Key Laboratory of Oasis Ecology

Urunchi, China

Key Laboratory of Oasis Ecology

Urunchi, China
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Zhang F.,Xinjiang University | Zhang F.,Key Laboratory of Oasis Ecology | Xiong H.,Key Laboratory of Oasis Ecology | Xiong H.,Beijing Union University | And 4 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2017

The impact of human activities on the global carbon cycle is one of the main concerns in the global climate change research. However, the mechanisms of the carbon cycle for the different regions, natural and human factors are very complex and different. Exploring the impact of human reclamation activities on the distribution pattern of net primary productivity (NPP) in arid oasis ecosystem will help to increase the understanding of human activities on terrestrial ecosystems and carbon cycle impacts in arid regions. This study aimed to investigate the change of NPP during the process of new artificial oasis expansion in Xinjiang based on the remote sensing data. June was selected as the optimal time for extracting vegetation cover types change information. Based on the long-term Landsat remote sensing data, the Carnegie-Ames-Stanford Approach (CASA) model was used to estimate the change of NPP during the expansion of Xinjiang Qitai artificial oasis from June 1976 to June 2016. The results showed that: 1) In 1976, the study area mainly was dominated by desert steppe, and the farmland was only 5 150 hm2, accounting for 3.25% of the area. By 2016, the amount of farmland expanded to 64 675hm2, which increased by more than 11 times; 2) While the artificial oasis was expanding, spring overflow zone disappeared, the swampland and the reservoir dried up, which resulted in the decrease of shrub area from 17 871 hm2 to 5 202 hm2; 3) Reclamation resulted in a significant decline in groundwater level, soil salinity development process was interrupted, and bare alkaline area was reduced from 58 859 hm2 in 1976 to 17 803 hm2 in 2016, which was reduced by nearly 70% and began to succession to the new grassland; 4) In June 1976, the unit area NPP of farmland was 68.6 g/m2, and the unit area NPP of farmland in June 2007 and June 2016 was over 90 g/m2. In the recent 40 years, the unit area NPP of grassland was fluctuated within the range of 30-40 g/m2, which was relatively stable; 5) In June 1976, the total NPP in the study area was 41 018 t, of which the contribution rate of farmland was only 8.62%. In June 2016, the total NPP of the study area reached to 90 602 t, which was 2.2 times higher than that in June 1976. The contribution rate of farmland to total NPP was 65.23%. In the same period, the net loss of shrub and swamp NPP was 8 265 t and 3 319 t, respectively; 6) Human activities were the decisive factors that influenced the distribution pattern of NPP in the study area. And NPP in 1976 were mainly composed of natural grassland and shrub, accounting for 56.68% and 26.61% respectively, NPP in 2016 was mainly composed of farmland and fresh grassland, accounting for 65.23% and 31.85%, respectively. In 1976, 66.93% of the shrubs, 75.58% of the swamps, 41.43% of the grassland, 23.86 % of the bare alkali land and 77.96% of the water bodies were evolved into farmland in 2016. The 43.62% of the grassland in 1976 was still grassland after 40 years, but was divided into fragments by the newly reclaimed farmland. Only 15.01% of the bare alkaline area in 1976 remained in 2016, while the rest came from degradation of grasslands, shrubs and swamps. In the recent 40 years, the original natural oasis landscape in the study area had been completely changed, and large areas of farmlands connected to each other become modern agriculture oasis that was suitable for large-scale agricultural machinery operations. © 2017, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.

Zhu B.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Yu J.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Qin X.,CAS Institute of Geology and Geophysics | Rioual P.,CAS Institute of Geology and Geophysics | And 7 more authors.
Journal of Hydrology | Year: 2013

Rivers draining the sedimentary platform of northern Xinjiang (the center of Asian continent) are characterized by low discharge under a temperate and arid climate. The influence of rock mineralogy, climate, relief and human activity on natural water composition and export as a result of weathering is a major scientific concern both at the local and the global scale. While comprehensive work on the controlling mechanism of chemical weathering has been less carried out in the sedimentary platform of northern Xinjiang. Thus, the effects of climate and rock weathering on the inorganic hydrogeochemical processes are not well quantified at this climatic extreme. To remedy this lack a comprehensive survey has been carried out of the geochemistry of the large, pristine rivers in northern Xinjiang, the Erlqis, Yili, Wulungu, Jingou and numerous lesser streams which has not experienced the pervasive effects of glaciation and subsequent anthropogenic impacts. The scale of the terrain sampled, in terms of area, is comparable to that of the Huanghe and includes a diverse range of geologic and climatic environments. In this paper the chemical fluxes from the stable sedimentary basin of the northern Xinjiang platform will be presented and compared to published results from analogous terrains in the monsoon basins of China and world. Overall, the fluvial geochemistry of northern Xinjiang in westerly climate is similar to that of the Chinese rivers (Huanghe and Yangtze) in the East-Asian monsoon Climate, both in property-property relationships and concentration magnitudes. The range in the chemical signatures of the various tributaries is large; this reflects that lithology exerts the dominant influence in determining the weathering yield from the sedimentary terrains rather than the weathering environment. The effect of different rock weathering ranges from rivers dominated by aluminosilicate weathering, mainly of granites, sandstones and shales, to those bearing the signatures of dissolution of carbonates and evaporites and of continental playa deposits. Carbonates are the general predominant lithology undergoing dissolution particularly within the lesser arid areas. The pCO2 in the study rivers is out of equilibrium with respect to atmospheric pCO2, about up to ∼20 times supersaturated relative to the atmosphere but not to such an extent as the Amazon in the floodplain. A roughly positive relationship is observed between solute concentrations and the drought index (DI) for natural waters in the region, indicating a coupled mountain-basin climate has a direct effect. The relative contributions of end-member solute sources to the total dissolved cations from each watershed have been quantitatively estimated using dissolved load balance models, showing the results as evaporite dissolution>carbonate weathering>silicate weathering>atmospheric input for the whole catchment. The areal total dissolved fluxes range from 0.05 to 2.53×106mol/km2/yr, 0.02-2.09×106mol/km2/yr and 0.01-1.04×106mol/km2/yr in the Yili, Zhungarer and Erlqis, respectively, comparable to those of Chinese and Siberia rivers draining sedimentary platforms, even though they are in drastically different climatic regimes. In general, the fluxes from rivers in sedimentary basins are comparable to those from orogenic zones, but are much higher than in the shield regions. The CO2 consumption by aluminosilicate weathering (0.2-284×103mol/km2/yr) is much smaller than in active orogenic belts (19-1750×103mol/km2/yr in similar latitudes and 143-1000×103mol/km2/yr in the tropical basins), but comparable to those of the Chinese (7-106×103mol/km2/yr) and Siberia (16-112×103mol/km2/yr) rivers. © 2013 Elsevier B.V.

Zhu B.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Zhu B.,CAS Institute of Geology and Geophysics | Yang X.,CAS Institute of Geology and Geophysics | Rioual P.,CAS Institute of Geology and Geophysics | And 4 more authors.
Applied Geochemistry | Year: 2011

In the arid region of northern Xinjiang, one of the least-studied areas in China, three watersheds, namely those of the Yili, Zhungarer and Erlqis, have become the focus of attention due to rapidly increasing human population and water demands. The hydrogeochemistry of natural water from the three watersheds was investigated. The ionic chemistry of natural waters from these watersheds changes considerably on a regional scale. The waters are neutral to alkaline in nature and most of them are soft-fresh waters. The total dissolved solid (TDS) varies over two orders of magnitude with a mean value of 580. mg/L, about 1.2 times and 4.6 times those of the Huanghe (Yellow River) and the world spatial median, respectively, but only 40% and 0.8% of those of the Tarim and the western Alashan watersheds, respectively. Much of the solutes and physicochemical parameters in these waters are under the highest desirable limits of the World Health Organization (WHO) for drinking purpose and a plot of sodium adsorption ratio versus EC shows that most waters are of good water quality for irrigation. Water-rock interaction and saturation index (SI) for selected minerals are evaluated. The SI of these natural waters is out of equilibrium (undersaturated) with respect to major carbonates (calcite and dolomite) and evaporites (gypsum and halite). The high concentrations of alkali earth metals, alkalinity and the high (Ca. +. Mg)/(Na. +. K) and Na/Cl ratios indicate that the release of major solutes in these waters is controlled largely by dissolution processes of carbonate and partly by silicate weathering, while, cation exchange reactions, soil-salt leaching and evaporation processes also play an important role. The effects of local pollution are minimal in the montane and piedmont areas of these watersheds but are significant in the oases and central areas of the drainage basins. © 2011 Elsevier Ltd.

Zhu B.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Zhu B.,CAS Institute of Geology and Geophysics | Yang X.,CAS Institute of Geology and Geophysics | Liu Z.,CAS Institute of Geology and Geophysics | And 3 more authors.
Environmental Earth Sciences | Year: 2012

Two large sandy seas in northern China, the Taklamakan and Badanjilin deserts, were investigated for geochemical variations of soluble salts in aeolian sands. The aim was to explore factors influencing the composition and distribution of soluble salts in aeolian sands and their environmental implications. The total concentrations of soluble salt in the aeolian sands range between 0.14 and 1.32‰, with pH ranging between 8.4 and 9.6, indicating a primary degree of salt accumulation and alkaline soil conditions in these regions. Sodium chloride and bicarbonate are the major salts. High inter-regional homogenization and small local differences in the chemical compositions and distributional patterns of salt occur in the two deserts. The spatial variations in salt content correlate with regional climatic parameters, such as precipitation and temperature. This suggests that the regional air temperature and moisture conditions of climate have a significant influence on the soluble salts in aeolian sands. The domination of sedimentation of soluble salts in aeolian sands deposited via atmospheric processes, which is heavily associated with dry deposition, is discussed. Case studies from the two deserts suggest that variations in salt content in sedimentary sequences, interlaid by aeolian and lacustrine sediments, should be interpreted with care if the aim is to reveal palaeo-environmental changes. To a certain extent, the two deserts, as inferred from the carbon-bearing salts and the alkalinity of the sandy soils, appear to have potential to provide a significant contribution to the global carbon cycle. © 2011 Springer-Verlag.

Zhu B.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Yu J.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Qin X.,CAS Institute of Geology and Geophysics | Rioual P.,CAS Institute of Geology and Geophysics | Xiong H.,Key Laboratory of Oasis Ecology
Geomorphology | Year: 2012

A natural water hydrochemical investigation was carried out on three watersheds in northern Xinjiang, China to evaluate the climatic, geological and anthropogenic influence on aqueous major element chemistry in an arid environment. Wide spatial variations are observed in the dissolved solids (TDS) and water chemistry. The hydrochemistry is typically carbonate and alkaline in nature, with Ca 2+, HCO 3 - and SO 4 2- dominating the major ion composition. Four major water types, Ca-HCO 3, Ca-NDA (non-dominant anion), Ca-SO 4 and NDC (non-dominant cation)-NDA or Na-NDA type, are identified in terms of the Piper model. The water chemistry agrees well with the "rock dominance" mechanism, with a TDS value of 80-600mg/L and a Na +/(Na ++Ca 2+) ratio of 0.1-0.6. Correlation analysis suggests that most of the ions derive from multiple sources. Stoichiometric analyses indicate that carbonate weathering is the primary source of dissolved ions, followed by silicate weathering and evaporite dissolution. The effects of local pollution have somewhat greater contribution on the oases and central areas of the Zhungarer watershed. Most parts of the rivers show an increasing trend in the dissolved load toward the lower reaches, which is primarily attributed to an evaporation process control along the water course. Variations in water chemistry show clear correlation with the regional lithological distribution, topography and atmospheric precipitation. Using rainwater as a baseline, contributions from atmospheric precipitation and rock weathering to the tributary chemistry are roughly evaluated to be in the range of 2-39% (average 13%) and 59-98% (average 86%), respectively, implying a high effective control of regional geology on stream chemistry compared with that of atmospheric input. © 2012 Elsevier B.V.

Zhu B.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Yu J.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Qin X.,CAS Institute of Geology and Geophysics | Rioual P.,CAS Institute of Geology and Geophysics | And 2 more authors.
Journal of Geographical Sciences | Year: 2014

Based on the palaeoclimatic and palaeoenvironmental evidences of geological history and human history periods, this paper reviews the researches and progresses on the development of the sandy deserts in Xinjiang. It pointed out that the features of tectonic structure in Xinjiang had made both the Tarim Basin and the Junggar Basin being influenced greatly by the foehn effects originated from the planetary wind system of westerly, the East Asian ocean-continental monsoon and the topographical mountain-valley winds. The regional patterns of climate and environment since the Quaternary were characterized by the overall persistent drought accompanied by fluctuations in the secondary scale. Formations of aeolian sediments in the basins and at the margins are a potential response to global climate change, particularly the aridification of the Asian hinterland deduced by the uprising of the Tibetan Plateau and its surrounding highlands. For the question about the formation time of the Taklamakan Desert, because the research methods, objects and information carriers used in previous studies are different, there are many disputes in the academic circles at present. Evidences from aeolian deposits/rocks at the edge and in the hinterland of these sandy deserts and their chronological data indicate that an arid climate and land surface aeolian processes have occurred at the edge of the Tarim Basin and its hinterland areas since the Tertiary period. However, the duration time of these processes at mass scale should have begun after the middle Pleistocene and lasted to the Holocene. Occurrence of dune fields in recent 2000 years in the oasis areas should be greatly influenced by human factors. © 2014 Science Press and Springer-Verlag Berlin Heidelberg.

Yimit H.,Key Laboratory of Oasis Ecology | Eziz M.,Key Laboratory of Oasis Ecology | Eziz M.,Xinjiang University | Mamat M.,Xinjiang University | Tohti G.,Xinjiang University
International Journal of Sustainable Development and World Ecology | Year: 2011

Groundwater levels and salinity are significant contributors to soil salinisation in irrigated areas. In this study, spatial and temporal variations of groundwater levels and salinity in the Ili River Irrigation Area in the western arid zone of China were analysed using a geostatistical approach. Results showed that: (1) groundwater salinity varied widely, with a maximum of 30.70g/L and minimum of 0.20g/L, while maximum groundwater level was 31.10m and minimum was 0.54m. The abundance of major ions in groundwater was in the order: Cl->SO42->Ca2+>Mg 2+>K+>Na+>CO32-=HCO3-. Groundwater salinity had a good positive correlation with EC, Cl-, Na+, HCO 3- and Mg2+ (correlation coefficient 0.90); (2) a Gaussian model was the most suitable semivariogram model to describe groundwater levels for four measurement periods, while a Spherical model was most suitable semivariogram model to describe groundwater salinity in March, September and November, and an Exponential model was most suitable variogram model for June. RA relatively strong spatial and temporal structure existed for groundwater levels and salinity due to very low nugget effects. The nugget-to-sill ratio indicated that groundwater levels and salinity in the study area have relatively strong spatial dependence. The groundwater levels and salinity showed an east-west, north-south U-shaped distribution in each measurement period; (3) maps of kriged groundwater levels and salinity showed that deeper groundwater was found in southern parts, with more shallow groundwater in northern parts of the study area. Higher groundwater salinity was found in central parts, with lower salinity in marginal parts of the study area. It is clear that substantial soil salinisation has taken place in central parts of the study area, and more attention should be paid to these areas to prevent future problems. © 2011 Taylor & Francis.

Eziz M.,Key Laboratory of Oasis Ecology | Eziz M.,Xinjiang University | Yimit H.,Key Laboratory of Oasis Ecology | Mohammad A.,Key Laboratory of Oasis Ecology | Zhifang H.,Xinjiang University
International Journal of Sustainable Development and World Ecology | Year: 2010

Land-use change in oases of arid zones play a significant role in the sustainable development and stability of oases. This paper presents a typical case of successful efforts to mitigate land-use change, its drivers and effects on the oasis eco-environment at Keriya Oasis in the western arid zone of China using remotely-sensed data, official statistics, and data collected by field investigation. Mathematical models were developed to quantify important elements related to land-use change, including net change and total change. The results indicate that: (1) approximately 17% of land-use types of Keriya Oasis changed between 1991 and 2002; (2) socioeconomic development, climate change, and economic polices contributed to land-use change in the oasis; (3) inappropriate human activities were the main cause of land-use change and eco-environmental degradation in the oasis; and (4) the stability of the oasis is threatened by land-use change and unexpected eco-environmental changes in the oasis and oasis-desert ecotone. The study suggests irrational human activity in arid zones, and that caution should be exercised to maintain stability and sustainable development of oases. © 2010 Taylor & Francis.

Zhang X.N.,Xinjiang University | Zhang X.N.,Key Laboratory of Oasis Ecology | Yang X.D.,Key Laboratory of Oasis Ecology | Yang X.D.,Xinjiang University | And 2 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2016

Diversity patterns play an important role in identifying the mechanisms of biodiversity maintenance. The soil of the Ebinur Lake Wetland Nature Reserve located in the western margin of the Gurbantonggut Desert, in the Xinjiang Uygur Autonomous Region of China, is short in water and rich in salinity. These regional conditions result in plants that have developed high sensitivity and vulnerability characteristics. Thus, the exploration of desert plant diversity patterns and response mechanisms along various soil water and salinity gradients can integrate community-wide information to reveal the mechanisms of plant adaptations in an arid region and provide scientific strategies for reserve management and biodiversity conservation. However, plant diversity patterns and responses to varying gradients of soil water and salinity in the Ebinur Lake remain unclear. In the present study, three transects were first established that were perpendicular to the north bank of the Aqikesu River (one of three rivers in the Ebinur Lake Wetland Nature Reserve). In each of the three transects, 10—12 plots (total of 32 plots) were set. The geographic data, abundance, richness, and soil volume water content (SVWC) were surveyed and recorded in each plot. The soil samples were then collected and taken to the Key Laboratory of Oasis Ecology of Xinjiang University. All soil samples were air dried, and soil pH (pH), electrical conductivity (EC), soil organic carbon (C), soil total nitrogen (N), soil total phosphorus (P), and soil total sulfur (S) of all samples were measured in the laboratory. Based on these values, abundance models, multiple comparisons, ordination analysis, and the regression method were used to explore plant abundance distributions, plant diversity patterns, and relationships with the soil environment across soil water and salinity gradients. The results showed that: (1) SVWC and EC in high (SW1) and low (SW2) soil water and salinity plots were 16.65% and 12.02 mS/cm; and 2.63% and 1.91 mS/cm, respectively. Species composition of herb and some shrub communities were mainly influenced by the variation in soil water and salinity. (2) The plant distribution pattern showed no significant relationship with soil environmental factors in SW1 plots; whereas in SW2 plots, significant variations were noted with SVWC, EC, and soil nutrient content, which presented a pattern of regional distribution. (3) Plant abundance patterns were fitted using the lognormal (LN) and Zipf models for SW1 and SW2, respectively. Variability in plant abundance patterns indicated the responses of community composition and structure to soil water and salinity in arid desert conditions. (4) Plant diversity in SW1 was significantly higher than that in SW2. To some extent, this diversity was significantly affected by soil pH, SVWC, and S. Overall, the relationships between distribution and diversity patterns, and the soil environment showed some response patterns to soil water and salinity gradients. In addition, the responses of a plant community to the soil environment across soil water and salinity gradients can provide reference points for the control of vegetation restoration and soil salinization under arid desert conditions. © 2016, Ecological Society of China. All rights reserved.

Zhang F.,Xinjiang University | Zhang F.,Key Laboratory of Oasis Ecology | Tashpolat T.,Xinjiang University | Tashpolat T.,Key Laboratory of Oasis Ecology | And 2 more authors.
Geo-Spatial Information Science | Year: 2010

This paper uses 3S technology in macroscopic. Combining the integrated technology of ecological quantity analytical method with GIS technology through ArcGIS and Fragstats, the authors study the images of 1972, 1990, 2001, and 2005 and obtained land use data in Jinghe County. Then, the change of land use/cover and landscape pattern had been analyzed in the Jinghe County of Xinjiang. The conclusions were as follows: (1) The trend of LUCC is that the area of oasis expands slowly in nearly 33 years between 1972 to 2005 in Jinghe County. (2) The water area is mainly influenced by Ebinur Lake, so the area expands a little in this period. (3) The area of salinization-land expands at first and reduces later. The area of sand land decreases and the other land class increases, while the probability of transfer is always high. (4) Landscape change is also obvious throughout the decades. Overall, landscape density increases, the largest path index decreases at first and expends later, the weight area index decreases, and the shape of landscape becomes regulated. The nearest distances, the degrees of reunite, and outspread decreases. It shows that the connection of the main path in 1972 is better than 2005, wherein the patch becomes more complex. From the changes of Shannon's Diversity Index and Shannon's Evenness Index, we know that the diversity of landscape and the Interspersion Juxtaposition Index increase. The degree of diversity landscape and fragmentation increase also shows that the land uses become more complex. All in all, it is essential to intensify the spatial relationships among landscape elements and to maintain the continuity of landscape ecological process and pattern in the course of area expansion. © 2010 Wuhan University and Springer-Verlag Berlin Heidelberg.

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