| Ecosystem provides essential material resources for human survival and is an important place for human survival and habitation.In recent years,with the rapid growth of the population,the acceleration of urbanization and the strong interference of human activities,the original landscape structure has been greatly damaged,and the ecological environment is deteriorating.Therefore,it is necessary to protect the ecological environment and maintain ecological safety.A key and urgent research topic in the process of sustainable development,the study of regional ecological security in our country is of special significance.Landscape ecological security is the study of ecological security from the perspective of landscape pattern.Combining ecological security with landscape ecology theory is of great significance to regional sustainable development and ecological environment management.The Three Gorges Reservoir area is a very important water source and ecological function area in my country,as well as an important ecological protection barrier for the Yangtze River Basin.Wanzhou District is located in the heart of the Three Gorges Reservoir area.It is a typical mountain city in the southwest region with a fragile ecological environment.Landscape ecological security and ecological security pattern are all representative in the Three Gorges Reservoir area,and this area can be used as a microcosm of the Three Gorges Reservoir area.Therefore,this article is based on the important ecological status of Wanzhou District,starting from the perspective of "production-life-ecological space",using the 2km×2km grid as the evaluation unit,and using the three phases of land use data in 2009,2013,and 2018 as the basic data.Based on the analysis of the evolution of the landscape pattern in Wanzhou District,a landscape ecological security evaluation model was constructed through the landscape pattern index.Geostatistics,spatial correlation analysis,and coupling coordination models were used to explore the temporal and spatial changes of landscape ecological security in Wanzhou District.The geographic detector model and the geographic weighting model have identified the main influencing factors that affect the landscape ecological security of Wanzhou District.The purpose of the research is to better understand the basic characteristics and laws of landscape ecological security changes in Wanzhou District,and to provide targeted opinions on the improvement of the ecological environment in Wanzhou District,so as to enrich and promote comprehensive research on landscape ecological security evaluation in my country.The main research conclusions of the thesis are as follows:(1)Dynamic change of "production-living-ecology" land use in Wanzhou DistrictFrom 2009 to 2018,woodland ecological space has always been the main land use space in Wanzhou District,with the largest increase in urban living space and the largest decrease in agricultural production space.On the single dynamic degree of land use,the dynamic degree of land use in urban living space,industrial and mining production space and other living spaces are all positive values,and the dynamic degree of land use in the remaining spaces are all negative values;in terms of comprehensive land use dynamic degree,2009-In 2018,the comprehensive land use dynamics were all less than 1%,and the overall trend was to increase first and then decrease,and land use types changed slightly.In terms of the degree of land use,the degree of land use has increased slightly,and the spatial distribution is high in the west and low in the east,and high in the north and low in the south.(2)Changes in landscape pattern of "Sansheng" land use in Wanzhou DistrictFrom the perspective of type scale,as the main landscape types in Wanzhou District,agricultural production space land and woodland ecological space land have good patch aggregation conditions,but affected by human disturbance,landscape patches are more complex and fragmented.The area of land for living space has increased significantly,and the degree of landscape agglomeration has increased significantly,especially the area of urban living space has increased significantly,patches are concentrated and regularly distributed,and the degree of complexity is low.The industrial and mining production space is small and the distribution is relatively scattered,so the degree of aggregation is the smallest and the connectivity is poor.From the perspective of landscape scale,affected by natural and man-made interference factors,the external boundaries and internal forms of landscape patches in Wanzhou District have become complex and irregular,the degree of fragmentation has increased,the heterogeneity and diversity of the landscape have increased,and the overall landscape has gradually changed.The sporadic distribution shifts to concentrated contiguous areas,and the stability and complexity of the landscape ecosystem increase accordingly.(3)Landscape ecological security evaluation of "production-living-ecological space" in Wanzhou DistrictFrom 2009 to 2018,the landscape ecological security in the "production space" of Wanzhou District was relatively good on the whole.The medium security area was the main type,the low value was mainly distributed in the central urban area and the mountainous area,and the high value was mainly distributed in the river flat land in the northeast and southwest.On the whole,the landscape ecological security of "living space" is low,and the restless area is the main type.The high value is mainly distributed in the central urban area,showing an "L" shape distribution with a small range,while the low value area is mainly distributed in the mountainous area,taking up a large area."Ecological space" on the landscape ecological security level is medium,medium security,the security and An Quan San kind of level is slightly more than half the total,the high value area are mainly distributed in the study area in the northwest edge region and southeast mountain area in the study area,low area are mainly distributed in three areas,one is the central city and parts of the Yangtze river region,is "I" type distribution,and the second is the study area over southwestern town,three is the Aries town northeast of the study area.On the whole,the landscape ecological security of "production-production space" in Wanzhou District is at a higher level,and presents an upward trend.In terms of spatial distribution,the safe areas are high in the central part and low in the northeast to southwest.The safe areas are mainly distributed in the center of cities and towns,showing an obvious L-shaped distribution.The distribution of the safe areas is relatively dispersed,some are mainly distributed in the vicinity of the safe areas,that is,the suburbs of the city,and the other part is mainly distributed in the mountainous areas with higher elevations.The restless area is mainly distributed along the Yangtze River Basin,which is divided into three parts,namely,northeast,west and southwest.The relatively unsettled area is roughly distributed around the unsettled area and spreads outwards with the unsettled area as the center.The area is dominated by low mountains and hills with broken landscapes,frequent human activities and high damage intensity.(4)Landscape ecological security space analysis of "production-living-ecological space" in Wanzhou DistrictThrough histogram and normal QQPlot distribution test,the landscape ecological security value from 2009 to 2018 basically conforms to the normal distribution.In2009,the best fitting model was Gaussian model,while in 2013 and 2018,the best fitting model was linear model.Medium spatial correlation in the space,there is an obvious high-high value area and low-low value area,high-high value area mainly concentrated in the center of the town landscape ecological safety and high altitude,low-low concentration distribution in a river gan ning town,the town of xiangshui,lonza town of regional landscape ecological insecurity.On the coupling characteristics analysis,overall,wanzhou district "extraordinarily space" the coupling coordination degree of landscape ecological security level is not high,moderate dislocation area always dominate,"around the central high,low" on the overall spatial distribution features of obvious regional differentiation,a serious imbalance between area mainly distributed along the river,highly coordinated area are mainly distributed in the center of the town.From the perspective of the coupling coordination degree of "production-ecological space",the landscape ecological security in urban centers has achieved coordinated development in "production-ecological space",while there is imbalance in "production-ecological space",while the landscape ecological security in river areas is in unbalanced development in "life-ecological space".(5)Factors influencing landscape ecological securityAccording to the analysis of geographical detector,the main influencing factors of landscape ecological security in Wanzhou District are land use type,landscape diversity,landscape loss degree,GDP and population.According to the local spatial regression analysis of the geographically weighted regression model,the land use type has a significant positive impact on the landscape ecological security in Wanzhou District,while the population number,GDP,landscape loss degree and landscape diversity have a negative impact on the landscape ecological security in Wanzhou District. |
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