Vegetation Coverage And Ecological Environment Study Of Alxa In The Past Two Decades

The southeast region of Alxa which located in the western part of InnerMongolia Autonomous Region with the Asian central desert climate type is ecologicalenvironment. Although the vegetation coverage of the area is in a very low level, butit played an important role in that against the invasion of the sand blown by the windfrom the northwest region, and it is an important barrier of national ecological security.Therefore, monitoring and analysis of the area in the vegetation cover changes and theecological environment evolution by the means of remote sensing interpretationwhich has a great significance.The paper based on the project of regional geological reconnaissance in the southeastof the Alxa. And in field investigations, we collect the data of grass box, vegetation,weather, terrain and remote sensing data at different phases and other kinds ofinformation, which combined with the specific geomorphology of the study area hasbeen used. We make full use of the technology of remote sensing, GPS and GIS in theextraction and analysis of the situation and changes of the vegetation coverage in theregion, which as a basis to explore the process of evolution of the ecologicalenvironment of the region as well as possible trends.The paper describes the traditional methods of measuring vegetation cover andthe technology of remote sensing. We selected the technology roadmap of the remotesensing interpretation of the suitable for the study area which vegetation cover is lowafter comparative study. And we measured the grass box data in the field investigation,used as the foundation and basis for evaluation of remote sensing methods. In thechoice of the pixel dichotomy methods to interpret the vegetation coverage basedNDVI, we make a suitable adjustment of the study area based on the measured data,especially for the value of NDVI and NDVI was analyzed and discussed. And thenthe region at different phases of vegetation cover classification map was made at thesupport of the measured data in the field.Subsequently we make precision evaluation to the vegetation cover classificationmap based on the grass grid data which is measured in the field investigation. And we found that the accuracy rate of more than80%, indicating that the remote sensinginterpretation technology is appropriate and the results of the remote sensinginterpretation are authentic.In the last we make grid computing to the vegetation cover classification map ofthe adjacent time by the GIS tools, and get the information of changes of the area andspatial location of each vegetation coverage level. After that we analysis the reasonsfor all these changes based on the information that we had collected from the studyarea, such as vegetation, meteorology, etc. And we found that the result ofenvironment control measures imposed by the local government such as forbiddengrazing and aerial seeding is relatively good. And the vegetation coverage of theentire region in general upward trend, we also propose several suggestions for furthermanagement to improve the environment to the local government.