are kind of plants having the capability to survive under arid environmental conditions; parts of their bodies are dormant fleshy underground as bulbs, corms, tubers or rhizomes. The present study was designed to throw light on the ecological features of five representative geophytes, namely, Cyperus capitatus, Cyperus conglomeratus , Elymus farctus , Lasiurus scindicus and Panicum turgidum . The soil characteristics and the associated species of these geophytes are described in their natural habitats of coastal desert (Deltaic Mediterranean coast) and inland desert (Cairo-Suez desert road). A total of 119 species (65 perennials, 3 biennials and 51 annuals) belonging to 97 genera and 28 families constituted their floristic composition. Asteraceae, Poaceae, Fabaceae and Chenopodiaceae are the largest families. Therophytes and chamaephytes are the most abundant life forms. The chorological analysis of the study area revealed that 63.02% and 47.33% belong to Saharo-Arabian and Mediterranean taxa, respectively. The highest species richness value (1.42 species stand –1 ) is recorded in the coastal desert. The application of TWINSPAN analysis yielded six distinct vegetation groups (A, B, C1, C2, D1 and D2); each is linked to one or more of the studied geophyte plants. The main soil factors affecting the study geophytes are electrical conductivity, organic carbon, sulphates, chlorides and bicarbonates as well as its silt composite.

Objective To determine the prevalence and associated risk factors of gastrointestinal and liver parasites in yak in the cold desert area of the Mustang District, Nepal. Methods Fecal samples were collected over a period of three months from 96 yaks from the high Himalayan District of Mustang, Nepal. The samples were tested for the presence of parasites by direct smear, sedimentation, and floatation techniques. Yak herders were surveyed with pre-tested questionnaires by participatory appraisals to explore their knowledge and awareness of parasitic diseases and health management. Results Examination of fecal samples revealed that 82 were positive for one or more parasites, giving an overall prevalence of 85.42%, in which 6.25% had single and 79.17% had multiple parasitic infections. Animals with poor body condition scores and young age were more susceptible than their counterparts. Inferior body condition scores were attributed to parasitic burden. No significant difference was noted between worm burden and either the sex of the animal or the altitude. Conclusions A high proportion of yaks in the lower Mustang Region of Nepal suffered from the mild to moderate parasitic infection, significant enough to contaminate the pasture and spread infection to healthy animals. Complementary studies are needed to establish the impact of parasitism on productive performance. Furthermore, nutrition and health management, including regular and strategic parasite monitoring programs are needed for better health and productivity.