关键词: 生态廊道, 生态网络, 景观连通性, 电路理论, 山地城市

Abstract:

Urban greenspace ecological networks are indispensable for addressing the multifaceted ecological challenges posed by rapid urbanization. In an era of unprecedented urban expansion, particularly in regions with rugged and mountainous terrains, preserving the ecological integrity of cities has become a complex and urgent task. As urban sprawl intensifies and pressure on natural landscapes grows, a systematic approach to planning and conserving urban green spaces is essential for maintaining critical ecosystem functions. This study focuses on Chongqing, a unique mountainous city in China, and examines its urban ecological network through a comprehensive analysis of its spatial characteristics, key ecological sources, and potential corridors that facilitate ecological flow. Furthermore, this study proposed strategies for optimizing these networks to ensure long-term ecological sustainability and resilience. To achieve these objectives, the research employs advanced analytical models have been developed, including the least-cost path (LCP) model, ecological network analysis, and the minimum cumulative resistance (MCR) model. These tools enable a detailed simulation of Chongqing’s ecological landscape, identifying regions of high ecological value and areas where ecological connectivity is compromised. Ecological network analysis provides insights into the overall structure and function of the network, highlighting the key nodes and corridors that serve as the backbone of urban biodiversity. One of the most significant findings of this study is the identification and mapping of 39 key ecological sources within Chongqing’s core urban area. These sources collectively cover an area of 975 km², accounting for approximately 67% of the core region. The ecological sources are predominantly concentrated in large contiguous green patches, such as the expansive forested regions of Tongluo and Zhongliang Mountains. These mountainous areas provide extensive habitats for diverse flora and fauna, and are critical for ecosystem services, including water regulation, carbon sequestration, and the maintenance of regional biodiversity. The conservation of these ecological sources is vital for sustaining urban ecological networks. In addition to identifying ecological sources, this study delineated 67 potential ecological corridors, spanning a combined length of 156 km. These corridors are strategically distributed along Chongqing’s north-south mountain ranges and river valleys, and are aligned with the city’s distinctive topography. They play a crucial role in connecting fragmented green patches, enabling species migration, genetic exchange, and uninterrupted flow of ecosystem services. Given Chongqing’s rugged landscape, characterized by steep slopes, deep valleys, and winding river systems, these corridors naturally follow the existing geographical features and reduce resistance to ecological flows. The findings underscore the importance of these corridors not only for species dispersal but also for maintaining the overall connectivity and resilience of the urban ecosystem. The study also employs a Pinchpoint Mapper to identify critical ecological pinch points—areas where connectivity between green patches is severely weakened, leading to high levels of landscape fragmentation. These pinch points are predominantly located in transitional zones between large and small green patches, where habitat discontinuity can disproportionately harm the local biodiversity and ecosystem stability. Notably, in northern Chongqing, certain corridors exhibited the highest cumulative current flow, indicating their capacity to sustain robust ecological flow. However, these areas are also vulnerable to urban expansion, which threatens to further fragment habitats and compromise the functionality of ecological networks. This study highlighted the significant spatial heterogeneity in the distribution of urban green spaces in Chongqing. Green patches are highly fragmented within the urban core, with substantial gaps in ecological connectivity. This fragmentation undermines the ability of the ecological networks to support biodiversity and provide essential ecosystem services. Rapid urban development, characterized by increasing density and infrastructural expansion, exacerbates this problem by isolating key ecological areas and reducing their effective spatial extent. Without targeted interventions to restore connectivity and enhance ecological corridors, the ongoing degradation of these networks may lead to biodiversity loss and decline in the quality of life of urban residents. To address these challenges, this study proposes several integrative strategies to optimize Chongqing’s ecological network. A primary recommendation is the protection and restoration of key ecological sources, particularly in mountainous areas, such as Zhongliang Mountain and Tongluo Mountain. These regions should be prioritized in conservation planning because of their critical role in sustaining ecological flow and supporting diverse habitats. Restoration efforts in areas affected by urban sprawl may include reforestation, the reintroduction of native plant species, and habitat improvements to enhance ecological connectivity. Another key strategy involves enhancing ecological corridors through the creation of green buffers, restoration of existing pathways, and development of new corridors to bridge isolated green patches. This study emphasizes the importance of continuous ecological corridors that facilitate species movement across urban landscapes and ensure the exchange of genetic material and ecosystem functions. In high-density urban environments, small-scale green spaces, such as city parks, green roofs, and vertical gardens, can serve as stepping-stone habitats, mitigating the effects of urban fragmentation. Furthermore, this research underscores the significance of river systems, particularly the Yangtze and Jialing Rivers, as natural ecological corridors. These rivers and their riparian zones form integral components of Chongqing’s ecological infrastructure, facilitating the movement of aquatic and terrestrial species, while maintaining water quality and regulating hydrological processes. Protecting and restoring these river corridors are essential, and efforts are required to reduce pollution, improve water quality, and restore riparian habitats to strengthen the overall connectivity of the ecological network. This study provides a comprehensive theoretical and practical framework for constructing and conserving ecological networks in mountainous urban environments. By prioritizing the protection and restoration of critical ecological sources, improving the connectivity of ecological corridors, and integrating green infrastructure into urban development plans, cities such as Chongqing can build more resilient and sustainable ecological networks. Such networks not only preserve biodiversity and maintain ecosystem functions but also enhance urban residents’ quality of life by fostering a healthier, more balanced urban environment. The strategies and insights from this study aim to inform future urban planning efforts and promote a harmonious coexistence between rapid urban development and ecological sustainability.

Key words: ecological corridors, ecological networks, landscape connectivity, circuit theory, mountain city