THE CHANGE OF LAND COVER/LAND USE IN EJINA OASIS OVER 20 YEARS

摘要

Land use and land cover change have been of great concern in global change research in recent years. Base on comparison with the remote sensing data in 1982 and 2000 and field investigation, the results of land cover and land use change were obtained by the method of landscape analysis. Ten types of land use were identified: riparian woods, riparian shrubbery, desert shrubbery, desert grassland, river-way and water area, salinised land, town, Gobi, shift sand dune, denudative upland. The results show that, (1) there were obvious Changes in land cover structure. The area of riparian woods decreased 0.97% and the number of patch decrease 376; The area of riparian shrubbery increased 0.92% and the number of patch decreased 1316. Meanwhile, the index of %LAND of desert shrubbery increased from 4.49% to 5.65%; Because of decrease of water quantity of discharge from middle reach. The patch of river-way and water area decreased from 40 to 6. The index of % LAND decreased 0.15%. At the same time, the index of % LAND of shift sand dune increased 0.42%. (2) the area of riparian woods dominated by Populus euphratica and desert grassland decreased to 45.02% and 14.55%. However, the areas of riparian shrubbery dominated by Tamarix SPP and desert shrubbery increase to 35.03% and 25.88%. The transition probability is 45.95% from riparian woods to riparian shrubbery. at the same time, they are 0.78% and 3.01% from riparian woods to desert→shrubbery and desert→ grassland. The succession trend of ecosystem was obtained: riparian woods riparian shrubbery and grassland desert grassland. Meanwhile, the succession velocity becomes higher and higher.