Acta Scientiarum Naturalium Universitatis Pekinensis

An Integrated CA-Markov Model for Dynamic Simulation of Land Use Change in Lake Dianchi Watershed

HE Dan, ZHOU Jing, GAO Wei, GUO Huai-cheng, YU Shu-xia, LIU Yong

Abstract: Land use change can cause changes in many natural phenomena and ecological processes and is also one of the primary factors that cause changes in environmental degradation of growing urbanization area. Studying the land use change can provide important information for decision-making of regional ecological environment construction. Taking Lake Dianchi Watershed as study area, the dynamics change degree of land use types in the watershed was analyzed based on Interpretation data from TM image in 1990 and 1999. The direction of land use conversion was quantitatively analyzed by land use transfer matrix based on the Markov model. Meanwhile, land use change tendency of 2008 was simulated and forecasted based on land use conversion rules which were defined by multi-criteria evaluation method form GIS and CA-Markov model. Comparing with the interpretation data of 2008, Kappa coefficient of the simulated results was 0.7338, which indicating that the simulated results were credible. Based on the above, the spatial patterns of land use change in 2017 and 2026 were simulated by using CA-Markov model. The results showed that land use change is also active in this watershed and ecological restoration and reconstruction is still confronted with pressure. Farmland, forest, water and unused land will reduce from 2008 to 2026, while the grassland and construction land will continue to increase. Comparing with 1990 to 2008, the simulated result indicated that farmland, forest and construction land from 2008 to 2026 would keep the same change trend while grassland, water and unused land showed the opposite change trend. Construction land will expand on the basis of the present and the change of water is little. Although forest resources will decrease in future, it is still the main land use types in watershed. Construction land expansion significantly increased the load of non-point source pollution in Dianchi. Land use that is unreasonable is one of major causes of the water quality degradation in Dianchi Lake currently, and that is going to increase the pressure on the water environment and ecology of water basin in the future. Therefore, to maintain enough arable land per capita, lower fertilization strength, improve land utilization levels, keep a sufficient amount of ecological land,use construction land frugally and intensively, is an important measure to reduce the potential of non-point source pollution in the area. The research can provide decision support for planning and management reasonably of land use and ecological restoration and economic development policies to develop in the watershed.

Keywords: Land Use change; CA-Markov; MCE; Dynamic Simulation; Lake Dianchi Watershed