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Abstract: In this paper we analyze the growth and early survival of two congeneric columnar cacti: the rare Neobuxbaumia macrocephala (with low population densities and a narrow distribution range), and the relatively common Neobuxbaumia mezcalaensis (with dense populations and a broader distribution range). Seeds of both species were germinated and seedlings were subjected to different radiation, nutrient and watering treatments in greenhouse conditions for six months. By the end of the experiment seedling average dry mass was similar in both species. Recently emerged seedlings of N. macrocephala were smaller than those of N. mezcalaensis; however, N. macrocephala showed higher relative growth rates (average RGR = 0.0138 mg/mg/day) than N. mezcalaensis (average RGR = 0.0126 mg/mg/day). For both species RGR decreased in the shade. Root:shoot ratio (R/S) and K were higher in N. mezcalaensis than in N. macrocephala and showed an increasing trend as water availability decreased. Seedling survival was followed in natural conditions for nine months. The survival of N. mezcalaensis was significantly higher compared to N. macrocephala. In both species a slightly higher seedling survival was observed under the shade of nurse plants. The two species displayed different growth and survival responses, which accounts to some extent for their contrasting level of rarity. [ABSTRACT FROM AUTHOR]

Abstract: The stability of many sand dunes and their interdunes is dependent on vegetation and surface crust cover. When this cover is removed, the sand can be activated and fine sediments deflated making the dunefields into sources of dust. This paper reports the impact of devegetation by wildfire on an interdune in the Simpson Desert, Australia. The fire occurred in 2001 and six years after the event pronounced differences between a pair of burnt and unburnt sites was clearly discernible. The variables examined included vegetation assemblage, cyanobacteria abundance and sediment aggregation, particle-size distribution and colour; but whether they apply to all such situations is uncertain. Rate of recovery has been slow and the differences are likely to have been sustained by a combination of negative feedback processes and climate. [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: In arid lands, the shifts in dominant plant types from grasses to shrubs can significantly alter the ecosystem function and biogeochemistry cycles. However, the magnitude of these alterations and its inherent mechanisms are still poorly understood. In this study, we measured soil respiration and NPP over two growing seasons in 2006–2007 in the co-occurring perennial grass and desert shrub ecosystems at the Ordos Plateau of Inner Mongolia, China. Over the two growing seasons, the desert shrub site presented higher aboveground biomass and NPP while lower soil respiration relative to the grass site (p < 0.05). In this paper, we can not determine that whether vegetation conversion or soil texture change drive the site difference in soil respiration because we did not control for soil texture. We suppose that the site difference in pulse response of soil respiration might play an essential role in regulating this soil respiration gap. In all the growing seasons, surface soil moisture (0–10 cm) was identified as the major driver of soil respiration at both sites. Compared to the linear soil moisture model, the integrated model incorporating both surface soil moisture and air temperature was performed better in predicting the dynamics of soil respiration. [Copyright &y& Elsevier]

Abstract: In extra-Andean Patagonia, wet meadows contrast with the prevailing arid steppes, and present a gradient of water availability from the periphery to the center. The objectives of this paper are to describe the spatial and temporal variation of aerial net primary production (ANPP) of Patagonian meadows, and to obtain a model for the relationship between the normalized difference vegetation index (NDVI) and ANPP. We determined ANPP in four regionally scattered meadows during 3–5 years and in three positions of the gradient of water availability. In one meadow, we correlated ANPP with NDVI during 2 years. Annual ANPP was 2–3 times larger in the center than in the periphery, and also varied 2–3 fold among the four meadows. The interannual variation of ANPP was high and similar across meadows and zones. ANPP was closely correlated with NDVI through a linear model. Within the growing season, the central zone had a more extended period of high NDVI into the summer than the peripheral and the intermediate zones. We conclude that (1) the local variation of ANPP across the gradient of water availability is strong and must be taken into account for management, and (2) the highly variable ANPP may be monitored by remote sensing. [Copyright &y& Elsevier]

Abstract: This paper reports on the relationship between the airborne pollen spectrum and the status of anemophilous flora in the south-eastern Iberian Peninsula. Variations in pollen counts with respect to data for a previous sampling period were also examined. The key finding was that the spectrum contained pollen from the most characteristic local species, such as xerophytes adapted to arid conditions, ruderal and nitrophilous species, sclerophyllous Mediterranean pine and holm-oak forest and vegetation in dry watercourses. The main variations with respect to earlier data were attributable to changes in land use, with increasing production of certain crops and a growing trend towards ecological agriculture, the introduction of allochthonous species and the recovery of local flora in dry watercourses. [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: In the southern part of the plain of El Qa'' there is a group of previously unknown tombs, probably dating to within 500–600 years of 7000 BP. They are adjacent to a freshwater playa, and east of the first access to the Gulf of Suez south of Gebel Qabiliat. This paper describes the largest of the tombs, which was quite elaborate and included prestige grave-goods (turquoise). [Copyright &y& Elsevier]

Abstract: The use of pollen analysis of herbivore middens in arid and semi-arid areas has facilitated palaeoenvironmental reconstruction and interpretation in places where this may otherwise be impossible due to the absence of organic sediments. This paper presents evidence based on pollen analysis and stable isotope data of hyrax (Procavia capensis) dung middens in the reconstruction and interpretation of the Holocene vegetation history of the Cederberg and Swartruggens mountains. Hyrax middens from upland sites in the Cape Fold Mountains, specifically at Katbakkies Pass (KB) in the Swartruggens and Truitjes Kraal (TK) in the Cederberg, are used to reconstruct past vegetation and palaeoenvironments. Radiocarbon dating of a 20cm sample at Katbakkies confirms a late Holocene sequence, with sedimentation commencing around 3700calyrBP and terminating within the last 600years. At Truitjes Kraal, a smaller (11cm) section appears to represent much of the Holocene, with accumulation spanning the period from around 9500 to 1300calyrBP. Stable isotope and pollen analyses concur in indicating only relatively subtle changes in vegetation conditions over the Holocene, a conclusion that is compared with and supported by other palaeoecological evidence from the region. [Copyright &y& Elsevier]

Abstract: Desert kites are stone-built, funnel-shaped installations comprising two long and low stone-built walls (‘arms’) converging on an enclosure or pit at the apex. They are found in the deserts of the Near East, and are generally accepted as representing game traps to catch herds of wild ungulates. Their chronology is debated but some desert kites appear to have functioned as early as the 7th millennium BC. The largest number of these structures is recorded in the deserts of eastern Jordan where they often form chains of up to 60km long. In contrast, in the Negev (Israel) and Sinai (Egypt) deserts, the desert kites are few in number and occur as small, individual installations. This paper presents the results of archaeological surveys and excavations of 16 desert kites from the Negev desert and northeast Sinai. We present radiocarbon dates, infrared stimulated luminescence ages and chronology of material culture to show that desert kites in this region were established in the late 4th–early 3rd millennia BC and ceased to function by the mid-2nd millennium BC. The size, shape and location of the desert kites fits the physical conditions of the terrain and also the ethology and ecology of the prey species hunted. [Copyright &y& Elsevier]

Abstract: Provision of surface water has been a long-standing management strategy to enhance habitat for large mammals in southwestern North America. In this paper, we use a resource selection function (RSF) developed from telemetered mountain sheep (Ovis canadensis) in three occupied mountain ranges in the Sonoran Desert, California, USA, to examine the effects of water development on habitat quality within those ranges. Further, we apply that model to four nearby and similar mountain ranges, but for which telemetry data are not available, and again examine the effects of water development. When distance to water was decreased to 2,000 m from an average of 3033 m (±522 [SD]) in three occupied mountain ranges, availability of high-quality habitat increased by as much as 92%. When distance to water was decreased to 2,000 m from an average of 3660 m (±799 [SD]) in three mountain ranges not occupied permanently by mountain sheep, and one occupied range for which telemetry data were not available, the proportion of high-quality habitat resulting from application of our model indicated increases that varied from 116 to 508%. We conclude that development of additional sources of surface water can increase availability of high-quality habitat for mountain sheep inhabiting Sonoran Desert mountain ranges, and that the technique has implications for population persistence and conservation of those large, specialized ungulates. [Copyright &y& Elsevier]

Abstract: In this paper we summarize the surface characteristics for six locations in western Mexico and southwestern USA (from a subhumid climate in Jalisco, Mexico to the Sonoran Desert climate in Arizona, USA), that lie along a meridional transect within the North American Monsoon (NAM) core region using available MODerate Resolution Imaging Radiometer (MODIS) satellite data and supplementary surface instrumental data for two of these sites in Sonora, Mexico. The climate analysis for each site is carried out for the period 2000–2008, that includes all available MODIS data. A comparison of seasonal and annual variability in surface conditions for the enhanced vegetation index (EVI), albedo and land surface temperature (LST) at each site is presented. With the help of available surface data from field observations, a more detailed analysis of Rayón and Rosario de Tesopaco sites is presented. The qualitative behavior and climate response of three types of vegetation: desert shrub, subtropical shrub, and tropical deciduous forest ecosystems are analyzed under the influence of the NAM summer wet season. The onset of the NAM warm wet season in early summer, is one of the main precursors of generalized EVI growth in all the NAM region. At all the sites, it is observed that the mean daytime LST cools several degrees as the NAM fully develops. During the warm wet season, in the case of open and sparse vegetation regions such as desert shrub and subtropical shrub, albedo values fall slightly during the NAM season, while in closed and dense tropical deciduous forest regions albedo shows a slight increase. Differences in soil reflectivity at these sites are probably responsible for this rather unexpected behavior. Additionally it is found that, desert shrub and subtropical shrub regions in northern latitudes show large LST and small EVI/albedo seasonal variability, whilst tropical deciduous forests in lower latitudes show much larger EVI/albedo and smaller LST seasonal variability. Thus MODIS data proves to be a valuable tool for assessing the dynamics of seasonal and interannual surface characteristics helpful in determining climate patterns. [Copyright &y& Elsevier]

Abstract: This paper explores the existence and potential causes of a stationary spatial anomaly, or pattern incoherence, in the seasonal distribution of warm season rainfall in western Mexico. The anomaly is evident in maps of the Month of Maximum Precipitation (MMP) variability over northwest Mexico (NWMx). Instead of occurring progressively as latitude increases, the MMP occurs in July in the southern part of western Mexico and along the main axis of the Sierra Madre Occidental (SMO) to the north, and in August in the central portion of the region, in Nayarit, Durango and Zacatecas. The Month of Maximum Streamflow (MMQ) occurs in a similar spatial pattern but shifts one month later. This feature is explored through inspection of the daily rainfall climatology of the region for stations with more than 20 years of data between 1940 and 2004. We hypothesize that this anomalous pattern in rainfall (and subsequent streamflow) is likely influenced by the complex thermodynamic interaction between the orography of the SMO and the regional monsoon circulation. The possibility that the canyon system known as the San Pedro Mezquital helps drive the anomalous increase of rainfall in August across latitudes limited to of Nayarit is explored. The correlation between rains that fall over watersheds on the western slope of the SMO and rainfall over the Mexican Plateau is also discussed. We also explore the relationship of the rainfall anomaly to the seasonal march of the Western Hemisphere Warm Pool (WHWP) and near shore Sea Surface Temperature (SST) variations as they may impact the land–sea thermal contrast. The results of this study based on daily rainfall and streamflow climatologies suggest that a region exists in Nayarit where atmosphere–ocean–land surface interactions lead to a relative phase-shift in the maximum precipitation and streamflow. [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: The nonparametric Mann–Kendall test was used to detect the trends of major hydroclimatic variables in the Tarim River Basin, the largest inland river basin in China for the period of 1960–2007. Results showed that both mean annual air temperature and precipitation experienced an increasing trend, while annual streamflow demonstrated a mixed trend of decreasing and increasing: The mountainous region upstream showed an increasing trend and the region downstream exhibited a decreasing trend. Impacts of the increased air temperature on streamflow have shown different characteristics depending on location and seasons: it has positive effect on the runoff at mountainous region due to snowmelt and glacier-melt in spring, but negative effect on the runoff at plain area due to the increase of actual evaporation in summer. In addition, human activity contributed to the declining of streamflow in the arid plain oases at downstream of the Tarim River Basin. The results obtained in this paper can be used as a reference for the planning and management of water resources to maintain the health of the river system. [Copyright &y& Elsevier]

Abstract: This paper examines the change in precipitation from 1900 to 2006 on a regional scale over a portion of the Central United States. Monthly precipitation data is kriged over the Kansas River Basin region. The Standardized Precipitation Index (SPI) is calculated at several time scales ranging from 1 to 12 months. The linear trend of SPI values over the time period is calculated and analyzed, showing many areas of increasing wetness throughout the area, with drying in isolated regions of the West and North. These isolated regions of drying overlap regions of heavy water use and irrigation, suggesting possible detrimental effects on agricultural production and aquifer levels if the trend continues. With the areas of increasing trend, however, it is unclear whether increased precipitation actually signifies any increase in water availability. Fourier analysis is also used to detect characteristic frequencies of SPI values. No difference in drought frequency patterns across the region was observed. [Copyright &y& Elsevier]

Abstract: This paper describes a manual-style Decision Support System that integrates land degradation indicators with adaptive management options and is designed for land managers to easily collect data and monitor progress towards environmental sustainability goals. A number of similar tools have been developed for ranchers in southern Africa, but there has been little help for land managers under common property regimes. Manuals were therefore primarily designed for use by communal pastoralists in three study areas in the Kalahari, Botswana. Separate manuals were developed for each study area in response to the differences in indicators and management options deemed relevant for each by local communities. The design of the DSS has been optimised using an “innovation-decision” approach combined with local and external expert review to enhance the likelihood of widespread uptake and application by land managers. Manuals are designed for regular use by pastoralists to identify detrimental environmental change early, and guide sustainable management responses. The recommended assessment procedure is flexible, and designed to make recording and interpretation of results simple for users. Full copies of each manual (in English) are provided (electronic version only). [Copyright &y& Elsevier]

Abstract: The urbanization process in the middle section of Silk-Road (He-Xi Corridor) bears noticeable inscriptions of its fragile physical environment. This paper develops an integrated research approach to examine urban growth under severe water shortage and to quantify the dynamic relationship between sustainable urbanization and restricted water supplies. This new approach is synthesized from the field survey often adopted in regional studies of resource management, the policy study of sustainable urban development and rational water utilization, and the regional predictive analysis of economic and demographic growths based on the economic base theory. The total available water resources and the water quotas by major economic sectors at present were calculated from the field survey. The water quotas and their change rates by economic sectors over the period of 2000–2030 were estimated on the basis of policy study of regional development goals and future trends of water usages and changes. Finally the water quotas and their change rates were integrated with regional models of demographic and economic predictions to compute sustainable economic development by economic sectors, and then to derive total population and urban population. Therefore, a sustainable urban growth under the limitation of insufficient water supplies in He-Xi was determined. [Copyright &y& Elsevier]

Abstract: The changes in wind velocity induced by dune topography have an important significance in dune dynamics. In this paper, the horizontal and vertical velocities over six transverse dune models were measured non-intrusively by means of Particle Image Velocimetry in a wind tunnel. The windward slope angle and the free-stream wind velocity both affected the horizontal and vertical velocity components. On the windward side, the acceleration of horizontal velocity depended mainly on the windward slope angle and the height above the dune surface, but was also affected by the free-stream wind velocity. The speed-up ratio increased with increasing slope angle but decreased with increasing height. The ascending vertical velocities also increased with increasing slope angle and free-stream wind velocity. The maximum values moved upper along the dune when the windward angle became steeper. In the leeward sides, the horizontal velocity decreased and reversed because of airflow separation; the maximum reverse velocity in the separation cell was about 17% of the free-stream wind velocity. Behind the dune crest, the airflow moves downwards, and its maximum downward velocity is found near the flow reattachment point. Finally, we discussed the significance of these velocity variations for sediment transport and dune dynamics. [Copyright &y& Elsevier]

Abstract: This paper reviews and summarizes the results of research projects conducted in the Aleppo pine provenance trial in the Yatir forest, located at the northern edge of the Israeli Negev desert, under semi-arid climate. Results show that to improve the sustainability of new Aleppo pine plantations at the edge of deserts, prospective seed sources (provenances) must be selected for heterozygosity on one hand, and for drought resistance and water-use efficiency on the other. Harsh environmental site conditions at the desert''s edge provide an opportunity to exert heavy selection pressure among and within provenances of a priori drought-tolerant species. The survivors should be used as the seed source for new forest plantations aimed at combating desertification. [Copyright &y& Elsevier]

Abstract: Annual growth rings are well-defined in some shrubby species distributed along the Patagonian steppe and provide useful information to identify the environmental factors that influence the radial growth of shrubs in the region. However, little is known about variations in ring width from these species and their relationships with local environment. In this paper we present 18 growth ring width chronologies covering the last 2–3 decades from the shrub Anarthrophyllum rigidum (Fabaceae) encompassing most of its natural range of distribution in Argentina. Interannual variations in growth were first analyzed collectively to identify common regional patterns. In addition, shrub growth at each site was compared with local climate records and site-specific characteristics. Based on a principal component analysis (PCA), sites were joined in four major groups related to the site proximity to the Andes (foothills versus Patagonian plateau) and latitude (north versus south Patagonia). The relatively similar percentage of PCA variance associated with each group reflects environmental differences among sites. Consistent with this observation, we noted large variability in the responses of the A. rigidum woody growth to regional climatic fluctuations. At most sites, this species is favored by abundant winter precipitation, warmer spring and autumn temperatures (controlling the duration of the growing season), cool summers, or a combination of these factors. However, deviations from these patterns are also recorded. Our study represents the first large-scale dendroclimatological analysis of a shrubby species in southern South America. The results presented here provide information on the main patterns and factors affecting the growth of A. rigidum in Patagonia, and may be useful for determining well-suited practices for management and conservation of this ubiquitous species. [Copyright &y& Elsevier]

Abstract: The Kuwaiti desert is swept by strong winds, particularly by northwesterly wind, during the summer months (April through September), causing mass-scale sand transport that poses a serious environmental hazard. Understanding that accurate transport rate data are very difficult to obtain either by field measurements or by using any existing sand transport formulae, this paper presents a mathematical model to predict the sand-transport rate for Kuwaiti desert by following a well-known theoretical approach of Lettau and Lettau (1978) and by taking into account the effect of seasonal wind variability. The validity of the model is next examined using the field data from the study of Al-Awadhi and Al-Sudairawi (2002). The examination showed that the model underestimates the rate of sand transport by an average ratio of 0.15. The application of the model, at some seven locations that are evenly distributed across the Kuwaiti desert, indicated that about 40% of the amount of sand transport in Kuwait prevails from the NW during the peak summer months (June and July). The resulting map of sand transport rate indicated that the zone of higher sand transport rate is located within the areas covered by most extensive mobile sand sheets and sand dunes. [Copyright &y& Elsevier]

Abstract: This paper describes evaluation of forest stand density combining satellite imagery with forest inventory data set. The degree of canopy cover is described in terms of fractional vegetation cover (FVC) obtained by a linear mixture model applied on multi-spectral IKONOS image and canopy cover (CC). CC was calculated from field measurements of crown width of 646 standing trees sited within 72 circular (200m2) plots. A comparison between CC and FVC shows that the former can be accurately represented by the latter linking in-situ measured forest characteristics with surface reflectance measured by a satellite. Stand density expressed as an absolute term (number of trees per unit area) showed high and significant positive correlation to FVC (R 2 =0.96) and to relative density measure (Crown Competition Factor; R 2 =0.89). In order to show the applicability of the presented approach for managerial practices, a map of the spatial distribution of stand density within the forest was produced using the above-mentioned correlations. Its quality was verified against an independent data set of ground measurements. The correlation between field- and map-based number of trees per unit area was found to be satisfactory (R 2 =0.4; p <0.05), even though a slight lack of sensitivity was evident for low-density stands. [Copyright &y& Elsevier]

Abstract: While research-article impact is routinely judged by citation counts, there is recognition that a much broader view is needed to better judge the true value of citations. This paper applies a developing framework based on the application of network theory, where the network consists of journal articles on arid-systems research which are listed on ISI Web-of-Science. Keywords were used to identify articles related to arid-systems research. Linkages between articles were defined by citations, and we bound our analysis by focusing on how the Australian subsample contributes to the international arid-systems literature. The analysis showed that impact based on how articles contribute structurally to the flow of knowledge within the literature offers an alternative metric to citation counts. The analysis also presented a partitioned view of the Australian arid literature. This showed that there exists some citation-based structure within the literature, and we showed this structure better describes the literature than a partition based on which journal articles are published in. [Copyright &y& Elsevier]

Abstract: Temporal variation of aboveground net primary production (ANPP) of arid ecosystems has been associated with precipitation regimes with different results. The objective of this paper was to characterize the relationship between interannual variation of annual and seasonal Normalized Difference Vegetation Index (NDVI), as a surrogate for ANPP, and precipitation in the steppes of Northern Patagonia. In 11 sites encompassing a wide range of conditions and vegetation physiognomies, we studied a 20-year monthly data set of NDVI and precipitation. We took into account the precipitation of current, as well as previous periods of variable length. Interannual variation of annual NDVI was little correlated with annual precipitation, either current or previous. In contrast, it was highly and widely correlated with precipitation accumulated during a few months of the previous growing season. Interannual variation of seasonal NDVI was little correlated with current seasonal precipitation. In contrast, it was significantly correlated with precipitation accumulated during previous periods of variable length according to the season and site under consideration. NDVI was more tightly coupled with precipitation in drier ecosystems. Lags of response between NDVI and precipitation provide an opportunity for forecasting ANPP and suggest even longer lags between climatic variation and herbivore performance. [Copyright &y& Elsevier]

Abstract: There is a growing requirement for techniques to assess land susceptibility to wind erosion, i.e. land erodibility, over large geographic areas (>104 km2). This requirement stems from a lack of wind erosion research between the field (101 km2) and regional scales, and a need to evaluate the performance of spatially explicit wind erosion models across these scales. This paper addresses this issue by presenting a methodology for monitoring land erodibility at the landscape scale (103 km2). First, we define criteria suitable for evaluating land erodibility based on empirical relationships between soil texture, vegetation cover, geomorphology, and wind erosion. The criteria were used to visually assess land erodibility over long distances (103 km) using vehicle-based transects run through the rangelands of western Queensland, Australia. Application of the data for testing the performance of a spatially explicit land erodibility model (AUSLEM) is then demonstrated by comparing the visual assessments of land erodibility with the model output. The model performed best in the west of the study area in the open rangelands. In regions with higher woody shrub and tree cover the model performance decreases. This highlights the need for research to better parameterise controls on erodibility in semi-arid landscapes consisting of forested and rangeland mosaics. [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: The aim of this study is to explore the environmental factors that determine plant community distribution in northeast Algeria. This paper provides a quantitative analysis of the vegetation–environment relationships for a study site in the Chott El Beida wetland, a RAMSAR site in Setif, Algeria. Sixty vegetation plots were sampled and analysed using TWINSPAN and Detrended Correspondence Analysis (DCA) in order to identify the principal vegetation communities and determine the environmental gradients associated with these. 127 species belonging to 41 families and 114 genera were recorded. Six of the recorded species were endemic representing 4.7% of the total species. The richest families were Compositae, Gramineae, Cruciferae and Chenopodiaceae. Therophytes and hemicryptophytes were the most frequent life forms. The Mediterranean floristic element is dominant and is represented by 39 species. The samples were classified into four main community types. The principal DCA axes represent gradients of soil salinity, moisture and anthropogenic pressure. The use of classification in combination with ordination techniques resulted in a good discrimination between plant communities and a greater understanding of controlling environmental factors. The methodology adopted can be employed for improving baseline information on plant community ecology and distribution in often critically endangered Mediterranean wetland areas. [Copyright &y& Elsevier]

Abstract: This paper provides an overview of the traditional uses of native flora and wildlife in the Monte Desert. The uses of several native plant products, such as Prosopis wood and pods, Cercidium gum, Bulnesia wax, and Larrea and Grindelia resin are discussed in an economic context. We provide a detailed description of the uses of animal products, such as hides, furs, bones, meat, feathers and fat. Legal regulations to guarantee wildlife conservation are discussed. We conclude that currently, the most feasible options for sustainable economic wildlife utilization seem to be guanaco live shearing and the use of rhea products obtained from captive-bred animals. We propose four options for the sustainable economic utilization of flora: (1) the harvest of non-wood forest products; (2) periodic selective logging of a limited number of mature trees in natural forests; (3) the establishment of native tree plantations; and (4) the domestication of native shrubs or herbs capable of yielding industrial raw materials such as fatty acids, resins or gums. [Copyright &y& Elsevier]

Abstract: In arid and semiarid ecosystems, primary productivity and nutrient cycling are directly related to the amount and seasonal distribution of precipitation. However, depending on morphological, phenological, physiological, and biochemical traits, plants may influence the quality and quantity of organic matter inputs to the soil and thus the biomass and activity of the soil biota responsible for carbon and nitrogen dynamics. In this paper, we review the available knowledge on plant functional traits and their impacts on ecosystem processes such as N and C cycling throughout the Monte Phytogeographical Province. We address the mechanisms of N conservation, the quantity and quality of leaf litterfall and root traits of the dominant plant life forms and their effects on decomposition processes, soil organic matter accretion, and soil-N immobilization and mineralization. We conclude that plant functional traits affect ecosystem processes in the Monte Phytogeographical Province since the chemistry of senesced leaves and root biomass exerts an important control on organic matter decomposition and N availability in soil. [Copyright &y& Elsevier]

Abstract: This paper documents the main features of climate and climate variability across the Monte Desert for the Last Glacial Maximum, the Glacial–Interglacial transition, and the Holocene on the basis of proxy records and for the 20th century using instrumental observations. The climate in the Monte is determined by interactions between regional physiography and atmospheric circulation in the 25–45°S sectors of South America. Although arid and semi-arid conditions prevail across the Monte, its large latitudinal extent and complex topography introduce many particularities at local scales. Paleoclimatic records and model simulations of past climates suggest significant variations in the atmospheric circulation, temperature and rainfall patterns since the Last Glacial Maximum. High-resolution proxy records east of the Andes support the existence of complex climatic patterns with similar temperature changes across the whole region but opposite precipitation variations between subtropical and mid-latitude sectors in the Monte during the past millennium. The present-day climate is depicted in terms of the space and time variability of the near-surface temperature, rainfall and tropospheric wind patterns. Uneven temperature trends over the Monte were recorded for two separate (1920–44 and 1977–2001) global warming periods in the 20th century. Additional warming evidence in the region is provided by extreme temperature records. The non-homogeneous regional pattern of precipitation shows a positive long-term increase between 30 and 40°S during the interval 1985–2001. Ensemble of climate experiments accomplished with general circulation models provide the most likely changes in temperature and rainfall to occur by the end of this century in relation to present climate. Temperature increases, larger in summer than in winter, will be concurrent with more abundant precipitations in summer, but almost no changes or even small reductions in winter across the Monte. [Copyright &y& Elsevier]

The Eastern Cape Province, and in particular, it's interior western Karoo region, has long been subject to periodic droughts, with significant implications for it's agricultural sector. From 2015, with some recovery in 2020, the area experienced a severe multi year drought, with negative impacts for a range of sectors, including extensive livestock farming. At the time of the drought, a common narrative in the media stated that the drought was unprecedented. In this paper, we analyze how the drought evolved climatically, as well as its impacts on vegetation and farming conditions. Our findings indicate that it would appear that the drought was not unprecedented. It was, however, considered to be extremely severe – with some local impacts found to be critical. Loss of production impacts, and loss of income, now compounded by the difficulties resulting from the COVID19 pandemic (which has impacted the South African economy severely) are likely to continue to impact the agricultural sector in the Eastern Cape for some time – and given the likelihood of increased frequency of extreme events in southern Africa in the future, we may see more frequent subsequent severe multi-year events. • From 2015, the interior Eastern Cape experienced a severe multi year drought • Popular media narratives described the drought as unprecedented. • In fact, the drought was not unprecedented, but was extremely severe. • The agricultural sector in the Eastern Cape is likely to continue to be vulnerable. [ABSTRACT FROM AUTHOR]

Abstract: This paper investigates endolithic microorganisms in modern gypsum crusts located in arid and saline areas of southern Tunisia. In arid regions, the endolithic mode of life facilitates the survival of the microorganisms and protects them from extreme environmental conditions. The gypsum crusts are the product of evaporite precipitation atop spring mounds developed at the margins of the Chott el Jerid, a saline lake close to the Algerian border. The early mineral precipitation has prevented the complete degradation of these microorganisms and their metabolic products because of the rapid sealing provided by the gypsum crusts. The spring mound structures of the Chott el Jerid offer an opportunity to study the endolithic communities in evaporite and arid environments. An understanding of where and how life survives in such extreme conditions, and how life signal prints in the rocks may help in search for life in the geological record and for astrobiological purposes. [Copyright &y& Elsevier]

Specific guidelines are needed to overcome dichotomous classifications of lands into degraded or not for leveraging the Land Degradation Neutrality (LDN) concept. Overlooking degrading lands or those at risk of degradation can block LDN. Therefore, this paper proposes a detailed land classification method, and complements LDN with an indicator α (wildfires, landslides and insights on aridity). Indicator α taps the rarely studied LDN-natural hazards nexus. For separating degrading, degraded and non-degraded lands, twelve categories were defined, and indicators were then established. Subsequently, a land potential-hazard informed LDN intervention was planned. These methods target sub-national scales via the Lebanese/Mediterranean Aley district. Findings first revealed that Aley's land cover developed without considering land potential or hazard potentiality. Second, land status categories are distributed as 65% stable (of which 20.18 are lightly used), 8.14% non-degraded (adequately used, recovered and improving), 13.67% degraded, and 13.13% at risk of degradation. However, the district risks shifting towards less healthy land states due to unplanned development and natural hazards inconsideration. Accordingly, the LDN intervention targeted the stable/lightly used, at risk of degradation-/lightly used, overused and lightly used lands for optimization. This approach shifted 33.33% of Aley to adequately used lands, increasing the latter from 8.05% to 41.38%. • The land degradation neutrality-disaster risk reduction nexus is investigated. • A comprehensive classification of land use/health status is presented. • Land Degradation Neutrality concept framework complemented by natural hazards. • A focus on land degradation in Mediterranean settings. • The proposed approach can serve as an inclusive land use planning tool. [ABSTRACT FROM AUTHOR]

Abstract: Semi-arid areas are often considered to be environmentally and economically marginal, a situation which has been exacerbated by economic change, shifts in agricultural production and land use, and changing state policy. These themes are explored with reference to a semi-arid landscape, namely the Karoo, which covers some 40% of the geographic space of South Africa and is used primarily for extensive livestock farming. Despite long-term decline in agricultural output, the traditional mainstay of the region, and weakening small town economies, the Karoo''s population and the economies of its largest service centres are growing. There are, real socio-economic needs and development backlogs, and the situation has been exacerbated by recent political marginalisation. In this study, the small towns of the region are focal points of investigation and provide a lens to investigate the changing demographic and economic dynamics of the Karoo. Most of the region''s population lives in these centres which are service, collection, and distribution points for what traditionally has been an agriculture-based regional economy. This paper explores the concept of marginalisation with specific reference to historical, economic, and demographic change. [Copyright &y& Elsevier]

Abstract: This paper deals with the periodic fluctuation of precipitation at three meteorological stations (Atar, Chenguitti, and Akjoujt) in the Adrar and Inchiri provinces in northern Mauritania and its links with sea surface temperature (SST). Trends for these three meteorological stations were evaluated using the Mann–Kendall (MK) nonparametric test, regression analysis, and autocorrelation for persistence analysis. The MK test showed a significant decreasing trend for Akjoujt and an insignificant trend for the other rainfall time series. However, the decreasing linear regression trends were highly significant for the different time series. On the other hand, persistence analysis indicated the presence of a linear Markov type. The cycles found by power spectrum analysis ranged from 0.5 years to about 11 years. The possibility of a connection between precipitation in this region and sunspot numbers was suggested. SST of the Atlantic Ocean, Indian Ocean, and Mediterranean Sea have significant cross-correlations with precipitation in the study area. The El Niño-Southern Oscillation effect was found to be marginal. [Copyright &y& Elsevier]

Abstract: Central Sahara rock shelters offer an early and middle Holocene environmental reconstruction. This paper summarises palynological research carried out within a multidisciplinary archaeological research project on the Wadi Teshuinat area (Tadrart Acacus Mts., in south-western Fezzan, Libya). The sites were occupied by hunter-gatherer and pastoralist cultures. On-site pollen data, treated as a single ‘regional site’, showed that different pollen stratigraphies and flora characterised the past phases. Plant macro-remains also helped to understand local plant exploitation and landscape evolution. Pollen spectra showed the following climate oscillations: wet and cool (approx. 8800–8250cal.BC), dry and warm (approx. 7920–7520cal.BC), wet (approx. 7550–7200cal.BC), dry (approx. 6340–6210cal.BC—geoarchaeological evidence), wet and warm (approx. 6250–4300cal.BC, including a wetter and warmer phase at approx. 5500–4600cal.BC); dry and warm (approx. 4250–2900cal.BC); drier and warm (approx. 2900–1600cal.BC, up to the present). Since the early Holocene, both climatic and anthropic factors have played an important and strictly interconnected role in transforming the environment. Thus, while subsistence strategies were adjusting to climatic and environmental changes, the plant landscape was also being slowly and continuously shaped by humans. [Copyright &y& Elsevier]

Abstract: This paper describes procedures used to map riparian vegetation in the middle Rio Grande River, New Mexico. Airborne multi-spectral digital images were acquired at 0.5m spatial resolution over the riparian corridor of the Middle Rio Grande River in July 2001. The images were corrected for lens vignetting effects, lens radial distortions, rectified to a base map, mosaicked, calibrated in terms of reflectance and classified. The classification accuracy was assessed using ground truth information obtained through comprehensive field campaigns and independent ground truth information. Surface areas of vegetation classes and in-stream features were extracted from the classified imagery. A longitudinal vegetation distribution analysis was conducted to study the changes in vegetation and water surface areas along the river. This analysis showed an increase in surface areas of the invasive type of vegetation Tamarisk (Tamarix ramosissima) in the downstream direction corresponding to decreases in water surface areas and flow. This indicates significant impacts on the river ecosystem due to many factors. The high resolution airborne remote sensing proved to be a powerful tool for mapping riparian vegetation which is very hard to map using satellite imagery due to its complexity, high diversity, and spatial variability occurring at finer scales. [Copyright &y& Elsevier]

Abstract: This paper provides a reappraisal of contemporary perspectives on climate change in southern Africa''s Okavango Delta sub-region by drawing on time-line evidence from historical/archival records, field-compiled information and multi-date remotely sensed imagery. By using temporal variations in stream discharge and surface and groundwater distribution as proxies of declining rainfall from the beginning of the 19th century, trends emerging from this reconstruction suggest that progressive contraction of the Delta''s permanent floodplains, the desiccation of Lake Ngami in its distal reaches, fossilization of receiver channels, sustained dewatering of aquifers, and changes in vegetation from grassland to drought-tolerant woody species are non-transient precursors of increasing aridity and deteriorating climatic conditions. With evidence pointing to persistent drying sequences and system failures to revert to moister climate conditions of the recent historical past, hypotheses that characterize deteriorating rainfall and recurring flood failures in this environment as isolated singularities in a punctuated equilibrium need to be reconsidered in order to provide empirically grounded planetary change perspectives that are consistent with evidence over long-term temporal horizons. [Copyright &y& Elsevier]

Abstract: This paper reports on an 8-year continuing project with the Sevilleta Long-Term Ecological Research program (LTER) in central New Mexico aimed at the study of dynamics of woodland ecosystems. The study of mast production was conducted at six experimental woodland sites situated across an elevational gradient of 1500–2000m in proximity to permanent meteorological stations. The dominant woody species were Juniper monosperma, Pinus edulis, and Quercus turbinella. Functioning of arid ecosystems of the Southwest undergoes seasonal, annual and multidecadal fluctuations which link to corresponding dynamics of available moisture. Results of the 1997–2004 study show a gradual decrease in mast production of all three species at all six sites, due to a continuing drought in this period. Mast production in a given year is determined to a considerable extent by available moisture during the entire growth year, from the previous spring to the current summer. The areas of oak–pinyon–juniper woodlands with higher elevation and highest precipitation generally have the highest yield of juniper berries, pinyon nuts and acorns. The severe drought of 2001–2003 has been accompanied by a mass dying of mature pinyon pines and loss of foliage in junipers. According to our observations, there is no correlation between mast production and amount of precipitation in the current year''s monsoon period (June–September). A high correlation between acorn production and non-monsoonal precipitation (October–May) was established, but no such correlation was found for juniper berries and pinyon nuts. Weather conditions (wind, temperature, and moisture) of late May are a critical factor determining the success of fertilization and subsequent mast production in all three species. [Copyright &y& Elsevier]

Abstract: Results integrated from several data sources such as the vertical distribution characteristics of dust aerosols detected by aircraft, optical particle counter and Lidar measurements in the troposphere, dust devils, dry heat convection, and cloud parameter characteristics monitored by satellites, allow the identification of a new upwards dust transport mechanism. During non-dust storm periods, fine dust particles can be firstly carried into the atmosphere about 10–200m by dust devils. Next, they can be carried to the height of the boundary layer at about 1000–6000m by strong dry heat convection, so that a well-mixed dust layer dominates, which may even develop an elevated dust layer over the desert in the warm and sunny season. These processes lead to high dust aerosol concentrations in the desert troposphere, which results in an increase of condensation nuclei in clouds, a decrease of the effective radius of cloud droplets, and thus the formation of precipitation is suppressed. This paper develops a mechanism of positive feedback, which follows the following sequence: dust aerosol increases—effective radius of cloud droplet decreases—precipitation decreases—arid climate is strengthened. This new mechanism is a distinct factor in the development of an arid climate, especially desert in North China, and gradually becomes one of the most important factors maintaining an arid climate in North China. The positive feedback can accelerate desertification in this area. [Copyright &y& Elsevier]

Abstract: Over the last decade, remote-sensing products found their use in numerous public applications and scientific research. Frequent validation of remote-sensing products is necessary to ensure the quality and accuracy. An important step in this process is the upscaling from field measurements of leaf area index (LAI) or other biogeophysical variables to the scale of a high-resolution satellite image. Unlike other vegetation types, semi-arid woodlands are often characterized by a distinct vegetation pattern, a low vegetation cover and site variations in bare soil reflectance which influence the upscaling process. This paper focuses on the upscaling of LAI field measurements of a semi-arid woodland in northwest China and the uncertainties associated with it. The LAI measurements were scaled up using two different approaches. The first upscaling method uses an ordinary average of the LAI measurements. The alternative method uses an area-based weighted average. The vegetation characteristics showed abundant small vegetation patches which were not accurately reflected in the systematic LAI field measurements. Therefore, the alternative method which reflected the vegetation structure more accurately needs to be considered. We conclude that an area-weighted average based on the fractional green vegetation cover is to be preferred over a simple average. If possible destructive sampling of the LAI is be preferred over indirect LAI measurements to reduce the errors associated with vegetation clumping and the presence of abundant non-green biomass. [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]

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: This paper provides results of an application of a holistic systematic approach of water accounting using remote sensing and GIS coupled with groundwater modeling to evaluate water saving options by tracking non-beneficial evaporation in the Liuyuankou Irrigation System (LIS) of China. Groundwater rise is a major issue in the LIS, where groundwater levels have risen alarmingly close to the ground surface (within 1m) near the Yellow River. The lumped water balance analysis showed high fallow evaporation losses and which need to be reduced for improving water productivity. The seasonal actual evapotranspiration (ETs) was estimated by applying the SEBAL algorithm for 18 NOAA AVHRR-12 images over the year of 1990–1991 (April 1990–March 1991). This analysis was aided by the unsupervised land use classification applied to three Landsat 5 TM images of the study area. SEBAL results confirmed that a fair amount (116.7MCM) of water can be saved by reducing evaporation from fallow land which will result in improved water productivity at the irrigation system. The water accounting indicator (for the analysis period) shows that the process fraction per unit of depleted water (PFdepleted) is 0.52 for LIS, meaning that 52% of the depleted water is consumed by agricultural crops and 48% is lost through non-process depletion. Finally, the groundwater modeling was applied to simulate three land use and water management interventions to assess their effectiveness for both water savings and impact on the groundwater in LIS. MODFLOW''s Zone Budget code calculates the groundwater budget of user-specified subregions, the exchange of flows between subregions and also calculates a volumetric water budget for the entire model at the end of each time step. The simulation results showed that fallow evaporation could be reduced between 14.2% (25.51MCM) and 45.3% (81.36MCM) by interventions such as canal lining and groundwater pumping. The reduction in non-beneficial ETs volumes would mean that more water would be available for other uses and it would allow the introduction of more surface water supplies in the area through improved water management strategies. This will ultimately lead to improved water productivity of the LIS system. [Copyright &y& Elsevier]

Abstract: Vegetation coverage and surface temperature are important parameters in describing the characteristics of land cover, which in combination can provide information on vegetation and soil moisture conditions at the surface. This paper aims to estimate spatial and temporal patterns of soil moisture in the Loess Plateau, China. Using Terra/MODIS images for each 10-day period in 2004 covering the semi-arid North Shaanxi Loess Plateau, a simplified land surface dryness index (Temperature–Vegetation Dryness Index, TVDI) developed by Sandholt [Sandholt, I., Rasmussena, K, Andersenb, J., 2002. A simple interpretation of the surface temperature/vegetation index space for assessment of surface moisture status. Remote Sensing of Environment 79, 213–224.] was used to determine the relationship between surface temperature and vegetation index. From the analysis, it can be inferred that the trend in seasonal change of TVDI is high values in the dry season (spring or summer) and low values in the rainy season (autumn or winter). Moreover, the land surface moisture of each watershed had its seasonal characteristics. The relationship between TVDI and land cover types indicated that water-retention in forest and shrub areas was better than cropland and rangeland in relatively wet conditions, and rangeland was better than forest and shrub areas in dry conditions. [Copyright &y& Elsevier]

Abstract: Vegetation restoration is one of the most common methods for combating desertification in northern China. The planting of shrubs on the southeast fringe of the Tengger Desert had significant effects on hydrological cycles, especially on the evaporation process. In this paper, a field experiment was conducted to investigate the effect of revegetation on evaporation process in a desert. The presence of shrubs reduced percolation from a lysimeter to zero. Caragana korshinskii Kom. showed greater evapotranspiration in the wetter of two study years, while Artemisia ordosica Krash. showed more evapotranspiration in the drier year. This was attributed to their different root distributions. The microlysimeter measurements showed that there was no significant difference in the evaporation rates between locations in the same quadrat, which means that the sparse vegetation had little effect on soil evaporation under the canopy, and thus modification of the microclimate was not a dominant factor in controlling soil evaporation in the revegetated desert area. The difference in soil evaporation between bare sand and the revegetated area was caused mainly by the formation of biological soil crusts. Simulated rainfall experiments showed that the crust had a retarding effect on evaporation under very low rainfall (⩽5mm), because its high proportion of finer particles slowed the evaporation rate, thus keeping the water in the soil surface longer. However, it allowed a higher evaporation rate under higher rainfall conditions. [Copyright &y& Elsevier]