Study On Land Use Change And Its Impact On Landscape Ecological Risk In The Yellow River Delta

The process of land use change leads to the change of landscape structure and the reduction of ecosystem function.Scientific and effective understanding of the characteristics of land use change and its impact on landscape ecological risk is the basic premise of regional ecological construction and optimal allocation of land use.This paper takes the Yellow River Delta region as the research object,takes "process change drive optimization" as the logical main line,and based on the remote sensing monitoring data of land use in multiple periods from 2000 to 2020,identifies the process and influencing factors of regional land use change,discusses the temporal and spatial evolution characteristics of landscape ecological risk and the impact process of land use change on it,according to the principles of zoning guidance and optimization,Formulate the land use optimization plan and relevant optimization countermeasures under the guidance of the dual objectives of rational land use and ecological risk avoidance.The results show that:(1)The chord-graph visualization model and geo-information atlas are used to identify the characteristics of regional land use change and its influencing factors.The main land use types in the study area are cultivated land and construction land.The change of land use scale and structure presents the characteristics of "many to one" and "one to many";From2000 to 2020,the process of land use change in the Yellow River Delta region was affected by natural,socio-economic,location and policy factors.The natural environment and socioeconomic played a leading role in land use change in the first ten years,and the location and policy factors had a significant impact in the last ten years.(2)With the help of landscape ecological risk assessment model,spatial autocorrelation and other models,the spatial-temporal transfer and evolution of landscape ecological risk and the distribution of land types in the study area were explored.In time,the landscape disturbance index in the Yellow River Delta region showed a trend of first high and then low,and the landscape vulnerability index showed a trend of decreasing.In space,the development trend of coastal areas was higher than inland areas.The overall landscape ecological risk level and conversion rate of the whole region showed a trend of "high in the southeast,low in the northwest","high in the center,low in the surrounding",and the trend of reducing the landscape ecological risk level was strengthened.In the past 20 years,the overall landscape ecological risk in the Yellow River Delta region has shown an improvement trend,and the degree of spatial aggregation and spatial differentiation have been increasing.However,the impact of external interference on the landscape ecosystem should not be underestimated.In the future,the research area needs to further strengthen its ability to resist external interference.(3)The landscape structure and fragmentation degree are caused by land use change.The improvement and deterioration of landscape ecological risk in the Yellow River Delta coexist.The overall landscape ecological improvement trend in the study area is greater than the deterioration trend,and the improvement degree of landscape ecological environment is increasing.The improvement of landscape ecological risk in hot spots,sub-hot spots and warm spots is better than that in cold spots and sub-cold spots,and the main land use change types that promote the improvement or deterioration of landscape ecological risk in different regions are different.(4)The proportion of multiple suitability,single suitability and unsuitable land use areas in the study area decreased in turn,and the comprehensive suitability and comprehensive development potential of land use showed an increasing trend from coastal to inland.By calculating the number and importance of land use types to be adjusted,and according to the zoning guidance and optimization principles,the land use in the study area is optimized and adjusted.After optimization,the area of cultivated land,forest land and grassland will increase and their increased area will decrease.The area of unused land,construction land and wetland will decrease and their reduced area will decrease,which is conducive to the effective avoidance of landscape ecological risks in the research area on the basis of reasonable land use.In the future,the study area should actively adjust the land use structure and layout in the process of land use change,thus strengthening the self-repairing function of the ecosystem,and restraining,reducing and avoiding the landscape ecological risks.