Study On Landscape Ecological Risk Assessment Of Qinzhou City Based On Land Use Change

Qinzhou City is located on the coast of Guangxi,on the north shore of beibu gulf,adjacent to Qinzhou bay in the south,facing southeast Asia and backed by the great southwest.It has unique geographical position and is an important portal connecting the Belt and Road organically.With the establishment of"China(Guangxi)pilot Free Trade Zone Qinzhou Port Area",it is expected that Qinzhou will usher in economic take-off in the future period.In the process of infrastructure construction,people’s livelihood construction and industrial structure adjustment and development,the demand for urban construction land will inevitably increase,and the regional natural ecosystem will continuously transform to the urban ecosystem,thus affecting the regional ecological security.Therefore,based on the change of land use in Qinzhou City,this paper carries out an evaluation study on landscape ecological risk in Qinzhou City,which is of great significance to promote the protection and sustainable use of land resources in Qinzhou City and the construction of ecological civilization.Taking the Landsat TM/ETM/OLI remote sensing image of 1990,2000,2010 and2019 as the data sources,using Arc GIS and ENVI software extracting land use information.And analyzes the land use changes and its influencing factors of Qinzhou City.Based on the land use data of 2000,2010 and 2019,and the CA-Markov model,predicted the land use pattern of the 2030.With the help of Fragstats4.2software,IDRISI and other software integration techniques,the spatial and temporal changes of landscape pattern and landscape ecological risks in the research area are analyzed,and the spatial autocorrelation of landscape ecological risks in the research area is studied.The results show that:(1)The land use pattern of Qinzhou City has changed significantly in the past30 years,and the area of the four land types of cultivated land,woodland,water area and construction land has changed significantly.Cultivated land increased by 186.11km~2,woodland decreased by 277.82km~2,water area decreased by 22.28km~2,and construction land type increased by 139.38km~2.At the same time,the grassland decreased from 521.42km~2 of 1990 to 496.00 km~2 of 2019.Based on CA-Markov model and 2000,2010 and 2019 of the land use data to prediction land use data of 2030,the land use data and compared with data of land use status of 2019 can be analysis:from 2019 to 2030 the cultivated land,woodland,grassland,water area and unused land area reduced,the construction land area is increased 32.41 km~2.It is mainly distributed near the built-up areas of Qinzhou port and Qinnan District,indicating the outward expansion of urban construction.These land-use changes are closely related to Qinzhou’s population change,economic development,urbanization,industrialization,transportation construction and related policies..(2)The landscape of Qinzhou City tends to be diversified,the landscape uniformity increases continuously,the landscape shape tends to be simplified,the degree of aggregation of different patch types decreases,and the degree of fragmentation becomes more and more serious.Among all land use types,the fragmentation degree of cultivated land type is the highest among all land use types,while the fragmentation degree of unused land is the lowest.In addition,the landscape change of construction land in Qinzhou City is the most affected by human activities,and the disturbance of cultivated land is relatively small;in terms of the degree of aggregation,the landscape pattern of cultivated land is relatively the most discrete,and the degree of aggregation of construction land is the largest.A series of index changes indicate that the economic development and urban construction speed of Qinzhou City are fast,which makes the construction land gather rapidly.Other land types are changed into construction land due to the influence of human construction activities,which makes the aggregation degree of landscape pattern smaller and fragmentation degree higher(3)Qinzhou high ecological risk areas are mainly concentrated in the northeast and southwest of Pubei County and the West and north of Qinbei district.High risk areas are mainly distributed in the northeast and southwest of Pubei County,the south central of Lingshan County and the middle of Qinnan District.Medium and low ecological risk areas are mainly distributed in Qinnan District,Qinbei district and Lingshan County.The spatial autocorrelation analysis shows that there is a positive spatial correlation between the landscape ecological risk level of Qinzhou City in the research period.The high value high value area is mainly distributed in the area with high ecological risk as the core,and the low value low value area is mainly distributed in the area with low ecological risk as the core.The spatial distribution pattern of agglomeration is obviously based on the evaluation results of landscape ecological risk It provides scientific basis for land spatial planning,land resource management and sustainable development.(4)According to the change of land use and the temporal and spatial evolution of landscape ecological risk in the study area,different management and protection measures are given for different landscape ecological risk areas from the perspective of protecting sustainable use of land resources and protecting ecology.