| With the increasing global warming,forest fire frequency has been increasing worldwide in recent decades.The response characteristics and driving mechanism of forest ecosystem to forest fire disturbance is a focal theme in ecosystem ecology and biodiversity studies.The results of the study are important for biodiversity conservation and the sustainability of ecosystem functions and services.The central Yunnan Plateau is the main distribution area of semi-humid evergreen broad-leaved forest and its typical secondary community Pinus yunnanensis forest under a subtropical semi-humid monsoon climate with distinct dry and wet seasons.Forest fires are frequent in this region due to it is characterized by a dry periodthrough winter and spring,especially high temperature and strong wind in spring.However,there are few reports on the dynamics of habitat restoration and the response of soil microbial community to forest fire disturbance in this region.In this study,the burned land of the mixed forest of P.yunnanensis,Lithocarpus mairei and Cyclobalanopsis delavayi was selected as the research object to analyze the dynamic changes of soil habitat and soil microbial community with different burning intensity and topography in one year after burning in Luquan County,Kunming City.The main results are as follows:1)The maximum daily temperature of topsoil after fire was significantly higher than the control,and the daily maximum and minimum temperature in the burned area is earlier than that in the control area.With the increase of post-fire time,soil temperature decreased gradually,and high intensity fire requires more recovery time than low intensity fire.The topsoil temperature anomaly on the south slope was higher than that on the north slope,and that on the upslope was higher than that on the downslope(P<0.05).2)A year after the fire,soil nutrient and pH decreased significantly,sand content increased in medium and low intensity fire burn,and clay content increased in high intensity fire burn.The variation of soil nutrients on south slope was higher than that on north slope,and that on downslope was higher than that on upslope.The nutrient loss intensity of surface soil was higher than that of bottom soil.3)After fire,the dominant prokaryotes in the study area were Acidobacteria(28%),Proteobacteria(23%),Chloroflexi(17%)and Actinobacteria(11%).The dominant phylum of fungi after fire were Ascomycota(44%),Basidiomycota(38%)and Mucoromycota(8%).Soil microbial community structure was significantly changed by fire,and the relative abundance of Firmicutes,Actinobacteriota,Dothideomycetes,Eurotiomycetes,Sordariomycetes and Agaricomycetes was significantly increased,while Mortierellomycota showed a decrease in burned sites.The effects of fire on the alpha diversity of soil prokaryotes and fungi were mainly reflected in the early and high intensity fire.In this study,the early recovery dynamics of microclimate,soil properties and soil microbial diversity in typical forest communities burned on the Central Yunnan Plateau were described for the first time.The results can provide a reference for ecological restoration and reconstruction of P.yunnanensis mixed forest. |
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