城市低效用地更新为绿色基础设施优先度评价

Priority evaluation of urban inefficient land renewal to green infrastructure

在以存量更新促进城市可持续发展的时代,将城市低效用地有序更新为绿色基础设施(Green Infrastructure,GI)是实现城市建成区生态空间再造和生态格局优化的可操作路径。现有低效用地的更新优先度评价多将经济效益作为发展潜力的判断依据,未能很好地考虑地块的潜在生态效益。以广西桂林市中心城区为例,采用层次分析法、熵权法和TOPSIS方法,从经济和社会效益角度构建综合指标体系定量评价城市低效用地的更新潜力,在此基础上,基于最小费用路径和电路理论方法,采用标准化最小费用廊道值与中心性值,评价低效用地对提升研究区景观连通性的重要性,最后利用二维判别矩阵方法,综合更新潜力与重要性分析结果,对低效用地更新为GI的优先度进行了评判。结果表明:(1)研究区更新潜力等级较高的低效用地面积占比达38%,集中分布在研究区西部和北部。(2)低效用地更新后充当廊道和踏脚石的潜力存在显著差异,对提升景观连通性重要性较高的低效用地面积占比达40%,主要分布在研究区北部、西部和南部。(3)低效用地更新潜力评价结果和基于景观连通性提升的重要性评价结果在部分区域差异明显,更新为GI优先度较高的低效用地主要分布在研究区北部和西南部,应根据其不同优先度等级采取差异化的更新规划措施。研究结果可为城市低效用地再开发的规划实践和绿色基础设施网络格局优化提供新框架和决策参考。

In the period of promoting urban sustainable development by stock renewal,orderly renewal of urban inefficient land to green infrastructure(GI)is an operational path to realize the reconstruction of ecological space and the optimization of ecological pattern in urban built-up area.In the existing researches,the evaluation of renewal priority of urban inefficient land mostly takes economic benefits as a basis of judging the development potential,and fails to consider the potential ecological benefits of the land parcels.Taking the downtown area of Guilin city as an example,this paper constructed a comprehensive index system to quantitatively evaluate the renewal potential of urban inefficient land from the perspective of economic and social benefits by using analytic hierarchy process,entropy weight method and TOPSIS method.Then,using the Least-Cost Path and the Circuit Theory method,we adopted the normalized least cost corridor value and the centrality value to evaluate the relative importance of urban inefficient land for the improvement of landscape connectivity in the study area.Finally,using two-dimensional discriminant matrix method,the priority of urban inefficient land renewal to GI was evaluated by integrating the results of renewal potential evaluation and importance analysis.The results showed that:(1)the area of inefficient land parcels with high renewal potential accounted for 38%,which were relatively concentrated in the west and north of the study area.(2)The renewal of inefficient land to GI could significantly improve the overall landscape connectivity of the study area,and for these inefficient land parcels,there were significant differences in their potential of serving as corridors and stepping stones after renewal.The area of inefficient land parcels which were highly important for improving landscape connectivity accounted for 40%,and they were mainly distributed in the north,west and south of the study area.(3)There were obvious differences between the results of inefficient land renewal potential evaluation and the results of importance analysis based on the improvement of landscape connectivity in some regions.The area of inefficient land parcels with high priority for renewal accounted for 21%,and they were mainly distributed in the north and southwest of the study area.For these inefficient land parcels,different renewal planning measures should be taken according to their different renewal priority grades.The research results can provide a new method framework and decision-making reference for the planning practice of urban inefficient land redevelopment and the optimization of green infrastructure network patterns.