Analysis Of Landscape Ecological Risk Assessment And Ecological Network Construction In Jinan Based On High Resolution Data

The rapid development of the city has led to large changes in the type of surface cover,and the landscape structure tends to be homogeneous and vulnerable to external interference;the fragmentation of ecological patches is serious,and the ability of the ecosystem to resist risks is reduced;the continuous conversion of land resources into land for construction has led to rapid depletion of land resources.After rapid urbanization in Jinan,the landscape types in the territory have been greatly affected by human activities and are facing problems such as simplification of landscape structure,fragmentation of patches and reduction of ecological environment quality.Based on the theoretical basis of landscape ecology and Jinan as the research area,this thesis firstly conducts a landscape ecological risk assessment in Jinan,and on this basis builds a full-element ecological network,provides a scientific basis for the rational allocation of existing resources,and practices Regional Ecological Civilization View.In this thesis,the land use data interpreted from 2-meter high-resolution images are used as the basic data for the study,and seven landscape pattern indices are selected from the dominance,shape,and diversity perspectives to assess the current landscape pattern of Jinan.A grid of 2500 × 2500 meters is used to divide the ecological risk plots,and the landscape fragmentation degree,landscape separation degree and landscape sub-dimensionality are calculated for each ecological risk plot to construct the landscape disturbance degree.The index factors closely related to environmental vulnerability are detected by geographic detectors,and the landscape vulnerability of each ecological risk plot is calculated by assigning weights to the factor detection results.Based on the landscape disturbance degree and landscape fragility degree,a landscape ecological risk assessment model is constructed to analyze the spatial distribution of landscape ecological risk in Jinan.Based on the "patch-corridor-matrix" model,the ecological source sites are extracted according to the ecosystem service value function,Morphological Spatial Pattern Analysis method,landscape connectivity,combined with the ecological risk assessment results and land use data to build a comprehensive resistance surface,and the Minimum Cumulative Resistance model and Gravity model are used to build a full-factor ecological network in Jinan and optimize it.The optimization of the landscape structure of Jinan in combination with the ecological network and Jinan planning provides a scientific basis for the future development planning of Jinan.The main conclusions are as follows:(1)According to the calculation results of the landscape pattern index at the two levels of class and landscape,the landscape types in Jinan are clustered in the same type and have a high degree of fragmentation,and construction land and forest land are the dominant landscape types.In terms of spatial distribution,the patch fragmentation degree is high,the separation degree and sub-dimension are large,indicating that Jinan's landscape type is greatly affected by human activities,and the ecological patch has a weak anti-risk ability.(2)Jinan's landscape ecological risk shows a spatial distribution of high values clustered in the central,northern,southwestern and southeastern urban concentrated areas,and other levels of ecological risk areas around the high ecological risk areas and decreasing with distance.The areas with high ecological risk are mainly concentrated in the areas with dense construction land or rapid development,while the areas with low ecological risk values are mainly concentrated in the southern mountainous areas and areas with less human activities and stronger ecological protection.There is a positive correlation between ecological risk and spatial location,which is a typical pattern of "high-high" and "low-low".The distribution characteristics of ecological risk are closely related to the geographical environment,and attention should be paid to the problem of excessive regional ecological risk.(3)Ecological source sites in Jinan are mainly distributed in the south,and the uneven distribution of ecological source sites leads to the uneven distribution of ecological corridors,and the fault phenomenon occurs in the north and south of Jinan.To solve this problem,stepping stones are introduced to supplement the ecological source sites and optimize the ecological network.Important corridors are mainly distributed in the south of Jinan City,and the corridors pass through landscape types mainly woodlands and gardens,and the corridors are stable and not easily destroyed;corridors in other areas are mainly secondary corridors,and pass through landscape types mainly arable land and urban greenways,and the corridors are unstable and easily destroyed.Optimizing and adjusting the landscape structure of Jinan according to the ecological network,it is recommended to improve the strength and stability of corridors by increasing the number of important corridors,and provide a scientific basis for future urban planning and management.