The role of policies in land use/cover change since the 1970s in ecologically fragile karst areas of Southwest China: A case study on the Maotiaohe watershed

Study of land use/cover change and its driving forces is one of the most significant fields in global environmental change research. Karst land is a type of important and unique terrain on the Earth's surface because of its extensive distribution, impressive landforms, and high ecological fragility. Recently, more and more researchers have realized that irrational land use practices are leading to a series of alarming environmental issues including rocky desertification in karst areas. Studies on land use/cover change and its driving forces in karst areas are significant in achieving regional ecological construction and sustainable development. Policy has long been considered as one of the major driving forces at national level for land use/cover change. In mainland China, designated and in-depth study on the interaction between land use/cover change and relevant policies is still very limited. Through an integrated technique of geographic information system (GIS), remote sensing (RS), and global positioning system (GPS), the authors attempted to address this issue by using the Maotiaohe watershed in Guizhou province in southwestern China as a case to examine its land use/cover change patterns, and the roles of policies in land use, agriculture, forestry, and eco-environmental protection from 1973 to 2007. The study indicated that land policies contributed largely to the increase of arable land in the 1980s, and helped prevent it from decreasing at the fringe of cities and towns since the 1990s; agricultural policies played active roles in the change of water area and indirectly contributed to the change of construction land. The forestry and eco-environmental policies were found to be the main reasons for the consistent increase of forest land since the 1980s and for the decrease of arable land and rocky desertification land since the 1990s.