The Study of Grassland Degradation in the Western of Songnen Plain

Based on RS and GIS technique,three-period(1986,1995,2000) remote sensing images are interpreted to extract spatial information of grassland landscape in the western of Songnen plain,then spatial-temporal dynamics of grassland and the natural and human factor of grassland degradation are analyzed.The results show that grassland area decreased 24.7%,grassland degradation is serious.Grassland is mainly converted into forestland,cropland,unused land and saline-alkalized land.During 1986-1995,low coverage grassland rapidly developed,and high coverage grassland declined greatly during 1995-2000.From 1986 to 2000,both natural factors and human activities result in grassland degradation in studying region,natural factors are basic condition of grassland degradation,and human activities are crucial factors.