[Objective] This study aimed to evaluate the environmental effects coming from land changes in Hotan oasis during 1980-2010. [Method] Based on the Driving Force-State-Response model, expert weight method and entropy method were used to determine weight, and then the composite indexes of environmental effects （CIE for short） were calculated. [Result] During the period from 1980 to 2010, CIE had presented a rising trend whether expert weight method or entropy method in the study area, while the CIE presents downtrend basically in lower reaches. [Conclu- sion] It was the arable land expansion in middle reaches that led to serious land degradation in lower reaches, and may endanger ecosystem safety in Hotan River green corridor. Therefore, it is suggested that the agricultural land use should be restructured, such as reducing the sown areas of some crops with large amount of water consumption. Meanwhile, the effective measures should be taken to distribute water resources and utilize them reasonably. In addition, the oasis-desert ecotone, as well as the groundwater resources, should be also protected.
[Objective] The study aimed to assess the ecosystem services value in Hotan Oasis, Xingjiang. [Method] The visual interpretation method was adopted to process TM/ETM＋ images based on field investigation in Hotan Oasis. These inter- pretation data, along with two periods of land use data, were reclassified to farm- land, forest, grassland and so on. Then, the ecosystem services value was calculat- ed and analyzed. [Result] Analysis indicated that the ecosystem services value had been increased by 30.44x108 Yuan （16.51%） in the study area during 1980-2010, which can be explained by the increase of glacier and snowfield distributed in the south mountain with the increase of annual precipitation. At the same time, the con- tribution rate of grassland to ecosystem services value had been decreased as a result of degradation of grassland and occupation from farmland. For the whole basin, the increase of ecosystem services value came from the upper reaches, while the ecosystem services value had been reduced in the middle and lower reaches. In the middle reaches, the reduction came mainly from wetland （-1.83x10s Yuan）, waters （-1.68x10s Yuan）, forest （-0.86x108 Yuan） and grassland （-0.80x108 Yuan）. But in the lower reaches, the ecosystem services values of waters, grassland and forest were -0.61 x108 Yuan, -0.24x108 Yuan, and -0.07x10s Yuan, respectively. [Conclusion] If some effective policies, such as the implementation of returning farm- land to forest and ceasing from farming to grazing, would be taken, the ecosystem degradation can be constrained and reversed in the northwest arid region.
[Objective] The main purpose is to reveal the laws and driving mechanism of oasification and desertification in Hotan River Basin during the period of 1972-2010. [Method] The visual interpretation method was used to process TM/ETM＋ image based on field work and investigation of Hotan Oasis. These interpretation dates have been reclassified to desert and oasis. Then, the driving mechanism of desertification and oasification was analyzed. [Result] The analysis indicated that the oasification velocity（91.24 km^2/year） was faster than the desertification’s（77.78 km^2/year）,with a rapid growth of 5.59 km^2/year in oasis area in the mid-lower reaches of the Hotan River. [Coclusion] There existed spatial coupling linked by water consumption between oasification in the middle reaches and desertification in the lower reaches.And the changing trends were opposite not only for the oasis area, but also for the oasification area and oasification velocity between the middle and the lower reaches of the Hotan River Basin. With climatic warming, population growth, economical development, scientific and technological progress, and in particular the implementation of national policies, the cropland area increased and oasis expanded, speeding up the oasification and water consumption in the middle reaches. Hence it is urgent to prevent the Hotan Oasis from exacerbating the current water supply-demand imbalance and prohibit the expansion of arable land to transitional belt between oasis and desert.
