区域尺度下道路网络对生态格局及生态网络的影响:以成渝城市群为例

The Impact of Road Network on Ecological Patterns and Networks at a RegionalScale:A Case Study of the Chengdu Chongqing Urban Agglomeration

在高质量发展国土空间布局背景下,科学评价和分析道路的生态影响对协调生态环境和经济社会可持续发展具有重大意义。选取成渝城市群为研究对象,基于2020年土地利用和交通数据,结合MSPA法、景观连通性指数和MCR模型构建生态网络,通过道路网络模型量化道路综合影响值,再运用景观格局指数、图论法和核密度分析法,点线面结合对比分析。结果显示:(1)研究区生态源地占总面积的51.37%,斑块间连通性良好,但在道路网络影响下生态源地数量增加56.00%,总面积减少了14640.21 km ^(2);(2)生态网络布局发生变化,重要廊道的长度降幅高达45.80%,α、β、γ指数分别下降76.67%、38.86%和40.54%;生态关键点的数量减少了17.80%,生态干扰点的高密度分布区呈现以成都和重庆为中心的“双核”发展趋势。研究表明,道路出现导致研究区约51.41%的生境丧失,其中道路沿线景观和优势景观的景观连接度受到严重影响,整体呈现生态格局破碎化、景观分布均衡化的趋势;生态源地的连接水平与网络连通率降低使得生态网络中的环路数量偏少,重要廊道长度减少了1890.43 km,生态关键点数量减少、距离拉远削减了生态源地间的物种交流,导致生态网络的生态效能降低,生态安全格局稳定性减弱。最后从源地保护和道路选线方面提出建议:在优先保护生态核心源地的同时,采用将交通量引导至已建高等级道路,低等级道路集中紧凑发展的策略,减少路网拓展对生态斑块的分割,以期为成渝地区生态空间保护提供参考。

In the context of high-quality development of land spatial layout,scientific evaluation and analysis of the ecological impact of roads is of great significance for coordinating the ecological environment and sustainable economic and social development.Based on the land use and transportation data in 2020,the ecological network was constructed based on the MSPA method,landscape connectivity index and MCR model,and the comprehensive impact value of the road was quantified through the road network model.The results showed that:(1)The ecological source areas in the study area accounted for 51.37%of the total area,and the connectivity between patches was good,but the number of ecological sources increased by 56.00%and the total area decreased by 14640.21 km ^(2) under the influence of road network.(2)The layout of the ecological network changed,and the length of important corridors decreased by 45.80%,and theα,β,andγindices decreased by 76.67%,38.86%,and 40.54%,respectively.The number of ecological key points decreased by 17.80%,and the high-density distribution area of ecological disturbance points showed a“dual-core”development trend centered on Chengdu and Chongqing.The study indicated that the occurrence of roads led to the loss of about 51.41%of the habitat in the study area,and the landscape connectivity of the landscape along the road and the dominant landscape was seriously affected,and the overall ecological pattern was fragmented and the landscape distribution was balanced.The number of loops in the ecological network is small,the length of important corridors is reduced by 1890.43 km,the number of ecological key points and the distance are reduced,and the species exchange between ecological sources is reduced,which leads to the reduction of the ecological efficiency of the ecological network and the stability of the ecological security pattern.Finally,some suggestions are put forward from the aspects of source protection and road route selection:while giving priority to the protection of ecological core sources,the strategy of guiding traffic volume to the built high-grade roads and the concentrated and compact development of low-grade roads is adopted to reduce the segmentation of ecological patches by road network expansion,in order to provide a reference for the spatial protection of Chengdu-Chongqing area.