Study On Ecological Risk Of Nanchang City Based On Land Use Change

Whether a regional land ecosystem can maintain its structural integrity and sustainable production and service functions is a prerequisite for the development of regional social and economic stability.Under external disturbance,the land ecosystem can rely on its own selforganization and self-regulation functions to maintain its relatively stable state through selfregulation.However,with the intensification of human interference activities and the increase in the intensity of land development and utilization,the structure and function of land ecosystems have been damaged,causing their functions to gradually degrade,even to the extent that it is difficult to self-repair.This puts land ecosystem health at great risk.The change of land use is one of the most important factors leading to the change of land ecological risk.The evaluation of land ecological risk on the basis of land use change is an important research content of land risk evaluation and an important method of ecological environment management.Therefore,the evaluation and analysis of the ecological risk of Nanchang City based on the changes in land use will help to unveil the local ecological and environmental problems,and provide a theoretical basis for Nanchang to optimize the land use structure and reduce the ecological risks of land use.Based on this,this article takes Nanchang City,Jiangxi Province as the research object,and uses remote sensing image data from three periods of 2005,2013,and 2017 as the data source to interpret and calculate the land use data of the three periods.Characteristics of dynamic changes in land use in 2017.On this basis,with the help of Fragstats 4.2 software,an ecological risk index model was established based on the landscape pattern.With the support of Arcgis 10.3 technology,358 grid evaluation units were divided,and the ecological risk index for each year was calculated and calculated.The evaluation analyzes the spatial differentiation characteristics of ecological risk of land use in three periods in Nanchang.Finally,the principal component analysis method was used to quantitatively analyze the main driving factors affecting the ecological risk of land use in Nanchang,and combined with the current status of the ecological environment in Nanchang,specific countermeasures were proposed for different levels of risk areas.The research conclusions are as follows:(1)From the perspective of the dynamic characteristics of land use,during the study period,the land use type in the study area was mainly dominated by cultivated land and waters,and the area accounted for about 70% of the total area of Nanchang.Specifically,from 2005 to 2017,the land use structure in Nanchang showed a trend of "three increases and three decreases" : the area of construction land,forest land and water areas increased,and the area of cultivated land,grassland and unused land decreased.Land use and cultivated land increased and decreased by 153.85km2 and 142.31km2,respectively.During the research period,the grassland area structure did not change significantly,and the conversion area was small.The area of unused land showed a decreasing trend,mainly converted into waters and cultivated land.The construction area changed significantly,and the main type of land transferred was cultivated land.(2)From the perspective of spatial differentiation of ecological risks in land use,from 2005 to 2017,the high-risk areas were distributed in the Poyang Lake watershed in the northeast of Nanchang;the higher ecological risk areas were mainly distributed in strips in the high-risk areas.Periphery,with less distribution areas;medium-risk areas are mainly distributed in the southeast;lower-risk areas and low-risk areas are mainly distributed in the central,western,and southwestern regions.During the study period,the area ofhigh-risk areas in Nanchang showed a decreasing trend,and the areas of higher-risk areas showed a rising trend.The areas of medium-risk and lower-risk areas experienced a process of first increase and then decrease,and the areas of low-risk areas continued to decrease.It shows that the landscape ecological risk of Nanchang City is decreasing year by year,and the regional ecological environment is developing in a good situation.(3)From the perspective of the factors affecting the ecological risk of land use in Nanchang,based on the principal component analysis method,16 social and economic factors such as population density,regional GDP,sewage treatment rate,and social employment were selected,and the factors were analyzed using SPSS17.0 Through analysis,the main factors influencing the ecological risk of land use in Nanchang are population increase,socio-economic development and urbanization factors.