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Climate change is rapidly challenging natural systems, ranking among the top drivers of biodiversity and ecosystem changes globally. Long-distance migratory bird species are particularly vulnerable to climate-induced changes and have already exhibited shifts in their distribution and phenology. In this study, we investigated the impact of climate change on the arrival fuel loads and stopover behavior of 16 trans-Saharan migratory passerines during spring migration aiming to highlight not only the direct effects on migration patterns but also the potential implications for later stages of their annual cycle. We showed that the double barrier crossing, i.e. the Sahara Desert and the Mediterranean Sea, imposes varying energy costs depending on geographic differences in the availability of stopover sites in northern Africa. The projected decline in the availability of these refueling sites is likely to pose a greater threat to migratory passerines than the changes in desert crossing distances. Moreover, arrival fuel load, migration timing, and, to a lesser extent, aridity, were found to influence stopover behavior. However, with deteriorating conditions across the Mediterranean, aridity is expected to play a more significant role in stopover behavior in the future. The predicted delays in the timing of migration and the reduction of arrival fuel loads could ultimately compromise the breeding success of these birds or even increase mortality en route. The study emphasizes the vulnerability of migratory birds to climate change and provides valuable insights for conservation planning, highlighting the need to protect critical refueling areas. [ABSTRACT FROM AUTHOR]

Hydroclimate variation and vegetation changes of the Nile River watershed area in northeast Africa since the Last Glacial Maximum (LGM) were reconstructed based on n‐alkanes, their carbon isotope ratios (δ13Cn‐alkanes), and their hydrogen isotope ratios (δ2Hn‐alkanes) in sediments from ODP Site 967 in the Eastern Mediterranean Sea. The results were compared with the present vegetation cover in the watershed areas using ArcGIS. The average proportion of current grassland in the Equatorial Lake and Ethiopian Highland Plateaus watershed areas was 45.8 and 64.7%, respectively. δ2Hn‐alkanes ranged from −199 to −127‰ and co‐varied with insolation change response to orbital forcing. Depleted δ2Hn‐alkanes were found from deglaciation to the middle Holocene, suggesting increased precipitation during the African Humid Period (AHP) from 15 to 5 ka caused by northward migration of the Intertropical Convergence Zone. However, lower precipitation was inferred by enriched δ2Hn‐alkanes during the LGM and late Holocene. δ13Cn‐alkanes at Site 967 did not show a trend in harmony with δ2Hn‐alkanes and instead exhibited millennial‐scale variations ranging from –25.9 to –33.2‰. These δ13Cn‐alkanes values consistently indicated a C4 grass‐dominated environment in the watershed areas of the River Nile since the LGM, persisting through the AHP and into the present. Reconstructions demonstrated orbital and abrupt forcing of hydroclimate variability while maintaining generally grass‐dominated vegetation with weak precipitation feedback over the late Quaternary. [ABSTRACT FROM AUTHOR]

Studies performed in North America, Africa, and South America have led to the isolation of four new species of Kastovskya, a filamentous cyanobacterial genus that before this manuscript had only one species, Kastovskya adunca from Chile. Kastovskya nitens and K. viridissima were isolated from soils on San Nicolas Island, K. sahariensis was isolated from hypolithic habitats from the Sahara Desert in Algeria, and K. circularithylacoides was isolated from hypolithic habitats in Chile. The molecular analyses are corroborated by morphological data, morphometric analysis, and ecological and biogeographical considerations for robust polyphasic descriptions of all taxa. The peculiar transatlantic distribution of this genus bears similarity to other taxa in recently published studies and is in agreement with a hypothesis suggesting that cyanobacteria in Africa may disperse to the Americas on dust particles during windstorms. This work is unusual in that species in a single rare cyanobacterial genus with a disjunct distribution are described simultaneously from three continents. The 16S rRNA gene analyses performed for this study also revealed that another recent genus, Arizonema, is clearly a later synonym of Symplocastrum. This issue is resolved here with the collapsing of the type species Arizonema commune into Symplocastrum flechtnerae. [ABSTRACT FROM AUTHOR]

Sedentary animals choose appropriate refuges against predators, while migratory ones may not necessarily do so. In ectotherms, refuge selection is critical during low temperatures, because they cannot actively evade predators. To understand how migratory ectotherms alter their defensive behaviors depending on refuge quality in cold temperatures, we evaluated migratory gregarious desert locust nymphs (Schistocerca gregaria) in the Sahara Desert, where daily thermal constraints occur. We recorded how roosting plant type (bush/shrub) and its height influenced two alternative defense behaviors (dropping/stationary) during cold mornings, in response to an approaching simulated ground predator. Most locusts in bushes dropped within the bush and hid irrespective of their height, whereas those roosting > 2 m height in shrubs remained stationary. These defenses are effective and match with refuge plant types because dynamic locomotion is not required. When nymphs roosted on shrubs < 1.5-m height, which was an unsafe position, nearly half showed both defensive behaviors, indicating that escaping decisions become ambiguous when the refuges are inappropriate. These results suggest that locusts display flexible defensive behaviors when finding appropriate refuges and selecting refuge before daily thermal limitations occur could be critical for migratory ectotherms, which is a risk associated with migration. [ABSTRACT FROM AUTHOR]

The North Atlantic Oscillation (NAO) is the most recognized and leading mode of atmospheric variability observed over the Atlantic sector of the Northern Hemisphere, and its impacts on weather and climate over the North Atlantic and Eurasia via large-scale teleconnections have been extensively studied. Here we use a multidata synthesis approach to analyze surface and tropospheric variables from multiple long-term observational and reanalysis datasets to identify the NAO's footprint on interannual temperature variability over the vast but least-studied Sahara Desert during December–January–February–March for the satellite era (1979–2022) and century-long periods. Our results present evidence for a solid teleconnection pattern in surface and tropospheric temperatures associated with the NAO over the Sahara and document some major spatial–temporal and vertical characteristics of this pattern. It is found that the Saharan temperature anomalies are negatively correlated with the NAO index and this correlation is very strong, consistent, and statistically significant between different periods and across different datasets. The teleconnection is closely linked to large-scale circulation anomalies throughout the troposphere over the North Atlantic–Sahara sector, where the anomalous horizontal wind components and geopotential height exhibit opposite changes in sign with altitude from the lower to upper troposphere. During the negative NAO− (positive NAO+) phase, above-normal (below-normal) temperatures over the Sahara could be mainly explained by three major processes: (1) advection of climatological warm and moist (cold and dry) air over the North Atlantic (northern higher latitudes) by the anomalous southwesterly (northeasterly) flow in the lower troposphere; (2) advection of anomalous North Atlantic warm (cold) air by the climatological strong westerlies in the middle and upper troposphere; and (3) strengthened (weakened) vertical mixing in the atmospheric boundary layer. These results suggest that the NAO plays an important role in modulating the interannual temperature variability over the Sahara, and that this NAO footprint is mostly realized through horizontal temperature advection and vertical heat transfer by turbulent mixing. [ABSTRACT FROM AUTHOR]

As a crucial aspect of the climate system, changes in Africa's atmospheric layer thickness, i.e., the vertical distance spanning a specific layer of the Earth's atmosphere, could impact its weather, air quality, and ecosystem. This study did not only examine the trends but also applied a deep autoencoder artificial neural network to detect years with significant anomalies in the thickness of Africa's atmosphere over a given homogeneous region (derived with the rotated principal component analysis) and examine the fingerprint of global warming on the thickness changes. The broader implication of this study is to further categorize regions in Africa that have experienced significant changes in their climate system. The study reveals an upward trend in thickness between 1000 and 850 hPa across substantial parts of Africa since 1950. Notably, the spatial breadth of this rise peaks during the boreal summer. Correlation analysis, further supported by the deep autoencoder neural network, suggests the fingerprint of global warming signals on the increasing vertical extent of Africa's atmosphere and is more pronounced (since the 2000s) in the south-central regions of Africa (specifically the Congo Basin). Additionally, the thickness over the Sahel and Sahara Desert sees no significant increase during the austral summer, resulting from the counteracting effect of the positive North Atlantic Oscillation, which prompts colder conditions over the northern parts of Africa. As the atmospheric layer thickness impacts the temperature and moisture distribution of the layer, our study contributes to its historical assessment for a sustainable ecosystem. [ABSTRACT FROM AUTHOR]

The House bunting (Emberiza sahari Levaillant, 1850) is a human commensal passerine bird species, characteristic of urban environments in the Sahara Desert of Algeria. Its distribution in Algeria, with particular emphasis in Ghardaïa, was investigated using two sampling methods: progressive frequency sampling and point abundance index, with ecological field data collected during 2017-2019. Morphological biometric measurements were carried out on free-living individuals for each sex. Reproduction phenology and success were surveyed through the breeding season (February‒September) during 2018‒2019. Trophic behavior was studied by direct observations of foraging individuals. Results showed that the species range in Algeria is larger than shown by data from the literature, with expansion northwards within the country. At a finer scale, in Saharan cities, the species prefers old and traditional urban environments, where its densities are higher than within modern urban habitats. At a national scale, we found that the species range is not restricted to desert climates, but extends towards the north of Algeria, including the semi-arid steppe rangelands of the Hauts-Plateaux region. Range changes are attributed to changes in building practices and climate change. Adult females were heavier and slightly larger than males, whose head plumage had different coloration patterns compared to females. Nests weighed 82.03 ± 20.77 g (mean ± standard deviation) and consisted of 72% plant materials, 19% animal-origin materials and 9% inert constituents. The nest cups were oval in form, top-lined and stuffed with diverse material. House buntings nest under the roofs of uninhabited houses, in stairwells, traditional water wells, and holes within walls. Nesting height averaged 2.14 ± 0.8 m. In Ghardaia, courtship and pair formation began mid-February. Females can raise up to three successive broods (March-September), with 31‒34 days/brood including 14‒15 days for egg incubation. Clutch size is typically 2‒3 eggs. The diet of the House bunting included seeds of annual grasses dominated by Poaceae species. The species also fed on anthropogenic food remains, and sometimes on insects, especially during the breeding period.

This article examines the ways in which past colonial figures, who emerged against the backdrop of the nineteenth-century conquest of North Africa, still resonate and are celebrated in contemporary Algerian Francophone and Arabophone literatures. It questions the wider implications of these celebrations for post-colonial societies, and in particular the place of nostalgia and the wish to distinguish between the iniquities of colonialism as a system on the one hand, and the fortuitous but productive encounters involving those who challenged it from within, on the other. By contextualising the contemporary productions of Malika Mokeddem and Said Khatibi, this article demonstrates how these authors celebrate the many ways in which the non-conformist colonial figure of Isabelle Eberhardt sought freedom and rebelled against power tropes – particularly through the recourse to male disguise, whilst simultaneously appropriating and domesticating the Sahara Desert, its cultures and its populations. This article also examines how Yasmina Khadra celebrates French authors like Roger Frison-Roche and prominent colonial figures such as Charles de Foucauld. These literary works appear as significant examples of memory across different cultural settings, informing the challenge to, and inheritance of, the colonial tropes. Unexpectedly, figures such as that of Eberhardt appear, in the eyes of Algerian authors, as valid examples to emulate, in order to celebrate, reach, or at least imagine, emancipation in the aftermath of Algerian independence. This ultimately reveals hitherto ignored continuity between the colonial past and the postcolonial present that has nurtured the emergence of hybrid identities. [ABSTRACT FROM AUTHOR]

Gazella leptoceros (F. Cuvier, 1842) is a monotypic African gazelle, most commonly called the slender-horned gazelle. It is one of 21 species in the genus Gazella and is distinguished by its pale sandy coloration, fawn-colored markings, and namesake long, slender horns. Gazella leptoceros is a dune specialist that inhabits the hyperarid northern Sahara Desert between Algeria and Egypt. It feeds on shrubs and low desert plants and ranges over large distances in small groups of 1–5 animals. Because of its very small, isolated populations, G. leptoceros is classified as "Endangered" (EN) on the International Union for Conservation of Nature Red List of Threatened Species and is on Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora. [ABSTRACT FROM AUTHOR]

This study evaluates the impact of assimilating moderate resolution imaging spectroradiometer (MODIS) aerosol optical depth (AOD) data using different data assimilation (DA) methods on dust analyses and forecasts over North Africa and tropical North Atlantic. To do so, seven experiments are conducted using the Weather Research and Forecasting dust model and the Gridpoint Statistical Interpolation analysis system. Six of these experiments differ in whether or not AOD observations are assimilated and the DA method used, the latter of which includes the three-dimensional variational (3D-Var), ensemble square root filter (EnSRF), and hybrid methods. The seventh experiment, which allows us to assess the impact of assimilating deep blue AOD data, assimilates only dark target AOD data using the hybrid method. The assimilation of MODIS AOD data clearly improves AOD analyses and forecasts up to 48 hr in length. Results also show that assimilating deep blue data has a primarily positive effect on AOD analyses and forecasts over and downstream of the major North African source regions. Without assimilating deep blue data (assimilating dark target only), AOD assimilation only improves AOD forecasts for up to 30 hr. Of the three DA methods examined, the hybrid and EnSRF methods produce better AOD analyses and forecasts than the 3D-Var method does. Despite the clear benefit of AOD assimilation for AOD analyses and forecasts, the lack of information regarding the vertical distribution of aerosols in AOD data means that AOD assimilation has very little positive effect on analyzed or forecasted vertical profiles of backscatter.

Bird intake and damage to fruits of Phoenix dactylifera is a common problem in date palm cultivation regions. Though plant vegetative characteristics and fruit nutritional values influence frugivory behavior in passerines, there is little knowledge about these parameters for sparrows feeding on dates, as most previous studies have focused on the impact of farm organization and location on the feeding choice made by sparrows. This study aimed to examine the effects of date palm tree traits and its fruit morphology and biochemical traits on the level of damage caused by hybrid sparrows to date fruits of three different date palm cultivars. In a traditional date palm plantation, three date varieties (Degla-Beida, Deglet-Nour and Ghars) were analyzed. The estimates of date production loss were correlated to several tree morphometrics and fruit morphological and biochemical traits, including the number of bunches/tree, bunch height, number of pedicels/bunch, number of dates per strand, total production/tree, and date fruit traits (length, width, weight, volume, pulp weight, ratio pulp weight/date weight, sugar content, water content and pH). We demonstrated that sparrows were attracted to bunches with low height and high fruit density, but they showed no interest to number of bunches per tree, number of pedicels per bunch, total number of dates and production per tree. Regarding date morphology, large and heavy dates were more likely to be selected by sparrows, although an unclear relationship was found between production loss per tree and date length, width and volume. In terms of fruit biochemical traits, sparrows damage rates increased with the increase in fruit pH, moisture, and total and reducing sugars. The average rate of lost dates per tree was 9.2 ± 7.66%, 8.4 ± 5.16%, and 3.9 ± 1.71% for Ghars, Deglet-Nour, and Degla-Beida, respectively. Significant differences were observed between cultivars in the amounts of damaged dates still on bunches or fallen on the ground. The hierarchical choice of dates by sparrows was also confirmed. Our results showed that soft dates were more preferred by sparrows than semi-soft and dry ones. The findings of this study indicated that it is necessary to provide extensive protection for highly attacked cultivars in palm groves.

First scientifically documented by the British explorer and soldier Ralph Alger Bagnold, the Selima Sand Sheet is an extensive low-relief area located within the modern hyperarid core of the Eastern Sahara. Field survey and trenching reveal a surface mantle of near 'pinstripe" laminated aeolian sands that comprise active chevron (or zibar) bedforms, which are apparent on satellite datasets. These active sands cover Quaternary paleosols with morphostratigraphic characteristics that reflect differing degrees of soil development over time as a function of in situ weathering of quartz parent materials, addition of silts and clays via illuviation and eluviation processes, the precipitation of carbonates, rubification, and bioturbation by plants and insects. A relative chronostratigraphy is inferred from the associated archaeological (Neolithic) and historical materials (Late Historic to World War II), and absolute ages for these deposits are provided by optical dates using single aliquot regeneration techniques (SAR). Constraining the timing of aeolian sedimentation provides a basis for reconstructing paleoenvironmental changes and pedogenesis over Late Quaternary timescales in this region of northeast Africa. Accretion of the sand sheet was episodic and occurred during time periods of enhanced aeolian activity at ∼20–14 and ∼5–3 ka years ago. Late Pleistocene deposition of the sand sheet was out-of-phase with the widely recognized period of rainwater-fed "pluvial" playa lake formation and wadi river drainage alluviation documented in the Sahara, which resulted from enhanced monsoonal rains associated with the orbitally-forced precessional insolation maximum in the Northern Hemisphere. Enhanced bioturbation processes associated with wet phases during the Holocene have completely obliterated most primary sedimentary structures in the Pleistocene-aged sand sheet, resulting in the development of a cohesive, coarse sand and granule-dominated deposit exhibiting incipient prismatic soil structural development. The younger sand sheets dating to the Late Holocene (∼4–3 ka years ago) preserve primary sedimentary structures (e.g. planar laminations), and increasing amounts of cohesion and structure with age. Reconstructing the maximum estimated accumulation rates, and assuming approximately uniform rates of sedimentation across the Selima Sand Sheet area, sediment storage within the sand sheet may be on the order of ∼7 km3/1000 years during the time period that has elapsed since the mid-Holocene onset of arid conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Date palm production loss was characterized using tree/fruit morpho-biochemical traits. • Fruit damages caused by sparrows were higher in Deglet-Nour and Ghars varieties. • Depredation levels of dates significantly varied between studied cultivars. • Sparrow depredation was high in cultivars with high fruit water content, pH and reducing sugars. • Production loss parameters were positively correlated with date morphometric and biochemical traits. Bird intake and damage to fruits of Phoenix dactylifera is a common problem in date palm cultivation regions. Though plant vegetative characteristics and fruit nutritional values influence frugivory behavior in passerines, there is little knowledge about these parameters for sparrows feeding on dates, as most previous studies have focused on the impact of farm organization and location on the feeding choice made by sparrows. This study aimed to examine the effects of date palm tree traits and its fruit morphology and biochemical traits on the level of damage caused by hybrid sparrows to date fruits of three different date palm cultivars. In a traditional date palm plantation, three date varieties (Degla-Beida, Deglet-Nour and Ghars) were analyzed. The estimates of date production loss were correlated to several tree morphometrics and fruit morphological and biochemical traits, including the number of bunches/tree, bunch height, number of pedicels/bunch, number of dates per strand, total production/tree, and date fruit traits (length, width, weight, volume, pulp weight, ratio pulp weight/date weight, sugar content, water content and pH). We demonstrated that sparrows were attracted to bunches with low height and high fruit density, but they showed no interest to number of bunches per tree, number of pedicels per bunch, total number of dates and production per tree. Regarding date morphology, large and heavy dates were more likely to be selected by sparrows, although an unclear relationship was found between production loss per tree and date length, width and volume. In terms of fruit biochemical traits, sparrows damage rates increased with the increase in fruit pH, moisture, and total and reducing sugars. The average rate of lost dates per tree was 9.2 ± 7.66%, 8.4 ± 5.16%, and 3.9 ± 1.71% for Ghars, Deglet-Nour, and Degla-Beida, respectively. Significant differences were observed between cultivars in the amounts of damaged dates still on bunches or fallen on the ground. The hierarchical choice of dates by sparrows was also confirmed. Our results showed that soft dates were more preferred by sparrows than semi-soft and dry ones. The findings of this study indicated that it is necessary to provide extensive protection for highly attacked cultivars in palm groves. [ABSTRACT FROM AUTHOR]

Background: This study investigates new dangers that West African migrants travelling through the Sahara Desert to Europe contend with. COVID-19 has left an unprecedented impact on all aspects of global politics, migration inclusive. In turn, limitations to migration have drastically increased, especially the stricter visa application measures set by European countries. This intensified attempts at crisscrossing the desert to Europe. In turn, several migrants used the Sahara as the highway to Europe. While some persons successfully travelled through the desert-scape, several others were unsuccessful. Notwithstanding the negative experiences of previous migrants, several other nationals across the region have plans to travel through the desert to Europe. Methods: As a descriptive study, mixed method of qualitative and quantitative approaches to data gathering and analysis were employed. Primary data for the study were gathered through key informants’ interviews with some emigrants, and electronic copies of an open-ended questionnaire were administered to the staffers of certain international non-governmental organisations (INGOs) that are focused on migration. In addition, the chain-referral sampling technique was employed. Through this, certain former migrants who were interviewed suggested other persons with whom interview sessions were conducted, in all 15 persons were interviewed while 85 persons responded to the questionnaire for the study. Results: The findings of the study indicated that there are new dangers to the lives of the migrants travelling through the Sahara Desert. Interesting however is the fact that migrants prefer being in harm’s way in their attempts to access European states illicitly through the Sahara Desert than to remain safe in their home countries in West Africa. Conclusions: The study holds that there are new dangers to the aspirations of West Africans travelling to Europe through the Sahara and the Mediterranean Sea.

Saharan dust storms, which originate from the Sahara desert, have a significant impact on global health, especially on respiratory conditions of populations exposed to fine particulate matter that travels across continents. Dust events, characterized by the transport of mineral dust such as quartz and feldspar, lead to the suspension of particulate matter in the atmosphere, capable of traversing long distances and affecting air quality adversely. Emerging research links these dust episodes with increased incidence and exacerbation of lung diseases, including asthma and chronic obstructive pulmonary disease, especially during peak dust emission seasons from November to March. The present review aims to synthesize existing scientific evidence concerning the respiratory health impacts of Saharan dust, examining the environmental dynamics of dust transmission, the physical and chemical properties of dust particles, and their biological effects on human health. Further, it assesses epidemiological studies and discusses public health strategies for mitigating adverse health outcomes. Given the complexity of interactions between atmospheric dust particles and respiratory health, this review also highlights critical research gaps that need attention to better understand and manage the health risks associated with Saharan dust. [ABSTRACT FROM AUTHOR]

In this study, the aerosol optical depth (AOD) from the Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 6.1 (C6.1) product was compared with ground-based measurements at five sites of the Aerosol Robotic Network (AERONET) in North Africa. The MODIS AOD showed a good correlation coefficient of ~0.78, a very small mean bias error of 0.009, and a root mean square error of 0.126 with AERONET. The Dark Target/Deep Blue (DT/DB) algorithm showed better performance at low aerosol loading while underestimating AOD at higher aerosol loading, mainly for coarse-dominated aerosol types. This work also showed the benefits of using MODIS retrievals as a reliable data source for aerosols and providing a long-term aerosol type classification. The primary aerosol type is dust emitted from the Sahara Desert, and the dusty atmosphere becomes gradually mixed with pollution aerosols approaching the coastal region. The annual mean MODIS AOD at 550 nm and Ångström exponent at 412–650 nm (AE) ranged from 0.17 to 0.45 and from 0.13 to 1.25, respectively, in Algeria between 2001 and 2019. Lower AOD (< 0.22) and higher AE (> 1) were found in the northern region, while the highest AOD (0.35 to 0.45) and the lowest AE (< 0.25) were observed over the Tanezrouft desert in southern Algeria. The seasonal mean AOD was highest in summer, while the lowest was in winter due to very high easterly and northeasterly Harmattan surface wind over Zone of Chotts and the Tidikelt Depression, respectively. The negative AOD trends observed over Algeria could be partially connected to the decline (increase) in surface (850 hPa) winds over potential dust source areas in southern Algeria. [ABSTRACT FROM AUTHOR]

Previous studies documented that near‐surface temperatures over the Sahara and Arabian deserts have been amplified in a warming climate, which is termed desert amplification (DA). DA has been linked possibly to the large‐scale greenhouse effects associated with increasing water vapour. With very limited moisture availability over the driest desert, two key questions unanswered are the desert moisture sources and the relative contributions of thermodynamic and dynamic processes to the changes in moisture transport. In this study, the atmospheric water vapour budget over the Sahara Desert from 1981–2020 is analysed to address these two questions. Results indicate that the water vapour content over the Sahara Desert has increased significantly since 1981, primarily during the boreal summer and in the lower to middle troposphere. The water vapour budget analysis indicates that in the boreal summer, most of the added moisture is transported into the Sahara Desert through the intensifying northerly inflow across the northern boundary of the desert, while the other boundaries are all export channels. The northerly inward moisture transport is associated with the ridge in the lower troposphere and the Saharan high above the lower troposphere. Further analysis indicates that both dynamic and thermodynamic factors contribute to the increase of the inward moisture flux at the northern boundary, while the associated interannual variability is dominated by the dynamic component related to the circulation pattern changes. The changes of the circulation pattern in the lower troposphere are manifested as the westward extension of the low over the Arabian Peninsula and as the strengthening of the Saharan high above the lower troposphere, both contributing to the increase of the northerly inward moisture transport. [ABSTRACT FROM AUTHOR]

This study was conducted to assess comparative annual and seasonal patterns described in morphometric parameters, sexual and thyroid activities in indigenous bucks native to Sahara Desert. Seven adult bucks were used to establish seasonal patterns of body weight, testicular volume, plasma testosterone concentration measured by radioimmunoassay and pituitary-thyroid axis activity estimated by plasma concentrations of TSH, FT3 and FT4 measured by enzyme-linked fluorescent assay. The results showed monthly and seasonal variations characterized by a minimum in January for body weight, from December to February for testicular volume, followed by plasma testosterone concentration in March; they progressively increased to their respective maxima reached in July, August and September when ambient temperature and photoperiod were the highest. In October, there was a rapid fall in testosterone levels, preceding that of body weight and testicular volume (P

Automated classification of satellite images is a challenging task that enables the use of remote sensing data for environmental modeling of Earth’s landscapes. In this document, we implement a GRASS GIS-based framework for discriminating land cover types to identify changes in the endorheic basins of the ephemeral salt lakes Chott Melrhir and Chott Merouane, Algeria; we employ embedded algorithms for image processing. This study presents a dataset of the nine Landsat 8–9 OLI/TIRS satellite images obtained from the USGS for a 9-year period, from 2014 to 2022. The images were analyzed to detect changes in water levels in ephemeral lakes that experience temporal fluctuations; these lakes are dry most of the time and are fed with water during rainy periods. The unsupervised classification of images was performed using GRASS GIS algorithms through several modules: ‘i.cluster’ was used to generate image classes; ‘i.maxlik’ was used for classification using the maximal likelihood discriminant analysis, and auxiliary modules, such as ‘i.group’, ‘r.support’, ‘r.import’, etc., were used. This document includes technical descriptions of the scripts used for image processing with detailed comments on the functionalities of the GRASS GIS modules. The results include the identified variations in the ephemeral salt lakes within the Algerian part of the Sahara over a 9-year period (2014–2022), using a time series of Landsat OLI/TIRS multispectral images that were classified using GRASS GIS. The main strengths of the GRASS GIS framework are the high speed, accuracy, and effectiveness of the programming codes for image processing in environmental monitoring. The presented GitHub repository, which contains scripts used for the satellite image analysis, serves as a reference for the interpretation of remote sensing data for the environmental monitoring of arid and semi-arid areas of Africa.

The present study represents an integrated study using the potential field maps and well geochemical data of the West Dakhla area in the western central area of the Western Desert area, Egypt. The potential field data are represented by the airborne gravity and total magnetic maps acquired by the Nuclear Material Authority (NMA), Egypt, on behalf of Dana Petroleum Company. The geochemical data consist of geochemical analysis in Ammonite-1 well that were done for source rock evaluation. Different processing techniques on the gravity and magnetic maps are carried out for separating the regional and residual separation and filtering. Modelling and Euler deconvolution tools are utilized for proposing the depth to basement and constructing basement-depth maps to infer the basin configuration of the study area. Before acquiring the present geophysical data, the study area wasn’t subjected to any exploration investigations. Therefore, these data and this study are considered as the first efforts carried out and submitted for publication in this area. In addition, a comparison of the present basin is done with matched basins in southern Libya, where this basin is expected to have similar geological features. The study indicates that the studied basin may be a part of a wider basin extending in Egypt and Libya. This basin is expected to have the thickness and features that are favourable for hydrocarbon habitat. The geochemical analysis shows TOC values ranging from poor to very good source rock potentiality. [ABSTRACT FROM AUTHOR]

The Sahara Desert is the largest source of dust on Earth, and has a significant impact on global atmospheric changes. Wind is the main dynamic factor controlling the transport and intensity of dust in the Sahara Desert. This study comprehensively analyzed the spatial and temporal variation in the wind regime of the Sahara Desert from 1980 to 2019 using data from 17 meteorological stations to improve awareness of global atmospheric changes and the intensity of regional aeolian activities. All wind speed parameters decreased from northwest to southeast. While there were significant differences in the trends of temporal variation in wind speed among the different regions, there was an overall decreasing trend across the Sahara Desert, with an average wind speed of 0.09 m s−1 10 a−1. This decrease was closely related to wind frequency. The easterly, westerly, and northerly winds dominated, with more complex wind direction in the northern region. Seasonal differences in wind direction were observed in all regions. The wind direction frequency of wind speeds >6 m s−1 exceeded those with wind speeds

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The Napoleonic campaigns paved the way for French metropolitan travellers, military officers and literary authors to roam the barren stretches of North African deserts. Initially, imperial expansion was what brought French explorers to these lands. As devoted adventurers, they were quick to predict the literary opportunities of showcasing emptiness in military, scientific and literary projections. At once empty and loaded with spiritual charge, the desert embodies the essence of mystical connotations, for those who master decrypting its unsettling silence. This article argues that this seemingly empty space is in fact the cradle of spiritual pursuits, deployed in Sèbe’s ‘Saharomania’ concept as a redemptive locus. Showcasing emptiness thus represented a challenge to the spread of the cult of Western materialism. This is illustrated in two ways: the vision of French authors (Saint-Exupéry, Ernest Psichari, Charles de Foucauld, and Eric-Emmanuel Schmitt) who, taken together, amount to the establishment of a French desert genealogy of ‘Saharomania’, and the ways in which it offers a different reading of the accompanying Orientalist understanding of such works, through the prism of the redemptive wisdom of the desert. While taking part in Said’s Western canon on the Orient, redemptive ‘Saharomania’ also participates in the wider definition of the ways in which the imaginary of emptiness fuelled the fin-de-siècle cult of the void. It is in light of the alterity of the desert that the concept of ‘Saharomania’, specific to France, can be read: because showcasing emptiness meant empowerment, the success of the inscription of bareness in the imaginary of the French metropolitan public, and also its literary inheritance, was necessary to celebrate the French national sentiment. Taking the demanding crossing of the desert to heart, often for nationalist pursuits, was necessary to triumph over the physically and mentally exhausting desert. However, this article argues, authors incline when faced with the grandeur of the Sahara Desert, and its emblematic nomad dwellers, amidst the journey of the conventional fate of loss in the sands, ultimately changing the initial motives of the crossing. Thus, rather than condemning the present French literary productions within the confines of the orientalist and exotic tropes, this article offers different but no less significant interrogations about how ‘Saharomania’ valorises the desert as a locus of the higher forms of humankind, particularly defying the cult of Western hollowness through articulating spiritual resonance in the realm of the void.

The arid climate of the Saharan regions is accentuated even more by the consequences of climate change and environmental threats, thus affecting normal plant development. The salinization of soils is one of the major stresses in the Moroccan Sahara Desert that strongly penalizes the production. In this sense, it would be interesting to explore the native flora of the target regions, and using it remains the best option to provide sustainable agriculture. The present study is part of a collaborative project with the aim of exploring desert plant species. Different parameters were taken for each species, including soil salinity and density. Two zones showed the highest levels of salinity, Daoura and Akhfennir, both in the Tarfaya province with 19.38 and 24.33 mS/cm, respectively. Although, several species were highly tolerant to salinity and were present at moderate to high densities. Among them, one can cite Aeluropus littoralis (Gouan) Parl., Halocnemum strobilaceum (Pall.) M. Bieb. and Suaeda ifniensis Caball. ex Maire.

The marginal populations of the Sahara blue-eyed pond turtle, Mauremys leprosa saharica (Testudines: Geoemydidae) in the pre-Saharan area in the Lower Draa Valley, are faced to extreme environmental conditions of arid climate and anthropogenic activities including overuse of water and land salinization. In this study, we investigated a small isolated population of the blue-eyed pond turtle at Sidi El Mehdaoui Oasis, Lower Draa Valley, to determine its population structure and morphometric characteristics. Water salinity was about 24% of seawater and dissolved oxygen concentration was less than 3 mg l−1 (sub-hypoxia). The average body size of adults (carapace length) was much lower in comparison to other Moroccan populations. Among adult individuals, the mean carapace lengths were 103 ± 21 mm and 104.4 ± 35 mm for males and females, respectively. The corresponding mean body mass were 173 ± 92.4 g and 135 ± 52 g. There were no significant differences between sexes for size or weight. The studied population is small, with a predominance of adults (75%). A significant sexual size dimorphism was found. In fact, the Sexual Dimorphism Index for size had the lowest level ever described for the species possibly because of the low productivity of this marginal isolated habitat. The increased drought and salinization are major threats to the long-term persistence of the vulnerable populations of the Saharan blue-eyed pond turtle and their habitats. Therefore, conservation measures of these populations through the protection of their habitats are very urgent. [ABSTRACT FROM AUTHOR]

Copyright of Cahiers Victoriens & Edouardiens is the property of Presses Universitaires de la Mediterranee and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract This study evaluates the impact of assimilating moderate resolution imaging spectroradiometer (MODIS) aerosol optical depth (AOD) data using different data assimilation (DA) methods on dust analyses and forecasts over North Africa and tropical North Atlantic. To do so, seven experiments are conducted using the Weather Research and Forecasting dust model and the Gridpoint Statistical Interpolation analysis system. Six of these experiments differ in whether or not AOD observations are assimilated and the DA method used, the latter of which includes the three‐dimensional variational (3D‐Var), ensemble square root filter (EnSRF), and hybrid methods. The seventh experiment, which allows us to assess the impact of assimilating deep blue AOD data, assimilates only dark target AOD data using the hybrid method. The assimilation of MODIS AOD data clearly improves AOD analyses and forecasts up to 48 hr in length. Results also show that assimilating deep blue data has a primarily positive effect on AOD analyses and forecasts over and downstream of the major North African source regions. Without assimilating deep blue data (assimilating dark target only), AOD assimilation only improves AOD forecasts for up to 30 hr. Of the three DA methods examined, the hybrid and EnSRF methods produce better AOD analyses and forecasts than the 3D‐Var method does. Despite the clear benefit of AOD assimilation for AOD analyses and forecasts, the lack of information regarding the vertical distribution of aerosols in AOD data means that AOD assimilation has very little positive effect on analyzed or forecasted vertical profiles of backscatter.

Copyright of Ardeola is the property of Sociedad Espanola de Ornitologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Long‐distance migratory flights are predicted to be associated with higher mortality rates when individuals encounter adverse weather conditions. However, directly connecting environmental conditions experienced in‐flight with the survival of migrants has proven difficult. We studied how the in‐flight mortality of 53 satellite‐tagged Black‐tailed Godwits (Limosa limosa limosa) during 132 crossings of the Sahara Desert, a major geographical barrier along their migration route between The Netherlands and sub‐Saharan Africa, is correlated with the experienced wind conditions and departure date during both southward and northward migration. We show that godwits experienced higher wind assistance during southward crossings, which seems to reflect local prevailing trade winds. Critically, we found that fatal northward crossings (15 deaths during 61 crossings) were associated with adverse wind conditions. Wind conditions during migration can thus directly influence vital rates. Changing wind conditions associated with global change may thus profoundly influence the costs of long‐distance migration in the future. [ABSTRACT FROM AUTHOR]