Scenario Simulation Of Land Exploitation And Soil Erosion Risk Assessment In The Low-slope Hilly Mountainous Area Of Dali City

China is experiencing rapid population growth,socioeconomic development and urbanization,which lead to increasing land demand while the land resource is becoming increasingly scarce,especially in the mountainous regions,where there is more serious contradiction between the land demand of grain production and the demand for built-up land.As the mountainous land exploitation in the low-slope hilly mountainous area goes by,it has become a key point of the land use planning how to implement scientifically explore the land resources in the low-slope hilly mountainous area in order to prevent the ecological and geological risks in the middle and later planning periods.This study constructed an integrated dataset based on multi-source and multi-scale data including the remote sensing data,statistical data and observation data,etc.Besides,the baseline and planning scenarios of land use change were established for the land exploitation in the low-slope hilly mountainous area of Dali City,and the spatial pattern of land use under each scenario was simulated with the Dynamics of Land System(DLS)model.In addition,the level and value of soil erosion risk were calculated with the soil erosion risk assessment model,and the current soil erosion risk and that under the scenarios were analyzed,which can serve the monitoring of the land exploitation in the low-slope hilly mountainous area of Dali City.Firstly,the spatial pattern of land use change in the low-slope hilly mountainous area of Dali City was simulated with the DLS model.The simulation results show that there are changes in both the area and spatial pattern of land use in Dali City to different degree by 2020 under the two scenarios.As for the land area,the cultivated land area decreased in most regions except flatland(Bazi),while the forest land area approximately keeps in balance,the grassland area decreased,and the built-up land area increased obviously.As for the spatial pattern,the land use under the two scenarios show a generally consistent spatial pattern,with some regional differences.The built-up land will expand to some degree on the basis of the core built-up regions,in particularly,there is contiguous expansion of built-up land in Xiaguan Town,Fengyi Town,Wase Town and Haidong Town where there are abundant low-slope hilly mountainous land resources.The built-up land will expand more obviously under the planning scenario,under which the cultivated land will decrease to a larger degree.While there is slight difference in the changes of forest land,grassland and water body under the two scenarios.Secondly,this study assessed the current soil erosion risk in Dali City based on the integrated dataset.This study assessed the soil erosion risk in Dali City and the low-slope hilly mountainous area in 2008 by calculating the value of soil erosion risk and classifying the level of soil erosion risk with the soil erosion risk assessment model.The results show that most part of the terrestrial regions in Dali City are at the safe,relatively safe and low risk levels.The land at the safe risk level accounts for 58.5%of the total land area of Dali City.Among the regions with soil erosion risk,the region at the relatively safe risk level accounts for 23.51%,while the region at the middle or higher risk level accounts for only 0.58%.Finally,this study carried out the soil erosion risk assessment of low-slope hilly mountainous area in Dali City under different land exploitation scenarios.The soil erosion risk in Dali City and the low-slope hilly mountainous area in 2020 was assessed on the basis of the simulation results of the spatial pattern of land use under different scenarios.The results show that there is no extreme change in the level and value of soil erosion risk under the two scenarios compared to that in 2008.The results under the two scenarios were compared,indicating that the soil erosion risk will change more dramatically under the planning scenario,but will be overall lower than that under the baseline scenario.The planning scenario is more favorable for the future development of Dali City according to the demand of socioeconomic development,policy constraint,land use planning,soil erosion risk,etc.This study simulated the spatial pattern of land use in the low-slope hilly mountainous area based on scenario analysis,and assessed the soil erosion risk under future scenarios,the results of which can provide valuable decision support information for adjusting the land exploitation scheme of the low-slope hilly mountainous area,formulating the land use planning and guaranteeing the sustainable development of ecological environment in Dali City.The results of this study can also provide methodological reference for formulating land use planning of the low-slope hilly mountainous area in other regions.