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Nuestra investigación se centra en el papel de la gestión de proyectos relacionados con el trabajo en los países en desarrollo, para aclarar qué habilidades son factores clave de éxito para el líder del proyecto. El propósito de este estudio es aclarar el posicionamiento y la contribución de este nuevo operador en el montaje de un proyecto particular en un contexto en desarrollo. En este trabajo hemos aplicado esto al proyecto de la Gran Mezquita de Argel, que es el proyecto piloto en la actualidad con una fuerte movilización de actores públicos y privados para llevarla correctamente. Abstract Our research focuses on the role of management assistance of project management-related work in developing countries, to clarify what skills are key success factors for the project leader. The purpose of this study is to clarify the positioning and the contribution of this new operator in mounting a particular project in a developing context. In this work we have applied this to the project of the Great Mosque of Algiers, that is the pilot project scale at present with a strong mobilization of public and private stakeholders to properly carry it.

El presente trabajo, busca conocer el posible aprovechamiento de residuos orgánicos, como es la cáscara de almendra, como sustitución de una parte de la fracción granulométrica del árido grueso para la fabricación de hormigones convencionales. Para ello, primero, caracterizamos los materiales, árido y cascara de almendra. Posteriormente, fabricamos las probetas de hormigón con distintas sustituciones (10%, 20% y 30%) de cáscara de almendra sobre la fracción gruesa del árido y procedemos a la realización de los ensayos marcados por las normas UNE, evaluando su comportamiento a compresión, tracción, flexión, penetración de agua, absorción de agua, hielo y deshielo y térmico. Abstract The present work seeks to know the possible use of organic residues, such as the almond husk, as a substitution of a part of the granulometric fraction of the coarse aggregate for the manufacture of conventional concretes. For this, first, we characterize the materials, arid and almond husk. Subsequently, we made the concrete samples with different substitutions (10%, 20% and 30%) of almond shell on the coarse fraction of the aggregate and proceed to the tests marked by UNE standards, evaluating their behavior to compression, Traction, flexion, water penetration, water absorption, ice and melt and thermal.

Abstract Studying nomadic animal movement across species and ecosystems is essential for better understanding variability in nomadism. In arid environments, unpredictable changes in water and forage resources are known drivers of nomadic movements. Water resources vary temporally but are often spatially stationary, whereas foraging resources are often both temporally and spatially variable. These differences may lead to different types of nomadic movements: forage‐ vs. water‐driven nomadism. Our study investigates these two different types of nomadism in relation to resource gradients from mesic steppe to xeric desert environments in Mongolia's Gobi‐Steppe Ecosystem. We hypothesized that in the desert, where water is a key resource, animals are more water‐dependent and may show water‐driven nomadism with frequent revisits to spatially fixed resources, while in the steppe, animals are less water‐dependent and may show forage‐driven nomadism, tracking high‐quality foraging patches with infrequent revisits to previously used resources. We utilized GPS movement data from 40 individuals of four ungulate species (Mongolian gazelle, goitered gazelle, saiga antelope, and Asiatic wild ass) in the Gobi‐Steppe Ecosystem. We calculated displacement distances and recursion metrics and subsequently performed a principal component analysis to quantify the variation in movement patterns. The satellite‐derived vegetation greenness served as a proxy for the resource gradient and was associated with variation in movement behaviors described by the first principal component, demonstrating that the variability in movements was closely related to the resource gradient from mesic to xeric habitats. We showed that ungulates in the resource‐rich steppe tended to move long distances with few revisits (forage‐driven nomadism), while ungulates in the resource‐poor desert tended to move shorter distances with more revisits (water‐driven nomadism). Our results suggest that xeric and mesic habitats promote different types of nomadic strategies. These results have important implications for conservation strategies: Forage‐driven nomads primarily require a high degree of landscape‐level permeability, and water‐driven nomads additionally require the protection of ephemeral water bodies and actions to maintain the functional connectivity between them.

The study analysed the records of 1,172 ewes maintained at ICAR–Central Sheep and Wool Research Institute at Avikanagar and Bikaner, Rajasthan over a period of 22 years (1994-2016). Eight reproductive traits were assessed, namely age at first service (AFS; 572.39±6.59 days), age at first successful service (ASS; 635.71±9.36 days), age at first lambing (AFL; 773±8.77 days), weight at first service (WFS; 25.16±0.11 kg), weight at first successful service (WSS; 25.85±0.16 kg), weight at lambing (WL; 28.61±0.21 kg), lambing interval (LI;371±6.87days) and service period (SP; 228.31±6.62 days). The effects of period of birth of ewe, ewe’s birth weight and sire were significant for all the traits except LI and SP with an improvement of 17.47% –37.6% observed over the period of study. Season of birth of ewe had significant effect on AFL. AFS, ASS and AFL were significantly influenced by their respective covariates (WFS, WSS and WL). The statistically significant improvement over the periods suggest that through suitable selective breeding policy and good managemental measures, the reproductive performance of the flock can be enhanced. The optimization of ewe weights could reduce the age of sexual maturity and the ewe’s weight at birth may serve as an indicator for future performance in this regard. Selection of superior sires may improve the genetic potential of the flock with respect to the reproductive traits.

A great stride is witnessed in area expansion under protected cultivation, particularly in arid-western parts of India, where cucumber (Cucumis sativus L.) is a predominant greenhouse crop. The early-summer crop of cucumber is highly remunerative owing to high prevailing market price. In current study, efforts were made to select suitable greenhouse cucumber hybrids for early season harvest under western Indian arid plains. Growth, yield and commercial quality traits of seven commercial gynoecious and parthenocarpic (seedless) cucumber hybrids were studied under greenhouse condition during 2015-16. Among the hybrids evaluated for early summer greenhouse production, Terminator was more precocious for fruit harvest (36 days after transplanting) followed by Rica and Dinamik. The per plant fruit yield was highest in Ekron (5.3 kg) followed by Terminator (4.2 kg). The vine length, leaf size and leaf dry weight were also found to be highest in Ekron, followed by Terminator. The fruit appearance, taste and texture, and overall consumer’s acceptability were also determined, which were found better in Rica, Terminator and Dinamik. Despite exhibiting highest production related traits, Ekron measured least score for sensory parameters, especially the fruit appearance due to presence of rudimentary spines on skin, and also the taste. Fruit pericarp thickness and dry matter content were significantly higher in Ekron but the values were at par with that recorded for Terminator and a few other hybrids. The character association analysis reveals that per plant fruit yield had significant positive correlation with vine length, leaf size, foliar (stem+leaf) dry mass and mean fruit weight. Based on targeted characters for earliness, fruit yield and commercial quality of evaluated hybrids, it is concluded that Terminator followed by Rica were highly suitable for early summer production under protected condition in western arid plains of India.

This work compares the performance of vertical subsurface flow treatment wetlands (VSSF TWs) for wastewater treatment, planted with Zantedeschia aethiopica (Za), here operated simultaneously under two different climate conditions, arid and Mediterranean. The experimental setup was divided into two treatment lines for each climate condition: three VSSF TWs planted with Schoenplectus californicus (Sc) (VSSF-S), as the control, and three VSSF TWs planted with Zantedeschia aethiopica (Za) (VSSF-Z), as the experimental unit. The four treatment systems were operated at a hydraulic loading rate of 120 mm/d during spring and summer seasons, in two locations, Iquique (Atacama Desert, Chile) and Talca (Central Valley, Chile). The water quality in effluents, plant development, and water balance were used as performance measures. In terms of the water quality, the influents’ characteristics were similar in both climates and classified as “diluted”. For the effluents, in both climate conditions, average COD and TSS effluent concentrations were below 50 mg/L and 15 mg/L, respectively. In both climate conditions, average TN and TP effluent concentrations were below 40 mg/L and 2 mg/L, respectively. Furthermore, only total nitrogen (TN) and total phosphorus (TP) in effluents to VSSF-Z had a significant effect (p < 0.05) in relation to the climate condition. Regarding plant development, Za showed a lower height growth in both climate conditions, with arid consistently 0.3 m and Mediterranean decreasing from 0.6 m to 0.2 m. However, the physiological conditions of the leaves (measured by chlorophyll content) were not affected during operation time in both climates. Water balance showed that it was not influenced by the climate conditions or plant, with water loss differences below 5%. Therefore, taking into account the water quality and water balance results, Zantedeschia aethiopica can be used in VSSF TWs in a way similar to traditional plants under arid and Mediterranean climates. However, its use has to be carefully considered because lower height could affect the esthetics for its implementation in the VSSF TWs.

Model evaluation against experimental data is an important step towards accurate model predictions and simulations. Here, we evaluated an energy-balance model to predict dew formation occurrence and estimate its amount for East-African arid-climate conditions against 13 months of experimental dew harvesting data in Maktau, Kenya. The model was capable of predicting the dew formation occurrence effectively. However, it overestimated the harvestable dew amount by about a ratio of 1.7. As such, a factor of 0.6 was applied for a long-term period (1979–2018) to investigate the spatial and temporal variation of the dew formation in Kenya. The annual average of dew occurrence in Kenya was ~130 days with dew yield > 0.1 L/m2/day. The dew formation showed a seasonal cycle with the maximum yield in winter and minimum in summer. Three major dew formation zones were identified after cluster analysis: arid and semi-arid regions; mountain regions; and coastal regions. The average daily and yearly maximum dew yield were 0.05 and 18; 0.9 and 25; and 0.15 and 40 L/m2/day; respectively. A precise prediction of dew occurrence and dew yield is very challenging due to inherent limitations in numerical models and meteorological input parameters.

Caves share unique conditions that have led to convergent adaptations of cave-dwelling animals. In addition, local factors act as filters on regional species-pools to shape the assemblage composition of local caves. Surveys of 35 Levantine caves, distributed along a climate gradient from the mesic in the north of Israel to hyper-arid areas in the south of Israel, were conducted to test the effect of cave characteristics, location, climate, bat presence, and guano level on the spider assemblage. We found 62 spider species and assigned four species as troglobites, 28 as troglophiles, and 30 as accidentals. Precipitation, elevation, latitude, minimum temperature, and guano levels significantly affected the composition of cave-dwelling spider assemblages. Caves situated in the Mediterranean region had higher species richness and abundance, as well as more troglobite and troglophile arachnids. These discoveries contribute to the knowledge of the local arachnofauna and are important for the conservation of cave ecosystems. By comparing spider assemblages of Levantine caves to European caves, we identified gaps in the taxonomic research, focusing our efforts on spider families that may have additional cryptic or yet to be described cave-dwelling spider species. Our faunistic surveys are crucial stages for understanding the evolutionary and ecological mechanisms of arachnid speciation in Levantine caves.

Nursery practices are considered major factors influencing seedling quality, which are likely to be maintained in the early establishment phase in the field. Here, we investigated the effects of container depth and substrate heterogeneity on the growth of Populus sibirica nodal seedlings to suggest an effective nursery practice for producing quality seedlings appropriate for forest establishment in a dry environment. We used two substrate heterogeneities (homogeneous and heterogeneous) and two container depth treatments (30 and 60 cm). Variations in root collar diameter (RCD) growth, height growth, stem and root biomass, root to stem ratio, and root mass in the first 15 cm depth from the soil surface across the treatments were computed. Results revealed that both substrate heterogeneity and container depth had no significant effects on the RCD and height growth of P. sibirica seedlings but significantly improved their root and stem biomass. Seedlings in the 60 cm containers generally accumulated higher root biomass than those in the 30 cm containers. There was an interaction effect of container depth and substrate heterogeneity treatments on root and total dry mass, such that seedlings grown in the 60 cm container using heterogeneous substrate resulted in the highest root and total biomass. Analyses of proportional root growth in the upper 15 cm of the containers compared to the total indicated that both the main effects of deeper containers (60 cm) and heterogeneous substrate have fewer roots at this depth, indicating a greater root density in the bottom of the deeper containers. Therefore, deeper containers and heterogeneous substrate may be used as an effective nursery practice to produce seedlings with root traits potentially suitable for harsh conditions, such as arid and semi-arid environments. However, further studies using other seedling morphological traits in conjunction with field-trial tests are needed for a definitive assessment of the effectiveness of deeper containers and heterogeneous substrate in producing good quality seedlings potentially suitable in a dry environment.

Rainfall partitioning into interception loss, throughfall and stemflow affects the amount and the spatial heterogeneity of water entering into the soil at the patch scale, strongly controlling net primary productivity of drylands. In this paper, we explored rainfall partitioning and its biophysical controls in Larrea divaricata (jarilla), one of the most abundant shrubs in the Dry Chaco rangelands (Argentina). On average, interception loss, throughfall and stemflow accounted for 9.4, 78.6 and 12.0% of total rainfall, respectively. Interception loss proportion decreased with the increment of rainfall event size and intensity, whereas throughfall proportion showed the opposite pattern. Stemflow proportion increased with the increment of rainfall event size but presented different relations with rainfall event intensity. The increment of rainfall event intensity increased the stemflow in small events (<20 mm), but decreased it in large events (>20 mm). Stemflow increased in plants with higher angles of insertion of stems (measured at 50 and 100 cm from soil surface; p < .05 and p < .01, respectively), but decreased in plants with larger canopy areas (p =.01). Spatial distribution of throughfall (coefficient of variation) decreased with the increment of rainfall event size and intensity. L. divaricata presented more stemflow generation and fewer interception losses than other similar woody species. Our findings help to understand the key role of vegetation canopy affecting the amount of water entering into the soil in drylands. [ABSTRACT FROM AUTHOR]

Diet analysis is an essential part in understanding the biology of a species and functioning of ecosystems. Traditional morphological identification of undigested remains in the scats and molecular analyses of prey species' DNA have previously been used to assess diet. In the present study, caracal diet in the Abbasabad Wildlife Refuge, Central Iran, was investigated using both molecular and morphological methods. We collected 22 scat samples from caracal dens in the region. Feces were washed on sieves and their remaining components were morphologically identified. We also targeted a 307-base pair fragment of the cytochrome b gene to amplify and sequence the species' DNA. Morphological analyses revealed that 76% of the diet comprised rodent species. We identified a total of nine prey taxa using the molecular method, including six rodents, one hare, one hedgehog and one wild goat. There was a general agreement between the molecular and morphological results; however, molecular methods tended to allow a better identification of the prey species. Therefore, the DNA-based approach acts as a valuable complement to current morphological methods in the study of a rare felid's diet when no hair reference library exists. [ABSTRACT FROM AUTHOR]

Studying nomadic animal movement across species and ecosystems is essential for better understanding variability in nomadism. In arid environments, unpredictable changes in water and forage resources are known drivers of nomadic movements. Water resources vary temporally but are often spatially stationary, whereas foraging resources are often both temporally and spatially variable. These differences may lead to different types of nomadic movements: forage- vs. water-driven nomadism. Our study investigates these two different types of nomadism in relation to resource gradients from mesic steppe to xeric desert environments in Mongolia's Gobi-Steppe Ecosystem. We hypothesized that in the desert, where water is a key resource, animals are more water-dependent and may show water-driven nomadism with frequent revisits to spatially fixed resources, while in the steppe, animals are less water-dependent and may show forage-driven nomadism, tracking high-quality foraging patches with infrequent revisits to previously used resources. We utilized GPS movement data from 40 individuals of four ungulate species (Mongolian gazelle, goitered gazelle, saiga antelope, and Asiatic wild ass) in the Gobi-Steppe Ecosystem. We calculated displacement distances and recursion metrics and subsequently performed a principal component analysis to quantify the variation in movement patterns. The satellite-derived vegetation greenness served as a proxy for the resource gradient and was associated with variation in movement behaviors described by the first principal component, demonstrating that the variability in movements was closely related to the resource gradient from mesic to xeric habitats.We showed that ungulates in the resource-rich steppe tended to move long distances with few revisits (forage-driven nomadism), while ungulates in the resource-poor desert tended to move shorter distances with more revisits (water-driven nomadism). Our results suggest that xeric and mesic habitats promote different types of nomadic strategies. These results have important implications for conservation strategies: Forage-driven nomads primarily require a high degree of landscape-level permeability, and water-driven nomads additionally require the protection of ephemeral water bodies and actions to maintain the functional connectivity between them. [ABSTRACT FROM AUTHOR]

In Ethiopia, soil salinity has become a challenge for agricultural production in irrigated arid and semiarid areas. This research investigates the effectiveness of leaching salt remediation under different soil textures and groundwater tables. Leaching was conducted in the bare parts of three abandoned saline fields. Soil texture of Field 1 (F1) is sandy loam while Field 2 (F2) and Field 3 (F3) are clay loam. The F1, F2, and F3 groundwater was located at 1.8, 1.5 and > 3 m, respectively. The leaching requirement water levels were 15, 20, 25, and 30% higher than the evaporation of the bare field needed for four consecutive weeks, respectively. The results of this study show that, after four days of leaching, the salinity of F1 with sandy loam texture was significantly (P < 0.05) and more strongly reduced than for the other fields exhibiting clay loam texture. For F1, salinity was reduced from 16.3 to 6.2 dS/m and from 12.4 to 5.5 dS/m at depths of 0-30 and 30-60 cm, respectively. In head parts of F1 and F3, the salinity level was reduced to 2.0 dS/m. However, in F2 with shallow groundwater and clay loam texture, the salinity levels were slightly higher after leaching, i.e. from 11.2 to 12.0 dS/m and from 8.1 to 11.6 dS/m at 0-30 and 30-60 cm depths, respectively. In our experiment, effective leaching was achieved only in the field with sandy soil and deeper groundwater table. We saw that the application of leaching with surface drainage at shallow groundwater levels may further exacerbate salinity problems. For such situations, the use of subsurface drainage could sustain the groundwater depth and prevent additional salinization. On clay-textured fields with shallow groundwater table, a prolonged leaching application is necessary to reduce the salt contents. [ABSTRACT FROM AUTHOR]

Of the 6,5 million ha with hydro agricultural infrastructure in Mexico, 10% have problems with salinity and drainage. 16% of the 7,5 million hectaresof humid tropic with agricultural potential, has shallow phreatic table, floods and soil acidity. This problem in the areas of irrigation is increased by 10 000 ha/year with productive decrease of 25%. Since 1992, IMTA developedand transferred subsurface drainage technologies for the rehabilitation of saline in arid soils and management of the regime of soil moisture with lot controlled subsurface drainage in wet areas. Production increases of 20% to 93% in wheat were obtained with agricultural drainage and about 200% in sugar cane, thus economic and production indices have increased with this technology. [ABSTRACT FROM AUTHOR]

We lack a defined suite of attributes that allow us to universally predict the distribution of bacterial diversity across and within globally distributed biomes. Using data from a global survey, including 237 locations and multiple environmental predictors, we found that only ultraviolet light, forest environments, soil carbon and pH can be considered as significant and globally consistent predictors of soil bacterial diversity, valid within and across biomes (arid, temperate and continental). Bacterial diversity always peaked in grasslands, with moderate-to-low carbon and ultraviolet light levels, and high soil pH. Using these environmental data, we generated the first global predictive map of the distribution of soil bacterial diversity. Our work helps to identify a unique set of environmental attributes for universally predicting the distribution of soil bacterial diversity. This knowledge is key to help predict changes in ecosystem functioning and the provision of essential services under changing environments. [ABSTRACT FROM AUTHOR]

Global distributions of most terrestrial large mammals have been dramatically reduced through the loss and fragmentation of natural habitat. These impacts are likely to be intensified by the effects of global climate change. Here we use two free roaming leopard (Panthera pardus) populations to explore the intersecting influences of climatic conditions and land use on the feeding ecology of a large carnivore. We predicted that greater aridity would influence land use, and that this would in turn influence species richness and consequently leopard diet. We compared diet, mammal species richness and land use patterns in two topographically similar regions of south-western South Africa, the Boland, a mesic temperate region and the Little Karoo, a semi-arid region located approximately 200 km to the east. The Boland has retained only ∼33% of natural land at low elevations, compared to over 90% in the Little Karoo. Extensive camera trap surveys in both regions revealed far lower mammal species richness in the Boland (22 species) than the Little Karoo (51 species). Leopard diet differed significantly between the two regions; leopards in the Boland fed on fewer (n = 15), smaller prey species (ranging from 3–25 kg) associated specifically with mountain habitat. By contrast, leopards in the Little Karoo had a broader prey range (n = 21), and were able to access larger prey (up to 138 kg). These results suggest that aridity has a significant influence on anthropogenic land use patterns, and that these changes are reflected both in the richness of the mammal community, and the diet of a large carnivore. However, the less intensive land use in the Little Karoo also increased the potential for conflict between leopards and people. Increased aridity as a result of global climate change may thus present opportunities to enhance the conservation status of free-roaming carnivores, but may also increase the potential for human-wildlife conflict as carnivores recolonize previously transformed areas. [ABSTRACT FROM AUTHOR]

Drylands (arid and semiarid ecosystems) cover nearly half of Earth's terrestrial surface, but biogeochemical pools and processes in these systems remain poorly understood. Litter can account for a substantial portion of carbon and nutrient pools in these systems, with litter decomposition exerting important controls over biogeochemical cycling. Dryland decomposition is typically treated as a spatially static process in which litter is retained and decomposed where it is initially deposited. Although this assumption is reasonable for mesic systems with continuous plant canopy cover and a stable subcanopy litter layer, dryland pools generally reflect discontinuous inputs from heterogeneous canopy cover followed by substantial litter transport. In the present article, we review horizontal and vertical transport processes that move litter from the initial deposition point and retention elements that influence litter accumulation patterns. Appreciation of the spatially dynamic litter cycle, including quantitative assessment of transport patterns, will improve estimates of the fate and distribution of organic matter in current and future drylands. [ABSTRACT FROM AUTHOR]

Some new scientific concepts about the genesis of soils in arid mountains of dry subtropical zone of Pamir were established. It was revealed that the main soil-forming processes, under influence of which developed all the soils of the Pamir are humus accumulation, argilization and leaching under the leadership of the humus-accumulative process. It was showed the leading role of humidity and duration of the biologically active period in the formation of plant landscapes and soil types in all vertical zones as well as the important role of thermal regime in the soil formation of cold and very cold thermal zones that differ by fulvate composition of humus and reddish color profile. [ABSTRACT FROM AUTHOR]

Copyright of Agricultura Sociedad y Desarrollo is the property of Colegio de Postgraduados 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.)

Copyright of Therya is the property of Asociacion Mexicana de Mastozoologia, A. C. 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 Dryland ecosystems have been threatened in recent decades by rapid climate change. However, the effects of climate change and rising CO 2 levels on the terrestrial carbon stock of the arid region of China remain unclear. In this study, we used three climate reanalysis datasets to drive an arid ecosystem model (AEM), which we used to assess uncertainties in spatial climate datasets. All simulations suggest that the arid region of China acted as a carbon sink (0.20–0.34 Pg C) from 1980 to 2014. However, we found large uncertainties in the spatial pattern of carbon stocks during this period, especially in northern Xinjiang and western Inner Mongolia. These uncertainties are related to changes in precipitation. To reduce the uncertainty of carbon stock assessment results in the arid region of China, efforts should be implemented to improve the reliability of climate data in northern Xinjiang and western Inner Mongolia. Specifically, China's policy makers should pay close attention to climate change and ecosystem health in southwestern Xinjiang. According to our study, this area experienced significant decreases in precipitation and increases in temperature from 1980 to 2014. The severe ecosystem degradation that occurred will very likely continue into the future. In addition, the Climate Forecast System Reanalysis (CFSR) dataset may overestimate ecosystem carbon sinks as this dataset overestimates the increase in precipitation in the arid region of China. Therefore, it is advisable to be cautious when using the CFSR dataset in ecological studies in northern Eurasian dryland areas. Graphical abstract Unlabelled Image Highlights • High uncertainty in climate-induced C dynamic in North Xinjiang & western Mongolia. • Recent climate change created C sink in the Tianshan & Jiaryuguan area, arid China. • Grassland has a great potential to sink more carbon than other land types. • Special attention should be taken to sustain the ecosystems in southwest Xinjiang. [ABSTRACT FROM AUTHOR]

Whether the dryland to cropland conversation in arid regions could lead to a decrease in soil carbon (C) and land degradation remains unclear. In this study, we investigated the vertical patterns of soil C change with different lengths of land use history in the arid regions of China and explored the controls and mechanisms of these changes. One native desert grassland and six croplands with similar management but different cultivation times (i.e., 1, 3, 5, 15, 30, and 50 years) and were selected in Xinjiang, Northwest China. We measured both soil organic and inorganic C concentrations and soil properties (e.g., total nitrogen [N], NO3−‐N, NH4+‐N, pH, and electrical conductivity) with a 20‐cm depth interval down to 2 m in all croplands. The results showed that soil organic carbon (SOC) stocks increased with cultivation year for the topsoils (0–120 cm), which could be a result of higher plant C inputs and decreased soil pH in cropland than in the native desert. Soil pH explained the largest variation (45%) of SOC concentration. Soil inorganic C (SIC) stocks decreased with cultivation year in topsoils layers (0–40 cm) but increased in deep soil layers (120–200 cm), resulting in the net increment of SIC to the depth of 200 cm. This pattern might be caused by changes in soil pH in the cropland. Overall, this study demonstrated that, instead of reducing soil C, proper management of the desert ecosystem can enhance soil C sequestration in the arid regions. [ABSTRACT FROM AUTHOR]

Copyright of Algerian Journal of Arid Environment (AJAE) is the property of University of Kasdi Merbah Ouargla 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 Woody shrub encroachment has been linked to environmental changes associated with pastoralism, such as fire regime shifts and overgrazing, throughout Earth's rangelands. Extinction of native fauna that are consumers of shrubs has also accompanied pastoralism in many areas; however fauna declines have rarely been considered as a driver of encroachment. Here we investigate the interacting impacts that wildfire and functional extinction of native granivorous rodents and a small introduced herbivore, the European rabbit (Oryctolagus cuniculus), have on shrub seedling density in the Strzelecki Desert, Australia. Using data from field surveys conducted following wildfires in 2012, we show that shrub seedling densities were higher at burned than unburned sites in areas where rodents and rabbits were rare. However, at sites where rodents and rabbits were common, seedling densities were higher at unburned than burned sites and rodent activity was greater on burned sites during an optimal recruitment period. Our results provide support for the hypothesis that post-fire shrub recruitment is facilitated by the extinction of small mammals which consume shrubs and their seeds. Our study suggests that "rewilding" of small mammal assemblages may provide a mechanism to curb shrub encroachment. Highlights • Post-fire shrub recruitment enhanced by small mammal extirpation and wildfire. • Shrub seedling densities greater at burnt sites where small mammals rare. • But densities higher at unburnt than burnt sites where small mammals common. • Native rodents more active at burnt than unburnt sites. • Rewilding of small mammal assemblages may curb shrub encroachment. [ABSTRACT FROM AUTHOR]

• Bacterial communities in arid soil environments differ along spatial and seasonal scales. • Arid soil bacterial communities depicted by the rDNA and rRNA significantly differed in the dry season but matched in the wet season. • The phylum Deinococcus-Thermus was detected only in the dry season and only by the rDNA but not by the ribosome. Studies describing the diversity of microorganisms in drylands are based mainly on the total (DNA), and seldom on the metabolically active (RNA) portion of the bacterial communities. We predicted that in desert environments, the majority of bacteria would display low activity during the hot and dry season, resulting in comparable diversity of the total and active communities. But during the wet periods, when rain activates certain bacterial groups, the total and active communities would differ. To test our predictions, the rDNA and rRNA extracted from desert soil, were analysed in samples collected during the dry and wet seasons from three patches: under the canopy of the dominant shrub, near ant nests and in open patches. The results disproved our predictions because the RNA- and DNA-based communities significantly differed in the dry season but matched very well in the wet season samples. Further comparative analysis of the rRNA/rDNA ratio revealed the composition and structure of metabolically active members within the patches' communities. Our results suggest that in desert environments, the activity of soil bacterial communities is not restricted by water availability or patch types and could be fully described only, by concomitant analysis of the total and active members. [ABSTRACT FROM AUTHOR]

Highlights • Declining forage production from shrublands dominates the perspective of stakeholders. • While shrublands provide other ecosystem services, they are rarely considered. • Shrub removal generated trade-offs between ecosystem services. • Sustainable land use should minimize trade-offs between different ecosystem services. • Sustainability requires socio-economical, not merely ecological understanding. Abstract In many shrub-encroached lands, livestock grazing is the dominant land-use type which shapes stakeholders' perspective on single ecosystem service provision (i.e., forage production). Although recent ecological studies suggested otherwise, recognition of multiple ecosystem services from shrublands is rarely translated into policy, likely due to the lack of robust scientific evidence on trade-offs between ecosystem services following shrub removal. Based on meta-analysis from global publications, we found that while shrub removal increased forage provision, such effect was generally short-lived (˜5 years). At the same time, shrub removal also increased bare soil, decreased soil nutrients and soil organic carbon, which potentially reduced erosion control and nutrient cycling service. These trade-offs tended to be more prominent with increasing disturbance intensity (i.e., higher shrub removal frequencies or switching from single to multiple shrub removal methods). To encourage adaptation to the provisioning of multiple ecosystem services from shrublands, we provided a framework on how to value such landscapes, including the estimated monetary values that could be generated from maintaining them. Since there will be a time-lag until most monetary values appear, initial incentives may be necessary to encourage the adoption of conservation practices, in addition to efforts to increase society awareness (e.g., eco-labelling, alternative food networks or social media) on multiple ecological benefits from shrublands and investment to provide capacity building for pastoralists. [ABSTRACT FROM AUTHOR]

Desert ecosystems are one of the fastest urbanizing areas on the planet. This rapid shift has the potential to alter the abundances and species richness of herbivore and plant communities. Herbivores, for example, are expected to be more abundant within urban desert remnant parks located within cities due to anthropogenic activities that concentrate food resources and reduce native predator populations. Despite this assumption, previous research conducted around Phoenix, AZ, USA has shown that top-down herbivory led to equally reduced plant biomass in both urban and outlying locations. It is unclear if this insignificant difference in herbivory at urban and outlying sites is due to unaltered desert herbivore populations or altered activity levels that counteract abundance differences. Small rodent herbivore/granivore populations were surveyed at four sites inside and four sites outside of the core of Phoenix during fall 2014 and spring 2015 in order to determine whether abundances and richness differ significantly between urban and rural sites. In order to survey species composition and abundance at these sites, 100 Sherman traps and eight larger wire traps that are designed to attract and capture small vertebrates such as mice, rats, and squirrels were set at each site for two consecutive trap nights. Results suggest that the commonly assumed effect of urbanization on herbivore abundances does not apply to small rodent populations in a desert city, as overall small rodent abundances were statistically similar regardless of location. Though a significant difference was not found for species richness, a significant difference between small rodent genus richness at these sites was observed, with altered community composition. The compositional differences likely reflect the altered vegetative community and may impact ecological interactions at these sites. [ABSTRACT FROM AUTHOR]

Atmospheric models are known to underestimate land surface temperature and, by association, 2 m air temperature over dry arid regions during the day due to the treatment of the thermal roughness length also known as roughness length of heat. The thermal roughness length can be controlled by the Zilitinkevich parameter, known as Czil, which is a tunable parameter within the models. Three different scenarios with the WRF model are run to test the impact of the Czil parameter on the simulations using two land surface models: the Noah and Noah-MP models. In this study, a modified version of the Noah-MP model is tested, in which the Czil parameter, and, therefore, the thermal roughness length varies depending on the land cover and vegetation height. The model domain is over the United Arab Emirates (UAE) where the major land cover type is desert. The following configurations are tested: the Noah model with Czil = 0.1, Noah model with Czil = 0.5 and the Noah-MP model with Czil = 0.5 over desert. Results of 2 m air temperature are verified against three stations in the UAE. Mean gross error of the diurnal 2 m temperature was reduced by up to 1.48 and 1.54 °C in the 24 and 48 h forecasts, respectively. This reduced the cold bias in the model. This improvement in air temperature showed to improve the diurnal cycle of relative humidity at the three monitoring stations as well as the duration of the sea breeze in some cases. [ABSTRACT FROM AUTHOR]

BAF200 is a subunit of PBAF chromatin remodeling complex that contains an N-terminal AT-rich interaction domain (ARID). ARID domain in general has been shown to bind to the AT-rich DNA sequences. The human BAF200 ARID (~ 110 residues) has the potential to bind the DNA sequences with high affinity, however, the structure and the exact contribution of hBAF200 ARID in PBAF functions as well its DNA binding specificities have not been established. In this study, we have expressed and purified the hBAF200 ARID for NMR studies. We report the complete backbone 1H, 13C, and 15N chemical shift assignment and secondary structure of hBAF200 ARID domain. [ABSTRACT FROM AUTHOR]

Background and Aims Alpine cushion plants can initially facilitate other species during ecological succession, but later on can be negatively affected by their development, especially when beneficiaries possess traits allowing them to overrun their host. This can be reinforced by accelerated warming favouring competitively strong species over cold-adapted cushion specialists. However, little empirical research has addressed the trait-based mechanisms of these interactions. The ecological strategies of plants colonizing the cushion plant Thylacospermum caespitosum (Caryophyllaceae), a dominant pioneer of subnival zones, were studied in the Western Himalayas. Methods To assess whether the cushion colonizers are phylogenetically and functionally distinct, 1668 vegetation samples were collected, both in open ground outside the cushions and inside their live and dead canopies, in two mountain ranges, Karakoram and Little Tibet. More than 50 plant traits related to growth, biomass allocation and resource acquisition were measured for target species, and the phylogenetic relationships of these species were studied [or determined]. Key Results Species-based trait–environment analysis with phylogenetic correction showed that in both mountain ranges Thylacospermum colonizers are phylogenetically diverse but functionally similar and are functionally different from species preferring bare soil outside cushions. Successful colonizers are fast-growing, clonal graminoids and forbs, penetrating the cushion by rhizomes and stolons. They have higher root-to-shoot ratios, leaf nitrogen and phosphorus concentrations, and soil moisture and nutrient demands, sharing the syndrome of competitive species with broad elevation ranges typical of the late stages of primary succession. In contrast, the species from open ground have traits typical of stress-tolerant specialists from high and dry environments. Conclusion Species colonizing tight cushions of T. caespitosum are competitively strong graminoids and herbaceous perennials from alpine grasslands. Since climate change in the Himalayas favours these species, highly specialized subnival cushion plants may face intense competition and a greater risk of decline in the future. [ABSTRACT FROM AUTHOR]

Interest in land application of organic amendments—such as biosolids, composts, and manures—is growing due to their potential to increase soil carbon and help mitigate climate change, as well as to support soil health and regenerative agriculture. While organic amendments are predominantly applied to croplands, their application is increasingly proposed on relatively arid rangelands that do not typically receive fertilizers or other inputs, creating unique concerns for outcomes such as native plant diversity and water quality. To maximize environmental benefits and minimize potential harms, we must understand how soil, water, and plant communities respond to particular amendments and site conditions. We conducted a global meta‐analysis of 92 studies in which organic amendments had been added to arid, semiarid, or Mediterranean rangelands. We found that organic amendments, on average, provide some environmental benefits (increased soil carbon, soil water holding capacity, aboveground net primary productivity, and plant tissue nitrogen; decreased runoff quantity), as well as some environmental harms (increased concentrations of soil lead, runoff nitrate, and runoff phosphorus; increased soil CO2 emissions). Published data were inadequate to fully assess impacts to native plant communities. In our models, adding higher amounts of amendment benefitted four outcomes and harmed two outcomes, whereas adding amendments with higher nitrogen concentrations benefitted two outcomes and harmed four outcomes. This suggests that trade‐offs among outcomes are inevitable; however, applying low‐N amendments was consistent with both maximizing benefits and minimizing harms. Short study time frames (median 1–2 years), limited geographic scope, and, for some outcomes, few published studies limit longer‐term inferences from these models. Nevertheless, they provide a starting point to develop site‐specific amendment application strategies aimed toward realizing the potential of this practice to contribute to climate change mitigation while minimizing negative impacts on other environmental goals. On rangelands, application of organic amendments such as compost and biosolids is increasingly proposed for climate change mitigation. Considering a range of ecosystem outcomes, this meta‐analysis found that organic amendments, on average, provide some environmental benefits (increased soil carbon, soil water holding capacity, aboveground net primary productivity, and plant tissue nitrogen; decreased runoff quantity), as well as some environmental harms (increased concentrations of soil lead, runoff nitrate, and runoff phosphorus; increased soil CO2 emissions). Our models can be used to design site‐specific amendment application strategies, helping to realize the potential benefits of this practice while minimizing environmental harms. [ABSTRACT FROM AUTHOR]

The zodariine spider genus Mallinus Simon, 1893 is redescribed and diagnosed. The type species, M. nitidiventris Simon, 1893 from South Africa, was originally described from subadult specimens. Adults of both sexes of M. nitidiventris are described for the first time, based on recently collected material, and the genus is rediagnosed, redescribed, and its relationships discussed. A single aberrant male specimen from Namibia is here described as a morphospecies, as it is presumed to only be superficially related. A second species, M. defectus Strand, 1906 from Tunisia, is considered a 'species inquirenda', as the type specimens could not be traced, but this species is in any case unlikely to be congeneric. The genus is one of 10 cases of a monotypic genus in the Zodariidae. Notes are provided on the biology of M. nitidiventris. [ABSTRACT FROM AUTHOR]

Highlights • Assessed impact of soil moisture on runoff in semi-arid area. • High antecedent moisture led to more runoff at plot and catchment scales. • Upscaling plot-scale parameters is difficult given high spatial variability. • Infiltration model performance depends on spatial scale. • Simplistic models may be preferable if data is limited. Abstract Antecedent soil moisture is an important factor in the generation of runoff, but guidance for modeling moisture conditions in semiarid catchments is limited and conflicting. In this study, the impact of antecedent moisture was assessed at the plot scale (2.8 m2) using a portable rainfall simulator, and at the catchment scale based on observed precipitation and discharge for a 2.8 km2 watershed in central New Mexico. Performance of three loss models commonly used for hydrologic analysis in the southwestern U.S. was tested at both scales. High initial moisture content led to substantially higher runoff ratios at both scales, confirming the importance of antecedent soil moisture for runoff predictions in semiarid drainages. Hydrologic parameters estimated based on plot experiments, however, were highly variable and cannot easily be upscaled to the catchment scale. Loss model performance was clearly scale dependent: more simplistic (one- and two parameter) loss methods out-performed a more complex (four parameter) model at the watershed scale, while the opposite held true for test plot simulations. At the catchment scale, all models performed poorly for small runoff events, but yielded acceptable results for storms causing large discharges if antecedent soil moisture was considered. Failing to account for antecedent moisture led to simulated runoff volume errors up to one order of magnitude. [ABSTRACT FROM AUTHOR]

Abstract With the proliferation of woody plant species in much of the world's grasslands, human has manipulated landscape fire to return their forage provisioning service. Yet other ecosystem services (e.g., carbon sequestration, biodiversity conservation, erosion control) in the post-managed areas compared to those previously available in the shrub-encroached area are largely unknown, including trade-offs between ecosystem services. Using data from previous publications, we quantitatively synthesized the sustainability of fire as shrub management practice, expressed as its efficacy to control shrubs and its capacity to maintain different ecosystem services. A simple indicator (δ), defined as the ratio of an observed ecological attribute between area experiencing shrub management and untreated control, was used to quantify the changes. Our results showed that fire could be an effective strategy to control shrubs and to increase forage provisioning service (δ herbaceous biomass = 1.39). However, there are possible trade-offs with other ecosystem services (e.g., erosion control, nutrient cycling) when a 54% increase in bare soil cover (δ bare soil = 1.54) and ~74% loss of biological soil crusts cover (δ biological crust = 0.26) were found. Because increasing forage provisioning at the cost of other ecosystem services might not be sustainable, management should focus on strategies to minimize such trade-offs, which may include but not limited to rotational grazing, adjustment in stocking rate, or supplementary external inputs (e.g., fertilizer). Unless those measures are employed, there is possible emergence of a novel crash (i.e., vegetation- and resource-poor scabland) resulting from a combination of soil erosion and high vulnerability of burnt landscape to exotic species invasion. Graphical abstract Unlabelled Image Highlights • Fire managed to reduce shrub cover and density. • Forage provisioning service in shrub-encroached lands recovered following fire. • Yet fire could jeopardize other ecosystem services (e.g., erosion control). • Subsequent management is the key to minimize trade-offs between ecosystem services. [ABSTRACT FROM AUTHOR]

Highlights • We present for the first-time vegetation patterns with the shape of spirals. These spirals were observed in the north of Chile. • The existence of spirals is based on an interaction between the dynamics of plants and grazing. • We propose excitability as the mechanism that explains the growth of these patterns. • We develop a simple mathematical model that reproduces the field observations at the quantitative level. Abstract When plant communities suffer the stress of limited resources, for instance adverse environmental conditions such as extreme aridity, the spatial homogeneity of the biomass is lost and self-organized patterns may arise. Here, we report the observation of spiral-shaped patterns in the biomass of grass (genus deyeuxia), under highland arid conditions in the north of Chile. The spiral arms are a few meters long and a few centimeters wide. These dynamic structures are observed in the grazing area of an herbivore member of the South American camelids, the vicuna, on the border of highland wetlands. These spirals cannot be explained by the well-established mathematical models which describe other vegetation patterns (that emerge from a Turing-type of instability) such as stripes, rings, or fairy circles. We attribute the formation of spirals to the coupling between the growth of vegetation in semiarid regions and the grazing of vicunas. The mathematical analysis of this coupling reveals an excitable behavior, i.e. small perturbations of the equilibrium generate large trajectories before coming back, that is the origin of the spirals. [ABSTRACT FROM AUTHOR]

A warming climate has been shown to drive thermophilization—shifts in species abundance toward those adapted to warm and dry conditions. The community dynamics shaping this process have been proposed to vary between temperature-limited alpine plant communities and those that are both temperature and moisture limited. In nine sites across the xeric alpine zone in the White Mountains, California, USA, we experimentally increased summertime temperature and precipitation for three seasons and quantified community responses with a climatic niche analysis. We asked if thermophilization occurred in response to experimental heating, and if this effect was ameliorated by experimental watering. Under experimentally warmer conditions, we found no change in the mean community-weighted climatic niche (CCN); however, thermophilization of this community was observed based on a shift in the seventy-fifth percentile of the CCN and an increase in the proportional abundance of the hottest, driest adapted species. In addition, total vegetation abundance increased and species richness decreased with heating. Experimental watering did not ameliorate these effects of heating. Together, these results suggest that warming in arid alpine areas may result in less diverse plant communities dominated by hot, dry associated species, although short-term responses may be limited because of community lags. [ABSTRACT FROM AUTHOR]

Highlights • The effects of a dry top soil layer (DSL) on evaporation depends on DSL thickness. • The thickness of the dry soil layer depends on the "dryness" of the system. • A DSL of ∼0.25 m greatly limits evaporation from bare soil with shallow water table. • In very dry conditions, DSL affects bare soil evaporation in semi-arid areas. Abstract Bare soils and grasslands in arid and semi-arid conditions constitute a large portion of the earth surface. Evaporation, which is the main component of the water balance in these conditions, often takes place through a dry soil layer (DSL). There is no scientific agreement yet on the DSL effects on evaporation rates. The implementations of three conceptual models of DSL-evaporation were tested for the simulation of evaporation rates in a semi-arid study area in Central Spain: (i) the daily-average model, based on the assumption that the daily average vapour transport in a DSL can be represented in analogy to isothermal liquid flow; (ii) the numerical model solving the Richards equation, in this case HYDRUS1D was used; and (iii) the pore-scale model, based on soil column experiments in laboratory conditions. The evaporation rates estimated by the three conceptual models for semi-arid field conditions were compared with the evaporation rates measured by an eddy covariance tower in the same area. The results indicate that the daily-average conceptual model assumption, in which the DSL has no effects on evaporation, does not hold in very dry conditions. The numerical model solving the Richards equation was not able to simulate the effects of the DSL on evaporation rates. The evaporation estimates obtained by the pore-scale conceptual model were closest to the eddy covariance measurements during the dry season, however this model was applicable only to the relatively steady evaporation conditions during afternoons and only assuming spatially constant DSL thickness. [ABSTRACT FROM AUTHOR]