Analysis of the land use changes based on remote sensing and GIS: a case study of the Dongting Lake area

By using the Landsat TM and ETM data which were acquired in 1989～1990 and 1999～2000 respectively, the characteristics of land use changes in the Dongting Lake area on scale of 100000 were analyzed. The result revealed that cultivated land area decreased by 0.9×10⁴ hm², and the proportion in total area declined by 0.32% during the 10 years. The built-up land and water area expanded by 0.75×10⁴ hm² and 0.16×10⁴ hm² respectively, and correspondingly the proportion increased by 0.26% and 0.06%. Changes of woodland, grassland and unused land were small. Large-scale reclamation that was a popular method to get arable land before 1980s has been limited. There are significant shifts among cultivated land, water body and built-up land. From 1990～2000, most of the lost arable land was converted to water body (including fish pond) and built-up land. Seventy-four percent of increased built-up land was obtained at the expense of cultivated land, while 21 percent of woodland was used. On the whole, the land use changes from 1990～2000 in the study area have been driven by urbanization and industrialization, infrastructure and agricultural intensification. The rapid growth of population and economics play an important role in the land use changes, and the advances in techniques also give rise to the changes obviously. To a great extent, the polices on land use, land price and taxes levied on agricultural products have definitively influences on the land use changes. In view of the results mentioned above, future land use and land consolidation, some strategies and polices should be reoriented to attenuate the conflicts among the protection of cultivated land and ecosystem and social-economic needs for land.