Effects Of Grassland Fire Prevention Policies On Probability And Drivers Of Grassland Fire In Inner Mongolia During Different Periods

Grassland fire is one of the important disturbance factors affecting grassland ecosystems.The implementation of different grassland fire prevention policies may lead to changes in the probability and drivers of grassland fires.This study is divided into three different periods and one full period(three different periods: 1981-October 4,1993,October 5,1993-2008,2009-2020;one full period: 1981-2020),based on the grassland fire statistics of Inner Mongolia Autonomous Region from 1981 to 2020,as well as meteorological,topographic,vegetation,infrastructure,population and economic data,and supported by Arc GIS,R Studio,Origin and Navicat Premium software.The analysis of grassland fire probability and drivers in Inner Mongolia was carried out by Random Forest(RF)model,and grassland fire probability and grassland fire risk zoning maps were drawn to interpret grassland fire drivers and fire risk changes in different periods.The results of the analysis are as follows:(1)The spatial distribution of grassland fires in Inner Mongolia is generally more in the east and less in the west,and Hulunbeier City is the area with the most serious grassland fire hazard.Spatial and temporal grassland fires in Inner Mongolia mainly occur in April,May and October each year,concentrated in spring and autumn,and human-caused fires are the main factors causing grassland fires.(2)The modeling accuracy of the stochastic forest model established with the boundaries of the implementation time of the old and new Grassland Fire Prevention Regulations was ROC/AUC=0.924-0.940,which showed excellent performance,indicating that the stochastic forest model has good ability to predict the occurrence of grassland fires in Inner Mongolia.(3)Meteorological factors(daily average relative humidity,daily difference in temperature,etc.)have always been the dominant factors affecting grassland fires at different times.In this study,factors such as elevation and distance from the nearest road to the fire point are also important drivers of grassland fire occurrence in Inner Mongolia.(4)The distribution of grassland fire probability and grassland fire risk level in Inner Mongolia is more in the east and less in the west,and the medium,high and very high grassland fire risk areas have changed significantly before and after the implementation of the old and new Grassland Fire Prevention Regulations.1981-October 4,1993 medium,high and very high grassland fire risk areas are mainly concentrated in most areas of Hulunbeier City and the northern part of Xing’an League,while 2009-2020 mainly in the western part of Hulunbeier City,the northern part of Xilinguole League,the southeastern part of Alashan League,Wuhai City and the eastern part of Ordos City,and the distribution of medium,high and very high grassland fire risk spatial distribution is much wider.