基于生态系统服务的生态安全格局构建与生态韧性评估——以长株潭城市群为例

构建生态安全格局对于保障区域生态安全、优化国土生态空间具有重要意义,科学评估生态韧性是城市高质量发展的重要议题之一。以长株潭城市群为研究对象,基于"源地识别-阻力面构建-廊道提取"的生态安全格局构建模式,定量评估固碳释氧、土壤保持和水源涵养三项生态系统服务功能以识别源地,结合自然和人为因素构建阻力面,使用Linkage Mapper工具基于最小成本路径理论识别生态廊道,提出了一套基于生态安全格局构建过程的生态韧性评估框架,并结合Fragstats和Conefor Sensinode软件对其进行综合评价。研究结果显示:(1)长株潭城市群共55块生态源地,面积为7747.75km²,占城市群总面积的27.58%,东部和南部源地较为集中,西部较分散,林地是生态源地的主要组成部分;生态廊道共113条,廊道总长度为1458.97km,平均长度为12.91km,主要分布于研究区西部和北部。(2)结合生态源地和生态廊道构建了长株潭城市群"一心一环"生态安全格局,可有效缓解长株潭城市群中部生态用地 "空心化"的格局。(3)研究区55块生态源地的韧性指数介于0.1265-0.4682之间,空间上呈现出东高西低,南高北低的特征;113条生态廊道的韧性指数介于0.0027-0.8002之间,韧性指数较高的廊道主要分布在研究区东部和南部,韧性指数较低的廊道分布在西部、中部和北部。西部和中部或将成为影响长株潭城市群生态安全的关键区域,在城市规划过程中应重点关注。研究结果对优化城市空间布局、维护区域生态安全和促进区域一体化发展具有重要意义,并为区域生态韧性的评估提供了新的思路。

Construction of ecological security pattern and assessment of ecological resilience based on ecosystem services: a case study of Changsha-Zhuzhou-Xiangtan urban agglomeration

Construction of ecological security pattern is of great significance for ensuring regional ecological security and optimizing the territorial ecological space. Ecological resilience assessment is an important issue for high quality urban development. Taking Changsha-Zhuzhou-Xiangtan (CZT) urban agglomeration as the study area, the ecological security pattern (ESP) was constructed based on the method of ecological source identification-resistance surface construction-ecological corridor extraction. Key ecosystem services such as carbon sequestration and oxygen release, soil conservation, and water conservation were evaluated to identify the ecological sources. The resistance surfaces were constructed by integrating natural conditions and human influences. Ecological corridors were identified by using Linkage Mapper tool based on the least cost path theory. An ecological resilience assessment framework was proposed based on the construction of ecological security pattern, then the ecological resilience was assessed by using Fragstats and Conefor Sensinode. The results showed that: (1) There were 55 ecological sources in the CZT urban agglomeration, with a total area of 7747.75 km², accounting for 27.58% of the CZT urban agglomeration. The ecological sources were mainly located in the east and south, and few were in the west. Forest land was the main component of ecological sources. There were 113 ecological corridors with a total length of 1458.97 km. The length of the ecological corridors ranged from 0.04 km to 102.70 km, and the average length of the corridors was 12.91 km. Most ecological corridors were distributed in the west of the study area. Few were distributed in the center of the study area. (2) Combining the ecological sources and ecological corridors, the "one point and one circle" ecological security pattern of CZT urban agglomeration was constructed. It improved the central area''s ecological condition of CZT urban agglomeration. (3) The resilience index of 55 ecological sources in the study area ranged from 0.1265 to 0.4682. The resilience index of the ecological sources was high in the east and south, but low in the west and north. The resilience index of 113 ecological corridors ranged from 0.0027 to 0.8002. Corridors with high resilience were mainly distributed in the east and south of the study area, while corridors with low resilience were distributed in the west and north areas. The resilience index of ecological corridors in the center of the study area was also low. However, these corridors played an important role in balancing urban development and environmental protection and needed to be protected. The western and central parts of the study area might become the key areas that affect the ecological security of the CZT urban agglomeration the most, and should receive special attention in the process of urban planning. The results can help to optimize urban spatial layout, maintain regional ecological security and promote regional integration development, and provide new insights for assessing regional ecological resilience.