基于生态系统服务价值的城市增长边界划定研究:以衡阳市中心城区为例

Delimitation of Urban Growth Boundaries Based on Ecosystem Service Value:A Case Study of Hengyang Central Area.

科学评估土地生态价值,并将其纳入城市规划实践,是落实国家生态文明战略要求的重要手段。城市增长边界是统筹城市开发建设与区域生态保护的重要政策工具,针对以往划定方法对生态系统服务功能考虑不足的问题,提出一种新的城市增长边界划定方法。以衡阳市中心城区为例,基于反规划理念,以2005—2015年区域生态系统服务价值评估为基础构建生态安全格局,通过耦合城市生态安全格局与基于未来土地利用模拟(future land use simulation,FLUS)模型的城市扩张模拟结果划定城市增长边界。结果表明:(1)2005—2015年衡阳市中心城区生态系统服务价值总量从25.71亿元下降到24.75亿元,水文调节和水资源供给服务功能价值量呈上升趋势,其余各项生态系统服务价值呈下降趋势。(2)研究区城市刚性增长边界面积为17325.72 hm 2,主要沿湘江及其支流蒸水和耒水分布,形成“三廊、三片”的空间结构。(3)2030年城市弹性增长边界面积为20238.57 hm 2,空间形态呈“一个中心区、多个组团”分布。考虑生态系统服务功能的限制开发条件后,研究区生态用地得到更多保护,区域生态系统服务总价值比基准情景高0.61亿元,更利于区域生态系统服务功能的维持和区域生态安全的发展。该研究方法和结果可用于科学评估城市扩张的生态成本,有效解决城市发展与生态保护之间的矛盾,同时也可为城市总体规划、生态保护专项规划以及国土空间规划提供重要依据。

An urban growth boundary policy is an important tool for integrating urban development and regional ecological protection plans.Incorporating the ecosystem service value of land into the urban planning process can help to implement the national strategy for ecological civilization in China.Previous delimitation mechanisms in studies of urban growth boundaries have rarely taken the ecosystem service value of land into account.Therefore,we designed a mechanism that combines an ecological security pattern(based on 2005-2015 data from ecosystem service value evaluations)with the future land use simulation(FLUS)model to delimitate the urban growth boundary in the Hengyang central area.It is found that:(1)the total ecosystem service values decreased from 2.571 billion yuan to 2.475 billion yuan from 2005 to 2015,the value of hydrological regulation and water supply service functions showed an upward trend,whereas the other ecosystem service values showed a downward trend;(2)17325.72 hm 2 of urban rigid growth boundary is distributed along the Xiangjiang River and its tributaries,Zhengshui and Leishui,and has formed a“three corridors and three pieces”space structure;(3)the area of urban elastic growth boundary in 2030 is projected to be 20238.57 hm 2 and will be distributed as“one central area and multiple groups”with the ecological land in the study area more protected in 2030 than today;(4)an increase of 0.061 billion yuan in ecosystem service value indicates that given the limited development of the Hengyang central area,ecosystem service functions will help to maintain its regional ecosystem services and develop its regional ecological security.These results indicate that the delimiting mechanism used to study urban growth boundaries can scientifically evaluate the ecological cost of urban expansion and effectively resolve the contradiction between urban development and ecological protection.Thus,these findings provide a foundation for urban master planning,ecological protection planning,and national territory development planning.