Effect Of Fire Disturbance On Soil Fauna Community And Spatial Heterogeneity In Coniferous And Broad-leaved Mixed Forest In Daxing’an Mountains

Fire is a common natural disturbance mode in forest,which will have a certain impact on the landscape composition of forest ecosystem,and form patches of different sizes,resulting in spatial heterogeneity of forest vegetation.Spatial heterogeneity is the basis and core content of landscape ecology,and also one of the important attributes of ecosystem,which involves the whole process of ecosystem activities.In the past,most of the researches on fire disturbance focused on the succession and restoration process of vegetation and the change of soil nutrient characteristics in the patch after fire disturbance,but the underground ecosystem was not paid enough attention.Soil fauna community is an important part of forest ecosystem,and its formation of underground soil food web is very important for the material and energy cycle of forest ecosystem.Due to the limitation of research methods and means,people’s understanding of underground ecosystem is still in a "black box" state.Therefore,it is of ecological significance to explore the effects of different fire intensities on soil invertebrate communities and their spatial heterogeneity.In this study,the community composition,diversity characteristics,spatial heterogeneity characteristics and spatial heterogeneity of soil fauna in different fire intensity slashes of coniferous and broad-leaved mixed forest in Daxing’an Mountains were studied by morphological identification,diversity analysis,trophic level division and soil physical and chemical properties analysis.The main influencing factors are analyzed,summarized and the results of this research are showing on the below:1.The influence of fire disturbance intensity on soil fauna abundance,community diversity index and relative abundance of each trophic level still exist,but not obvious;2.The most abundant soil fauna in the disturbed sites are Acari and Collembola.Fire disturbance intensity has a significant influence on the community structure of Collembola and the abundance of various trophic levels;3.The samples were taken in June and September,and the fire disturbance intensity had significant influence on electrical conductivity(EC),soil water content(WCS)and total phosphorus content(TP)in June,but in the soil samples in September,differences in humidity,electrical conductivity(EC)and p H value;4.RDA analysis shows a positive correlation between soil total nitrogen(TN),soil water content(WCS),soil total phosphorus(TP),p H and the order Hymenoptera,and Collembola shows a positive correlation between soil total phosphorus(TP),p H,soil organic carbon(SOC);5.It can be seen in the map of spatial distribution pattern of soil fauna and related soil environmental factors,it is seen that under different fire disturbance intensity,both irregular and irregular spatial distribution states and similar island spatial distribution pattern appear.Finally,the main reasons for different spatial distribution patterns are interbiological action,environmental filtering and random diffusion.