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Abstract Archaeological studies typically describe arid areas as extremely unpleasant areas for human occupation and use. Without suggesting that arid areas are pleasant places, however, this paper provides a reassessment of the meaning of aridity for an area showing a vast amount of evidence of (past) human activities. Several climatic proxy data suggest that at the transition between the late Bronze Age and the Early Iron Age (around c. 1300-1100 BC) the southern Levant witnessed more arid conditions, while after 1100 BC relatively moist conditions would have prevailed. In drylands, small changes in temperature and water availability can have large effects on subsistence options. Building on cooperation between an archaeologist and a water scholar, this paper offers an approach to study how people in the past were able to craft a livelihood in the arid environments in the southern Levant and elsewhere. Focusing on the Zerqa area, the paper explores the potential of this cooperation by studying effects of climatic changes at the transition from the Late Bronze Age to the Iron Age through a modelling approach. Changes in temperature and moisture availability were simulated, showing that increased aridity could have been met by either naturally available water (especially groundwater) or artificially added water (although the timing appears to be crucial). While the model approach under discussion offers an approximation of the past, it shows the potential impact of climatic changes on the subsistence of past communities. It shows that details can mean the difference between survival or collapse. Highlights • Modelling provides boundaries for thinking about ancient resilience. • Rainfed crop yields could be sustained with irrigation, even in the frequent dry years. • Increasing aridity might have been a trigger for expanding the irrigation system. • The Zerqa Triangle was affected by the LBA crisis, yet continuity is visible as well. • Aridity did not necessarily bring crisis, even in arid areas like the Zerqa Triangle. [ABSTRACT FROM AUTHOR]

Abstract Over the last 30 years, geoarchaeological surveys undertaken in the Near East have offered a powerful way of studying, inter alia, water supply systems at a microregional to regional scale. However, efforts to synthesize the results of surveys at a sub-continental scale in order to understand local differences and similarities, and compare local strategies through time, require specific tools. In this paper, we develop a methodology designed to characterize and facilitate comparison of strategies employed across the arid areas of Western Syria. This requires microregional field studies undertaken at the level of specific landscapes to be integrated within a wider GIS framework, based upon thematic layers (soils, rainfalls, hydrology) at a uniform spatial scale of assessment (in this case the pixel of a Landsat image), and a common description of the agronomic potential in those areas in which specific hydraulic installations were employed. In contrast to the usual practice of modelling, which depends upon the downscaling of environmental data (land cover, rainfall maps) generated at a continental scale, we stress here the need to generalize upwards, from observations made at the microregional level, by using common descriptors and qualitative indicators. The GIS analysis of these data provides a weighted average model derived from field evidence for the different technical choices made (i.e. the decision to utilize specific water management devices) in relation to the various agronomic landscapes. Highlights • Long term history of Syrian arid steppic landscapes enlighted by water mastering techniques • Modelling spatial location of past water management devices in arid areas • Modelling the regional agronomic potential in Near East arid areas [ABSTRACT FROM AUTHOR]

Abstract MARAS (Monitoring of Arid and Semiarid Regions) consists of 379 ground monitors in Patagonia, a 624.500 km2 semiarid area of southern Argentina and Chile. The objective of this paper was to describe the system and analyze four variables of the initial data base. Floristic composition, diversity and cover were analyzed with intercept lines (500 points). Patches (resource-sinks areas) and Interpatches (areas that loose resources) were described using Gap intercept lines (50 m). Eleven Landscape Functional Analysis indicators were recorded in 10 interpatches: Soil stability, Infiltration and Nutrient cycling. Vegetation Cover was 43 ± 2%, Richness 15 ± 7 species/monitor, Interpatch Size 154 ± 134 cm and LFA Stability Index 46 ± 1%. Cover, Richness and Stability maps had bimodal distribution and maximum in S and NE areas, following rainfall gradients. Variability analysis shows that cover estimations are within 5% error at site and regional scales. Graphical analysis of single monitors shows observational biases in interpatch size and LFA Stability index. Richness estimations correlate significantly with α diversity (R2 = 0.80). Analysis of 5-year change in 115 monitors shows significant reductions in cover and interpatch length, especially N of the region. These base line evaluations enable analysis of future changes that were not possible with multiple techniques and isolated data bases. Highlights • 379 ground monitors of vegetation and soil were installed in Patagonia. • Six teams in two countries shared a single protocol and data base. • Errors of estimations at site and regional scales are acceptable. • Contour maps of main variables show gradients associated to aridity. • This baseline enables future change evaluation. [ABSTRACT FROM AUTHOR]

Abstract Past water resource developments in dryland regions rarely estimated the full suite of environmental and social impacts arising from damming and diverting water for food production. Nowadays there is a greater focus on sustainable resource development which considers the economic, social and environmental costs and benefits. A challenge is to apply tools and methods which can capture the often disparate knowledge and data describing many costs and benefits. This paper describes a proof of concept application of a large Bayesian Decision Net to estimate the total utility of water resource development according to criteria of social, economic and environmental sustainability. We focus on two water-scarce catchments in remote northern Australia which are under investigation for development. The study catchments contain a diverse set of ecosystem services and socio-cultural values, including important Indigenous values and high value freshwater ecosystems. The Bayesian Decision Net was shown to have many properties that made it useful for performing a social, economic and environmental sustainability assessment, in particular its ease of construction; its ability to handle quantitative and qualitative data types; its preservation of system knowledge and; its ease of use in aiding decision making. From the perspective of the sustainability assessment in our case study, the total utility of water resource development for new irrigation is negative in both the studied catchments. The overall utility of water resource development could be positive if irrigation development is highly sensitive to the environment and there are very low environmental impacts, and much higher net economic returns to irrigators eventuate, possibly through higher commodity prices, lower capital costs of irrigation development or some combination of both. Highlights • Development of water resources involves trade-offs between economy and environment. • Integrated social-environment-economy sustainability (SEES) assessments support trade-offs analyses. • Bayesian Decision Networks (BDNs) support SEES assessments with diverse data types. • BDN applied to irrigation development scenarios of two remote catchments in north Australia. • The economic and ecosystem service benefits of the case study irrigation developments are questionable. [ABSTRACT FROM AUTHOR]

Desert tourism has grown steadily in several regions of the world, due to a post-modern fascination with remoteness, barrenness, silence and solitude. This paper evaluates the trend towards tourism development in South Africa's arid Karoo region. It utilises several methodologies – analysis of discourse, demand and supply – to track the changing profile of tourism in the Great Karoo. The paper concludes that the reputation of the Karoo has shifted profoundly from being hostile, dangerous and boring to being attractive, enticing and spiritual. At the same time, tourists are increasingly expressing favourable opinions of the Karoo as a destination, while accommodation facilities are growing apace. The overview also finds that tourism services in some Karoo towns are developing at a much faster rate than others, so the tourism performance is uneven. A survey of tourists in the Karoo found that the arid environment and small-town ambience offer significant attractions, and Karoo guest houses have a positive outlook for the future. These findings suggest that the Great Karoo is indeed in the process of becoming a tourism destination. [ABSTRACT FROM AUTHOR]

The aspirational goal of a land degradation neutral world, to be realized by reducing the rate of land degradation and increasing the rate of restoration of degraded land, was agreed at the Rio+20 Conference in 2012. This paper evaluates the feasibility of introducing a Land Degradation Neutral (LDN) scheme as an activity of the United Nations Convention to Combat Desertification (UNCCD). It concludes that national and international implementation would involve political, organizational and technological challenges. Monitoring restoration of desertified land by revegetation would be feasible immediately, but monitoring cuts in national rates of desertification would not, because no baseline rates are currently available; national and international scientific capacities to measure desertification are limited; and further scientific knowledge is required to supplement existing knowledge of desertification processes and of land use and land cover change processes generally. This paper therefore suggests introducing an LDN scheme in phases. Phase 1 would focus on restoring degraded lands, improving national land use planning systems, and establishing international and national monitoring capacities. Phase 2 would reduce desertification rates with the help of fully integrated land use planning and monitoring systems. Phase 3 would set a target year for realizing an LDN goal, based on experiences in Phases 1 and 2. All three phases would be informed by accessing existing scientific knowledge, and gaining new knowledge by launching a scientific LDN process that can evolve in parallel with the political process. [ABSTRACT FROM AUTHOR]

Water is a scarce resource in arid regions, and hence water harvesting is critically important in these regions for which many different means are adopted including groundwater and rainwater harvesting. This paper examines the feasibility of rainwater harvesting from roof catchments in arid regions of Australia. For this, ten representative locations in the arid regions of Australia are selected. Also, ten different sizes of rainwater tanks ranging from 5 kL to 50 kL and three different combinations of water uses are considered. A model is developed to simulate the performance of a rainwater harvesting (RWH) system. It is found that the reliability of a RWH system is highly dependent on mean annual rainfall at the location of interest. It is found that a 20 kL tank can provide a reliability of 61%–97% for toilet and laundry use depending on the location within the Australian arid regions. At the current water price, RWH system is not financially viable in the Australian arid regions. The methodology adopted in this paper can be adapted to other similar arid regions of the world. [ABSTRACT FROM AUTHOR]

Abstract: Biofuels are considered as a climate-friendly energy alternative. However, their environmental sustainability is increasingly debated because of land competition with food production, negative carbon balances and impacts on biodiversity. Arid and semi-arid lands have been proposed as a more sustainable alternative without such impacts. In that context this paper evaluates the carbon balance of potential land conversion to Jatropha cultivation, biofuel production and use in arid and semi-arid areas. This evaluation includes the calculation of carbon debt created by these land conversions and calculation of the minimum Jatropha yield necessary to repay the respective carbon debts within 15 or 30 years. The carbon debts caused by conversion of arid and semi-arid lands to Jatropha vary largely as a function of the biomass carbon stocks of the land use types in these regions. Based on global ecosystem carbon mapping, cultivated lands and marginal areas (sparse shrubs, herbaceous and bare areas) show to have similar biomass carbon stocks (on average 4–8 t C ha−1) and together cover a total of 1.79 billion ha. Conversion of these lands might not cause a carbon debt, but still might have a negative impact on other sustainability dimensions (e.g. biodiversity or socio-economics). Jatropha establishment in shrubland (0.75 billion ha) would cause a carbon debt of 24–28 t C ha−1 on average (repayable within 30 year with yield of 3.5–3.9 t seed ha−1 yr−1). Land use change in the 1.15 billion ha of forested area under arid and semi-arid climates could cause a carbon debt between 70 and 118 t C ha−1. This debt requires 8.6–13.9 t seed production ha−1 yr−1 for repayment within 30 years. If repayment is required within 15 years, the necessary minimum yields almost double. Considering that 5 t seed ha−1 yr−1 is the current maximum Jatropha yield, conversion of forests cannot be repaid within one human generation. Repayment of carbon debt from shrubland conversions in 30 years is challenging, but feasible. Repayment in 15 year is currently not attainable. Based on this analysis the paper discusses the carbon mitigation potential of biofuels in arid and semi-arid environments. [Copyright &y& Elsevier]

A practical approach for the assessment of surface water and groundwater resources in rain-fed mid-mountain domains of arid to semi-arid zones is much needed, especially in rural areas for which groundwater is the only reliable and permanent water supply source. This is the case in the Coquimbo region (29°15′- 32°10′ S latitude) of north-central Chile, where groundwater is needed for human consumption but also for agricultural and mining activities at a small to medium scale. This paper examines the usefulness of community knowledge, as encoded in the historical record, for identifying water resources. The existing record of wells and springs in the Coquimbo region is used as a guide to the identification and characterization of structural patterns that may influence the distribution of water resources. The proposed approach combines simple graphical, statistical and geostatistical methods to identify patterns, likely related to local and regional structural controls that influence the distribution of groundwater resources. In the Coquimbo area, these influences tend to align in NW and NE orientations that approximately coincide with regional geological trends. The methodology presented has the potential to form a first step in the search for additional water resources in the Coquimbo region, and may be useful for targeting detailed field studies on the basis of community and historical knowledge in many arid and semi-arid rural areas. [ABSTRACT FROM AUTHOR]

Long-term impacts of drought, such as groundwater decline, can emerge during a persisting drought. Though not easily visible, they are severe and harder to cope with. Groundwater is considered a resilient source during drought in semi-arid areas. In this paper the response of a coastal aquifer to meteorological drought severity is investigated. The relation between drought severity and natural undisturbed coastal aquifer flow conditions is determined, based on the seawater intrusion extent, at a temporal scale. The Reconnaissance Drought Index (RDI) is used to assess the meteorological drought severity, since it incorporates precipitation and potential evapotranspiration, which both affect the recharge processes. Recharge volumes for different timeseries, estimated through a hydrological model, are used as input to a transient variable-density and salt transport numerical model. An indicator based on the freshwater volume and RDI index, are used to assess the aquifer response to drought. The multi-year drought effect is also investigated. The results show that the RDI index can be utilised successfully to associate the meteorological drought with aquifer flow conditions. Specifically, a reliable early prediction of the freshwater availability at the end of the hydrological year can be achieved by the RDI of the first semester. [ABSTRACT FROM AUTHOR]

Mammalian species inhabiting arid landscapes exhibit various levels of mobility in order to cope with unpredictable spatiotemporal dispersion of resources. However, the space use and ranging behavior of many species in drylands is poorly understood, especially for large carnivores in Asia. Accommodating the long-distance movements of mammalian carnivores is a major challenge in conservation, particularly for threatened and highly mobile species. The Asiatic cheetah Acinonyx jubatus venaticus , a critically endangered subspecies found only in arid areas of Iran, exhibits high levels of mobility. In the absence of satellite collars, this paper outlines ranging patterns of the majority of the Asiatic cheetah’s known population. A total of 17 independent cheetahs (11 males; 6 females) were detected with camera traps that were deployed on eight reserves between January 2011 and May 2016. The animals displayed extensive movements (up to 217 km between furthest known locations) and at least nine adult cheetahs were known to move between multiple reserves in central Iran. This mobility may follow a “nomadic” ranging pattern, a non-sedentary behavior with irregular timing and movement directions. The ranging behavior documented here must be considered when designing monitoring efforts to determine population and occupancy trends for this wide-ranging elusive carnivore. Although preliminary, our results show that improving protection beyond the current network of cheetah reserves, particularly along corridors, should be a top priority to safeguard the persistence of the Asiatic cheetah. [ABSTRACT FROM AUTHOR]

Abstract: Southern Spain’s semi-arid habitats are a Mediterranean ecosystem modelled mainly by historic factors which make them unique in comparison with North African deserts. Southern Spanish vertebrates have adapted to the recent emergence of semi-arid habitats in varying degrees of success. This paper reviews the current status of these terrestrial vertebrates (amphibians, reptiles, birds and mammals), their origins and their main features in relation to this biogeographic area. The vertebrate fauna of the semi-arid southeast of the Iberian peninsula differs widely from the one in the semi-arid Maghreb mainly because the former is composed by generalist vertebrates and much less so by species adapted to arid conditions. Moreover, a large fraction of the vertebrates in the semi-arid Iberia does not exploit the semi-arid areas but depends on riparian and human-managed habitats. The species diversity is rather low since only a small fraction of Palaearctic, European or Mediterranean species can adapt to the ecological limitations imposed by aridity and dwell in these semi-arid habitats. Such adaptations comprehend features like trophic plasticity, low morphological specialization, high dispersal ability, shortened life cycles and behavioural mechanisms to exploit the limited resources available. This paper identifies major conservation issues and proposes specific courses of action. [Copyright &y& Elsevier]

Abstract: This is the first of two papers that describe the surface hydrology of the Lake Eyre Basin (LEB) (1,140,000km2) in central Australia and compares some key characteristics with those observed from arid regions globally. This paper concentrates on annual rainfall, whereas the second paper is devoted to streamflow. The first part describes the LEB''s climate (arid to semi-arid), which is dominated by a subtropical high pressure ridge stretching latitudinally across central Australia. Then follow major analyses that include the characteristics of rainfall, wet and dry spell lengths and cumulative surpluses and deficiencies, rainfall trends and intra- and inter-decadal fluctuations, and the relationship between rainfall and El Niño-Southern Oscillation (ENSO). The paper concludes with six conclusions, the key ones being: the variability of the annual rainfall (based on the coefficient of variation) in the LEB is approximately 60% greater than that found for stations located in arid regions in the rest of the world; there is a bias towards longer lengths of dry years than observed in the rest of Australia; and, there is a significant lag correlation between rainfall and ENSO, particularly in the east and in the latter part of a year. [Copyright &y& Elsevier]

Abstract: This is the second of two papers examining the surface hydrology of the Lake Eyre Basin (LEB) (1,140,000km2) in Australia. The streams are unregulated and are characterised by extreme discharge variation. The analyses reported cover only surface hydrology and include comparisons with arid zone catchments globally. The paper discusses spatial runoff and annual streamflow characteristics, flow duration and baseflow index (BFI) analyses, annual flood frequency analysis and flood transmission losses, a water balance study, wet and dry run length analysis and, finally, yield from hypothetical reservoirs located across the LEB. There are 12 conclusions listed at the end of the paper. We identify two highlights as follows: [•] The coefficient of variation of annual flows, Cv, varies from 0.98 to 2.62. Compared with 45 arid zone rivers world-wide excluding Australian rivers, the annual Cv of the LEB streams are approximately double the average variability found world-wide. [•] Large transmission losses occur as flood flows move down the middle reaches of the major river systems. The transmission losses vary non-linearly with flood size as a result of differing transmission efficiencies between primary channels and the floodplain, and varying floodplain utilisation. [Copyright &y& Elsevier]

Abstract: We discuss a new conceptual framework for arid and semi-arid systems that accounts for nonlinear dynamics and cross scale interactions in explaining landscape patterns and dynamics. Our framework includes a spatial and temporal hierarchy, and five key interacting components that connect scales of the hierarchy and generate threshold behaviors: (1) historical legacies that include climate, disturbance, and management regimes, (2) dynamic template of patterns in ecological variables and spatial context, (3) vertical and horizontal transport processes (fluvial, aeolian, animal), (4) rate, direction, and amount of resource redistribution between high and low resource areas, and (5) feedbacks among plants, animals, and soils. We illustrate how this framework can be used to understand, forecast, and manage ecological systems that exhibit nonlinear dynamics across a range of spatial and temporal scales. This paper provides the foundation for a series of papers from the Jornada Experimental Range ARS-LTER research site in southern New Mexico, USA that support this new conceptual framework. [Copyright &y& Elsevier]

With their modest rainfall, arid regions are characterized by relatively fewer species than the better-watered biomes. But this makes it all the more important that the biodiversity that is present in arid environments be given even higher priority; for each species lost from an arid region, the percentage of loss for the region''s biodiversity is much higher than in more species-rich regions. And some species, such as bees and ants, are particularly diverse in arid habitats. Realizing the importance of biodiversity in the arid regions where they live, local people have devised numerous ways of limiting their impact. Historically, such regions have been especially subject to changes in climate, which affect productivity; these changes have often been accompanied by conflicts. The paper will describe these from various parts of the arid world, as a basis for comparison. The paper will also examine economic issues relating to biodiversity in arid lands, focusing especially on the relationship between biodiversity and various kinds of development projects. The major challenges in implementing the Convention on Biological Diversity (CBD) in arid lands lie not so much in the biology of the species concerned, but rather in the social, economic, and political arenas within which people operate. We need to build a broader constituency for conserving biodiversity, extend the responsibility for conserving biodiversity far beyond government, bring local people into the conservation movement, ensure that sufficient information is available to those who need it, restore degraded ecosystems, and stimulate far greater public support for biodiversity. [Copyright &y& Elsevier]

With conservation of biological diversity depending as much on socioeconomic as on biological processes, this paper stresses the importance of clear policy objectives to guide strategies for preserving biological diversity. The first requirement is to define the essential elements and socioeconomic importance of biological diversity, so that these can be accommodated adequately in a national programme for sustainable rural development.Efficient application of this programme requires that its goals be clearly enunciated in national policy. There should also be maximum political support for its effective sociopolitically, economically and ecologically rationalised implementation by an accountable authority through a conducive institutional framework. Experience suggests that proprietorship and price are prime elements that need to be reconciled in such a framework of positive and negative incentives to individuals, to mitigate the opportunity costs and encourage the conservation of biodiversity. The present paper considers how these institutional requirements may be met, with particular reference to the special characteristics found in arid areas. [Copyright &y& Elsevier]

The present paper examines the influence of physical catchment properties on baseflow in semi-arid environments. It relates the dimensionless quantity, baseflow index (BFI) derived from data-based mechanistic modelling approach to dimensionless indices representing topographic, geologic and climatic properties. The relationship is derived using a progression of techniques, from inspection and correlation analysis, through stepwise regression and finishing with multiple regression. The BFI has a strong relationship with climate and geology. Catchments with high rainfall or low evapo-transpiration underlain with granites or basalt tend to give high baseflow. Within the topographical parameters tested, drainage density index has strong relationship with BFI. The approach used in this paper provides a viable alternative for baseflow estimation on ungauged semi-arid catchments using drainage density, geology and climate indices as key factors. [Copyright &y& Elsevier]

Urbanization has brought about dramatic changes in the urban environment in China and its associated human population and transportation systems in recent years. However, urbanization in the oases of arid regions of China has been little studied and remains poorly understood. This paper aims to analyze spatiotemporal changes in an urban landscape along major vehicular road transects and compare the relationship between urban growth and transportation in Jiuquan, an oasis city in an arid region of China. We integrated remote sensing images, landscape metrics, and urban-rural gradient analysis to address these questions. The results showed that major vehicular roads stimulated Jiuquan's urban expansion, especially with regard to built-up land containing urban green land areas. Oasis urbanization not only increased landscape fragmentation and structural complexity, but also followed a linear branching, leapfrogging growth pattern characterized by “axial clumps” extending from downtown into rural areas along the road network. The primary source of urban land was not agricultural land, but unused land. These results also indicated that the transect approach implemented along representative roads was effective for studying the urbanization of oasis cities. Such an approach could be applied to master planning in similar oasis cities throughout arid China. [ABSTRACT FROM AUTHOR]

This paper investigates how Borana pastoralists of southern Ethiopia have adapted resource use and livestock mobility practices amid multiple constraints including rising population, loss of rangeland to other pastoral communities and changing access rights, among others. This study uses an innovative multi-scalar methodology to understand how herders' grazing management decisions are made within a context of communal regulations governing access to resources. Grazing itinaries specifying the grazing units used during the past year were established for 91 cattle herds and daily mobility was recorded through 12 months of GPS data monitoring of three herds in three zones within the Borana rangelands. The results revealed communal reorganisation of the grazing areas into units with designated periods of access. Despite the reorganization, herd mobility is severely limited, but to different degrees. In the zones facing most constraints, herd mobility is restricted to the grazing areas within proximity of the respective herder's settlement. However in all the areas, movement outside the herd owners' zone of residence is only practiced as escape mobility, ‘ baqa’ (to flee); instead of the formerly common ‘ godanna’ (to move). These constraints impede fundamental herd mobility needed to meet livestock nutrient requirements, which then affects resilience of the pastoral system. [ABSTRACT FROM AUTHOR]

This paper develops and applies an integrated and participatory methodological framework to assess land degradation in pastoral systems through an ecosystem services (ES) lens in a semi-arid region of northern Nicaragua. We initially integrated local and scientific knowledge to assess ecological changes and understand the links with ecosystem services supplied by the local grazing system. Hence, we discuss land degradation features and test a state-and-transition ecological model, that is, we developed jointly with local farmers the hypotheses to understand transitions between ecological states and these hypotheses were then evaluated through an inventory of vegetation and an assessment of soil properties and seed bank composition. The assessment reveals that shifts in ecological state do not cause permanent soil properties changes, but that at a landscape scale they can limit production, affecting local livelihoods. The framework proposed provided local farmers with relevant information and facilitated communication with researchers, enabling them to use the co-constructed knowledge to implement adaptive management strategies to improve local productive systems. [ABSTRACT FROM AUTHOR]

Identifying, recording and monitoring land cover change on the Earth's surface is a complex procedure. Spatio-temporal modelling is an effective approach to simplifying and simulating the process. Existing spatio-temporal modelling methods are typically based on either, an overlay of multi-temporal land cover maps, or temporal trend analysis of spatial pattern indices. Consequently, an understanding of the spatial dynamics of any changes is either fragmental in the former case, or invisible in the latter case, due to the lack of adequate geographical location information. In the arid zone of western China, a widely accepted belief is that rapid farmland expansion and the subsequent abandonment of the farms, or their mis-management, would lead to soil salinisation and desertification. In order to better understand the spatio-temporal pattern of farmland change, this paper proposes an integrated approach that combines the two methods of pixel-based trajectory analysis and class-level spatial pattern metrics. Multi-temporal remote sensing images were collected beginning in 1994, a year that captured the initial effects of the period of rapid farmland expansion. Historical change trajectories were established for each pixel and categorized according to change types ( i.e . expanding or shrinking). The spatial dynamics of farmland change can then be illustrated by mapping the change trajectory classes. Spatial patterns of farmland change were quantified by employing distribution-related landscape metrics, such as indices of interspersion (IJI), connectivity (COHESION) and isolation (ENN), to analyse farmland development models of the two river basins in the study area. Shape indices, including overall shape (nLSI) and edge shape (FRAC), were applied to appraise the structural stability of the farmlands over time. Results indicate that, over the past two decades, the area subject to farmland expansion was significantly larger than that experiencing farmland abandonment. The relatively rapid expansion of farmland exhibited a concentrated pattern, and generally followed a layer-based development model. The study showed that the proposed research method effectively visualized and quantified the spatio-temporal dynamics of farmland change. [ABSTRACT FROM AUTHOR]

The paper analyzes local perceptions and practices related to the quality, extraction, and use of fuels firewood by the inhabitants of two protected areas. Our working model assumes the existence of patterns of preference, use and acquisition of firewood, depending on the social actors involved, and their perceptions. Our research developed through: the making of a reference collection and the applicationand of in-depth interviews and semi-structured surveys. We identified the most frequently used species and those with the greatest number of uses. The presence of patterns in the provisioning of energy source, and of firewood gathering and use, were identified in different actors. Through the application of a PCA analysis, and the study of native categories, patterning in the grouping of species was established, according to the local firewood classification. The latter relate to differences in the ease of ignition, in the durability and temperature of the flame and/or embers and the amount and type of smoke or ash produced. On the basis of ecological and perceptual information, a ranking of local priorities for the conservation of woody species is proposed. Finally, we discuss the relevance of sociocultural patterns of local perceptions of firewood use for conservation. [ABSTRACT FROM AUTHOR]

The paper focusses on the impact on dryland ecosystems of conflicting governance in the regulations of land use, water for irrigation and electric energy from photovoltaic installations (PV). The research uses the empirical results of a panel data model based on long time series that enable sensitivity of the main crops to energy cost and the viability of the solar panel system connected to the grid to be identified. We present evidence of the private and social benefits of investments in PV to improve the gross margin of farmers and decrease the carbon footprint of the irrigated areas. Relevant regional disparities in the sensitivity of the main crops explain the regional competition for low-cost water resources and the social conflicts associated with water governance. The Feed-In Tariff system for a PV system is evaluated as a tool to reach clean energy targets and preserve the populations working and living in irrigated drylands. An evaluation of the water desalination plants based on PV is analysed as an alternative to balance the hydric resources of intensive irrigated systems. The main conclusion is that coordinated regulation in energy and water policies may improve farmers' profitability and accelerate the speed in reaching environmental targets in drylands. • The paper assesses the economic viability of grid-connected photovoltaic installations of principal crops. • Since the liberalisation of the energy market, the electricity bill of irrigators become substantially higher. • Adaptation to climate change means to switch to PV irrigated systems to preserve gross land margins. • The contradictory and time unstable regulations send conflicting signals slowing the path to a clean irrigation system. • Our main conclusion is that the European Commission has a relevant task in coordinating water and energy regulations in arid lands. [ABSTRACT FROM AUTHOR]

Native desert plants have structural adaptations that maximize photosynthesis rates and minimize water loss. They can be successfully utilized as soil cover crops in drip-irrigated vineyards where water availability is low. The objective of this paper is to study seed germination conditions and to recommend which best species is most apt as soil cover crop in drip-irrigated vineyards. Seed weight (the higher the seed weight, the greater the success of mechanical seeding) and germination tests (at 15, 20, 25, 30, and 35 °C in light and dark conditions) were carried out for six species native to Mendoza, Argentina. Germination percentage (GP) and mean time germination (MTG) were calculated. Digitaria californica (C 4 ) had the highest GP (97% in light condition), which is recommended as a cover crop because of its seed germination potential. Pappophorum phillippianum (C 4 ) had a 70% GP in light conditions (regardless of temperature) and a high seed weight. Leptochloa dubia (C 4 ) and Sporobolus cryptandrus (C 4 ) reached the highest GP at the highest temperature, although S. cryptandrus had the lowest seed weight. Nassella tenuis (C 3 ) averaged 54% GP at 25 °C in light conditions. The GP of Setaria leucopila (C 4 ) was not affected by temperature (26% in light, and 16% in darkness). Based on the GP results, S. leucopila was the worst choice of the six species. Hence, during seeding, soil temperature should be high (>20 °C) to ensure a rapid plant establishment of all species. [ABSTRACT FROM AUTHOR]

A significant part of the world's largest river basins are located in areas of arid and semi-arid climate, such as the Amu Darya, Jordan, Murray-Darling, Yellow River, and Aksu-Tarim river basin. These river basins are experiencing water scarcity resulting in conflicts between upstream and downstream, conflicts between water users, and degradation of the natural ecosystems. Therefore, in many river basins, including the Aksu-Tarim river basin, water quota systems have been established, in order to allocate water under scarcity. The Aksu-Tarim river basin (NW China) has developed into one of the most important cotton production areas worldwide. In this paper, we aim at assessing the water consumption through irrigated agriculture, mainly cotton, and natural vegetation in the Aksu-Tarim river basin against the background of this water quota system. Firstly, we map the evapotranspiration (ET a ) as water consumption of irrigated agriculture and natural vegetation in the Aksu-Tarim river basin. Secondly, we calculate water balances and relate them to the water quota system. We employed the remote sensing method Simplified Surface Energy Balance Index (S-SEBI), in order to map ET a based on MODIS satellite images for the growing seasons 2009, 2010, and 2011. Thereby, the MODIS products 8-day land surface temperature (MOD11A2), 16-day albedo (MCD43A3), and 16-day NDVI (MOD13A1) were used. The ET a of cotton ranges from 884 to 1198 mm. The ET a of the natural vegetation of a total coverage ranges from 715 in 2009 to 960 mm in 2011, clearly following the annual runoff of the Aksu and Tarim River. The water balance of the Aksu-Tarim river basin is −3.25 to −3.73 km 3 , 0.1–0.53 km 3 , and −3.55 to −4.12 km 3 in 2009, 2010, and 2011, respectively. The water quotas along the Aksu River and the upper reaches of the Tarim are exceeded by water consumption, while the quotas along the middle and lower reaches are not met. Considerable amounts of groundwater, including fossil groundwater, are exploited for irrigation along the Aksu and Tarim River, which must be regarded as exploitation of a non-renewable resource. [ABSTRACT FROM AUTHOR]

Since the Achaemenid Empire in 532-332 BCE, the 'Qanat' became the central irrigation system in the arid and semi-arid lands. Several terms are used for 'Qanat' in different regions, including the Karez, Qanat, Falaj type Daudi, Qanat Romani, Fuqara (Foggara), or Khettara as known in Central Asia, Persia, Southeast Arabia, Levant, North Africa, or Morocco respectively. Typically, the ground, spring or surface water (i.e. seasonal floods or river-fed) sources feed similar irrigation system. Based on thirteen years of extensive survey and analysis work (i.e. Sinai Peninsula Research 2000-2013 CE), this paper presents a rediscovered-new Qanat system in the High Mountains of Sinai Peninsula (i.e. UNESCO World Heritage Site 'WHS' no. 954) under chronological open question with Levantine reflections. In 1970s CE, the present Sinaitic site of Farsh Abu A'lwan or the anciently known Farsh Shamma'a was archaeologically surveyed without a direct reference to the Qanat system in-situ. Scientifically, it is an argumentative and unique Qanat system in terms of chronology, location (region), site (local-setting), water source, size and household utility. It is the only discovered 'Qanat' across the Sinai, connecting the Near East and North Africa. [ABSTRACT FROM AUTHOR]

Abstract: In many parts of the world the boundaries between grassland and shrubland biomes have changed substantially over the course of the last century. Many are projected to shift further from being grass-dominated to shrub-dominated by 2050 under global climate change and land use change projections. This paper used long-term surveys and repeat photography to assess vegetation change at the shrubland-grassland ecotone in semi-arid, South Africa. Changes in several climate variables as well as in the cover of grasses and dwarf shrubs over three time periods (1962, 1989 and 2009) were investigated at eight localities within a broad 500 km ecotone between the Grassland and Nama-karoo biomes. Results showed that for most sites grass cover has increased and that dwarf shrub cover has decreased over time. This contradicts earlier views which warned against the expansion of dwarf shrublands in response to over-grazing as well as more recent views which suggest that more mesic biomes in the Karoo Midlands will contract in response to climate-induced aridification. The decline in stocking densities and more conservation-friendly land management practices together with an increase in large wet events in the Nama-karoo biome may have contributed to the increase in grass cover. [Copyright &y& Elsevier]

Abstract: Mediterranean environments are typical of semi-arid regions, dominated by episodes of torrential rain in which the critical variable is not the total rainfall, but the intensity. This paper studies the maximum rainfall intensities at different observation time scales, from 5 min to 24 h, over eastern Spain from 1994 to 2007. The statistical rainfall characteristics for each time scale are analysed and the effects of specific geographical factors – altitude, aspect and distance to the sea – for each observation interval are tested. The results show that extreme intensities are heavily dependent on the time scale. There are two important turning points in this trend, at 1 h and 6 h. With regard to the influence of geographical factors, distance from the sea is particularly important as it is significant for almost all observation time scales. Altitude is only significant between time scales of 30 min and 6 h. Aspect is not significant. Two intensity patterns are also observed: the first includes the highest intensities, at altitudes from 200 to 400 m and at locations 20–30 km from the sea, while the second is related to lower intensities, higher altitudes (900–1000 m) and longer distances to the sea (90–100 km). [Copyright &y& Elsevier]

Abstract: Degradation in arid rangelands is an on-going concern, as they appear to be trapped in a vicious circle of desertification–marginalization–impoverishment. Recent theoretical developments in dryland research strive to provide keys to understanding linked social-ecological systems and land management. One approach, the desert-syndrome, depicts the socio-ecological evolution of drylands as being determined mainly by ecological factors. A second approach, the adaptive management paradigm, acknowledges the existence of socio-ecological systems in drylands which are considered to have adapted to a given political–economic context and a given range of economic and ecological variability. This paper proposes a conceptual framework integrating both approaches in order to point out supplementary important drivers of the socio-ecological evolution of drylands systems, especially rangelands at the global economic and political scale. The analysis is broadly conducted from a political ecology and co-evolutionary perspectives and discusses three main factors: (1) world-wide application of western-based paradigms in resource management and their effect on rangelands, (2) the fossil-fuel based Green Revolution, and (3) capitalist institutions used to regulate agricultural trade and the corresponding tools and policies. The marginalization of arid rangelands is avoidable, but requires real changes in the current general political and economic rationale under which resources are allocated. [Copyright &y& Elsevier]

Abstract: We describe in this paper a traditional charcoal making technology occasionally adopted by Tuareg people in the hyper-arid central Sahara (SW Libya). This methodology (called esed) has been identified thanks to ethnobotanic and ethnographic interviews with people living in the Tadrart Acacus massif (the kel Tadrart Tuareg) and confirmed by macroscopic and micromorphological analyses of residual field evidence. Esed consisted of burning in situ trunks of dead Acacia tortilis (Forssk.) Hayne; subsequently, small portions of collapsed and still-burning wood were buried with sand in an attempt to ensure combustion under anoxic conditions. Our interviews elucidated that the esed technology is well known by people living in the region and has possibly been practiced for a long time. Surprisingly, local informants highlighted that esed was employed to made charcoal only during years marked by abrupt reduction of precipitation and consequently of natural resources. The last employment of esed dates to the dry phase of the mid-1970s, when charcoal was used as an exchangeable good. The discovery of this charcoal making technology shed new light on the capability of Tuareg to manage the few natural resources available in marginal environments and to cope with rapid climate changes. [Copyright &y& Elsevier]

Abstract: This review is concerned with the aeolian geomorphology of the Namib Sand Sea, part of the Namib Desert in Namibia, south-west Africa, concentrating in particular on studies made over the past 50 years. The paper covers: sand sea organisation and dune patterns; and the dynamics of individual dunes. It demonstrates that studies in the Namib Sand Sea have been important to a much wider understanding of the geomorphological development of global sand seas. [Copyright &y& Elsevier]

Abstract: Carbon stocks and carbon accumulation in the earth''s drylands have gained increasing attention. The winter-cold deserts of Middle Asia, i.e. in Kazakhstan, Uzbekistan, and Turkmenistan, cover an area of 2.5 million km2. Within these deserts, the two Saxaul species White Saxaul (Haloxylon persicum Bunge ex Boiss. & Buhse) and Black Saxaul (Haloxylon aphyllum (Minkw.) Iljin) are dominant woody species with a potential distribution area of about 500,000 km2. From the 1950s until today, the Saxaul vegetation has been degraded through logging and over-grazing. In this paper, we estimate the current and potential living above ground and below ground biomass of the Saxaul vegetation and its carbon stock. The living above ground biomass ranges between 1.5 t/ha and 3 t/ha. The potential carbon stocks above ground and below ground amount to 29.4–52.1 million t and 22–81.4 million t, respectively. Today, only 11%–28% of the potential biomass and carbon stock have remained. The carbon stock of the Saxaul vegetation is low compared to other ecosystems of the earth, but restoration and conservation of Saxaul vegetation is one way to sequester carbon through vegetation for Uzbekistan and Turkmenistan, which do not have much other woody vegetation. [Copyright &y& Elsevier]

Abstract: In arid and semiarid regions of Central West Argentina, paleoenvironmental conditions and history of the Holocene vegetation is still scanty. This paper presents the analysis of palynological records of two Mid- to Late Holocene alluvial sequences (La Escala -LES- and Brazo Abandonado -BA-) in the fluvial basin of the Arroyo La Estacada (33°27′S and 69°03′W), placed in the Cordillera Frontal central piedmont of Mendoza province. Variations in pollen assemblages of the two sequences related to the environments developed in the floodplains of the arroyo allowed us to infer the evolution of local plant communities. Between the ca. 4000 and 3000 14C years BP and between ca. 500 and 400 14C years BP, a larger representation of hydrophytic communities related to environments with local water availability was inferred; and between ca. 3000 and 500 14C years BP an increase in shrubby xerophytic communities related to environments with lower water availability was detected. These results led us to propose that the Holocene pollen spectra fluctuations observed in the alluvial sedimentary sequences prove mainly changes in plant communities of the floodplain environment in response to the fluvial dynamics of the arroyo. [Copyright &y& Elsevier]

Abstract: Soil fauna are considered to be an important determinant of the litter decomposition in terrestrial ecosystems. However, the contributions of soil macrofauna and mesofauna to litter decomposition in semi-arid environments are not well-recognized. In this paper, litterbags with different mesh sizes (4.7 mm, 2 mm and 0.01 mm) were employed to examine the intraspecific differences in the decomposition of Stipa baicalensis, Achnatherum avinoides, Lespedeza davurica and Agropyron cristatum. In addition, the effects of soil macrofauna and mesofauna on litter decomposition were determined in Songnen sandy land. The results of this study showed that Prostigmata, Psocidae and Oribatida were dominant fauna in the litterbags. Significant intraspecific differences were found in litter decomposition rates, and the process of litter decomposition can be separated into two apparent stages. Ac. avinoides exhibited the highest contribution rate to litter decomposition, followed by Ag. cristatum, L. davurica and S. baicalensis. Contribution rates of macrofauna and mesofauna to litter decomposition were different. The rate of litter decomposition was positively correlated with the group density of fauna. Our results suggested that both macrofauna and mesofauna could accelerate litter decomposition and, consequently, nutrient cycling in semi-arid ecosystems, although their functional roles were different in litter decomposition. [Copyright &y& Elsevier]

Abstract: The changing climate is affecting biological and physical processes occurring in the biosphere, including the biogeochemical cycles of water and carbon. The response of ecosystem carbon exchange to changes in temperature and the water balance is still very uncertain, a fact that highlights the need for research in order to understand the role of the biosphere in the future global carbon budget. South east Spain is on the borderline between the tropical and mid-latitude climate zones, with climates ranging from sub-humid to arid, and the majority representing the driest area in Europe. Initial predictions on climate change for this region point to decreases in total precipitation and the number of precipitation events, meaning a decrease in water availability underlining the vulnerability of the region to desertification. This region, due to these special climatic conditions, has been the subject of experimental carbon and water field research in recent years. This paper defines the state of the art of carbon and water balance measurement and modelling studies in this region, analyses the different processes involved in aggregate exchanges (vegetation and soil; net ecosystem carbon balance–evapotranspiration, photosynthesis–transpiration, soil respiration–evaporation), and identifies needs for future research. [Copyright &y& Elsevier]

Abstract: Climate, lithology, soil and especially, intense land use/cover changes, make SE Spain very vulnerable to runoff generation and water erosion leading to loss of nutrients and organic matter and to infrequent but devastating floods, reservoir siltation and mass failures. This susceptibility has led to heavy economic investment and research efforts since the 1980s, making this region a worldwide reference for understanding the hydrology and geomorphology of semiarid ecosystems. Runoff and soil erosion have been intensively studied throughout the last decades in various natural ecosystems as well as in abandoned farmlands. Research has considered a wide range of methods and spatial and temporal scales. This paper reviews the methods and data describing runoff generation and water erosion, synthesising the key processes involved, rates, thresholds and controlling factors from a scale-dependent perspective. It also identifies the major gaps in current knowledge to provide recommendations for further research towards solutions that reduce the negative impacts of erosion. Research in SE Spain has contributed significantly to a better understanding of the effect of spatial and temporal scale on runoff and sediment yield measurements, and highlighted the important role of distinct erosion and sediment transport processes, hydrologic connectivity, spatial and temporal patterns of rainfall, the occurrence of extreme events and the impacts of land use changes. The most effective ways and challenges to predict runoff, soil erosion and sediment yield at the catchment scale are also discussed. [Copyright &y& Elsevier]

Abstract: As in most semiarid regions, the main source of freshwater in SE Spain is its aquifers, and their exploitation has enabled the development of highly profitable irrigated agriculture and tourism industries. The application of sustainable water management plans requires aquifer recharge to be quantified and its spatial pattern evaluated. This paper gives a comprehensive review of various recharge studies in mountainous carbonated aquifers, the most important groundwater reservoirs in SE Spain. Quantification of potential recharge rates and their spatial variability are illustrated using satellite-based modeling and tracer techniques. Actual recharge figures from the application of a lumped model based on water table fluctuations are also presented. Potential recharge relative to actual recharge is around 1 in small aquifers and flat areas and may increase up to 1.3 in heterogeneous mountainous aquifers with deep water levels due to losses of recharge in transit in the vadose zone. The complex interaction between climate, geology, aquifer geometry, topography, soil properties and the degree of karstification prevents the systematization of any particular technique to quantify potential recharge. The use of water table fluctuation methods for actual recharge evaluation requires daily time steps to compute unnoticed small recharge events. Therefore, the monitoring of environmental variables and the use of complementary techniques for comparison are recommended. Despite their importance for the correct assessment of recharge in the region, uncertainty analyses are still scarce, and the natural variability of recharge is unknown in most cases. Effort is required to improve the spatial and temporal characterization of recharge through the integration of interdisciplinary sciences. [Copyright &y& Elsevier]

Abstract: The management of dryland environments involves the interaction of multiple government agencies and citizens, and is required to respond to a wide range of responsibilities and aspirations for a given region. This paper focuses on the characteristics of engagement between management agencies and citizens in a dryland region, presented here as a series of success factors. These factors are based on empirical research carried out in the Lake Eyre Basin in Australia, one of the world’s largest inwardly draining basins. The results reinforce generic and dryland-specific factors supporting successful community engagement. The former, such as building trust, working in partnership, supporting community champions, and maintaining transparency, are necessary but insufficient for achieving successful community engagement in the case study region. In addition, community engagement in the case study region also required respecting the extreme conditions and extraordinary variability of the Basin and committing to longer timeframes even if the outcomes of community engagement are slow to accrue, in order to take advantage of opportunities in more prosperous times. [Copyright &y& Elsevier]

Abstract: In grazed semiarid ecosystems, considerable spatial variability in soil infiltration exists as a result of vegetation and soil patchiness. Despite widespread recognition that important interactions and feedbacks occur between vegetation, runoff and erosion, currently there is only limited quantitative information on the control mechanisms that lead to differences in infiltration from different vegetation types. In this paper, we determine (i) the relationship between vegetation and soil surface characteristics and (ii) the soil infiltration rate by using rainfall simulations on runoff plots (0.60 × 1.67 m) in three plant communities of northeastern Patagonia: grass (GS), degraded grass with scattered shrubs (DGS), and degraded shrub steppes (DSS). Our results clearly indicate that vegetation and soil infiltration are closely coupled. Total infiltration was significantly higher in the GS (69.6 mm) compared with the DGS and DSS (42.9 and 28.5 mm, respectively). In the GS, soil infiltration rate declined more slowly than the others communities, reaching a terminal infiltration rate significantly greater (57.7 mm) than those of DGS and DSS (25.7 and 12.9 mm, respectively). The high rate of water losses via overland-flow may limit the possibilities for grass seedling emergence and establishment and favor the persistent dominance of shrubs. [Copyright &y& Elsevier]

Abstract: Although numerous factors influence soil-water content, it is considered a key indicator of rangeland health. This paper investigates the effect of grazing on soil-water content using three treatments within the same soil association. The treatments, simulated holistic planned grazing (SHPG), rest-rotation (RESTROT), and total rest (TREST) applied stocking rates of 36, 6, and 0 animal days/hectare respectively. Soil-water content was measured continuously from 2006 to 2008 using 36 capacitance sensors. Statistical analyses revealed differences in percent volumetric-water content (%VWC) and in all treatments, the SHPG pasture had the highest %VWC. Mixed procedures models indicate strong environmental and treatment effects as explanatory variables for the observed difference in %VWC. Although results of vegetation cover analyses indicated no difference in percent shrub cover in the two production pastures (SHPG and RESTROT), percent litter cover differed in the latter years of this study. It was concluded that in addition to a variety of other factors, management decisions (grazing and rest) can have substantial influence upon soil-water content and that soil-water content can vary substantially as a result of animal impact and the duration of grazing. [Copyright &y& Elsevier]

Abstract: In the highlands of northern Ethiopia, degraded hillslopes are closed for grazing and agriculture for environmental rehabilitation. In order to assess the effect of these exclosures on water balances, a correct assessment of evapotranspiration is needed. A common method for calculating evapotranspiration employs the reference evapotranspiration in combination with a crop coefficient. However, for natural vegetation, these crop coefficients are not readily available. Therefore, the objective of this study was to derive crop coefficients for semiarid natural vegetation using two different approaches. The crop coefficients were assessed with the dual crop coefficient approach as outlined in the FAO Irrigation and Drainage Paper n°56 and compared with crop coefficients derived from a simple soil water balance. A good agreement between both methods was found. The mid-season crop coefficients ranged from 0.50 to 0.85 for open vegetation with small shrubs and from 0.85 to 0.95 for well developed shrubland. Vegetation with a closed tree canopy was characterized by a mid-season crop coefficient between 0.95 and 1.1. Additionally, a significant logarithmic relation between vegetative soil cover and crop coefficient was found. Using this relation, crop coefficients can be easily derived for semiarid shrub savannahs in similar environments and used for the calculation of evapotranspiration. [Copyright &y& Elsevier]

Abstract: Many researchers have used time-series analysis of remotely sensed images to gain understanding of the dynamics of loss of vegetation cover in drylands. However, complex interactions between vegetation and climate still mask the potential of remote sensing signals to detect human-induced loss of vegetation cover. This paper presents mixed-effect modelling method for time-series NDVI-rainfall relationship to account for the complex interaction between vegetation and climate. Mixed-effects method is a form of statistical modelling that can simultaneously model environmental relationships for a population and for different groups within the population. In this study, it was used to model the NDVI-rainfall relationship in Somalia and for different vegetation types in the country. Its time-series application removed the interaction between vegetation and rainfall and identified areas experiencing human-induced loss of vegetation cover in the country. On average, it gave an accurate relationship between rainfall and NDVI (r 2 >60%) and detected areas with human-induced loss of vegetation cover (kappa=75%). Although the potential of mixed-effects was shown using vegetation types, other factors such as soil types and land use can also be included in the method to improve accuracy of time-series NDVI images in detecting human-induced loss of vegetation cover in the drylands. [Copyright &y& Elsevier]

Abstract: The paradigms in respect of arid areas have shifted from efforts to prevent desertification to the Dryland Development Paradigm. In this respect, the basic principles and socio-economic implications related to dryland development have been identified. However, the application of these paradigms has mainly focused on pastoral societies. This paper considers these principles in relation to the South African housing policy in a more formal settlement environment, and argues that the South African low-income housing policy scarcely considers the basic principles of the Dryland Development Paradigm, or the basic socio-economic realities associated with arid areas. At the same time, the question is asked as to how relevant these principles and socio-economic realities are in more formal settlements where the South African low-income housing subsidy is applied, and whether there is not, in reality, an inherent conflict between settlement development through low-income housing subsidies, on the one hand, and the basic principles of the Dryland Development Paradigm, on the other. [Copyright &y& Elsevier]

Abstract: Monitoring changes in soil and vegetation is crucial in fragile Mediterranean semiarid environments. To identify early perturbation warnings using radiometric techniques, the spectral variability of the ecosystem components must be understood and the ranges of their natural variability established. This paper aims to assess the potential of hyperspectral information for analysing spectral variability and to provide guidelines for using spectroscopy to monitor semiarid environments. Spectral field measurements of different soil (volcanic and calcareous), vegetation (esparto and dwarf palm) and natural mixtures (NPV and BSC) were acquired; spectral assessment focused on albedo, spectral shape and absorption bands. Results show high variability of soil background between and within soil typologies. The presence of biotic elements masks the distinctive characteristics between soil typologies, making combination of the VIS-NIR and SWIR regions necessary for correct discrimination and quantification of soil properties. Plant species are discriminated by taking advantage of their spectral properties based on the differences in absorption by chlorophyll, water and lignin. In summer, these differences are more significant, predictably due to their specific survival strategies. Radiometric techniques enable discrimination of ecosystem components, although the high variability of the landscape and subtle differences between components makes it necessary to use high-spectral resolution information. [Copyright &y& Elsevier]

Abstract: In the Tarim River Basin, the desert riparian forest vegetation is under high-temperature and aridity stress. However, the vegetation can grow continuously because of deep rooting that can reach groundwater, which can thus redistribute water into the upper soil profile. This paper describes patterns of hydraulic lift by Populus euphratica Oliv. and discusses its ecological effects. Our results show that the tap root sap velocity of P. euphratica Oliv. is positive during the day and night. However, a reverse sap flow was observed in the lateral roots during the night. The soil water content of the subsoil was higher than that of the topsoil at depths of 0–120cm. When the sap flow of the lateral roots was reversed at night, the soil water content clearly increased. In particular, at depths of 60–120cm, the soil water content at 4:00 was 28–38% greater than that at 16:00. The vapor pressure deficit was a factor that predominantly affected the root sap velocity, and the smaller vapor pressure deficit often facilitated a reverse sap flow in the lateral roots. Our findings demonstrate the hydraulic lift characteristics and ecological effects that occur in the desert riparian forest in extremely arid regions of middle Asia [Copyright &y& Elsevier]

Abstract: Israel is a country with mostly arid environments where is localized extremely large number of archaeological objects of various age, origin and size. The archaeological remains occur in multi-layered and variable geological–archaeological media. In many cases physical properties of the ancient objects are disturbed by long-term influence of arid conditions. These disturbances strongly complicate interpretation of observed geophysical anomalies since the useful signal/noise ratio is often sufficiently reduced. Another disturbing factors are the influence of uneven topography, oblique polarization (especially, for magnetic field analysis) and industrial-engineering objects of different kinds situating in the vicinity of studied remains. From a rich arsenal of the developed techniques (the most part of them is described in ) in the paper are presented the methods of advanced quantitative analysis of potential geophysical fields and 3D magnetic field modelling. A brief archaeological-geophysical review indicates that in Israeli archaeological sites were applied practically all near-surface geophysical methods: beginning from the paleomagnetic examination and ending by microwave remote sensing. Such a diversity of applied methods and constant accomplishing of geophysical, archaeological and other data stipulate creating of a multi-linkage as between the various geophysical methods, so also with other archaeologically related databases. [Copyright &y& Elsevier]

Abstract: Pollen concentration has been commonly used to indicate vegetation cover and moisture change. However, this practice may not always be justified in arid and semi-arid regions. This paper investigates potential problems with the approach based on modern pollen assemblages and fossil pollen data from arid and semi-arid China. The results show that pollen concentration has no direct relationship with vegetation cover and effective moisture in our study region. Pollen representation and sediment accumulation rate may have contributed to the complication. We conclude that pollen concentration cannot be used as a reliable index of effective moisture in arid and semi-arid regions. [Copyright &y& Elsevier]

Abstract: Individual preferences, changing market conditions, environmental constraints, and regulatory interventions can all contribute towards livestock-keepers in arid environments moving away from their traditional livestock production systems. As a consequence, certain local breeds and the genetic resources they represent may become used less and less, eventually becoming threatened with extinction. Where society considers the maintenance of such genetic diversity to be important, conservation initiatives must be established. The paper presents results from an empirical case study carried out in the Borana lowlands of Ethiopia and Kenya. Conservation costs in the form of local livestock-keeper opportunity costs incurred from keeping the breed targeted for conservation rather than an alternative breed were measured. A contingent valuation, involving 370 households each completing an iterative bidding game, was applied. Respondents stated their willingness to accept compensation for conserving traditional Borana cattle instead of keeping other cattle breeds. The data was analysed using a Tobit model and we conclude that the costs of a community-based conservation programme split between Ethiopia and Kenya, based on a safe minimum herd size, would require €25,400 per year in terms of direct support payments and management and monitoring costs. [Copyright &y& Elsevier]

Abstract: Establishing forest cover in arid or drought-stricken regions is a challenging task facing countries with a high degree of desertification or risk of desertification. China''s Loess Plateau is one such area, an extremely dry climate, especially in spring, and that has a highly dissected topography. A new tree-planting technique to improve drought resistance, in which planting holes are lined with biodegradable plastic to reduce drainage and evaporation, was tested in an arid, erosion-prone, hilly area of the Loess Plateau between 1997 and 2006, during a period of lower-than-normal precipitation. In this paper, we report the survival and growth of 15 tree species grown with and without the new plastic lining. The new tree-planting technique promoted root growth in the topsoil by keeping the soil moisture than the surrounding soil evident during the first 4 months after planting. Tree survival rates, branch growth increment per year, tenth-year canopy area, and tenth-year canopy density in trees planted using the new method increased by an average of 41.4%, 29.0%, 16.9%, and 65.3%, respectively, compared with the values for the conventional planting technique. This suggests that the new planting technique is more suitable than the conventional method for the study area''s soil environment and climate, and may prove suitable for similar areas elsewhere in the world where survival and growth rates are low. The results of our study thus represent a potentially valuable alternative for forest restoration and soil conservation in arid zones. [Copyright &y& Elsevier]