汉江流域生态综合网络构建与生态安全格局识别研究

Research on the Construction of Ecological Integrated Network and Identification of Ecological Security Pattern in the Han River Basin

汉江流域生态环境优越、自然资源丰富,是“南水北调”的重要水源区,也是连接我国中西部地区社会经济发展的重要纽带,近年来水土流失加剧,洪涝灾害频发,已影响流域社会经济可持续发展,生态安全格局科学构建有利于生态系统保护和生态风险防控。基于景观生态学“斑块—廊道—基质”理论,分别从生态系统服务和生态风险两方面构建汉江流域生态综合网络,通过分析网络要素结构识别生态安全格局。研究发现:(1)流域生态系统调节功能极重要区占流域总面积的25.71%,主要集中在秦巴山地和汉江流域下游地区;生态极敏感区占流域总面积的9.18%,零星分布在汉江谷地、南阳盆地和江汉平原。(2)通过生态网络识别出生态源19个、生态廊道34条、生态保护节点14处,呈现出“大分散、小聚集”的格局;通过生态风险网络识别出风险源22个、生态风险廊道43条、生态修复节点15处,呈现出“大分散”的格局。(3)汉江流域呈现出“西高东低、南高北低”的生态安全格局,保护斑块、保护廊道和保护节点多位于秦巴山地;修复斑块、修复廊道和修复节点多集中在汉江谷地和流域中下游地区;保护与修复节点多位于汉江流域上游地区。(4)秦巴山地承担着保障流域中下游地区生态安全的功能,需要构建山地生态安全屏障;河流水系是生态风险网络中胁迫因子扩散的主要廊道,流域生态保护与修复亟待重视。构建的生态风险网络可进一步完善流域生态安全格局识别方法,并为汉江流域生态环境改善和国土空间高效利用提供参考依据。

The Hanjiang River Basin has superior ecological environment and abundant natural resources.It is an important water source area for the'South-to-North Water Diversion'and an important link connecting the social and economic development of the central and western regions of China.In recent years,soil erosion has intensified and floods have occurred frequently,which affected the sustainable development of the basin's social economy.The scientific construction of the ecological security pattern is conducive to ecosystem protection and ecological risk prevention and control.Based on the'patch-corridor-matrix'theory of landscape ecology,this paper constructed an ecological comprehensive network of Hanjiang River Basin from two aspects of ecosystem services and ecological risks,and identified the ecological security pattern by analyzing the structure of network elements.This study found that:(1)The extremely important areas of watershed ecosystem regulation function accounted for 25.71%of the basin,which were located mainly in the Qinba Mountains and the lower reaches of the Hanjiang River Basin;The ecologically extremely sensitive areas accounted for 9.18%of the basin,and were scattered in the Hanjiang Valley,Nanyang Basin and Jianghan Plain.(2)In terms of the ecological network,19 ecological sources,34 ecological corridors and 14 ecological protection nodes were identified,showing a pattern of'large dispersion and small aggregation'.In terms of the ecological risk network,22 risk sources,43 ecological risk corridors and 15 ecological restoration nodes were identified,showing a pattern of'great dispersion'.(3)The Hanjiang River Basin presented an ecological security pattern of'high in the west and low in the east,high in the south and low in the north'.The protection patches,protection corridors and protection nodes were mostly located in the Qinba Mountains.Restoration patches,restoration corridors and restoration nodes were mostly concentrated in the Hanjiang River valley and the middle and lower reaches of the basin.The protection and restoration nodes were mostly located in the upper reaches of the Hanjiang River Basin.(4)The Qinba Mountains bore the function of ensuring the ecological security of the middle and lower reaches of the basin,and it was necessary to build a mountain ecological security barrier;The river system was the main corridor for the diffusion of stress factors in the ecological risk network,and the ecological protection and restoration of the river basin should be paid high attention.The ecological risk network constructed in this study further improved the identification method of watershed ecological security pattern,and provided reference for the improvement of ecological environment and the efficient utilization of land space in the Hanjiang River Basin.