Probing into the patterns of land use and protection in Karst region based on RS & GIS—A case study from Huanjiang County in Northwest Guangxi

The land use changes in Karst region of Southwest China lead to serious ecology problems.Huanjiang County located in Karst region in Northwestern Guangxi Zhuang Autonomous Region of China is a typical environment-forced immigration county.In addition to it,the rapid growth of population makes notable changes in land use and,at the same time,causes serious environment troubles,such as the reclamation of arable land or grass land at unsuitable slope and altitude zone causes the vegetation degeneration,soil erosion,and land rocky desertification. According to the datum derived from Landsat TM/ETM images in 1988 and 1999,associating with 1∶250000 DEM and the field investigation, a discussion on how to suitably utilize land resource is put forward in this paper,accordingly dividing Huanjiang County into three zones,namely collective utilization zone,moderate utilization zone and protection zone.