| Forest ecosystem is one of the most important terrestrial ecosystems,which is rich in species and diversity.To understand its biological structure and diversity is of great scientific significance to maintain the structural diversity and functional stability of the ecosystem.Soil microorganism is one of the important components of forest ecosystem,and plays an important role in the material conversion,energy flow and biogeochemical cycle of forest ecosystem,and plays an important role in maintaining the structure and functional stability of forest ecosystem.Explore forest soil microbial community building and maintaining mechanism have been the core of the micro ecology research,although a number of studies have focused on forest soil microbial space-time distribution and the response mechanism of global change and human disturbance,we on soil microbial space-time distribution and the driving mechanism of understanding is limited,at least compared with the known macroscopic creatures.Due to the differences in research scale and biological characteristics,the conclusions obtained from the existing studies are controversial,and there is no consensus on the relevant theories to explain the mechanism of microbial community construction and maintenance.In addition,most studies focus on the local or regional scale,and there is a lack of relevant studies on the continental or global scale.In particular,large-scale studies on forest soil forest microorganisms in China are rarely reported.Therefore,it is urgent to carry out large-scale research on the spatial distribution and driving mechanism of forest soil bacteria in China,and to explore its community building mechanism,so as to provide theoretical basis for predicting the change of soil microbial community and exploring its construction mechanism.The main results and conclusions of this study are as follows:Our study shows that the core phylogeny community structure of forest soil bacteria in China is not uniformly distributed,but shows the rule of a small number of dominant species and a large number of rare species,and a small number of core populations have a high abundance.Analysis of the alpha diversity of core species of forest soil bacteria found that although core species are common,their alpha diversity showed significant differences on a large scale.In addition,distance attenuation relationship analysis found that,under the condition of large scale soil core species bacteria community diversity did not appear with the increase of distance and the law of diminishing,confirmed that the core soil microbial species in the community diversity of large scale distribution is different from the ecological and microbial diversity found in the small scale distance attenuation model.We used restrictive sequencing to explore the main environmental factors driving the distribution of forest soil bacterial communities,and the selected environmental factors could significantly explain 38.49% of the distribution differences.Among them,climate factor annual average rainfall(MAP)had the highest explanatory degree to the distribution of forest soil microbial community(47.22%,P < 0.05),followed by pH and annual average humidity(MAH).The results of the variation decomposition of the distribution of forest Soil bacterial core phyletic communities show that Climate factors have a higher explanatory degree for the microbial distribution variation than Spatial factors and Soil factors.Compared with other factors,climate factors are the main factors driving the spatial distribution of forest soil microbial communities under large-scale conditions.In addition,just as previous studies have found that pH can also well explain the differences in microbial community distribution at large scales.On this basis,Structural Equation Model(SEM)was used to analyze how the major environmental factors found affected the distribution differences of microbial communities.The results showed that MAP indirectly affected the distribution by affecting the physical and chemical properties of soil,while pH mainly directly affected the distribution of microbial communities.The results of analyzing the community distribution of forest soil bacterial core species showed that the distribution trend of forest bacterial core species was obvious along the gradient of soil environmental factors such as pH,nitrate nitrogen,available state calcium and available state magnesium,but there was no obvious pattern along the distribution of spatial and climatic factors.Combined with the previous factor analysis that drives the distribution of forest soil bacteria core species diversity,we speculate that deterministic processes play a more important role in the community construction of forest soil bacteria core species at a large scale. |
