Fractal characteristics of land use and land cover change in a watershed of arid zone in last 30 years: A case of the Manas River Watershed

The Manasi River watershed is located at the south of the Junggar Basin and at the center of Northern Tianshan Slope Economic Belt.It is the model of oasis exploitation and economy development in Xinjiang.The ecological environment has fragility in the watershed.In recent years,because of natural environment variation and population growth,the overall change of land use and land cover has taken place in the watershed,affected the oasis stability.This paper studied fractal complexity and stability characteristic of land use and land cover change(LUCC) in the typical watershed of arid zone-the Manas River watershed in last 30 years since 1976,using geographic information systems(GIS) and fractal theory with remote images in 1976,1989,and 2005.The results showed that the distribution of land use and land cover type in the Manas River watershed has the fractal property.The complexity and stability characteristics of land use and land cover type are fluctuant.The average fractal dimensions are 1.3940,1.3634,and 1.3899 in 1976,1989,2005,respectively.The average stability indices are 0.6060,0.6366,and 0.6101 in 1976,1989,2005,respectively.The average stability indices of different land use and land cover types arranged in number order from big to small are as follows: sand land unused land residence land water area forestland grassland cropland saline-alkali land in 1976,1989 and 2005.Saline-alkali land,cropland,grassland,forestland have poorer stability.The research of fractal complexity and stability characteristic of land use and land cover change would be a valuable basis for establishing harmonious mechanism of water and soil and adjusting land use structure.