Analysis On Land Use Change And Ecological Risk Assessment In Yanchang Based On GIS

Land use change is one of the most important factors that lead to global change.Land use and its related research have become one of the focus issues discussed in the academic fields.Through analysis on characteristics of land use change and exploration of spatial distribution of ecological risk and reasons for changes,suggestions and countermeasures for regional land use and development,overall land use planning and ecological construction are put forward in this paper,in order to improve the ecological environment,to promote coordinated development of society.Taking Yanchang County,Yanan as study area,the spatial-temporal feature of Land Use and ecological risk were analyzed under the support of relevant theories and GIS technology.Firstly,based on DEM and land use status data,the Spatial-Temporal Features of Land Use in Yanchang County were extracted by using dynamical change models,information entropy model and Density mapping.Secondly,the ecological risk assessment model was constructed based on the landscape pattern,on the best scale,partition the evaluation unit,and Geo-Statistical analysis was adopted to make data exploratory.Through spatial interpolation,the spatial distribution of ecological risk was obtained.On this basis,the ecological risk and land use change response characteristics were further analyzed.Finally,according to the analysis results,the risk control areas were divided and different control measures were put forward.The results indicated that the land use change correlates with the ecological risk distribution in Yanchang county.Land use change rate,structure and concentrated areas are higher in eastern and western regions,and lower in the middle.The ecological risk is basically the same as the land use change.The higher risk areas in the east and the west are expanding gradually while the lower risk areas at the edge of the research area are lessening gradually.The ecological risk increases in the east as new energy sources have caused land fragmentation.It also increases in west and central regions as ecosystem vulnerability rises affected by adjustment of agricultural structure.The ecological risk is negatively correlated to the rate of land use change,positively correlated to land use structure,and nearly consistent with the land use type.And the ecological risk value of the concentrated areas generally increases.In terms of research methods,powerful spatial analysis and data mining based on GIS can effectively reveal the spatial distribution and change rule of land use change and ecological risks,analyses the reason of local ecological risk changes,and improve the accuracy and scientificalness of ecological evaluation results.