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Ecological vulnerability is one of the core issues in the study of achieving sustainable development and is important for ecological conservation and environmental management, especially for ecologically vulnerable regions. Scientific assessment of ecological vulnerability can improve decision-making capacity and provide appropriate information for sustainable development. The Hexi Corridor is located in the inland northwest of China, and its ecological environment is very fragile. Under the influence of climate change and human activities, the Hexi Corridor is facing a crisis of ecological degradation. Therefore, this paper assessed the influence of various factors on ecological vulnerability, followed the principles of scientificity and data accessibility, and constructed a comprehensive assessment framework to reflect the spatio-temporal characteristics of ecological vulnerability in the Hexi Corridor from three aspects: natural factors, socio-economic factors and human interference factors so as to provide theoretical and practical guidance for regional ecological protection. The results showed that: (1) The ecological vulnerability of the Hexi Corridor was dominated by extreme vulnerability, mainly in the arid desert region, while mildly and lowly vulnerable areas were mainly distributed in the southern Qilian Mountains and the plain oasis region, which was closely related to its physical geography. The index values showed an overall decreasing trend, and the environmental situation was improving from 2000 to 2020. (2) The distribution of ecological vulnerability had obvious directional characteristics, and it gradually decreased from north to south. Moreover, it exhibited a significant positive spatial correlation, and its spatial aggregation pattern was basically consistent with the spatial distribution state. (3) Based on the spatio-temporal patterns of ecological vulnerability, the Hexi Corridor was divided into five zones: ecological core protection zone, integrated ecological monitoring zone, ecological optimization concern zone, ecological restoration management zone and ecological potential governance zone. Different environmental protection policies have been taken for different zones according to its basic conditions. Spatial principal component analysis (SPCA) method was used to analyze the ecological vulnerability factors based on the GIS technology. The partitions of ecological vulnerability for configuration and optimization has been classified and practical application. Geographic detector and national policies were considered for ecological vulnerability driver factors. [ABSTRACT FROM AUTHOR]

Based on the features of environment and the fact of successful artificial afforestation, the paper points out that the restoration of vegetation in Arid-hot valleys along the Jinshajiang River should be implemented mainly by planting sparse — arbor/ shrub/ tussock Combination. Four ways to restore vegetation in the area are given in the paper. [ABSTRACT FROM AUTHOR]

Validation of Moderate-Resolution Imaging Spectroradiometer (MODIS) land surface reflectance products is important to effective utilization of such products for earth systems science. Ground-based measurements are normally utilized for such validation. However, the major scale mismatch between the ground ‘point’ measurement and MODIS resolution (500 m and 1 km) makes direct comparison infeasible over many land surface types. In this paper, an indirect comparison between ground ‘point’ measurements and MODIS land surface products via high-resolution remotely sensed imagery (Landsat Thematic Mapper/TM) was utilized in semi-arid grassland of Inner Mongolia in summer 2005, where ground measurements are relatively sparse in comparison with other locations around the world. Within the validation, the TM reflectance imagery was first calibrated by the ground ‘point’ measurements, and then aggregated to MODIS data resolution for determination of their accuracy. Besides common direct spectral band comparison of reflectance between TM and MODIS, empirical/indirect comparison between TM and MODIS was also implemented. Both types of validation showed that the absolute error of bidirectional reflectance from atmospheric correction (MOD09) is less than 9.4%, and for nadir bidirectional reflectance distribution function (BRDF)-adjusted reflectance (MOD43B4) it is less than 3.1%, in which the error of visible bands of two data sets is less than 1.35% and 0.95%, respectively. This validation will help improve the accuracy of MODIS products used in this area. [ABSTRACT FROM AUTHOR]

It appears that two main factors hinder the effective incorporation of ecological information derived from computer modeling in resource management at large spatial scales: (1) some models are not ecologically sound and (2) most models based on ecological principles are often too sophisticated or detailed, having complex structures and requiring a large range of input data. This paper employs a generic model based on well-established ecological principles, but with appropriate detail, to better serve decision-making in sustainable resource management. The model was used to simulate aboveground net primary productivity (ANPP), foliage projective cover (FPC), and the evaporation coefficient (k) for large arid areas in northwest China, where there has been serious desertification recently. Observation data of ANPP and FPC in the study area were used to validate the model, and the model results were in good agreement with observation data and other published data. The model was then used to simulate the evaporation coefficient, FPC, and ANPP for the study area. The simulation results indicated that except for several sites, the k parameter was lower than 0.35 × 10-2 and implied a typical arid climate in the study area. Estimated FPC of the plant community was lower than 50% at most sites, and the annual ANPP was very low-less than 1 tons · ha-1 · yr-1 at 93.8% of sites. These simulation results could serve as references for vegetation restoration and livestock husbandry management in arid areas of China. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Over the past decade, rapid landscape pattern change has taken place in many arid and semi-arid regions of China, such as the Yellow River Basin. In this paper, landscape evolution was investigated by the combined use of satellite remote sensing, geographic information system (GIS) and landscape modelling technologies. The aim was to improve our understanding of landscape changes so that sustainable land use could be established. First, the changes in various landscape metrics were analysed using the landscape structure analysis programme. Second, the mathematical methodology was explored and developed for landscape pattern change, which included: the status and trends change model for individual landscape types, the 1-km2 area percentage data model and the transition matrix of landscape types. The results show that the area of the Yellow River Basin was about 794 000 km2 during the period from 1990 to 2000; cropland, built-up land and unused land expanded significantly whereas woodland, grassland and water bodies contracted substantially. The area of cropland increased dramatically by 2817 km2, and the areas of grassland and woodland decreased by 4669 and 33 km2, respectively. Meanwhile, the landscape pattern in the study area also experienced numerous changes over the past decade. The major factors that caused the landscape changes in this area over the past decade were found to be governmental policies for environmental protection, population growth, and meteorological and environmental conditions. [ABSTRACT FROM AUTHOR]

Evapotranspiration (ET) plays an important role in the hydrological cycle and it is essential to estimate ET accurately for the evaluation of available water resources. This is most important in arid and semi-arid regions. In this paper, the long-term changes in daily ET in the semi-arid Zhangye Basin in northwest China and its impact factors were studied. The spatial distribution of ET was assessed by using the Surface Energy Balance System (SEBS). Cloud-free National Oceanic and Atmospheric Administration Advanced (NOAA) Very High Resolution Radiometer (AVHRR) September images over the Zhangye Basin from 1990 to 2004 were used in combination with SEBS to estimate ET at a spatial resolution of 1.1 km. This daily ET was converted to a monthly ET (for September) using daily pan evaporation values from a meteorological station in the study area. Spatial aggregation of all pixels yielded the total monthly ET for the whole study area. Subsequently, the monthly ET was extrapolated to annual ET values using the pan evaporation data. The results were validated with ground-based measurements on the water balance for the whole Zhangye Basin. The annual ET increased gradually from 23.7×108 m3 in 1990 to 26.9×108 m3 in 2004 for the Zhangye Basin. The main cause appeared to be change in vegetation. [ABSTRACT FROM AUTHOR]

Groundwater plays a critical role in arid West China where water is the limiting factor for development. This paper first describes groundwater characteristics in a region of four arid inland river watersheds and the problems associated with groundwater consumption. This region exhibits a unique alternating pattern of high mountains and depressions, which results in extensive interactions of surface water and groundwater. Then the authors propose six strategies to support adequate exploitation and use of groundwater in the region. These strategies are: 1) setting up a groundwater monitoring system; 2) forming a unified watershed authority, 3) protecting mountain ecology; 4) increasing the efficiency of groundwater usage; 5) protecting groundwater; and 6) supporting advanced research. The implementation of these strategies should be built upon the promotion of sustainable economic development and broad public support. [ABSTRACT FROM AUTHOR]