2000年以来长江经济带土地利用时空演化分析与模拟研究

Analysis and simulation of spatio-temporal evolution of land use in the Yangtze River Economic Belt since 2000

开展土地利用空间格局分析与模拟是国土空间规划优化管控的重要依据,对促进区域生态文明建设和土地节约集约利用具有重要意义.以长江经济带为研究区域,基于2001年、2009年、2017年三期MODIS全球500m土地利用数据,采用元胞自动机马尔科夫模型(cellular automata Markov,CA-Markov)和多准则评价方法(multi-criteria evaluation,MCE),进行长江经济带的土地利用时空演化模拟.结果表明:1)2017年土地利用模拟结果与实际土地利用分类结果交叉验证,Kappa系数为0.8942,表明利用CA-Markov模型和MCE方法进行土地利用时空演化模拟是可行的.2)2000年以来,长江经济带针叶林、阔叶林和混交林的面积明显增加,分别增加0.42万km^2、2.67万km^2和2.44万km^2,而热带多树草原、热带稀树草原和草地分别减少4.76万km^2、1.2万km^2和0.91万km^2,说明我国西部草场转化为林地较为显著.长江经济带土地利用类型发生变化的区域达到33.53%,其中农用地和热带稀树草原之间的相互转移最为活跃,表明长江流域防护林体系建设正在稳步推进,长江经济带实行的退耕还林还草政策,已经在农用地的整治和质量优化中初步见成效,对生态保护和恢复发挥了显著作用.3)模拟结果表明,目前到2025年,长江经济带热带稀树草原的面积将继续增长,达到3.84万km^2,主要得益于退耕还林还草等生态恢复政策的持续推进.但热带多树草原面积减少最大,达到了2.68万km^2,将在一定程度上影响林地的整体生态功能效应,应引起一定的重视.农用地减少的面积仅次于热带多树草原,为2.27万km^2,预示着长江经济带全域范围需要继续加强监管耕地红线,并进一步提升城市土地节约集约利用的力度,实现区域可持续发展的目标.

Analyzing and simulating the spatial pattern of land use is important basis for optimizing the management and control of land spatial planning, and is of great significance for promoting the construction of ecological civilization and the intensive use of land conservation.Based on MODIS Global 500 m land use data of 2001, 2009 and 2017, this paper uses Cellular Automata Markov (CA-Markov) model and Multi-Criteria Evaluation (MCE) method to simulate the spatial and temporal evolution of land use in the Yangtze River Economic Belt (YREB).The results show as follows.1) The Kappa coefficient is as high as 0.894 2 by cross-validating the results of land use simulation and actual land use classification in 2017, which indicates that it is feasible to use CA-Markov model and MCE method to simulate the spatial and temporal evolution of land use.2) Since 2000, the area of coniferous forest, broad-leaved forest and mixed forest in the YREB increased significantly by 4 200 km^2, 26 700 km^2 and 24 400 km^2, respectively, while the area of tropical multi-savanna, savanna and grassland decreased by 47 600 km^2, 12 000 km^2 and 9 100 km^2, suggesting that the grassland in western China has been seriously degraded.The change of land use types in the YREB is 33.53%, among which the transfer between agricultural land and tropical savanna was the most active, implying that the construction of shelter forest system in the Yangtze River Basin is steadily advancing.The policy of returning farmland to forestry and grassland in the Yangtze River Economic Zone has achieved preliminary results in the improvement and quality optimization of agricultural land, and has played a significant role in ecological protection and restoration.3) The simulation results show that the area of tropical savanna in the YREB would continue to increase to 38 400 km^2 in 2025, which is due to the promotion of ecological restoration policies such as returning farmland to forests and grasslands.However, the area of tropical multi-tree grassland has decreased the most, reaching 26 800 km^2, which will affect the overall ecological function of forest land to a certain extent and should be paid attention to.The area of agricultural land decreased by 22 700 km^2, second only to tropical multi-tree grassland, which indicates that continuously strengthening the supervision of the red line of cultivated land and enhancing the intensive use of urban land are required to achieve regional sustainable development in YREB.