This study seeks a routine to quantify spatial pattern of land cover changes in semiarid environment of China based on post-classification comparison method. The method consists of three major steps: (1) the image classification and unification of classified results based on two-level land cover classification themes, (2) the establishment of land cover change classes based on an unification land cover classification theme, (3) the reclassification and mapping of land cover change classes with three overall classes including no-change, gain and loss based on the unification land cover class. This method was applied to detect the spatial pattern of land cover changes in Yinchuan Plain, one of famous irrigation agricultural zones of the Yellow River, China. The results showed the land cover had undergone a remarkable change from 1991 to 2002 in the study area (the changed area was over 30%). Rapid increase of cropland (12.5%), built-up area (131.4%) and rapid decrease of bare ground (51.7%) were alarming. The spatial pattern of land cover changes showed clear regional difference in the study area and was clearly related to human activities or natural factors. Thus, it obtained a better understanding of the human impact on the fragile ecosystem of China’s semiarid environment.

The grain size composition, distribution characteristics and spatial variation of eolian sand soil on distinct positions across two longitudinal dunes and interdune areas were studied by means of conventional grain size analysis and geostatistical methods. In the study, 184 samples of eolian sand soil from the 0-30cm layer were systemically collected and measured from two longitudinal dunes and interdunes in the southern Gurbantunggut Desert. The results show that the dominant grain sizes are fine and very fine sands, and the differences of grain size compositions between the distinct geomorphologic positions are significant. The contents of clay and silt are highest on the interdune areas and lowest on the crests, and higher on the leeward slopes than on the windward slopes. The contents of very fine and fine sands are highest on the windward slopes and lowest on the crests. The contents of medium, coarse and very coarse sands are lowest on the interdune lands, and highest on the crests, and are identical on the two slopes. The coarser sizes (φ1) and mean sizes (Mz) for eolian sand soil all have a varying tendency from fine to coarse sizes with interdune area → leeward slope → windward slope → crest, and the sorting (σ) are poorly to well sorted. The results of geostatistical analysis reveal that φ1, Mz and σ values are moderately to strongly spatially autocorrelated. The values of the spatially correlated ranges are φ1＜σ＜Mz. The spatial variation for these grain size parameters is significant across the longitudinal dune landscape. From the crests towards the bottom of the slope, there is a varying gradient of zonal distribution, and the gradient values on the leeward slopes are larger than sites on the windward slopes.

The biodiversity－productivity relationship is an important topic in the research of biodiversity and ecosystem function. The plant diversity－productivity pattern is commonly unimodal and positively correlated. This paper researches the characteristics of plant diversity-productivity patterns in the Bayanbuluk alpine steppe in the central Tianshan Mountains, Xinjiang, China, and analyzes the effects of environmental factors on the distribution of plant communities, species composition, plant diversity and productivity in the steppe. The results show a positive correlation between plant diversity and productivity. DCCA (detrended canonical correspondence analysis) ordination reveals a significant relationship between the effects of air temperature, soil moisture content, available soil nitrogen, relative humidity and pH value on the distribution and composition of plant communities. There are significant correlations between the soil moisture content, relative humidity, pH value, air temperature and species richness and the aboveground biomass of Gramineae and Cyperaceae, and also significant correlations between the relative humidity, pH values and the total aboveground biomass of plant communities.

The distribution and migration of houbara bustard in China was studied by range investigation and tracking through PTT satellite transmitter from 1997 to 2004. The houbara bustard occurs in the Junggar Basin, north part of Tacheng Basin and valley of Ulungur river in northern Xinjiang, southern part of Turpan Basin and Barkol in eastern Xinjiang. In Inner Mongolia, the houbara bustard occurs in Urathouqi, Alxahouqi and Ejinaqi. In Gansu province, the houbara bustard occurs in Wuwei, Minqin and Shandan. The whole range is not contiguous area. Houbara bastard started migration from Junggar Basin in northern Xinjiang, Turpan Basin and Barkol in eastern Xinjiang, Wuwei in western Gansu Province and Bayan Nur in western Inner Mongolia in the middle of September. Flying to the west and northwest, via Junggar Basin and area between Bole and Habahe in northern Xinjiang, entered Kazakhstan, they turned toward southwest, passed Uzbekistan and Turkmenistan, arrived in Arabia Bay of southern Iran or flied over Afghanistan, arrived in southern Pakistan for wintering. The whole migration usually took 35 ± 13 days covering a distance of 4 800-7 000 km. In the next year, houbara went back to the breeding grounds in China through the same routes at the beginning of March. However, it took the birds 64 ± 17 days to finish the spring migration. They arrived in breeding site between middle of April and late May. The sub-adults arrived later and did not breed.

In order to study convergence zones or discontinuous lines formed locally in the Taklimakan Desert, we analyzed available MODIS images onboad TERRA or AQUA satellite for ten cases: 29 March 2002, 14 April 2002; 2 January 2003; 21 April 2003; 26 March 2004; 28 April 2004; 30 January 2005; 25 June 2005; 3 December 2005; and 26 July 2006. We used weather maps published by the Japan Meteorological Agency for the Asia and Pacific region at 500 hPa, 700 hPa and 850 hPa, at 00Z and 12Z to analyze the meteorological conditions occurring in each case. We estimated the positions of air streams, convergence zones or discontinuous lines between them, and thermal conditions on the maps and confirmed the presence of cumulus and cumulonimbus clouds through satellite images in particular. After a review of previous studies, this paper introduced the results of the present study. Closed warm areas in the Taklimakan Desert and on the Tibetan Plateau and local convergence zones or discontinuous lines in the Taklimakan Desert were discussed together with their diurnal changes, using composite maps of the ten cases. Along the long axis of the desert the convergence zones or discontinuous lines normally extend 70–80 km in a west-east direction, but are suspected to exceed 100 km in extreme cases. On the other hand, the convergence zones or discontinuous lines extending in a north-south direction on the southern fringe of the desert have a length of 40–60 km. The closed warm areas show clear diurnal changes, but they were not detected at the 500 hPa level. An example of a clear convergence zone running in a north-south direction on 26 July 2006 was presented in detail with corresponding satellite images.

We analyzed the 1961–2006 mean surface air temperature data of 138 stations in China’s northwest arid and semi-arid areas (CNASA), to measure climate change in terms of annual mean air temperature changes. We used methods of linear regression analysis, multinomial fitting, Empirical Orthogonal Function (EOF), Rotated Empirical Orthogonal Function (REOF), Mann-Kendall, Glide T-examination, wavelet analysis and power spectrum analysis. The results show that (1) the warming rate of the annual mean air temperature in CNASA was 0.35oC/10a during the 1961–2006 study period. Some places in the west part of Xinjiang and east part of the Qinghai plateau, which is impacted by the terrain of leeward slope, exhibit smaller increasing trends. However, the majority of region has shown distinct warming in line with general global warming; (2) The standard deviation of the annual mean temperature distribution is non-uniform. The south Xinjiang and east Qinghai–south Gansu areas show relatively small standard deviations, but the inter-annual variation in annual mean air temperature in the greater part of the region is high; (3) Inner Mongolia, Shaanxi, Gansu, Ningxia and Tarim Basin are the areas where the temperature changes are most sensitive to the environment. The degree of uniformity in annual mean air temperature increase is higher in the arid and semi-arid area. From the early 1970s, the trend in temperature changed from a decrease to an increase, and there was a marked increase in mean temperature in 1986. After that mean temperature went through a period of rapid increase. The entire area’s 10 hottest years all occurred in or since the 1990s, and 90% of various sub-districts’ hottest years also occurred after 1990. The process of temperature change appears to have a roughly 5-year and a 10-year cycle; (4) Annual mean air temperature variation has regional differences. In Inner Mongolia–Xinjiang and Shaanxi– Gansu–Ningxia–Qinghai areas, the temperature variation in their northern areas was very different from that in their southern areas; (5) Using the REOF method we divided the region into 4 sub-regions: the Northern region, the Plateau region, the Southern Xinjiang region and the Eastern region. The region’s annual mean air temperature transition has regional differences. The Plateau and Southern Xinjiang regions got warmer steadily without any obvious acceleration in the rate of warming. The Northern region’s warming started about 5-years earlier than that of the low latitude Eastern region. The ‘Startup region’ of the Qinghai-Tibet Plateau, appears to undergo temperature changes 3 to 10 years earlier than the other regions, and exhibits inter-decadal variations 1 to 2 years ahead of the other regions.

Hydraulic resistance components and water relations were studied on Haloxyolon ammodendron, a small xeric tree, growing at sites significantly differed in soil texture. Soil water content, leaf water potential (ψl), xylem water potential (ψx), root water potential (ψroot), leaf transpiration rate (TR) and stomatal conductance (gs) were measured at the two sites during the growing season of 2005 and 2006. Leaf specific hydraulic resistance (Rplant) during the whole growing season, hydraulic resistance of plants (Rp), shoots (Rshoot) and roots (Rroot) in the August of both years were calculated and expressed on leaf area basis. The results showed the proportion of the hydraulic resistance of the aerial part (Rshoot) to the Rp was the same to the proportion of the hydraulic resistance of the soil part (Rroot) to the Rp, indicating that both parts were equivalent important to plant water hydraulic system from soil to leaf. Positive significant correlations were found between Rp and Rroot, suggesting that root hydraulics resistance was a major determinant of plant hydraulic resistance (Rp) and transpiration rate. The integrated effect of stomatal control, hydraulic regulation and morphology adjustment enabled plants at heavy soil site surviving the extreme water deficit period.

The study of soil microbial populations and diversity is an important way to understanding the soil energy process. In this study we analyzed the characteristics of soil microbial populations of the Tarim Desert Highway shelter-forest, by identifying microbial fatty acids and using methods of conventional cultivation. The results illustrated that the amount of soil microbial activity and the diversity of soil microbial fatty acid increased significantly with the plantation age of the shelter-forest; the soil microbial population was dominated by bacteria. The fatty acids of C14:0, C15:0, C16:0, C17:0, C18:1ω9, C18:0, C18:2ω6 and C21:0 were found to be dominant soil microbial fatty acids in the shelter-forest soil. Principal analysis and regression analysis showed that (1) concentrations of fatty acids of C14:0, C16:0 and C18:0 could be used as indicators of total soil microbial population; (2) soil bacteria and actinomycetes populations were closely correlated with the amount of fatty acids of C15:0 and C17:0; and (3) soil fungi were closely correlated with the amount of fatty acids of C18:1ω9 and C18:2ω6.

Based on a database of more than 40 years of second production process and energy flow records for Maduo, Qumalai and Yushu counties, a dynamic model of the stress within grassland ecosystems was established using a nonlinear regression method for this source regions of the Yangtze and Yellow Rivers. The results show that dynamic curves of stress within grassland ecosystems in the three counties were in the shape of an inverted “U” during the period 1965–2007. It also revealed that the variation in actual amount of livestock inventories reflected the general trends of the stress within the grassland ecosystems in the source regions, although there were many other factors for the increase or reduction in grassland ecosystem stress.

The middle and lower reaches of the Tarim River are currently one of the main regions of ecological restoration in the arid areas of western China. Using the principles and method of landscape ecology, this study has chosen the fluvial corridor landscape in the middle and lower reaches of the Tarim River, and discusses the region’s ecologically functional regionalization system and issues related to its practical classification. On this basis the corresponding regionalizing principles and standards were developed which were used to qualitatively divide the three main landscapes as the ecologically functional areas in the drainage basin. The paper has also analyzed the characteristic of the study areas, and has put forward the measures for its ecological restoration.

The organic carbon and humus content in oil polluted brown and grey-brown soils in Mangyshlak, Pre-Caspian Sea Region, was analyzed from 2000 to 2008. The results indicated that bitumen substances from crude oil pollution deteriorated the soil property, however, the organic carbon content increased significantly. The products of oil pollution changed the composition of carbonaceous substances which formed soil humus, and changed the ratios of the humus components. Residual insoluble carbon increased with the rise of oil organic carbon. The mobility of humus components was significantly increased because of the high oxidation-reduction process in the topsoil, and the humus content and microorganism activity increased. The organic carbon content increased significantly, while it decreased with the distance away from the oil well. The rearrangement of physical, physical-chemical and chemical properties of the polluted soils was significant.

As an example of atmospheric nitrogen (N) deposition, the paper summarizes the definition, form and amount of nutrient from the environment (NFE) and the relationship between NFE and anthropogenic reactive N emission. Based on our own study and published articles, we find that N wet and dry deposition has been an important nutrient resource in agricultural and natural ecosystems in China. The total amount of N deposition and other environment-derived N in China was up to 18 Tg N/a, equal to approximately 60% of the national N fertilizer consumption. Nitrogen deposition is expected to contribute substantially to nutrient cycling and net primary productivity in various ecosystems. Therefore, it is crucial to utilize this environment-derived nutrient resource by integrated nutrient resource management in order to realize the sustainable development of both agricultural and non-agricultural ecosystems.

In many arid and semiarid regions, saline playas represent a significant source of unconsolidated sediments available for aeolian transport, and severe saline dust storms occur frequently due to human disturbance. In this study, saline dust storms are reviewed systematically from the aspects of concept, general characteristics, conditions of occurrence, distribution and ecological impact. Our researches showed that saline dust storms are a kind of chemical dust storm originating in dry lake beds in arid and semiarid regions; large areas of unconsolidated saline playa sediments and frequent strong winds are the basic factors to saline dust storm occurrence; there are differentiation characteristics in deposition flux and chemical composition with wind-blown distance during saline dust storm diffusion; and saline dust storm diffusion to some extent increases glacier melt and results in soil salinization in arid regions. An understanding of saline dust storms is important to guide disaster prevention and ecological rehabilitation.

The Relict Gull (Larus relictus) is recognized as a vulnerable species, with a worldwide population of about 6,000 individuals. Always inhabiting the extreme arid regions of Central Asia, their migratory routes and winter grounds are unclear. This research focused on distribution sites, habitat, behavior, population size and seasonal changes of Relict Gull. Line transects and point counts in every month were used to investigate the gulls around the Ebinur Lake. The result showed Relict Gull was summer visitor to Xinjiang, Western China. Population curve with a single peak was obtained. This gull appeared in early April and was 63 individuals (1% of the global population). The number remained stable from May to July in 2009. The discovery of fledglings indicates that Relict Gull may breed here. They left Ebinur Lake in August. Relict Gull in Ebinur Lake should belong to the Central Asian subpopulation, which was the most westerly record in China.

Land use change (LUC) in trans-boundary watersheds is of great importance to environmental assessment. The Aksu River is the largest trans-boundary river crossing Kyrgyzstan and China, but there was little information on the LUC of the watershed. We quantitatively investigated the processes and trends of its LUC by using analytic models based on the land use data derived from the remote sensing images and topographic maps. The LUC was in the quasi-balanced status with a slight difference between the loss and the gain of the area for most land use types during the period of 1960-1990, whereas transferred to the unbalanced status with significant difference between the loss and gain of the area during the period of 1990-2008. At the same time, land conversion direction changed from two-way transition to one-way transition for the most land use types. The integrated rate of net change of land use during the period of 1990-2008 is 2.1 times of that during the period of 1960-1990. Information on the processes and trends of LUC is valuable for better understanding the environmental changes across the whole trans-boundary watershed, and helpful to decision-making management for Kyrgyzstan and China.

Owing to global climatic changes and human activities, the lakes have changed dramatically in the Junggar Basin of Xinjiang in recent 50 years. Based on the remote sensing images from Beijing Satellite No.1 in 2006 together with the measured topographical data in 1999 and other data since the 1950s, this paper analyzes mainly the features of landforms around the Manas Lake and the changes of feeding sources of the lake. The results are as follows: (1) Tectonic movement brought about the fundamental geomorphological basis for lacustrine evolution, and the Manas Lake is one of small lakes broken up from the Old Manas Lake due to tectonic movement and drought climate; the Manas Lake had existed before the Manas River flowed into it in 1915. The geomorphologic evidences for evolution of the Manas Lake include: (a) Diluvial fans and old channels at the north of the lake indicate that the rivers originating from the north mountains of the Junggar Basin had fed the Old Manas Lake and now still feed the lake as seasonal rivers; (b) The Old Manas Lake was fed by many rivers originating from the mountains, except for the Manas River, from the evidence of small lakes around the Manas Lake, old channels, alluvial fans, etc.; (c) The elevations of the alluvial and diluvial fans are near to the 280 m a.s.l. and all of the small lakes and lacustrine plains are within the range of the 280 m a.s.l., which may prove that the elevation of the Old Manas Lake was about 280 m a.s.l.; (d) Core analysis of the Manas Lake area also indicates that the Manas Lake has existed since Late Pleistocene epoch. (2) Analysis on the feeding relations between the lakes and the lacustrine evolution shows that human activities are one of main driving forces of the lacustrine evolution in recent 50 years, and it is the precondition of restoring and maintaining the lacutrine wetlands in the study area to satisfy the feeding of the Baiyang and Manas rivers to the Manas Lake.

In order to investigate the spatio-temporal variability of soil water content to rainfall under Caragana microphylla shrub in Horqin Sandy Land, a plot of 25 m × 25 m, where there were 6 shrub canopies of C. microphylla, was sited for measuring soil water content at two soil layers of 0-20 cm (top layer) and 20-40 cm (lower layer). Soil water content was measured on the 1st, 5th, 10th and 15th day after a 42 mm rainfall in Naiman of Inner Mongolia. The results showed that soil water contents at both layers under C. microphylla shrub were gradually decreased after the rain. Soil water content at the top layer outside the shrub canopy was higher than that inside the shrub canopy within 5 days, and became similar inside and outside the shrub canopy on the 10th day after the 42 mm rainfall, and it was lower outside than that inside the shrub canopy on the 15th day. The soil water content at lower layer in the area without shrubs was higher than that under shrub canopy all along. All the measured values of soil water content can be fitted to a variogram model. There was significant autocorrelation of the values of soil water content between top layer and lower layer, except for the fourth measured values of soil water content at top layer. The range and spatial dependence of soil water content at top layer were lower than that at lower layer.

As one of the most important biological factors that maintain the stability of the largest fixed and semi-fixed desert in China, the Gurbantunggut Desert, the biological soil crusts (BSCs) develop well and play critical ecological roles in the desert ecosystem. In this paper, we briefly summarize our research findings since 2002 including species composition, distribution pattern and ecological functions of BSCs in the desert. Our results indicate abundant species diversity of BSCs in the Gurbantunggut Desert in comparison to other deserts in China. At the scales of sand dune or whole desert, the distribution patterns of BSCs are location-specific. The existence of BSCs in this desert could: (1) accelerate the formation of desert soil and the weathering of minerals; (2) accumulate organic matter in surface soil through related species in soil crusts; (3) enhance the abilities of sand surface to resist wind erosion; (4) influence seed germination of vascular plants; and (5) enhance the production of dew deposition on sandy soil surface.

Na+ ions play an important role in the growth of halophyte. The effect of Na+ ions on nitrate uptake and osmotic adjustment in the euhalophyte Suaeda physophora was investigated under glasshouse conditions. Seedlings were exposed to 1 mmol/L NaCl (control), 300 mmol/L NaCl, 150 mmol/L NaCl plus 150 mmol/L KCl or 300 mmol/L KCl treatments for 24 d. Dry weight was not affected greatly by different salt treatments, but water content and succulence in leaves of S. physophora were significantly increased at 300 mmol/L NaCl and 150 mmol/L NaCl plus 150 mmol/L KCl treatments. The concentrations of Na+ and NO3- in leaves of S. physophora were the highest at 150 mmol/L NaCl plus 150 mmol/L KCl, but lowest at 300 mmol/L KCl treatment. Moreover, the increase of NO3- concentration did not result in the decrease of Cl- concentration at 150 mmol/L NaCl plus 150 mmol/L KCl treatments. The estimated contribution of NO3- to osmotic potential (CNO3) in leaves of S. physophora was 9.8% at 150 mmol/L NaCl plus 150 mmol/L KCl, and CNa and CCl were 31.0% and 23.3%, respectively. However, CNO3, CNa and CCl were respectively 1.6%, 7.9% and 11.9% at 300 mmol/L KCl treatment. It is concluded that Na+ stimulates NO3- absorption and the stimulation is independent on the internal or the external Cl- concentration in the euhalophyte S. physophora. These characteristics may explain the high levels of N in leaves of saline desert plants in arid ecosystem.

Kanas is a National Nature Reserve and National 5A Scenic Area, and it is also high on China’s National Natural Heritage List. In this paper, with an integrated analysis and comparative geographical approach, the genesis and current features of the Kanas landscape are analyzed systematically according to the criteria for outstanding universal values that must be met for designation by the United Nations as World Natural Heritage. It is concluded that Kanas has outstanding universal values in geosciences, biology and aesthetics. Through comparison with other World Natural Heritage sites of the same geological types, in the same biogeographic zone and in the same latitude, it is concluded that Kanas meets criteria vii, viii, ix and x for designation as World Natural Heritage. Thus, this work establishes a scientific foundation for nomination of Kanas for such a status.

Taking Gansu province as a model case, this study provides an integrated analysis on the eco-economic system of arid and semi-arid region based on emergy synthesis theory. Through calculating the values of renewable emergy flow, non-renewable resources, imported emergy, exported emergy, waste emergy, and total emergy during the period of 1978-2007, the performance of Gansu eco-economic system was analyzed. The results indicated that the renewable emergy flow within the province basically remained steady state which was estimated at 2.99×1022 solar emjoules (sej) from 1978 to 2007. The imported emergy and exported emergy were estimated at 3.75×1017 sej and 2.99×1020 sej in 1978 and increased to 1.07×1022 sej and 1.44×1022 sej respectively in 2007. The nonrenewable emergy flow was estimated at 1.62×1022 sej and increased to 1.85×1023 sej, with annual growth rate of 8.7%, while the estimated total emergy was 4.58×1022 sej in 1978 and increased to 2.11×1023 sej in 2007, with annual growth rate of 5.41%. Our results indicate a deteriorate situation between economic development and environmental protection in the region. The rapid economic growth in the past thirty years was based on a great consumption of nonrenewable resource and caused continuous decrease in the capacity of sustainable development. The environmental loading ratio was 0.53 in 1978, increased to 6.06 in 2007, indicating a rapid degradation of the regional environment quality. We calculated that the actual population was 1.53 times the renewable resource population in 1978, increased to 7.06 times in 2007. During the period of 1978-2007, the emergy rose from 2.45×1015 sej/(capita·a) to 8.07×1015 sej/(capita·a). Our analysis revealed that the emergy density presented a trend of gradual increase, and then the emergy currency ratio in Gansu decreased from 7.08×1013 sej/Chinese Yuan to 7.82×1012 sej/Chinese Yuan.

In this paper, the oasis cities in Kashgar Prefecture and Kizilsu Kirgiz Autonomous Prefecture are taken as an example, through the factor analysis, spatial attraction interaction model and location quotient methods, urban hierarchy system, the intensity of urban economic ties, economic subordination degree, and structure of city functions were analyzed. The results indicated: (1) The urban hierarchy system takes Kashgar city as the main center, Artux city, Yarkant county and Maralbexi county as the sub-centers; (2) The intensity of economic ties among Kashgar city and each county is much higher than others. The interaction of Kashgar city, Shufu county and Shule county are the strongest, and the economic ties of Yarkant, Kagilik, Poskam counties are relatively close; All cities in the study area are economically subordinate to Kashgar city. (3) Three cities of Kashgar city, Shufu county and Shule county should connect strongly, with Kashgar city as the core. The cities and towns along the Southern Xinjiang Railway and along National Road 315 should be regarded as two strips, and the two city strips along the border, and the city strip along Provincial Road 215 should be treated as three axes. The ring structure strategy of “core ring, closer ring and radiated ring” was proposed. (4) It was proposed to build Kashgar city group in the north, and Yarkant city group in the south, Maralbexi city group in the southeast, and Taxkorgan border city group with four inner groups’ development strategy.

Altai (also named Altay in China) Mountain Country (Mountain System) is a unique natural region, located on the border between different floristic regimes of the Boreal and ancient Mediterranean sub-kingdoms, where distribution of plant species is actually limited. It is known to have sufficient endemic floral biodiversity in the Northern Asia. Many plants of Altai Mountain System need effective care and proper conservation measures for their survival and longer-term protection. Important Plant Area identified as the IUCN (the International Union for Conservation of Nature), specified criteria attract global attention for protection of floral biodiversity across the world. The records of 71 plant species from the Chinese Altai Mountains attributed to the criterion A and the dark conifer forests of Chinese Altai Mountains satisfied the criterion C, which may help qualify to fulfill the national obligation of the Convention on Biological Diversity.

By examination of Calligonum pumilum A. Los. and Calligonum ruoqiangense Liou f., collected from natural habitats, and the analysis of their variance, this paper revealed that the morphological characters of these specimens are quite different from each other, especially in the twist direction of ribs on fruits, rows of bristles along each rib, rigidity, interweaving degree of bristles, and their geographical distribution. Therefore, it is suggested that C. pumilum and C. ruoqiangense should be considered as two independent species.

The paper analyzes the hypothesis that the distribution of dominant plant species and characteristics of plant communities are related to groundwater depth. The results showed that variations of groundwater depth impacted distributions and characteristics of dominant plant communities. However, besides groundwater depth, the community composition and species diversity were also influenced by physiognomy of the habitat. Based on the similarity coefficient, the differences between dominant plant communities were significant at different groundwater depths. Compared with other results relating to desert vegetation and groundwater depth, variations of community distribution were similar at the large spatial scale. However, in this extremely arid region, there were significant differences in community type and community succession when compared with other arid regions, especially in relationship to deep groundwater depth. With groundwater depth from deep to shallow, communities transformed with the sequence of Alhagi communities, Tamarix spp. communities, Populus communities, Phragmites communities, and Sophora communities. At groundwater depth of less than 6.0 m, the community type and composition changed, and the species diversity increased. Among these dominant species, Tamarix exhibited the biggest efficiency in resource utilization according to niche breadth, which means it possessed the best adaptability to environmental conditions at the oasis margins.

Populus euphratica Oliv. is widely distributed along the Tarim River. Maintaining stability of P. euphratica population is important to local development. This study explored the static life table, survivorship curves and four function curves (survival rate, cumulative mortality rate, mortality density, and hazard rate), and development index of P. euphratica population in the middle reaches of Tarim River. The results indicated that the age structure of P. euphratica population belonged to positive pyramidal type, which meant young age-class individuals occupied most populations. The number ofⅠ-Ⅱage classes accounted for 66.2% of whole population, and this indicated that there were abundant subsequent seedlings resources to support the growth of P. euphratica population in the middle reaches of Tarim River. The survivorship curve of P. euphratica belonged to the Deevey Ⅲ (concave-type) and the development index was 47.72%. Four function curves revealed that the individuals of P. euphratica sharply decreased at the initial stage and then leveled off at the late stage of survival curve. Time sequence prediction models predicted that the number of midlife individuals would increase in future 10, 20, 30 years, and P. euphratica population grew steadily as a result of rich saplings.

Spatial heterogeneity is a ubiquitous feature in natural ecosystems, especially in arid regions. Different species and their discontinuous distribution, accompanied by varied topographic characteristics, result in soil resources distributed differently in different locations, and present significant spatial heterogeneity in desert ecosystems. In this study, conventional and geostatistical methods were used to identify the heterogeneity of soil chemical properties in two desert populations, Haloxylon persicum Bunge ex Boss., which dominates on the slopes and tops of sand dunes and Haloxylon ammodendron (C. A. Mey.) Bunge, which inhabits interdunes in the Gurbantunggut Desert of Xinjiang, China. The results showed that soil pH, electrical conductivity (EC), soil organic carbon (SOC), available nitrogen (AN) and available phosphorus (AP) were significantly higher in H. ammodendron populations than that in H. persicum. The coefficient of variation (CV) indicated that (1) most parameters presented a moderate degree of variability (10% < CV < 100%) except pH in both plots, (2) the variability of soil pH, EC and AP in H. ammodendron populations was higher than that in H. persicum populations, and (3) SOC and AN in H. ammodendron populations were lower than that in H. persicum populations. Geostatistical analysis revealed a strong spatial dependence (C0/(C0+C) < 25%) within the distance of ranges for all tested parameters in both plots. The Kriging-inter-polated figures showed that the soil spatial distribution was correlated with the vegetation distribution, individual size of plants, and the topographic features, especially with the plants nearest to sampling points and the topographic features. In each plot, soil EC, SOC, AN and AP presented similar distributions, and fertile islands and salt islands occurred in both plots but did not affect every individual plant, since the sampling distance was larger than the size of such fertile islands. The results of topographic effects on soil heterogeneity suggested significant differences between the interdunes and dune-tops. Different topographic characteristics (physical factors) between plots result in the differences in SOC, AN and AP, while the heterogeneity of soil pH and EC arise from plant species and their distribution (biotic factor). Such biotic and physical factors did not occur in isolation, but worked together on soil heterogeneity, and played important parts in improving the soil properties. Hence these factors were ecologically valuable in the highly resource-stressed arid study area.

The role of the leaves of Robinia pseudoacacia L., which is widely distributed in the arid lands, on improving soil physical and chemical properties was analyzed at various incubation periods. The incubated soils added with 0, 25, 50 and 75 g Robinia pseudoacacia leaves were tested after consecutive incubation intervals of 6, 8 and 10 months and the different soil parameters were measured. The results showed the increases in organic matter (OM), extractable K, cation exchange capacity (CEC), aggregate stability and water holding capacity, but the decreases in pH value and bulk density after 6 months' incubation. The gradual decrease in change rates of soil properties indicated less microbial population and organic residual mineralization under acidic conditions, which were resulted from fast decomposition of leaves after the first 6 months incubation. The increases in soil organic matter content, extractable K, CEC, aggregate stability and water holding capacity and the decreases in soil pH and bulk density provide favorable conditions for crop’s growth.

The dynamical processes of a typical linear dune including morphological features, dune ridge swing range and crest height were investigated at different monitoring periods in the hinterland of Tengger Desert. The results indicated that the development of linear dune depends on not only the northwesterly prevailing wind, but also the winds from northeast and southwest. The dune ridge swayed along its fundamental strike and took on an eastward movement gradually. The original dune strike was NW70° on August 3, 1994, and then changed to NE15° on April 21, 2001. The dune crest increased by 1.8 m longitudinally, which manifested strong wind-blown sand activities in this region. Wind erosion frequently occured at the bottom of sand dune, while sand accumulation appeared on its mid-upper section. The mean wind erosion depth was 25 cm on the bottom of linear dune and the height difference of the control points on the dune’s ridge was 1.13 m. Although the linear dune swayed laterally, the horizontal displacement of its ridge moved eastward 5.8 m averagely. The swing range of the dune crest line is very distinct, with a maximum value of 13.2 m. The highest site on the K-profile swayed on both sides of the dune ridge and the heights were 19.88 m at the control point K5, 19.61 m at K6 and 19.05 m at K7, respectively. The results indicated that the lateral swing of the linear dune was distinct under the northwesterly wind and it moved toward east gradually.

Xinjiang Uygur Autonomous Region of China, with its unique topography and geographical location receives very less precipitation in summer as compared with other parts of China. The region is a land locked where moisture is supplied only by westerly winds from Atlantic Ocean as the moisture coming from Indian Ocean is mostly blocked by the Himalayas Range and the Tibetan plateau. In such a scenario, Xinjiang faces severe drought conditions offering significant challenges to water management. In this paper, we analyzed the drought periods in Xinjiang and discussed the various factors that might have influenced precipitation over the past forty-four years. For this purpose, we defined three periods of consecutive four years for high and low precipitation intensities. The average observed precipitation was 1.05 mm/day and 0.7 mm/day in summer (June-July-August) for the Tianshan Mountain region and Junggar Basin of Xinjiang, respectively. The drought conditions indicated that high sea level pressure, wind divergence and low convection were the prominent features that caused the droughts, which often do not allow the condensation process to coagulate the tiny water droplets into relatively large raindrops reducing the amount of precipitation in the region. The period of 1983-1986 is the lowest precipitation interval indicating the severe drought in the western Xinjiang (i.e western Tianshan Mountain region), for which, less moisture availability, strong divergence and less convection could be the most influencing factors.

Based on the analysis of the correlation between the tree-ring width of Pinus tabulaeformis and the climate factors in the western Hedong sandy land of Ningxia, a conversion equation between the annual precipitation and the tree-ring width since 1899 was reconstructed. The results of cross verification indicated that the conversion equation is stable and the reconstructed results are reliable. The result of reconstructed annual precipitation showed the remarkable fluctuation of precipitation and dry-to-wet variation before the 1940s. The smaller fluctuation and high frequent changes of precipitation occurred during the period of 1940s-1980s and after the 1980s the change trend of the precipitation became high periodic extent and low frequent. The study found that there were some coincidences with the climate change in Changling Mountains, Helan Mountains and the east of Qilian Mountains. The relatively dry periods in the beginning of 20th century, 1920s to 1930s, the end of the 20th century and 2004 to 2006 in the western Hedong sandy land of Ningxia accelerated the desertification, while the relatively humid period during the periods of the 1910s-1920s, 1930s-1940s and 1990s is favorable to prevent and control the desertification, and to weaken the climate warming and drying. The periods of annual precipitation variation in the western Hedong sandy land of Ningxia since 1899 are approximately 2-4 years, 5-7 years and 10 years.

The causes of the disappearance of the ancient town of Loulan in Xinjiang, China have been generally agreed to derive from two factors: human activities and natural factors (environmental variations). In this paper, the Muzart Glacier was selected as an example, and found that the length of the glacier has been gradually decreasing and the snow line has been retreating to a higher altitude, both results contributing to a decrease in river flow below the Muzart Glacier. From the distribution of moraines in the Tianshan Mountains and adjacent areas in different periods, the paper speculates that there have been four minor glacial periods since the Quaternary. Although the durations and scales of the four minor glacial periods were different, they all indirectly influenced the formation and disappearance of the Lop Nur Lake. The events of the fourth minor glacial period are the important impact factors in the existence and disappearance of Loulan. Whether the disappearance of Loulan can be related to the events of the three previous minor glacial periods needs further investigation.

Based on the analyses of environmental proxy data in lake sediments and instrumental records of Xinjiang in northwest China, the Holocene climate and hydrological variability and its environmental responses were studied in different time scales and regions. The results showed that the Holocene climate variability had obvious differences between the north and south of Xinjiang. In northern Xinjiang, the Holocene climate was dry in the early period, humid in the middle period, and then changed to dry in the late period. However, the climate transition times were not consistent in different regions. In southern Xinjiang, although there were many different types of climate change patterns inferred from different catchments, the warm and wet climate was recorded in most lake sediments in the middle Holocene. According to comparisons of some millennium scale records in lake sediments, the climate was warm and dry in the past 100 years. It can be concluded the climate showed a trend of aridity in Holocene. Especially in recent 50 years, the lake area has been shrinking rapidly because of the population growth and social economic development, which brings some environmental problems. Lake level and area changes were sensitively affected by the climate variation in geological history of Xinjiang and the lake level will continue to shrink because of the drought climate and strengthened human activities.

The development and progress of soil wind erosion are influenced by the factors of climate, terrain, soil and vegetation, etc. This paper, taking Tazhong region, a town in the centre of the Taklimakan Desert, as an example and using comparative and quantitative methods, discussed the effects of climate, surface roughness (including vegetation cover) and surface soil properties on soil wind erosion. The results showed that the climate factor index C of annual wind erosion is 28.3, while the maximum of C is 13.9 in summer and it is only 0.7 in winter. The value of C has a very good exponential relationship with the wind speed. In Tazhong region, the surface roughness height is relatively small with a mean of 6.32 × 10-5 m, which is in favor of soil wind erosion. The wind erosion is further enhanced by its sandy soil types, soil particle size, lacking of vegetation and low soil moisture content. The present situation of soil wind erosion is the result of concurrent effects of climate, vegetation and surface soil properties.

This paper reports the characteristics of plant flora in the region of the northern slope of Karlik Mountain to Naomaohu basin, based on field investigation of the vegetation and referring to relevant literature. The results show that the flora of the study area mainly consists of communities of single species or a limited number of species, genera and families. The flora composition is marked by the phenomenon of dominant families and genera; the temperate element occupies a dominant position, while in terms of the genera the Tethys element is an important component. Areal-types of the species are dominated by the floral element of Asian Central-part with xerophytic characteristic, and the life-forms of plants are mainly perennial and herbaceous. These characteristics reflect that the compositions of the species in this region possess both ancient and young elements. Analysis of the relationship between the species composition, plant community diversity and altitude gradient, we found that the structure of the vegetation has an obvious vertical distribution. The lower and higher altitude areas, where the climate conditions are relative inclement, are mainly occupied by the plant communities with simple structure and single dominant population, while the species richness in the mid-altitude area increases with favorable temperature and precipitation. Consequently, the species diversity and evenness indices show single-peak distribution with increasing elevation (about < 2500 m), while the dominance indices decrease in elevation from 500 m to 2500 m and increase in elevation of > 2500 m.

In this paper the spatio-temporal variation of vegetation cover in northwest China during the period of 1982-2006 and its driving factors were analyzed using GIMMS/NDVI data. The annual average NDVI was increased with a rate of 0.0005/a in northwest China and there was an obvious difference between regions. The trend line slopes of NDVI were higher than 0.0005 in the Tianshan Moutains and Altay Mountains of Xinjiang, the Qilian Mountains of Gansu and the eastern part of Qinghai, which indicated the vegetation cover was significantly increased in these areas. The trend line slopes of NDVI were lower than -0.0005 in the southern region of Qinghai, the border regions of Shaanxi and Ningxia, the parts of Gansu and Tarim Basin, Turpan and Tuoli in Xinjiang, which indicated the vegetation cover was declined in these areas. The NDVI of woodland, grassland and cultivated land had an ascending tendency during the study period. The study shows that the vegetation cover change was caused by both natural factors and human activities in northwest China. The natural vegetation change, such as forests was influenced by climate change, while human activities were the main reason to the change of planting vegetation. The changes of vegetation covers for different elevations, slopes and slope aspects were quite different. When the elevation is exceeded to 4,000 m, the NDVI increasing trend was very low; the NDVI at the slope of less than 25° was increased by the ecological construction; the variation of NDVI on sunny slope was stronger than that on shady slope. The temperature rose significantly in recent 25 years in northwest China by an average rate of 0.67oC/10a, and precipitation increased by an average rate of 8.15 mm/10a after 1986. There was positive correlation between vegetation cover and temperature and annual precipitation changes. Rising temperature increased the evaporation and drought of soils, which is not conducive to plant growth, and the irrigation in agricultural areas reduced the correlation between agricultural vegetation NDVI and precipitation. The improvement of agricultural production level and the projects of ecological construction are very important causes for the NDVI increase in northwest China, and the ecological effect of large-scale ecological construction projects has appeared.

Eremosparton songoricum (Litv.) Vass is a dwarf clonal shrubby legume developed on the windward slopes of mobile or semi-fixed sand dunes of Central Asia. It is assumed that E. songoricum must possess a high degree of phenotypic plasticity for such a heterogeneous habitat. The variations of E. songoricum plants growing in two typical microhabitats (the upper slope and the lower slope of semi-mobile dune) were investigated. The morphological characteristics and the biomass allocation patterns were measured and compared at the clonal fragment level. Compared with the clonal fragment on the lower slope of dune, the clonal fragment on the upper slope of the dune (a) declined in total biomass and ramet height, (b) increased the length of rhizomes and the number of roots, (c) increased the degree of asymmetry, and (d) heightened allocation to the belowground biomass. Our results confirmed the hypothesis of high phenotypic adjustment capacity of E. songoricum to habitat moisture availability. Phenotypic plasticity of E. songoricum contributed to reduce the damage risk, led to an environmentally induced specialization in function of resources exploitation, resulted in its persistence in heterogeneous environments and was adaptive in sand dune environment.

The International Association of Hydrological Sciences (IAHS) recognized the lack of hydrological data as a world-wide problem in 2002 and adopted the Prediction of Ungauged Basins (PUB) as a decadal research agenda during the period of 2003 to 2012. One of the objectives is to further develop methodologies for prediction in ungauged basins and to reduce uncertainties in model prediction. Estimation of stream flows is required for flood control, water quality control, valley habitat assessment and water budget of a country. However, the majority of water catchments, streams and valleys are ungauged in most developing countries. The main objective of this paper is to introduce the IHACRES (Identification of Hydrographs and Components from Rainfall, Evaporation and Stream) model into African hydrological planning as a methodology for water resources assessment, which in turn can be used to resolve water conflicts between communities and countries and to study the climate change issues. This is because the IHACRES model is applied for the estimation of flows in ungauged catchments whose physical catchments descriptors (PCDs) can be determined by driving variables (i.e. rainfall and temperature); and also in gauged streams but whose gauging stations are no longer operational but historical data are available for model calibration. The model provides a valuable insight into the hydrologic behaviour of the upper water sources for valleys as well as provides a useful methodology for water resources assessment in situations of scarce financial resources in developing countries. In addition, it requires relatively few parameters in its calibration and has been successful applied in previous regionalization studies. It will also make possible the equitable distribution of water resources in international basins and rivers’ catchments. This paper does not apply the model anywhere, but recommends it as a methodology for water resources assessment in order to cure water conflicts on the African continent.

Based on a long-term field investigation and other research results, we reviewed the status and distribution of ungulates in Xinjiang, China. The ungulates in Xinjiang included 19 ungulate species (30 subspecies) from 6 families and 2 orders. Among them, 3 species (2 subspecies) relate to Equidae (Perrisodactyla), and 16 species (28 subspecies) are from 5 families of Artiodactyla. In this paper, we analyzed the conservation status of most rare and important 13 ungulate species. Firstly, we proposed the protection of genetic diversity of Camelus ferus and the distribution areas of Moschus sifanicus, Procapra przewalskii and Saiga tatarica in Xinjiang. We found that Moschus sifanicus but not Procapra przewalskii distributed in Xinjiang. It was not clear whether the remnant populations of Saiga tatarica existed in Xinjiang and China-Kazakhstan border or not. We discussed that the protection level and rational use of Capra sibirica and enhancing protection level and enlarging monitoring and research projects for Pantholops hodgsoni and Gazella subgutturosa. And we would like to suggest Forestry Department to develop the captive breeding of Tibetan antelope for rational use. In addition, the captive breeding of Cervus elaphus in Xinjiang was reviewed. Local government should lessen strong control to Cervus elaphus because of many breeding centers’ establishment.

Liquid manure storage may contribute to methane (CH4) emission and this emission can be greatly reduced if appropriate management practices are applied. Biofiltration has been used in other fields for mitigating greenhouse gas (GHG) emission (e.g., landfill) and shown promise for mitigation CH4 emission from liquid manure storage. It has been reported that biofilter was capable of reducing 80% of CH4 emissions from manure storage. The CH4 removal efficiency is influenced by many factors, including CH4 and O2 concentrations, temperature, moisture, composition of the filter bed, nutrient, and empty bed residency time (EBRT). Biological conversion of methane of a biofilter is a slow process due to the low water solubility of methane. The residence times (EBRT) between 5 min and 5 h have been used, whereas a typical EBRT of 25 s is used for common biofilter applications. Temperature at which methanotrophic bacteria are active ranges from 10oC to 45oC. The maximum activity is found at around 30oC. The optimal filter bed water content depends on both the gas flow rate and the type of filter bed (soil, compost, etc.) and ranges from 30%–70% of the water holding capacity. Compost is the best material for filter bed. The optimal pH for methanotrophic bacteria is neutral to slightly acidic. Copper and nitrogen compounds especially nitrate are important nutrients to methanotrophic bacteria but their optimal concentrations have not been founded. Phosphorus and other elements such as potassium and manganese are reported to affect the performance of methanotrophic bacteria but need further confirmation.