长三角城市群城市洪涝韧性与生态系统服务的耦合协调关系

厘清城市洪涝韧性与生态系统服务之间耦合协调关系,可为城市防洪减灾和生态文明建设提供重要决策参考。综合运用基于麻雀算法的投影寻踪模型、InVEST模型和耦合协调度模型,在分析2000-2020年长三角城市群的城市洪涝韧性与水源涵养、水质净化、土壤保持和气候调节四种生态系统服务时空格局基础上,尝试探索两者耦合协调关系及其时空演变特征。研究发现:(1)长三角城市群的城市洪涝韧性水平呈现"N"型增加趋势,并呈现"上海>江苏>浙江>安徽"的空间格局,表明经济水平越高的城市展现出更强的洪涝韧性,经济是影响城市洪涝韧性波动的主要因素,而自然韧性成为城市洪涝韧性提升的关键短板;(2)生态系统服务存在显著的空间异质性,高植被覆盖的南部地区提供了更高的生态系统服务,从时间维度看其空间分布是稳定的,水源涵养和水质净化服务总体呈向好趋势,土壤保持服务整体呈现倒"N"型增加,气候调节服务呈现微弱的下降趋势;(3)城市洪涝韧性与生态系统服务的耦合协调度在研究期内较为稳定,且与生态系统服务的时空变化趋于一致,呈现"南高北低、由西南向东北逐渐减弱"的趋势,生态系统服务较高的城市,表现出更好的耦合协调性,且随着生态系统服务的增加而改善。因此,长三角城市群有必要从提高生态系统服务功能的角度出发,因地制宜、分类施策,促进城市洪涝韧性与生态系统服务的协调发展。

Coupling coordination between urban flood resilience and ecosystem services in the Yangtze River Delta urban agglomerations

With global climate change and continuous urbanization exacerbating flood disasters, urban flood resilience and ecosystem services have become the focus of research. Clarifying the coupling coordination relationship between urban flood resilience and ecosystem services can provide significant decision-making reference for urban flood control, disaster reduction, and ecological civilization construction. Based on the comprehensive application of projection pursuit based on sparrow algorithm model, InVEST model and coupling coordination degree model, this study analyzes the spatiotemporal patterns of urban flood resilience and ecosystem services (water conservation, water purification, soil conservation, and climate regulation) in the Yangtze River Delta urban agglomerations from 2000 to 2020, and attempts to explore the spatiotemporal evolution characteristics of the coupling coordination degree between them. The results show that: (1) The level of urban flood resilience in the Yangtze River Delta urban agglomeration presents a N-shaped trend, with a spatial pattern of Shanghai > Jiangsu > Zhejiang > Anhui, indicating that cities with higher economic levels exhibit stronger urban flood resilience. The impact of economic resilience, social resilience and infrastructure resilience is much greater than that of natural resilience. Economy is the main factor affecting fluctuation in urban flood resilience, and natural resilience is a key weakness in improving urban flood resilience. (2) There is significantly spatial heterogeneity in the ecosystem services, but their spatial distribution is stable from perspective of time dimension. The southern regions with high vegetation cover provide higher ecosystem services. Water conservation and water purification services demonstrate a good trend in general, soil conservation service presents an inverted N-shaped increase, and climate regulation service displays a weak downward trend. (3) The coupling coordination degree between urban flood resilience and ecosystem services is relatively stable during the research period, and tends to be consistent with the spatiotemporal changes of ecosystem services. Among them, the coupling coordination degree between urban flood resilience and water conservation service shows a weak trend of first decreasing and then increasing, with a best overall performance, while the coupling coordination degree between water purification, soil conservation and climate regulation services has a weak decline. From perspective of space, the coupling coordination degree between urban flood resilience and ecosystem services shows a trend of high in the south and low in the north, gradually weakening from southwest to northeast. The cites with higher ecosystem services tend to have better the degree of coupling coordination, and improves with the increase of ecosystem services. Therefore, from perspective of improving ecosystem services, it is necessary for the Yangtze River Delta urban agglomeration to promote the coordinated development of urban flood resilience and ecosystem services according to local conditions and classification.