长江经济带生态系统格局特征及其驱动力分析

为了分析长江经济带生态系统的变化及其驱动力，采用生态系统年变化率、动态度、景观格局指数研究2000—2015年长江经济带生态系统格局特征，并分析城镇化、生态保护与修复等驱动力的贡献.结果表明:①长江经济带生态系统以林地、农田和草地为主，三者共占92.63%；上、中游以林地为主；下游城镇化率最高，分布着全区60.47%的城镇用地、39.85%的湿地和28.62%的农田.②长江经济带生态系统年变化以江苏省、上海市和浙江省为代表，快速城镇化特征显著；贵州省、江西省、云南省林地和草地的年变化较显著.③长江经济带生态系统生境破碎化和景观多样性指数均上升.④长江经济带上中下游均表现为建设用地增幅最大，农田减幅最多.⑤快速城镇化是长江经济带生态系统格局变化的首要驱动力，贡献率为65.49%，表现出“下游为重心，向中上游蔓延”的特征，下游贡献率为77.51%，但上游在2010—2015年的扩张速率远超过中游和下游；生态保护与恢复政策为第二大驱动力，贡献率为17.64%，上游贡献为25.90%.研究显示，保障长江经济带生态可持续发展需要优化国土空间结构、控制开发强度、加强生态环境保护联防联治. 

Spatial Pattern of Ecosystems and the Driving Forces in the Yangtze River Economic Zone

In order to analyze the changes of ecosystems and its driving forces in the Yangtze River Economic Zone, the annual change rate, and the dynamic degree and the driving force contribution rate of the ecosystem were used to study ecosystem changes driven by urbanization, ecological protection and restoration during 2000-2015. The results showed that:(1) Forestland, farmland and grassland were the main land types in the Yangtze River Economic Zone. The upper and middle reaches were dominated by woodland, and the lower reaches had the highest urbanization rate, of which the urban area accounts for 60.47%, the wetland accounts for 39.85%, and the farmland accounts for 28.62%. (2) Jiangsu Province, Shanghai City and Zhejiang Province represented the annual changes of ecosystem, with remarkable urbanization rate. Guizhou Province, Jiangxi Province and Yunnan Province have remarkable annual changes in forest and grassland. (3) Both indexes of ecosystem fragmentation and landscape diversity increased in the study area. (4) The upper, middle and lower reaches showed the greatest increase in construction land and the greatest decrease in farmland. (5) The primary driving force for the ecosystem evolution was rapid urbanization with 65.49% of the contribution rate and the lower reaches contributed 77.51%. It showed a pattern of 'the greatest influence of urbanization was exerted to the lower reaches, radiating to the middle and upper reaches', and the urbanization expansion during 2010-2015 in the upper reaches was much faster than that in the middle and lower reaches. The second driving force was the policies of ecological protection and restoration with 17.64% of the contribution rate, and the upper reaches contributed to 25.90% of the changes. The research shows that in order to guarantee the ecological sustainable development of the Yangtze River Economic Zone, it is necessary to optimize the territorial spatial structure, control exploitation intensity, and strengthen the coordinated efforts in control and treatment of pollution for better ecological and environmental protection.