Simulation and prediction of land use change in Three Gorges Reservoir Area based on MCE-CA-Markov

Abstract: In order to achieve better coordination between land use and ecological environment in the Three Gorges Reservoir Area, this paper explored the pattern and mechanism of the evolution of land use since the reservoir was built and impounded. Based on Landsat TM image data of the Three Gorges Reservoir Area in 2000, 2007 and 2014, the first step of the research was to obtain basic information of present land use through ArcGIS 10.1, then generate land use change map to analyze land use changes in 2000-2014, and calculate land use transfer matrix to analyze the flow characteristics of land use in the Three Gorges Reservoir Area in 2000-2007 and 2007-2014, respectively. Second, multi-criteria evaluation (MCE) - cellular automata Markov chain (CA-Markov) model was used to simulate self-organizing evolution of land use in the reservoir area. In particular, the MCE model was used to make maps of land use suitability and the CA-Markov model was used to calculate the land use transfer matrix. The accuracy of MCE-CA-Markov simulation was tested against multi-temporal remote sensing images and the Kappa coefficient was found to be 0.971 2. Third, land use structure in 2028 was forecasted with the tested constraints and the combinations of factors of land use evolution. Overall, findings included: 1) It was feasible to simulate land use evolution with MCE-CA-Markov. 2) During 2000-2014, types of land use change areas, sorted from large to small, were stable change > late change > early change > repeated changes > continuous change. Especially, areas of cropland and forestland were mainly changed to water area and construction land, while the changes of the areas of grassland and unused land were not very obvious and scattered in space due to their smaller areas. 3) The land use pattern in 2014 from the simulation was consistent with that from interpreted remote sensing images and the relative accuracy reached 84.48% after verification. 4) Our model predicted that, up to 2028, cropland and forestland are still 2 main land use types in the Three Gorges Reservoir Area although their areas continue to decline. Most of their areas change to water area and construction land. The areas of water and construction land will continue to increase and they expand mainly around their original sites. Compared to the period of 2000-2014, their future increases will be bigger. Grassland and unused land are still scattered and have smaller changes. In general, the prediction shows that land use change is very active in the Three Gorges Reservoir Area and, by 2028, the pressure for ecological environment restoration and reconstruction in the reservoir area is still very high. Therefore, it is urgently needed to strengthen the protection of cropland, forestland and grassland in the Three Gorges Reservoir Area, to control and prevent blind reclamation of cropland and illegal construction, to correctly balance economic development and ecological environment and to protect and improve the ecological environment in the reservoir area. This research is expected to provide theoretical support for land use planning, urban construction and ecological environment restoration in the Three Gorges Reservoir Area.