Spatial Analysis of Land Use and Land Cover Changes in Recent 30 Years in Manas River Basin

Manas River Basin, best represent the mountain basin system in arid area, is the major part of the economic belt on the northern slope of the Tianshan Mountains. Based on the 3S technology and four periods of remote sensing image data of MSS image in 1976, TM image from USA Landsat in 1987 and 1998, and CBERS image in 2006, combining GIS and quantitative analysis of landscape ecology, this paper analyzed the spatial changes of land use and land cover in Manas River Basin among 1976-2006 by using ARCGIS and FRAGSTATS. Analysis on four periods of remote sensing image showed that there was a wide change in land use and land cover of Manas River Basin in recent 30 years. Natural grassland decreased with a rate of 91.426km(2)/a and cultivated land increase with a rate of 121.383km(2)/a. The rapid expansion of cultivated land converted mainly by reclamations of wasteland and natural grassland. And there were little changes of other land use types. From the relationship of transformation between various types of land use and land cover, it could be found that unused land is relatively stable land-use types, the areas of residential land and industrial land increased gradually and the cultivated land and natural grassland were the main source, a larger proportion of natural grassland mainly changed into cultivated land, forest land and residential land and industrial land, land changed into cultivated land was larger than cultivated land changed into the other land and the increased land main converted by natural grassland, and the forest land converted to other land increased gradually and the they mainly converted to salt and kaline land. However, land use and land cover change was resulted from the interaction of human activity (social and economic factors) and natural environmental changes (natural factors). So, it is necessary to consistently improve the natural environment of Manas River Valley which can provided stable basis of the theory and practice for sustainable development of Manas River Valley.