Study On The Evolution Of Landscape Pattern And Landscape Ecological Risk In The Fuchunjiang River Basin

Rapid urban expansion and widespread human disturbance have accelerated the land cover change,directly leading to the evolution of landscape patterns and the increase of various ecological risks.As the important indicators of environmental change,the evolutionary characteristics of landscape pattern and ecological risk can reflect the impact of human activities on the ecological environment,thus playing an important role in indicating the sustainable supply capacity,health status and management level of ecosystem services.However,most of the current studies focus on a single level of landscape pattern or ecological risk,and few of them take small-scale areas as the research unit,so there is still improvement room in fieldability and implementation.Therefore,based on the perspective of combining landscape pattern and landscape ecological risk,this study takes the township as the research unit and the Fuchunjiang River Basin as the research object to analyze the spatiotemporal changes of basin ecosystems in rapidly urbanizing areas,with a view to providing scientific support for subsequent land management,pattern optimization and risk regulation.Firstly,spatial analysis and landscape index methods are used to identify the general characteristics of spatiotemporal changes of land use and landscape pattern;on this basis,a landscape ecological risk assessment model is constructed to analyze the spatiotemporal evolution of landscape ecological risk in the Fuchunjiang River Basin,and the main influencing factors of dynamic changes of landscape ecological risk are explored at several levels with the help of Geodetector model.The main research findings are as follows:(1)Land use in the Fuchunjiang River Basin has changed significantly during the period 1990-2020.Overall,the significant changes are found in arable land,urban and rural residential land and other construction lands,among which the areas of urban and rural residential land and other construction lands keep increasing,with 68.53% and 94.66% originating from arable land,respectively.The high single dynamic attitude of the two types of construction land causes a dramatic change in the comprehensive dynamic attitude of landuse.By time period,all three land types change drastically in 2000-2020,especially other construction lands,which has a dynamic attitude up to 84.53% in 2000-2010.(2)The landscape pattern undergoes a transformation from optimization to deterioration during 1990 to 2020.The ecological environment has generally improved,but it has undergone an "optimizationdeterioration" process on a shorter time scale.During 1990 to 2000,the landscape fragmentation,separation and complexity of the basin decrease significantly,and the ecological environment is restored to a certain extent.However,during 2000 to 2020,with the deepening of human interference,the landscape pattern development trend reverses.Landscape fragmentation and separation increase,and the connectivity of dominant landscape also decreases,which makes the environmental quality deteriorate continuously.(3)The overall spatial pattern of landscape ecological risk in the Fuchunjiang River Basin from 1990 to 2020 is "high in the northwest and low in the southeast".The evolution of ecological risk over time shows different trends at different spatial scales.From the perspective of the basin as a whole,the landscape ecological risk has been decreasing during the study period,and the decline rate has been gradually decreasing,especially in 2010-2020,which has remained almost unchanged.At the township level,during the study period,there are 17 townships with declining ecological risk levels,while there are only 2 townships whose ecological risk levels increase,but more than 40% of the townships have increasing ecological risk between 2000 and 2020.In general,both at the basin and township scales,the landscape ecological risk shows a decreasing trend at long time scales,although the changes are relatively drastic in short time periods.(4)The socio-economic and land use transfer category factors are the dominant influencing factors of landscape ecological risk from 2000 to 2020.Human interference factor has always been the dominant driving factor in socio-economic category,with a three-year average q value of 0.74,and the explanatory power has increased year by year;The dominant driving factor in the land use category has changed,from area of arable land transferred-out to area of arable land transferred-in.