Gao Meng-Wen, Hu Ye-Cui, Liu Xin-Wei, Liang Meng-Yin, Kong Fan-Jie, Bai Yu-Ping
1 School of Land Science and Technology, China University of Geosciences, Beijing 100083, China.
2 Key Laboratory of Land Consolidation and Rehabilitation, Ministry of Natural Resources, Beijing 100035, China.
Ying Yong Sheng Tai Xue Bao. 2024 Jun;35(6):1661-1670. doi: 10.13287/j.1001-9332.202406.023.
Water ecological restoration zoning, which involves articulating goals for restoring water ecosystems upwards and guiding the spatial layout of restoration projects downwards, is key to achieving systematic restoration of water resource elements. There are many challenges in water ecological restoration zoning, including disparate hierarchical systems, incomplete indicators, and vague boundaries. With Guangxi Hechi, a karst ecologically fragile region, as a case, we developed a multidimensional zoning system framework based on "watershed natural unit-dominant ecological function-ecological stress risk". The first-level zoning employed river systems and geomorphic types as indicators and delineated the sub-watershed unit as the boundary. The second-level zoning adopted a "top-down" division method to clarify the goal of water ecological restoration based on watershed natural geography and select three indicators (water conservation, biodiversity, and landscape cultural services) for evaluation. We used the K-means clustering method to identify dominant ecological functions in spatial units, with the sub-watershed unit demarcating second-level zoning boundaries. The third-level zoning was the specific implementation unit for ecological restoration projects. We used three indicators (soil erosion, flooding risk, and human interference) to characterize water ecosystem risk from external coercion, and defined the third-level zoning. We delineated 11 primary water ecological zones, four secondary zones, and three tertiary zones. Synthesizing tertiary zoning results accounted for spatial differentiation characteristics of watershed natural geography, dominant ecological functions, and ecological coercion risks, and combining sub-watershed and township administrative units determined zoning boundaries, water ecological restoration zoning was comprehensively classified into five categories and 32 sub-ecological zones. Corresponding ecological restoration strategies were proposed based on zoning and classification.
水生态修复分区，即向上明确水生态系统修复目标，向下指导修复工程的空间布局，是实现水资源要素系统修复的关键。水生态修复分区存在诸多挑战，包括层级体系不一、指标不完善、边界模糊等。以喀斯特生态脆弱区广西河池为例，我们构建了基于“流域自然单元-主导生态功能-生态胁迫风险”的多维分区体系框架。一级分区以水系和地貌类型为指标，划定以子流域单元为边界。二级分区采用“自上而下”的划分方法，依据流域自然地理明确水生态修复目标，并选取三个指标（水源涵养、生物多样性、景观文化服务）进行评价。利用K均值聚类法识别空间单元中的主导生态功能，以子流域单元划定二级分区边界。三级分区是生态修复工程的具体实施单元。我们采用三个指标（水土流失、洪水风险、人为干扰）表征水生态系统受外界胁迫的风险，并划定三级分区。我们划定了11个一级水生态区、4个二级区和3个三级区。综合三级分区结果，兼顾流域自然地理、主导生态功能和生态胁迫风险的空间分异特征，结合子流域和乡镇行政单元确定分区边界，将水生态修复分区综合划分为5大类32个亚生态区。并基于分区与分类提出了相应的生态修复策略。
