Effects Of Environmental,Spatial And Temporal Heterogeneity On Species Diversity Of Macrofungi In Baiyun Mountain National Forest Park

As one of the decomposers,macrofungi is an important part of the ecosystem,which is of great significance to maintain the normal flow of energy and the cycle of chemical elements on the earth.Taking the 5 hm2 fixed monitoring sample plot of Baiyunshan National Forest Park as the experimental plot,a field survey of macrofungi in the sample plot was conducted in 2016-2018 to understand the species composition and species diversity distribution pattern of macrofungi in the sample plot,and to explore the effects of time differentiation,environmental spatial heterogeneity and habitat differentiation of forest ecosystem on the species diversity of macrofungi.The results are as follows:(1)There are 217 species of macrofungi,belonging to 33 families and 103 genera.There are more than 10 families and 6 families,totaling 166 species,accounting for 76.5%of the total number of macrofungi in Baiyun Mountain.The main ecological types of macrofungi in the plot were ectomycorrhizal fungi,accounting for 53.69%of the total,followed by woody fungi,accounting for 23.34%of the total.103 genera of macrofungi are divided into three distribution types:60 genera in the world,accounting for 55.34%of the total genera;9 genera in tropical-subtropical zone,accounting for 7.77%of the total genera;34 genera in northern temperate zone,accounting for 36.89%of the total genera.The diversity and abundance of macrofungi increased from May to August,peaking in July and peaking in August.(2)The monthly distribution of macrofungi showed a high degree of specialization and heterogeneity.64.98%of the species were only distributed in one month,and the abundance and abundance of macrofungi were significantly different in different months.Linkage index analysis showed that 24.73%of the macrofungi had potential association with the month,and the specialization index of the macrofungi-month network was 0.749.Species composition of macrofungi also varied significantly between different months.83 species(38.25%of total species)were positively correlated with months.Time differentiation plays an important role in maintaining the diversity of macrofungi.(3)The explanations of four kinds of environmental factors for ectomycorrhizal fungi and non-ectomycorrhizal fungi are spatial variables,light environmental factors,topographic factors and stand structure from large to small.The explanations of environmental factors for ectomycorrhizal fungi are larger than those for non-ectomycorrhizal fungi,which indicates that ectomycorrhizal fungi are more susceptible to environmental impact.Total radiation under canopy had significant effect on ectomycorrhizal fungi(P<0.01),but had no significant effect on non-ectomycorrhizal fungi.(4)The differentiation of forest ecosystem has a significant impact on the species distribution of macrofungi in the sample plot.The macrofungi show a significant ecological preference for the differentiation of terrain habitat,light habitat and woody plant community habitat.The number of macrofungi and woody plants increased with the increase of sampling area.Based on network analysis and connectivity index,42.53%of macrofungi may have habitat preference for ridges,24.73%and 22.11%of macrofungi may have habitat preference for valleys and gentle slopes,21.12%and 22.33%of macrofungi tend to distribute in low and high light habitats,respectively,and 18.22%of macrofungi tend to distribute in medium light habitats.28.10%and 34.23%of macrofungi tended to distribute in Quercus acuteus forest and miscellaneous forest,respectively.