南宁快城市化区生态网络时空演变及优化研究

Spatio-temporal Evolution and Optimization of Ecological Networks in the Rapidly Urbanized Area ofNanning

关键词:  风景园林  生态网络  时空演变  快城市化区  南宁市

Key words:  landscape architecture  ecological network  spatio-temporal evolution  rapidly urbanized area  Nanning

摘要:

以南宁快城市化区为研究对象，利用形态学空间格局方法和最小累计阻力模型构建2003、2013和2023年的生态网络，通过景观连通性指数与重力模 型识别重要生态源地和生态廊道。结果表明：近20年研究区建设用地面积增加约2.4倍，城市扩张速率较快；快城市化下人类活动对生态基底破坏较大，景观连 通性变弱；高生态阻力面集中于老城区并向东部及西部蔓延；生态源地和生态廊道的数量均呈先增再减的变化特征，生态源地变化与城市发展政策和土地收储开 发有关，而生态廊道变化与城市扩张速率和发展方向有关。研究提出了增设踏脚石、修复生态断裂点、生态廊道差异化保护、存量地块高效利用等优化策略，揭 示了快城市化进程生态网络变化的主要驱动力是城市发展政策。

Abstract:

Ecological network wellness is an important approach to achieving synergistic development of the region's economy, society, and ecology. However, most of the current studies have been conducted from a static perspective, without paying attention to the continuous impact of fast urbanization development on ecological networks. As the relationship between land use change and ecological security is a complex interaction and coupling process, insufficient consideration of the dynamic impacts of environmental, economic, and policy changes on ecological networks during the urbanization process will make it difficult to meet the long-term needs of ecological construction in rapidly urbanized areas. Therefore, the rapidly urbanized area of Nanning City was selected as the study object, and the morphological spatial pattern analysis method and the minimum cumulative resistance model were used to construct the ecological networks in 2003, 2013, and 2023, and important ecological sources and ecological corridors were identified through landscape connectivity index and gravity models, to clarify the evolution of the ecological network in the study area during the rapid urbanization process and formulate relevant optimization strategies to enhance urban resilience. The results showed that the construction land area in the study area increased about 2.4 times in the past 20 years, and the rate of urban expansion was relatively fast, while the forest land and agricultural land decreased to different degrees, thus the ecological regulation is urgent; the largest MSPA landscape area is the core area, mainly distributed along Yongjiang River, and rapid urbanization has caused greater damage to the ecological substrate, resulting in increased fragmentation of the landscape pattern and weaker landscape connectivity, which is not conducive to biological migration and energy flow; high ecological resistance values are concentrated in the old urban area and increase with the expansion of the construction land to the east and the west, which is mainly affected by the increase of construction land; the number of ecological source areas and ecological corridors both show the characteristic of increasing and then decreasing, changes in ecological sources are related to urban development policies and land storage, and changes in ecological corridors are related to the rate and direction of urban expansion, and the phenomenon of ecological corridors traveling around the city has emerged; based on the ecological network in 2023, 36 stepping stones, 81 primary fracture points, and 101 secondary fracture points were identified. Accordingly, optimization measures are proposed, including the addition of stepping stones, restoration of ecological breaks, differentiated protection of ecological corridors, and efficient use of greenfield-based areas, to form an ecological network pattern of "one axis, one area, two cores, and four corridors"; the response of ecological network changes to urban development policies, the impact of land resumption and development on ecological network changes, and the differences in study scales on the results of analyses are discussed. The study reveals that the main driver of ecological network changes in the fast urbanization process is the urban development policy. The study aims to furnish scientific backing for the ecological sustainability of Nanning's swiftly urbanized region, and to serve as a valuable reference for the establishment of ecological networks in other regions experiencing fast urbanization.