摘要:生境破碎化导致生物多样性锐减，影响生境的生态系统服务，合理而有效的生态网络建设可以恢复城市内破碎生境斑块之间的连接。现有城市生态网络的构建与模拟多基于二维数据信息，未能很好地考虑植被三维结构信息所表征的多元生态位对生境质量的影响，致使生态网络的功能有效性有待验证。选取南京市主城区为研究区，基于高分辨率遥感影像与机载激光雷达数据，对研究区三维绿地植被结构进行了量化，在二维、三维两种情景下分别进行生态源地的提取与景观阻力面的设定，基于最小费用路径识别出两种情景下的生态廊道，并依据电路理论方法识别出廊道中需要重点保护的生态关键节点，进而分析使用二维、三维生态空间信息对生态网络构建结果产生的影响。研究结果表明：1）研究区不同情景下提取的生态源地共有11处不同，与传统二维情景下仅使用绿地面积指标作为斑块属性相比，使用三维植被参数可以更准确地识别具有丰富植被结构的生态源地；2）二维与三维情景下构建的生态廊道分别有137条与129条，平均每条廊道的单位距离阻力值分别为18.2与24.0，运用传统二维信息的模拟结果会在一定程度上高估研究区的景观连通性；3）不同情境下生态关键节点的空间分布基本一致，主要集中于研究区的西北侧、中部以及东南侧，并较多出现在距离较近的源地斑块之间。基于以上分析结果，有针对性地提出了南京市主城区生态网络格局优化的相关策略。



Abstract:Habitat fragmentation leads to a sharp decline in biodiversity, affecting habitat ecosystem services. A rational and effective ecological network construction can restore the connection between broken habitat patches in cities. The construction and simulation of the existing urban ecological network are mostly based on two-dimensional data information, and the impact of the multi-ecological niche represented by the three-dimensional structure information of vegetation on the habitat quality is not well considered, so the function effectiveness of the ecological network remains to be verified. This paper quantified the three-dimensional green space vegetation structure based on the airborne LiDAR and high-resolution remote sensing image data in the main urban area of Nanjing city. We extracted the ecological source area and built the landscape resistance surface in two-dimensional and three-dimensional scenarios, and identified the ecological corridor under the two scenarios based on least-cost path method. Meanwhile we identified the ecological key nodes in the corridors that need to be protected according to the circuit theory, then analyzed the impact of using two-dimensional and three-dimensional ecological spatial information on the results of ecological network construction. The results show that: 1) there are 11 different ecological sources extracted under different scenarios within the study area. Compared with the traditional two-dimensional scenario, using three-dimensional vegetation parameters can more accurately identify ecological sources with rich vegetation structures. 2) There are 137 and 129 ecological corridors constructed in the two-dimensional and three-dimensional scenarios, and the average unit resistance of each corridor is 18.2 and 24.0, respectively. The traditional two-dimensional information simulation overestimated the landscape connectivity of the study area. 3) The spatial distribution of key ecological nodes in different scenarios is similar, mainly concentrated in the northwest, middle and southeast of the study area, and more often appear in the source patches with close distance. Based on the above results, this paper proposes some targeted strategies to guide the construction and optimization of the ecological network pattern in the main urban area of Nanjing city.





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