| The world is facing a great challenge to deal with conflict between socio-economic development and ecological protection.Research on ecological security pattern is an effective mean to bridge the ecosystem service and ecological protection of human society.The effective identification,planning and protection of key eco-section that maintain the ecological security pattern can provide the reference for the construction of regional ecological security pattern and improvement of regional ecological environment.From the perspective of regional connectivity,this thesis took Pei County of Jiangsu province as a research case,analyzed the optimal particle size,established a positional key eco-section identification system based on the composition of landscape components,and simulated the regional landscape pattern considering key eco-section constraint.(1)Based on the classification of patch types and the selection of landscape pattern indices,the response curve of various landscape pattern indices was analyzed.The results show that: The regional optimal grain size was various across patch types.By premising of not causing the heavy redundancy of the calculation process,and integrating the optimal scale of land use patches and ecological contribution patches,this thesis determined the optimal grain size as 60 m.(2)The MSPA analysis was performed using parameters such as 8 neighborhoods and 60 m edge widths.The study was divided into 7 landscape types,which were characterized by uneven spatial distribution and largest proportion of Core.Extraction of Core?Edge?Perforation?Bridge?and Loop in the MSPA landscape type as the initial analysis objects of ecological sources,combined with connectivity evaluation of different ecological sources under optimal threshold distances,20 key ecological sources were identified,which mainly concentrated in the area near the Weishan Lake in the east.It is recommended that townships governments should promote the planning of ecological land use,improve the level of existing ecological source,and develop suitable ecological source areas.(3)The preliminary distribution of ecological corridors and nodes were obtained using the Cost Path tool,Linkage Mapper tool and hydrological analysis.On this ground,104 key ecological corridors(35 key radiation corridors)and 42 key ecological nodes were identified by using the gravity model to analyze the interaction strength between key ecological sources.The composition ratio of key ecological corridor landscape types and node analysis found: The relatively high-quality key ecological corridors and nodes in the study area were narrow and vulnerable to external influences,which resulted in the weakening of connectivity functions.It is recommended to improve the quality of key ecological corridors and nodes to optimize key eco-section.(4)Based on the simulation accuracy test(Kappa=0.768),with 2016 as the base year,the 2026 landscape pattern were simulated with unconstrained and key eco-section constraints.Compared with the results of unconstrained simulation,the characteristics of the ecological risk index with the key eco-section constraint simulation in 2026 were as follows: Quantitatively,the average increase in the ecological risk index was smaller,and the maximum risk index value and the proportion of higher ecologi cal risk levels were decreased.Spatially,the expansion of high ecological risk areas and higher ecological risk areas in the study area alleviated,the maximum increase value of ecological risk reduced,and the increase of the ecological risk in the central and northern regions was significantly reduced. |
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