Landscape Pattern And Dynamics And Desertification Causes Of Minqin Oasis

Oasis is a kind of intrazonal landscape developed under the background of arid climate, which plays an important role in arid regional economic development. Water is the basis for oasis to exist and develop, so the water resources spatial distribution patterns decide the oasis spatial distribution landscape patterns. While with the growing population and overusing natural resources, the incoordinate relationship between oasis economic development and environment become serious, by which the stability and sustainable development have been threatened.The process of landscape pattern and dynamics and desertification causes of oasis are proundly studied based on a case study carried out in Minqin Oasis of Gansu Province, China, under the theory of landscape ecology, by using remote sensing data as basic information resource and with support of GIS, the oasis landscape pattern change from 1987 to 2001 and the role of oasis evolution and influence factors are analyzed with the climate and social and economic data from the 1950s. At the end of this paper, the author also put forward some advices to control oasis desertification. The results are as following:1 Landscape Structure and Changes From 1987 to 2001, first, the heterogeneity of Minqin oasis increases for the value of Shannon's diversity index (SHDI) and Shannon's evenness index (SHEI) decrease, from 1.79 to 1.60 and 0.66 to 0.59, respectively. Second, the value of contagion (CONTAG) increased, from 42.50 to 47.98. The distinct manifest is the decreasing of numbers of patch (NumP) and the increasing of mean patch size (MPS), from 20873 to 18801 and 21.56 hm~2 to 23.54 hm~2, respectively. Third, the shape of patches become more complex, for the value of mean shape index (MSI) and mean patch fractal dimension (MPFD) both increase, from 18.91 to 22.90 and 1.38 to 1.41, respectively.2 Landscape Dynamics from 1987 to 2001, the area of farmland, Nitraria tangutorum and shifting sandy land increased evidently, the area of farmland has increased 245.48 km~2. The other landscape elements also increased, such as residential area, forest of Elaeagnus angustifolia and Haloxylon ammodensron, the desert of Artemisia areanaria and the meadow of Calamagrostis epigejos, but the increased area are not as evident as the first three.3 Desertification Causes and controlling measures Desertification is the result of natural factors (mainly climatic factors ) and human impact together. The especial geographical location and worsen climate is the good condition for the development of...