Soil Microbial Diversity And Its Distribution Mechanism In Temperate Deciduous Broad-leaved Forest In Baiyun Mountain,henan Province

Soil microbes(bacteria and fungi),as the main decomposing agents of forest ecosystem,directly or indirectly participate in soil material cycle,energy flow and information transfer,and play an important role in maintaining soil ecosystem functions and services.It is of great significance for maintaining the stability and health of forest ecosystem,developing forest soil microbial resources and promoting the sustainable development of forest in the future to explore the distribution mechanism and driving factors of soil microbial community and reveal the basic ecological process of soil microbial community construction and the micro-ecological mechanism of plant-microbe interaction.However,there is still a lack of systematic understanding of the distribution mechanism and community building process of soil microbes in different habitats of temperate deciduous broad-leaved forests.In this study,we used the dynamic monitoring plot of Baiyun Mountain National Forest Park as the research platform,and used high-throughput sequencing technology to study the moisture gradient,plant community types,and the distribution mechanism of soil bacteria and fungi during succession,as well as the ecological process of soil microbes during succession.Specific research results are as follows:(1)The spatial distribution mechanism of soil bacteria and fungi communities was determined by analyzing the characteristics of 30 woody plant communities in three moisture gradients(low moisture ridge,medium moisture slope and high moisture valley)in the region.The results showed as follows:1)The distribution of most soil microbes in different moisture gradients in temperate deciduous broad-leaved forest was not random,but ecological specialization;2)Different microbes had different distribution preferences in different humidity gradients;3)Fungi tend to be distributed in places with high water content,and bacteria are not sensitive to water changes;4)Fungi and bacteria formed obvious symbiotic network in different humidity gradients,and the interspecific relationship between fungi and bacteria was significantly different.Fungal symbiotic network has low modularity,while bacterial network has higher stability.5)There were differences in the main environmental factors affecting the distribution of bacteria and fungi in different humidity gradients in the temperate deciduous broad-leaved forest.The stability of soil microbial community under low water content will become more fragile due to the influence of water change on environmental factors.(2)Through analyzing the characteristics of soil bacteria and fungi community in 18 woody plant communities of 6 kinds of plant communities in this region(Quercus aliena var.acutiserrata forest,Quercus serrata var.brevipetiolata forest,Larix gmelinii forest,Pinus armandii forest,Forsythia suspensa forest and Sorbus hupehensis forest),their spatial distribution mechanism was determined.The results showed as follows:1)The distribution of most soil microbes in different plant communities in temperate deciduous broad-leaved forest is not random,but follows ecological specialization;2)Bacteria and fungi have different distribution preferences for woody plant communities;3)Fungi showed higher specificity than bacteria in different plant community types.4)The main environmental factors affecting the distribution of bacteria and fungi were different among different plant communities in the temperate deciduous broad-leaved forest.Light was the main driving factor of fungal community,while soil physicochemical factors were the main driving factor of bacterial community.(3)In order to determine the distribution mechanism of soil bacterial and fungal communities in different succession communities of temperate deciduous broad-leaved forest(Plantation forest,Twice-cut forest,Once-cut forest and old-growth forest),we characterized soil bacterial and fungal communities in different succession communities.The results showed as follows:1)The distribution of soil microbes in different successional communities of temperate deciduous broad-leaved forest is not random,but follows ecological specialization;2)Bacteria and fungi had different distribution preferences in different succession communities;3)Fungi are more sensitive than bacteria in the secondary succession of temperate deciduous broad-leaved forest.4)The microbial-environment relationship changed during secondary succession.The relationship between soil microbes and the environment is affected by the different types of plant succession community.(4)By characterizing soil bacterial and fungal communities in different successional communities(Plantation forest,Twice-cut forest,Once-cut forest and old-growth forest)and in different functional groups(Generalist species,Specialists species,and Neutral taxa)of temperate deciduous broad-leaved forests,the ecological processes of these communities were determined.The results showed as follows:1)The ecological process of bacteria in different succession communities was random,while that of fungi was deterministic;2)The ecological processes of bacteria and fungi are different in different stages of succession.The balance of deterministic and stochastic processes changes with succession,and deterministic processes have a great influence in the early stage of succession.3)Environmental variables have different effects on bacterial and fungal community assembly.In conclusion,the species composition and community structure of soil bacteria and fungi in different humidity gradients,different plant communities and different succession processes were studied based on the dynamic monitoring plot of Baiyun Mountain National Forest Park.The results showed that habitat differentiation had an important effect on soil microbial diversity.In the temperate deciduous broad-leaved forest,fungi showed higher specificity than bacteria in different habitats.The succession process plays an obvious role in the construction of soil microbial community.Bacterial ecological processes are random,whereas fungi are deterministic.These findings advance our understanding of forest soil microbial diversity,distribution mechanisms and ecological processes,and provide important information for future sustainable forest management based on precise regulation of soil,plants and microbes.