Based on some remote sensing data and software platform of image processing and analysis, the standard image for ecological thematic mapping is decided. Moreover, the vegetation type maps and land sandy desertification type maps are made. Relaying on differences of natural resources and ecological environment in Tarim River Basin, the assessment indicator system and ecological fragility index (EFI) of ecological environment are built up. The assessment results are very severely. That is, EFI is only 0.08 in Akesu River Basin, it belongs to slight fragility area. EFI of Yarkant River Basin and upper reaches of Tarim River Basin are 0.23 and 0.25 respectively, both of them belong to general fragility areas. Meanwhile, EFI of Hotan River Basin and middle reaches of Tarim River Basin are 0.32 and 0.49 respectively; they all belong to middle fragility areas. However, the fragility of the lower reaches of Tarim River Basin belongs to severe fragility area that the EFI is 0.87.The maladjustment among water with hot and land as well as salt are hindrance of energy transfer and material circulation and information transmission. It is also the main reason that caused ecological environment fragility.
In the recent 50 years, the exploitation of mineral products and water resources in XinJiang has developed greatly, which contributes a lot to the development of economy and society in the region. However, the ecological environment problems caused by it have already aroused great attention. It is also an urgent mission for the researcher to solve the problems of harmonizing the relation between the exploitation of resources and the sustainable development of ecological environment.
Xinjiang, which lies in the middle of Eurasia, is one of the aridest areas in China, its ecological environment is vulnerable. For a long time, the irrational exploitation of oil and gas resources, solid mineral products resources (such as coal resources, nonmetallic metal and precious metal resources) and water resources has already brought about serious ecological environment problems.
Driven by anxiety of population growth and decline of living standard of human beings, Research on environment in arid zone has been received significant attention in recent years. The flourishing landscape ecology provides a suitable way to study on environment. Meanwhile, the application of RS techniques brings essential data for landscape study. Integration both of them promotes study on environment. Among them, as key substances, the landscape pattern analysis is one of good methods to discuss regional environment. Although a number of papers about it have been published, little practical work has been done for arid zone in China. For these reasons, it is very important and urgent to understand the landscape pattern characteristics and environment trends in arid zone in China, especially in continental river basin in west of China.
Supported by the modern techniques of RS, GIS and GPS and CBERS-1 data and aerial photograph, using the methods of landscape pattern analysis, the paper analyzed the landscape pattern characteristics and environment trends in the middle reaches of Hetian River. The main conclusions has been given as follows:
(1) On macroscale, there have two kinds of typical deserted landscape patterns in arid zone: in the north of region, dominated by river corridor, the landscape is symmetrically distributed with waters and wetland-forestry and grass based on desert matrix; in the south of the region, indicated central line by river, linked by sub-rivers and irrigation canal network, the landscape shows artificial oasis with primary cultivated lands on desert matrix.
(2) Compared landscape pattern figures of 1959 with the one of 2000 and measured values of landscape patterns, fragmentation of each landscape types becomes low and connectivity is good. Landscapes controlled by human are increasing shapely, such as artificial rivers, irrigation canals, reservoirs, residences, cropland and so natural landscapes are been greatly reduced, especial in desert and Gobi area.
(3) The landscape trends of landscape pattern are equalizing, distribution by human is enhancing, landscape structure is rationalizing, and the regional quality of environment is optimized. While, the whole region is still under a vulnerable ecological environment.