流域生态空间与生态保护红线规划方法——以长江流域为例

生态空间是指以提供生态系统服务为主要目标的地域范围,确定生态空间范围是协调保护与发展、保障生态服务持续供给的基础。长江流域是中华民族的摇篮与中国文化发祥地之一,是中国经济发展的重要增长极,以及具有全球意义的生物多样性热点区。以长江流域为对象,探讨面向流域生态空间规划的方法与管理对策。研究中,选择生态系统服务指标(水源涵养、洪水调蓄、水质净化、水土保持和生物多样性维护)和生态敏感性指标(水土流失、石漠化和土地沙化),基于流域水文路径分析和与其关联的生态系统服务的受益人口,提出一种流域尺度的生态空间规划方法。研究结果显示,长江流域生态空间面积为102.25万km^2,占长江流域总面积的57.42%,森林占52.87%,灌丛占19.51%,草地占18.96%,湿地占4.26%,保护了79.47%的水源涵养功能,86.99%的洪水调蓄功能,78.09%的水质净化功能,80.60%的水土保持功能,以及86.49%的自然栖息地。在生态空间规划的基础上,进一步探讨了长江流域生态保护红线的格局,现阶段生态保护红线面积为59.25万km^2,占长江流域总面积的33.27%,其中上游占比59.24%,中游和下游分别占比38.05%和2.71%。本文提出的规划方法与研究结果,不仅可以为长江流域生态空间规划、保障流域生态安全和促进流域经济社会可持续发展提供依据,还可以为其他流域的生态空间的规划提供参考。

A method for evaluating ecological space and ecological conservation redlines in river basins: A case of the Yangtze River Basin

Ecological space refers to the region that aims to provide ecosystem services. Determining the scope of an ecological space is the basis for coordinating conservation and development, and ensuring sustainable supply of ecosystem services. The Yangtze River Basin is the cradle of the Chinese nation; it plays an important role in the economic development of China, and it is a biodiversity hotspot with global significance. In our study, we used the Yangtze River Basin as an example to discuss the watershed-oriented methods of ecological space planning and management policies. On the basis of analysis of the watershed hydrological path and beneficiary populations of its associated ecosystem services, we selected ecosystem service functions (water retention, flood mitigation, water purification, and soil retention) and biodiversity conservation and ecological sensitivity indicators (soil erosion, rocky desertification, and land desertification), and proposed an ecological space planning method at the watershed scale. The results showed that the area of the ecological space in the Yangtze River Basin was 102.25×10⁴ km², accounting for 57.42% of the total area of the basin. The forest, shrub, grassland, and wetland accounted for 52.87%, 19.51%, 18.96%, and 4.26% of the total area of the ecological space, respectively. The ecological space of the Yangtze River Basin could conserve 79.47%, 86.99%, 78.09%, 80.60%, and 86.49% of the total amount of the water retention service, flood mitigation service, water purification service, soil retention service, and natural habitat, respectively. On the basis of the ecological space determined by us, the spatial pattern of the ecological conservation redline was analyzed. The area of the ecological conservation redline was 59.25×10⁴ km², accounting for 33.27% of the total area of the basin; the redline areas within the upper reaches, middle reaches, and lower reaches accounted for 59.24%, 38.05%, and 2.71% of the whole redline area, respectively. Our study is not only the basis for ecological space planning of the Yangtze River Basin, ensuring the basin''s ecological safety and sustainable development of the economy and society, but also referential for similar ecological space planning of other river basins.