Dynamic Study Of Desertification In Hunshandake Sandy Land Of Inner Mongolia

The Hunshandake sand land located in the warm temperate zone which is continental monsoon climate area. However, desertification is the serious problem for the development of the economy and eco-safety. In order to do the better dynamic monitoring of the desertification development in the area and further understanding the dynamic development and the internal mechanism of desertification, this paper, use the techniques of RS and GIS, prepare the principles of the landscape ecology, the theory of DEM, the method of mathematical statistic and modeling, to analyze the dynamic changes of land desertification in Hunshandake sand land that the time period about 17 year. At same time discuss the monitoring of land desertification in three ways that are TM, MODIS and DEM data and the drive mechanism of Hunshandake sand land desertification. The results are as follows:1. The distribution degree of Hunshandake sand land desertification is increased gradually from east to west. The area of the land desertification increased and the degree of the land desertification extended; the land desertification deteriorated as a whole from 1989 to 2000 year. Between 2000 and 2007, the land desertification is limited in the whole and reversed in some area. From 2000 to 2007 year, the ecological environment is improved and the vegetation has been restored.2. The results of NDVI vegetation coverage shows that the changes of vegetation cover and land desertification are closely related. With the increasing of vegetation cover, the land desertification is reversed; and with the reducing of vegetation coverage, the land desertification is extended.3. The calculation results of desertification landscape index indicated, in the period of 2000-2007, the index of landscape patch number, patch fragmentation and patch density are increased. The average patch area and edge density are decreased. The variation of landscape index of land desertification indicated perfectly the deterioration and reversion of land desertification in above. It can be known, the index of landscape of desertification is a valid method of the studies in land desertification from landscape ecology.4. Using the EOS-MODIS remote sensing data calculated the index of normalized difference vegetation (NDVI) and the index of vegetation cover (PV), to obtain the results of the desertification index (DI): the trend of land desertification changes and the changes of land desertification degree are coincided basically with the climate changes in this area. Especially, the changes of land desertification and the fluctuation of precipitation are agreement. Between 2000 and 2007, the land of moderate, severe and very severe land desertification are decreased significantly. Considering the slight land desertification is increased. The index of normalized difference vegetation (NDVI), the index of vegetation cover (PV) and the land desertification index (DI) are fitting with the results of TM remote sensing visual interpretation.5. Take DEM to analyze the desertification distribution and land use dynamic change, it can commendably represent the distribute regulation that based on different elevation, slope and aspect variation. The final results, the classified degrees of desertified land are concentrated between two and three elevation grade, it is most obvious in 2, 3 and 4 elevation grade; Take the reference of slope grade, the desertified land variation are mainly distributed in grade 4 slope which is below 15 degree, the desertification variation change most in grade 3 slope which is below 10 degrees. According to the desertification dynamic change regulation based on slope that the pivot and key of desertification prevention and control should be focused on the slope gradient of less than 10 degrees.6. The occurrence and the development of land desertification are results of natural and socio-economic development. The natural cause of the land desertification consist of topography, soil texture, vegetation changes and climate change, for the key item, the climate change is the most important natural dynamic condition. The socio-economic factor included many aspects, such as population, land using, economic structure and policy factors.