基于生态安全格局的国土空间生态修复关键区域识别——以贺州市为例

国土空间生态修复是落实生态文明建设战略的重要举措。科学识别国土空间生态修复关键区域,合理布局全域生态修复空间是当前国土空间规划面临的难点之一。以广西壮族自治区贺州市为例,从生态保护重要性、景观连通性、生态功能重要区域和自然保护区四个方面识别生态源地,运用电路理论提取生态廊道,构建生态安全格局。通过电流密度诊断生态廊道中的生态"夹点"和生态障碍点,判定生态廊道宽度,识别国土空间生态保护修复关键区域,制定生态修复的空间布局策略。研究结果表明：（1）市域生态源地面积3656.89 km²,呈"东西重,中部轻"的空间分布特征;生态廊道总长度639.50 km,以中部分布为主,关键生态廊道133.96 km。（2）市域生态"夹点"共16处,面积124.24 km²,主要分布在钟山县,亟待保护修复的生态"夹点"8处,面积45.02 km²,零散分布于市域;生态障碍点共32处,面积426.56 km²,主要分布在市域东部和南部,需优先保护修复的生态障碍点6处,面积166.05 km²,集中在平桂区。通过综合分析国土生态修复关键区域土地利用现状和空间分布特征,制定了分级分类的生态修复措施,以期进一步优化生态安全格局,为国土空间生态修复区域识别和国土空间生态修复规划编制提供参考。

Identifying key areas of ecosystem restoration for territorial space based on ecological security pattern: A case study in Hezhou City

Ecosystem restoration for territorial space is an important measure to implement the strategy of ecological civilization construction. It is vital to scientifically identify key areas of territorial space for ecological restoration, which can help to make policy to maintain the ecosystem integrity. However, how to identify the restoration area is a controversial question in the current territorially spatial planning. In this study, ecological security patterns were employed to identify the key areas of ecological restoration. We followed the paradigm of ecological sources identification-resistance surface construction-corridor extraction to construct the ecological security pattern in Hezhou City, Guangxi Zhuang Autonomous Region. Four kinds of ecological condition including the ecological protection degree, landscape connectivity, ecological important degree and nature reservation areas were used to identify the ecological sources. Then, A Circuitscape model based on circuit theory was used to extract ecological corridors and build the ecological security pattern. After that, the current density of landscape was used to diagnose ecological pinch points and ecological barriers in ecological corridors, and determined the width of ecological corridors. We also established grading rules to identify key areas of territorial space and formulate spatial strategies for ecological restoration. The results showed that Hezhou City has quite good ecological condition, which can identify 18 ecological sources with a total area of 3656.89 km². It also needs 37 of ecological corridors to connect the ecological sources with the total length of 639.50 km. We also found that 16 ecological pinch-points covering area of 124.24 km² need to repair, while 8 ecological pinch points in urgently dangerous condition with area of 45.02 km². There are 32 ecological barriers with area of 426.56 km² and 6 ecological barriers in urgently dangerous condition. After comprehensive understanding the land use policy, we carefully design the spatial planning of ecological restoration through the classification and formulation rules. The study can provide a scientific mode for the identification of ecological restoration in territorial space planning.