考量生态系统服务供需关系的流域城市 生态空间优化研究——以青弋江流域泾县段 为例

Ecological Space Optimization in River BasinCity Based on Ecosystem Service Supply andDemand: A Case Study of Jing Country Section ofQingyi River Basin

关键词:  风景园林  生态系统服务供需  流域城市  生态空 间  情景模拟  青弋江

Key words:  landscape architecture  ecosystem service supply and demand  river basin city  ecological space  scenario simulation  Qingyi River

摘要:

快速城市化阶段，流域城市对生态系统服务的需求 与日俱增，生态系统服务供需失衡加剧，厘清及优化流域城市 生态系统服务的供需关系对于流域生态保护与经济发展的协同 具有重要意义。以长江下游最大支流——青弋江所贯穿的安徽 省泾县为例，运用生态系统服务空间定量评估方法，测算固碳 释氧、水文调蓄、土壤保持、生境支持、粮食生产、休闲游憩 6种关键生态系统服务的供需水平；通过四象限法，判定供需 关系并辨明平衡、赤字、盈余3类区域；以供需平衡为目标， 基于“保护平衡区与赤字区，开发盈余区”的策略设定用地情 景，利用CA-Markov模型获取供需约束的生态空间布局。结 果表明：1)生态系统服务供给的分布以高质量生态要素为基 底，呈南高北低态势，需求分布与人类活动集中区较吻合，在 县域中部和南部突出；2)研究区供需关系整体匹配，平衡区占 比最大，盈余区其次，赤字区最小；3)供需约束情景在非生 态空间向生态空间转入上表现较好，能增加林地、水域、草地 3类重要生态资源的存量，且在形态上可维护大型生态斑块的 完整性并引导城镇空间走向紧凑；4)依据供需关系设定的生态 保护空间与生态保护红线在平衡区较一致，但在盈余区与赤字 区，后者出现“开天窗”式的管控缺口，使青弋江破碎，而前 者未有该现象。

Abstract:

In the rapid urbanization phase, the demand for ecosystem service in river basin cities has been increasing, exacerbating the imbalance between ecosystem service supply and demand. Clarifying and optimizing the ecosystem service supply-demand relationship in river basin cities is of great significance for achieving synergies between regional ecological conservation and economic development. Taking Jing County, traversed by Qingyi River, the largest tributary of the lower Yangtze River, as an example, this study applied an ecosystem service spatial quantitative assessment method to measure six key ecosystem services supply-demand levels: carbon sequestration and oxygen release, rainwater retention, soil conservation, biodiversity, food production, and recreational activities. By using the quadrant model, the ecosystem service supply-demand relationship was determined, and the region was classified into three categories: balance, deficit, and surplus. With the goal of supply-demand balance, land-use scenario was set based on the strategy of "conserving balanced and deficit areas while developing surplus areas". The CA-Markov model was employed to obtain the ecological spatial layout under supply-demand constraint. The results indicate: 1) The distribution of ecosystem service supply relies on high-quality ecological elements and shows a trend of being higher in the south and lower in the north. The distribution of ecosystem service demand aligns relatively well with areas of human activity, particularly in the central and southern parts of the county. 2) The overall ecosystem service supplydemand relationship is relatively balanced, with the largest proportion in the balanced category, followed by the surplus category, and a smaller proportion in the deficit category. 3) The supply-demand constraint scenario demonstrates a favorable transition from non-ecological to ecological space, allowing for an expansion of important ecological resources such as forests, water bodies, and grasslands. It also maintains the integrity of large ecological patches and guides urban areas towards compactness. 4) The designated ecological conservation space and ecological conservation red line based on the supply-demand relationship align well in the balanced area. However, in the surplus and deficit areas, the latter exhibits a control gap known as the "skylight" phenomenon, leading to fragmentation in Qingyi River, which has not been observed in the former.