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Abstract: Although many papers have been published on the role of wind speed on wind erosion, most of them did not consider the probability or return period of wind speed and its role in wind erosion. This study deals with this characteristic of wind speed in arid and semi-arid regions of Iran. Because at-site frequency analysis is not sufficient for extending wind frequency to locations with no data, the method of L-moments was applied for regional frequency analysis. The results of this study showed the Generalized Logistic (GLOG) distribution model to be the best regional distribution model for 3-h maximum mean annual wind speeds within homogeneous region based on goodness-of-fit test measurement, Z Dist. The extension of different wind quantiles to the region showed that the center, southwestern and northwestern parts of the study area could be more vulnerable regions to wind erosion than other parts. The comparison of wind energy for different wind speed return periods indicates a nonlinear trend in wind energy when the return periods increase. Therefore, it is important to apply wind frequency analysis in wind erosion control projects because the risk of higher wind speed does not increase with linear function. [Copyright &y& Elsevier]

Abstract: Rodents from arid and semi-arid deserts are faced with the problem of water conservation. The physiological responses of small rodents to such conditions have been intensively investigated over broad geographically disjunct areas. Despite the presence of xeric habitats in South America since the late Tertiary, some studies suggest that sigmodontine South-American desert rodents do not display the same diversity of physiological responses at the species level as those observed in other desert-dwelling species of rodents. In this paper, we analyzed the physiological responses to water deprivation, at the interespecific and interindividual level, among eight species of sigmodontine desert-dwelling rodents from different geographical areas within South-American deserts. Using randomization tests, we found no significant phylogenetic signal for resistance to water deprivation or for individual variability in this response. Contrary to our initial predictions, we observed that sigmodontine rodents from arid/semi-arid habitats (Monte Desert) had significantly lower rates of body mass loss per day (higher tolerances to water deprivation) than species from the hyperarid deserts. We showed that sigmodontine rodents from South America showed a remarkable diversity of physiological mechanisms for coping with water shortage resulting from different evolutionary adaptive strategies. This diversity, however, displays a rather unexpected pattern in terms of its geographical distribution. [Copyright &y& Elsevier]

Abstract: This paper describes and compares the hydrological responses of runoff, soil moisture and groundwater levels to rainfall events for two small semi-arid catchments over a 2-year period. Romwe received 1430 and 756mm of rainfall in the 19999/00 and 2000/01 season, respectively. Mutangi received 756 and 615mm of rainfall in the same years. Romwe generated 520 and 102mm of runoff in the 19999/00 and 2000/01 seasons, respectively, while Mutangi generated 82 and 69mm of runoff in the same years. The runoff response of the catchments was dominated by a relatively quick response to rainfall and with little or no significant contribution from regional groundwater or ‘old water’ sources. Total soil moisture storage to a depth of 120cm was higher at Romwe than Mutangi for the entire study period reflecting the differences in the soil types. The groundwater level was closer to the surface and responded more quickly to rainfall at Romwe compared to Mutangi where water levels were between 12 and 16m below the surface. There was a significant relationship between profile soil moisture and water table level at Romwe and none was observed at all in Mutangi. Significant (p<0.05) monthly rainfall runoff relationships were observed at both Romwe and Mutangi. At Romwe and Mutangi 91% and 76% of the runoff variation was accounted for by rainfall in the 1999/00 season, respectively. The rainfall–runoff relationship were different at Romwe for the two seasons, it was higher in the 1999/00 season than the 2000/01 season when 91% and 49% of the runoff variation was due to rainfall, respectively. The relationships were almost similar at Mutangi during the two seasons. [Copyright &y& Elsevier]

Abstract: Australia has not always been arid, and the central desert was once well watered. This paper traces the changes in climate and vegetation, leading to the present aridity. At the beginning of the Cenozoic, continental Australia had a warm and humid climate, and the vegetation was mainly meso–micro-thermal (warm to cool temperate) rainforest. Central Australia experienced seasonal rainfall and there may have been limited aridity in the northwest. By the mid–late Eocene, rainforest in central Australia was restricted to the well-watered valley bottoms, with sclerophyll vegetation on the slopes and ridges. In the latest Eocene–earliest Oligocene, there was an abrupt cooling of ocean waters and the diversity of megathermal angiosperms decreased. The early–mid-Miocene was warm–humid and there was a considerable diversity of forest types. Woodlands and Casuarinaceae forests became more common. Central Australia was seasonal, with a very warm season of high evaporation. In Western Australia, regular flows in the palaeodrainage systems had stopped by the mid-Miocene and this marked the first major step towards aridity. The late Miocene was cool and dry, with a major reduction of rainforests and an increase of Eucalyptus/casuarinaceous sclerophyll forests in inland southeastern Australia. Regular burning became a feature of the eucalypt forests. Rainforest persisted, however, along the east coast and highlands of Australia. Central Australia became more arid with dry woodland and chenopod shrublands. Rainforests continued to decrease during the Pliocene and grasslands developed in central northern Australia. By the early Pleistocene, the modern climatic regime had been established, but precipitation was higher than today. Cycles of open, shrubland/grasslands/herbfields and wooded vegetation accompanied the arid glacial and humid interglacial cycles (respectively). About 0.5Ma, there was a change to a drier climate, but it was still wetter than today. The last glacial period was particularly harsh, and the present interglacial period is drier than the previous interglacial. Aridity has thus increased in a number of steps, following the first major step towards aridity in the early Miocene. Distinctive elements of the vegetation can be traced back to times when the arid zone was humid and supported rainforest. The elements, which have remained in arid regions, are the few that could tolerate or adapt to the drier climates. The taxa, which could not cope with these changing conditions, were eliminated from the arid regions. [Copyright &y& Elsevier]

Abstract: Current and past settlement strategies in Central North Namibia are explored with historical aerial photographs, maps of indigenous land units (ILUs), GIS analysis, field observations and interviews on indigenous knowledge to improve understanding of livelihood strategies, described as an agro-sylvi-pastoral system. The objective is to assess the role of ILUs, indigenous fruit trees and termites in human settlement. Livelihood strategies take into account unpredictability of the semi-arid environment by having high diversity of ILUs on farm, not by selecting a certain elevation above water level as previously suggested. ILUs are classified according to hydrological properties and other aspects. Farming practices like kraal and homestead rotation and selection of ILUs with pronounced termite activity for cropping are suggested to maintain soil fertility. Selection of termite-rich areas causes a trade-off with homestead longevity and homesteads are located at least termite rich ILUs, but are encroached upon by termites. The amount and distribution of more fertile ILUs causes a trade-off between grazing and cropping when enclosed for farming. It is suggested that indigenous fruit tree species have been encouraged indirectly to grow on farm. It is shown that some fruit tree species never occurred in the area before. This is in contrast with the general view that fruit trees are left when farmers clear land. While some indigenous farming practices may degrade the land, this paper demonstrates that others don’t. [Copyright &y& Elsevier]

Abstract: This paper analyses the role of climatic aridity on the spatial differences of vegetation activity and its inter-annual variability in a semi-arid region of the North East of the Iberian Peninsula. The vegetation activity was quantified by means of a monthly Normalized Difference Vegetation Index (NDVI) database from NOAA–AVHRR satellite images (1987–2000) at 1km2 of spatial resolution. Coefficients of variation (CoV) from temporal NDVI series were also calculated. The greater temporal variability of NDVI was recorded in areas with low vegetation cover (steppe and dry farming lands), whereas the lowest temporal variability of NDVI was recorded in the irrigated lands and forests located in the most humid areas. There is a strong and negative relationship between the CoV and the NDVI distribution, but we recorded important differences among land uses. Using maps of annual precipitation and temperature obtained by means of a regression-based method, we studied the influence of aridity on spatial patterns of NDVI and CoV values. The results show the high influence of aridity on the spatial distribution of vegetation activity in the Middle Ebro Valley. Aridity causes a general decrease of NDVI and an increase of CoV. Nevertheless, non-linear relationships between aridity and NDVI and CoV were recorded for the whole of the study area and for the different land uses. The relationships between aridity and vegetation patterns in the semi-arid region studied are discussed in depth. [Copyright &y& Elsevier]

Abstract: Mobile wind tunnels are essential tools for the field examination and quantification of wind erosion processes on natural non-imitated surfaces under standardized, quasi-natural wind conditions. A mobile wind tunnel was constructed at the IBS of the University of Hohenheim to measure wind erosion susceptibilities under different conditions and sediment emission on dominant surfaces formed under semi-arid conditions on a transect in the Republic of Niger/West Africa. This paper gives an overview which considerations are necessary for the construction of a mobile field wind tunnel, presents calibration data and reports on first field measurements. Designing a wind tunnel for wind erosion research, several aerodynamic prerequisites need to be considered, mainly the tunnel''s dimension and the related specifications of the fan (power, size, the ability to overcome pressure drag). Main requirement is the establishment of a quasi-natural boundary layer featuring realistic energy transmission and an equilibrated layer of saltating particles with reduced flux-limitations. Specific project requirements need also to be included in the design. In the present case, this affects mainly the choice of the instruments (what should be measured) and their spatial arrangement (to minimize air resistance and to avoid crosswise influence on measurements). Instruments at the end of the 9.40m test section include sediment catchers and pitot tube anemometers for wind profile measurement, both arranged in a logarithmic profile, an isokinetic filter sampler and a saltiphone for saltation flux measurement. During calibration and field work, the tunnel proved to simulate quasi-realistic wind conditions. Technical problems occurred only with the use of the saltiphone. A first analysis of the obtained data shows similarities with field measurements during natural monsoon storm events in the same investigation area. Nevertheless, a direct comparison of the results is complicated, mainly due to the physical restrictions of wind tunnel employment. [Copyright &y& Elsevier]

Abstract: Science is frequently touted as the solution to dryland management problems, yet most management decisions are, by necessity, based primarily on expert knowledge and experience. This paper describes an integrated framework for organizing, synthesizing, and applying our growing understanding of aridland ecosystems using a flexible, multi-objective assessment, monitoring, and management approach. The framework is dual-purpose: (1) to coordinate the use of existing tools, resources, and diffuse knowledge, and (2) to facilitate the integration and application of new knowledge as it is developed. In particular, this framework must facilitate the integration of new knowledge about linkages among landscape units across scales. The framework includes five elements: (1) an ecological site-based approach for categorizing land based on soils and climate, (2) a repository for organizing existing data and knowledge about each ecological site, (3) conceptual models that organize information on the impacts of management and climate variability, and protocols for (4) assessing and (5) monitoring key ecosystem attributes fundamental to a variety of management objectives. Within this framework, basic and applied research are explicitly linked to management of arid and semi-arid ecosystems to more effectively articulate research questions and set research priorities. [Copyright &y& Elsevier]

Abstract: The objective of this paper is to illustrate the concept of the soil-geomorphic template and its relationship to biotic change in arid and semi-arid regions. Such biotic change is typically accompanied by and linked to geomorphic change that involves soil, topography, and soil parent material, which together form the soil-geomorphic template. Soil is a factor in biotic change because it is the substrate that provides water, nutrients, anchorage for plants, and habitat for burrowing animals. Topography is a factor in biotic change because it influences local microclimate by means of elevation, lateral redistribution of water, and slope orientation. Soil parent material is a factor in biotic change because it provides the lithic inheritance from the geologic landscape that gives rise to soils with different particle size distribution (i.e. available water holding capacity) and nutrient status. Numerous linkages and feedback loops occur between the soil-geomorphic template, microclimate, vegetation, and animals. A perturbation in any of these factors can steer an ecosystem from one state to another. The integral relationship between the soil-geomorphic template and biotic change is an example of how biological and geological systems are coupled and co-evolve over long-term (Quaternary landscape evolution) and short-term (human-induced desertification) time-scales. [Copyright &y& Elsevier]

Abstract: The objective of this paper is to illustrate the importance of variation in water availability to temporal variation in vegetation dynamics in arid and semi-arid ecosystems. We hypothesize that fine-scale pulses of precipitation interact with longer scale variation in climate and weather to generate temporal variation in plant community composition. Arid and semi-arid regions exhibit great temporal variability in water availability as a result of variation in climate and weather at multiple scales and vegetation-soil water feedbacks. The scales of variation include: shifting climate regimes over centuries and decades, inter-annual variation in weather patterns, seasonal differences in winter and summer precipitation, and within-season variability in precipitation frequency and magnitude. In arid and semi-arid regions, pulses of rainfall are separated by intervening dry periods of variable lengths. This situation results in fluctuating availability of water that limits plant production and controls other ecological processes, such as rates of nutrient cycling. In some semi-arid and arid systems, temporal variation in water availability may create positive feedbacks that facilitate encroachment of C3 woody plant species into areas formerly dominated by C4 grasses. Our ability to predict these complex shifts in vegetation composition may be improved by including temporal variation in climate, weather, and ecosystem processes. [Copyright &y& Elsevier]

Abstract: Terrestrial chelonians of arid regions are frequently faced with highly variable food quality and/or quantity and these problems could be aggravated in overgrazing areas. Then, it is crucial for species conservation to possess precise data on feeding ecology. In this paper, we provide the first quantitative data on Testudo graeca graeca feeding ecology, in the central Jbilets (Morocco). Diet composition was obtained by faecal analysis and compared to plant assemblages in the field. Interestingly, T. g. graeca seems rather a specialist herbivorous tortoise. The five main plant species found in faecal samples (Leontodon saxatilis (Asteraceae); Malva parviflora (Malvaceae); Astragalus cruciatus, Medicago hispida and Lotus arenarius (Fabaceae)) represent 70% of the identified material and are highly preferred whereas several other plant species, common in the field (e.g. Eryngium ilicifolium (Ombellifereae); Emex spinosus (Polygonaceae); Spergula flaccida Caryophyllaceae)) are actively avoided. Fabaceae made up 27% of the diet and may be important forbs in the diet of terrestrial tortoise owing to their high nutritional value. The diet composition of T. g. graeca suggests that diet overlap may occur between domestic ungulates and tortoises in overgrazed landscape and could generate a competition context. However, T. g. graeca seems to focus its foraging effort under the spiny shrubs where the impact of overgrazing is strongly attenuated. [Copyright &y& Elsevier]

Abstract: Between 1998 and 2001, wind data from eight meteorological stations were analysed to examine sand drift potential (DP) in Kuwait, using Fryberger''s [1979. In: McKee, E.D. (Ed.), A study of global sand seas. Professional Paper 1052, United States Geological Survey, US Government Printing Office, Washington, pp. 137–169] method. Resultant DP and directional variability of wind are also calculated and explained. The average annual sand DP is predicted to be 354VU (vector units). This puts Kuwait, in general, among the intermediate wind energy deserts. Potential sand drift environment is markedly variable from place to place, and 77% of the annual resultant DP occurs during the summer period i.e. May to September. Directional variability is also relatively high in the summer period. [Copyright &y& Elsevier]

Abstract: The current paper analyses various environmental parameters in relation to wheat yields in Bordenave, Province of Buenos Aires, Argentina. The variables used are: precipitation (ppt), maximum (Tx) and minimum temperature (Tmi) as well as those obtained by applying the Palmer model. Decadic and phenological scales are used for data corresponding to the period 1977–2000. The stepwise method is used to obtain a multi-variate equation to calculate yield taking into account environmental variables only. For a five variates model the coefficient of determination, equals 95.79% and the standard error of estimation is 129.0kgha−1. In the sample yields, the incidence of total variability for thermal variables is 42.7% and for hydrological variables, 53%. The value and sign of the correlation coefficients were analysed throughout the cultivation cycle. The coefficient is mainly responsible for yield variance during tillering and stem elongation. There is good correlation with the values of Palmer''s Drought Severity Index (PDSI) for the flowering and grain filling stages. [Copyright &y& Elsevier]

Water is a main controlling factor for economic development and eco-environmental protection in the inland river basins of arid western China. Ground-water, as a component of total water resources, plays a dominant role in the development of western China because of its stable quantity and quality. In recent years, the utilization ratio of surface water has been raised, the ground-water recharge rate from surface water has been reduced, and ground-water has been exploited on a large scale. This has led to the decline of ground-water levels and the degradation of eco-environments. Taking the Heihe river basin as an example, this paper describes ground-water characteristics in the water cycle, deals with the status of ground-water resources, analyses the problems of ground-water resource development and, finally, suggests strategies for rational use of ground-water resources in the arid inland river basins of western China. [Copyright &y& Elsevier]

The rating of biodiversity in arid and semiarid regions on the basis of ecological function and genetic traits of adaptation to severe environmental stresses produces significantly higher values, than that based solely on the commonly applied structural criteria of forms of life and levels of organization. The indirect driving forces of biodiversity impoverishment listed in the Global Biodiversity Strategy that are particularly effective in arid and semi-arid regions are (a) population growth, (b) economic systems and policies that fail to value the environment and its natural resources; (c) inequity in the ownership, management and flow of benefits from both the use and conservation of biological resources; and (d) weakness in legal and institutional systems. The most effective direct human impacts are (a) habitat destruction and fragmentation, (b) overexploitation of biological resources, (c) biological invasion, and (d) agriculture. The problem in arid and semiarid regions, particularly in developing countries, is exacerbated by the lack of knowledge and awareness, the paucity of research, and the diminishing number of competent systematists.This paper discusses the theoretical and practical aspects of each of the indirect driving forces, and the direct human impacts on biodiversity, and reviews case studies related to these impacts, with special reference to those carried out in arid and semiarid regions. These studies include monitoring of the human impact on land cover by remote sensing, effects of landuse on species diversity, impact of habitat fragmentation by summer resorts on coastal dunes, consequences of protection from grazing on biodiversity, comparison of biodiversity in nature reserves and the traditional ema system with that of nearby territories, and the impact of desertification on animal life and endangered species. Case studies also include the tools applied for biodiversity conservation in arid and semiarid lands with special emphasis on endangered species, restoration of degraded habitats and their biodiversity, the significance of nature reserves and captive breeding, the importance of conserving the populations below the species level throughout their geographical range of distribution, and ecotonal biodiversity. [Copyright &y& Elsevier]

Countries of semi-arid West Africa are experiencing growing populations, expansion of cultivated land and intensification of crop and livestock production an ever-increasing burden on the region''s limited natural resources, consequently increasing degradation rates. A broad range of technologies combating degradation currently exist. This paper presents and discusses both traditional techniques as well as modern techniques which are derived from the traditional ones. Various methods of mulching and application of manure or mineral fertilizers are used to maintain or increase soil fertility. The use of mulch as well as various methods of integrating shrubs, trees and herbaceous vegetation into the cultivation systems are the technologies currently used to decrease the effects of wind erosion. Similarly, water erosion can be prevented with lines of stones, mulch and grasses. The most promising methods which impede decreasing natural vegetation are promotion of natural regeneration and to some extent the implementation of agricultural parks. In contrast, community-based management of grazing land or forested areas are difficult to establish.Most conservation strategies are limited by the availability of mulch, fertilizer or manure to fertilize fields or to protect sufficient land areas from wind and water erosion. Household constraints of individual farmers also play a crucial role in increasing such protection. Great efforts are needed to distribute the knowledge of the various conservation strategies throughout the different regions of semi-arid West Africa, and to develop new technologies, preferably with farmers'' participation, to enable adoption. As degradation continues and populations increase, this must be accomplished in the near future in order to hinder devastation of land resources. [Copyright &y& Elsevier]

This paper describes strongly developed vegetation bands that are not aligned along the contour. This previously unreported oblique vegetation banding is developed in an arid region of mixed tussock grasses and chenopod shrubs in western New South Wales, Australia.In two of four contour-mapped, 0·5 ha quadrats, the vegetation bands are oriented at angles of 45–70° to the direction of slope. Various soil features indicative of a runoff and runon hydrology, very similar to those classically reported from contour-parallel vegetation banding, suggest that the oblique configurations have been stable for a considerable time.In addition to the unusual band orientation, marked variations in the ratio of intergrove width to grove width were found within the study area, spanning the range 0·21–4·95, and there was generally no correlation between intergrove width and the width of the grove receiving runoff water from it. These findings cast doubt on the supposed close adjustment of intergrove dimensions to grove water requirements.In nearby plots having ordinary contour-parallel vegetation banding, the absence of any upslope motion of the pattern was demonstrated using monuments installed at band margins 6 years previously.These properties do not accord with the predictions of many models of the development of vegetation banding. However, soil changes associated with the runoff–runon system operating within vegetation bands may be involved in stabilizing their configurations. Thus, future investigations into the origin of vegetation banding must distinguish between their form and hydrologic functioning once established, and the fundamental origin of the vegetation pattern, which may be altogether different. In addition, pedologic and other processes which may inhibit free pattern adjustments must be incorporated into models addressing the development of vegetation banding. [Copyright &y& Elsevier]

The Farasan Archipelago is an Important Plant Area near the Arabian Peninsula. The islands are small, low-lying and subject to considerable tourist and industrial development, putting their native flora at risk. Here, we report an updated checklist covering 52 families, including 152 genera and 245 species, which is being published online for the first time. This inventory was performed by a baseline survey of the literature followed by field surveys across the entire archipelago. Taxonomic updates result in four new family reports: Cleomaceae, Asphodelaceae, Loranthaceae and Asparagaceae. Forty percent of the flora has been reclassified at the family, genus or species level based on modern treatments, and the remaining sixty percent remains unchanged. This checklist will help to focus conservation efforts and provide a framework for research, conservation and policy development for The Farasan Archipelago flora. • The vegetation richness' papers of the natural systems of Farasan Archipelago, it's main to keep updated list of its flora. • Describe the distribution patterns of taxa on the islands from field survey it will help to allow conservation planning. • Study confirms biodiversity of Farasan Archipelago tends to be different from the closet area on the mainland (Jizan region). • In Farasan Archipelago the small Islands are dominated by halophyte plants While the large Islands contain of shoreline types. [ABSTRACT FROM AUTHOR]

In this paper, a new approach for mapping polygenic depressions colonised by vegetation is presented. These spatially periodic vegetation patterns situated in the arid areas of North Africa are known locally as "Dayas". The mapping of these structures is an important component in monitoring their evolution which can be regarded as an indicator of socio-environmental conditions. For this purpose, a method based on satellite image analysis is proposed. First, Landsat Thematic Mapper image inspection is performed to highlight the vegetation spots using the Normalized Difference Vegetation Index (NDVI). Then, a Differential Morphological Profile (DMP) which includes both spectral and morphological information, is built for each NDVI pixel. We adapt the F-Score technique combined with the SVM classifier, to select and classify the most effective DMP images in order to extract the Daya's signature. Using feature selection, overall classification accuracy reached 97.8% with a kappa value of 95.61 but also reduced the dimension of the DMP vector. Dayas' morphological and vegetation characteristics are related to their degree of evolution. Furthermore, we categorise categorise the 170 extracted Dayas into three classes according to their size. On the resulting map, each class corresponds to a specific morphological and vegetation evolution stage. • The established methodology allows Dayas identifying in semi-arid areas. • Differential Morphological Profile is a powerful tool for spots vegetation mapping. • Size-based classification of Dayas enables a chronological distribution. • F-Score combined with SVM for feature selection improves classification accuracies. [ABSTRACT FROM AUTHOR]

The diagnosis of land degradation requires a deep understanding of ecosystem functioning and evolution. In dryland systems, in particular, research efforts must address the redistribution of scarce resources for vegetation, in a context of high spatial heterogeneity and non-linear response. This fact explains the prevalence of eco-hydrological perspectives interested in runoff processes and, the more recent, focused on connectivity as an indicator of system resource optimisation. From a geomorphological perspective and reviewing the concepts of eco-hydro-geomorphological interactions operating in ecosystems, this paper explores the effects of erosion on vegetation configuration through two case studies at different spatio-temporal scales. We focus on the structure-function linkage, specifically on how morphological traits relate with different stages in the erosional sequence, both in the abiotic and the biotic domain. Results suggest that vegetation dynamics are affected by structural boundary conditions at both scales, i.e. by surface armouring related with rock fragments at the patch scale, and by the degree of hillslope-channel coupling at the hillslope scale. Our preliminary results can serve as new working hypotheses about the structure-function interplay on hillslopes. All this, taking advantage of the recent technological achievements for acquiring very high-resolution geospatial data that offer new analytical possibilities in a range of scales. • Structure/function approach evidences erosion effects on vegetation configuration. • Composition of abiotic patches modulates source-sink dynamics by surface armouring. • Channel linear incision diffuses the upslope erosion, biasing vegetation. • Erosional sequence across-scales sets boundary conditions to hillslope connectivity. • Eco-geomorphic frameworks are needed to address explicitly space-time scale dependencies. [ABSTRACT FROM AUTHOR]

Dryland smallholders are faced with the challenges of achieving resilience and agricultural sustainability. This is in addition to constraints such as lack of capital, inputs, and often poor extension services. The risk of extreme weather events poses a great challenge to food security in drylands as the impacts of climate change increases. This paper examines the challenges faced by smallholders and the limitations of traditional farming systems in Sudano-Sahelian zones amidst climate change and emerging armed conflicts with special focus on the Sudano-Sahelian Nigerian drylands. The review reports three key findings as follows: first, smallholders have been active in managing short-term environmental risks and challenges by using local knowledge to improve production and short-term resilience. Secondly, concerns about potential longer-term climatic changes such as longer droughts, desertification, the impact of the drying of the Lake Chad, armed conflicts and extreme weather events could hinder resilience. Third, an increasing rainfall variability, soil/nutrient degradation and farming systems adopted could limit or undermine resilience strategies, especially if new environmental challenges exceed those previously experienced. This review suggests a need for additional research into innovative drylands' sustainability and resilience practices in response to a changing climate linked to other social challenges. • Drylands smallholders are resilient to changes in the climate they have experienced. • Production is restricted by new social challenges. • Climate change, and other challenges will limit food security. • Current adaptation not sufficient if new environmental challenges emerge. • More innovative strategies should be researched into for resilience. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to examine the beef value chain and identify climate change adaptation and investment options in the semi-arid areas of northern Kenya. The research uses an innovative approach to value chain analysis, namely the three-step Value Chain Analysis for Resilience in Drylands (VC-ARID) that considers the specific characteristics of semi-arid systems. All the respondents interviewed along the value chain have perceived changes in rainfall, temperature and climate extremes – especially drought – over the past 15 years and have experienced the impacts of these changes on their livestock. The findings show that pastoralist producers need to invest in fattening programmes at their ranches or via feedlots to increase the quality of the beef they produce. There is significant potential to improve the fattening stage in the value chain, since it would contribute towards meeting demand in the expanding high-end markets that require finished, top-quality meats. • Pastoralists beef value chain is more informal, traditional, extensive pastoralism. • Private ranches value chain is formal and incorporates fattening of livestock. • Pastoralists rely on mobility for coping with climate risk. • Climate change has negatively impacted on semi-Arid livestock production. • There is potential to improve and expand the fattening stage of the value chain. [ABSTRACT FROM AUTHOR]

Earth-to-air heat exchanger (EAHE) is used for heating and/or cooling of dwelling and buildings in arid regions. In the present paper, experiments are performed to investigate the efficiency of an earth-to-air heat exchanger without external devices (fans, air blowers, etc.). The climatic conditions of the region of Bechar, which is located in the Southwest of Algeria, are considered. The EAHE is made of a PVC pipe with 66 m in length and 0.11 m in diameter. It was buried at a depth of 1.5 m in the agricultural zone, where the annual undisturbed subsoil temperature at 1.5 m is 28 °C. An increase of 19% in the relative humidity (RH) of EAHE has been observed in the humidification regime. While a decrease of 27% in RH has been reached in the dehumidification regime. For the hygrometric regime, the daily working regime was 62.5% of dehumidification (from 00 h to 09 h and from 18 h to 23 h) and 37.5% of humidification (from 10 h to 17 h). The EAHE technique has excellent potential for the enhancement of building hygrometry in arid regions. • The performance of an earth to air heat exchanger is studied by experiments. • The exchanger is used to provide the thermal comfort inside houses in arid regions. • The study is achieved in the region of Bechar, which is located in the Southwest of Algeria. • The studied region is known by its hard environment and arid climate. • The exchanger under investigation acts without external devices (fans, air blower, etc.). [ABSTRACT FROM AUTHOR]

In arid and semi-arid regions, unregulated land use changes as a result of poor planning, and the expansion of agricultural and livestock activities increase the risk of desertification and other potentially severe environmental impacts. Several consequences of improper land management practices are soil deterioration and erosion, which may be intensified by meteorological events. This paper presents a historical evaluation of the temporal and spatial evolution of soil deterioration in the southern Chihuahuan Desert in Mexico. A multi-temporal analysis of the study area during the 1995–2016 period was carried out using satellite data (Landsat series). Two seasons were analyzed to determine the influence of external events such as rainfall and wind: dry and rainy. The identification of soil conditions was based on the Brightness Index (BI) considering the complete satellite data set. The soil conditions were classified into five categories according to their reflectance values: highly deteriorated, deteriorated, in the process of being deteriorated, in good condition and other (clouds, water, non-soil). The change detection maps clearly show a growing trend wherein areas of deteriorated and eroded soil increase over time. Agriculture and strong winds are the two main factors involved in the soil deterioration process of the study region. • Deficient agricultural practices and strong winds precursors to desertification. • Spatial-temporal identification of deteriorated soil in arid/semi-arid zones. • Spectral analysis based method for categorization of soil conditions. • Comparative analysis of sensitivity in rainy and dry seasons. [ABSTRACT FROM AUTHOR]