| The resent survey research about grassland ecosystem placed more attentions on grass biomass productivity on the grassland, and take no integrative consideration about various types of land use. Studies about grassland ecosystem change, lacking of the analysis of spatial trend and drivering force,were also not be operated in a multi-scale integrative analysis. Many models that had been built for grassland survey can only work correctly in particular condtion and in limited period. There is still no survey model that can be used in large area extent to inspect land-use changes in gralssland ecosystem.In this dissertation, the changes of land use in the Alpine Grassland Ecosystem (AGES) were analyzed by using the technologies of Remote Sensing (RS) and Geographical Information System (GIS), and a new set of methods suitting to analysis spatial change in the AGES were worked out and proved effectively in experiment area. With large quantity of analysis, the following results were mainly reached.(1) With the analysis of land use characteristics of experiment region in Alpine grassland ecosystem, and taking consideration of the aims research, the two gainned images, Landsat TM image gainned in 1987 and Landsat ETM+ image gainned in 2002, were segmented by used the arithmetic of Iterative-Orgnizing Data Analysize Technique (ISODATA). Then these fragments were identified by using land-use indicators, which were built during the image interpreting work prcocess in field, such as, the color, texture, shape, position, etc.,and also by using the methods of NDVI and characteristic analysis of spectrum of land-use types in a man-compute interactive manner. The final land-use thematic maps were achieved in the images, and also the land-use types of the High Coverage Grassland (HCG), the Middle Coverage Grassland (MCG), the Low Coverage Grassland (LCG), Field (F), abandoned/rested Field (F1), Bareness land (B), and Water body (W) were achieved. The distribution condition of resident sites, roads and rivers were got from digited maps. Precision was assessed on the final land-use classified results, and a precision of 90.91% was gainned.(2) For the purpose of meeting the need in land-use change research, a new land-use change survey model were built and carried out to use on the basis of commom business Remote Sensing software ERDAS in this study. Finally, this model was used to inspect the land use changes in the experiment area from 1987 to 2002. Outcome showed that the precision of land use change inspection was only influenced by the precision of land-use classification, and for the land-use thematic maps, the precision of land-use type change detection can reach 100%. It is simple to beunderstood and easy to use, suitable to generalization and use in LUCC research field.(3) Two types of gravity center model were detected and compared by using the land-use thematic maps of the experiment area in this study. It was concluded that model 2 is super to model 1. Considerring the 3-dimension characteristics of objects studied in geo-science field, the gravity center model 2 was advanced from 2-dimension to 3-dimension.(4) By analyzing the area of different land-use types in the experiment region from 1987 to 2002, it was found that the area of High Coverage Grassland reduced 90634hm2, the area of Middle Coverage Grassland reduced 124600hm2, the area of Low Coverage Grassland increased 157539hm2, the area of Bareness Land increased 21675hm2, the area of Field increased 18840hm2, and the area of abandoned/rested Field increased 18409hm2.(5) Analyzing the spatial distribution and changes of different types of land use in experiment with the advanced gravity center model, the results showed the distribution of different types of land use , that the High Coverage Grassland mainly distributed in mountainous area, the Middle Coverage Grassland mainly distributed between mountainous sub-region and flat sub-region in the experiment area, the Low Coverage Grassland, the Field, the abandoned/rested Field, the Bareness land,...
|
PDF Full Text Request