Relationship Between Soil Microbial Diversity And Plant Community Functional Characteristics In Alpine Meadows

Soil microbes play key roles in nutrient cycling and energy flow in alpine meadow ecosystem.The mechanisms underlying assembly and maintaining of soil microbial diversity are one of the key topic of community assembly research.A large number of studies have shown that soil attributes are important in driving the assembly of soil microbial diversity.Based on the fact of interactive effect among soil,microbes and plants,theories predicted that soil microbial diversity was influenced not only by soil attributes but also by plant diversity.Existing studies showed that plant species diversity is associated weakly with soil microbial diversity.Several studies based on broad scale found that soil microbial diversity was associated with vegetation characteristics.Yet little is known about linkages between variation in soil microbial diversity and functional characteristics of plant community(Community-weighted mean,CWM;Functional diversity,FD).In this study,I attempt to explore the relationship between spatial variation in soil microbial diversity(soil bacterial and fungal diversity)and variation in plant community functional characteristics locally.We selected three plots in each of four habitats(Valley,North,South and Top)at each of three sites(Sitel,Site2 and Site3)in alpine meadows at the eastern Tibetan plateau.In each plot,we measured five key functional traits for each species to quantify CWM and FD,and sampled soil to analyze soil microbial diversity with high-throughput sequencing technology.We employed a generalized linear mixed model to examine the effects of sites and habitats on dominant phyla and genera of soil bacterial and fungal community.We used a generalized canonical discriminant analysis and a partial regression to analyze the correlation among soil microbial diversity,CWM,FD and soil attributes.(1)The dominant phyla of soil bacterial community in alpine meadows were Verrucomicrobia,Proteobacteria,Acidobacteria and Planctomycetes;with the dominant genera as GP4,GP6,Halomonas and GP1.The dominant phyla of soil fungi community were Zygomycota,Ascomyceta,Basidiomycota and Glomeromycota,with the dominant genera are Mortierella,Cryptococcus,Inocybe,Sebacina and Hygrocybe.The distribution of dominant phyla and genera of soil bacterial community differed among four habitats,with significantly for Zygomycota,Glomeromycota and Mortierella.(2)Change in soil attributes acorss plots took accounted for 43%and 37%of variation in soil bacterial richness and Shannon index,respectively.Soil bacterial diversity was associated positively with soil moisture,soil total phosphorus,soil available phosphorus,soil organic carbon and soil total nitrogen,but negatively with soil available nitrogen and soil pH.Soil attributes took accounted for 21%of variation in soil fungal richness,which was associated positively with soil pH,total nitrogen and available nitrogen,but negatively with soil organic carbon,soil organic matter and C/N ratio.(3)Change in CWM of five traits took accounted for 28%and 46%of variation in soil bacterial richness and Shannon index,respectively.Soil bacterial diversity was correlated positively with CWM of leaf specific area and plant height,but negatively with CWM of leaf dry matter content.CWM of five traits took accounted for 20%of variation in soil fungal richness,which was negatively correlated with CWM of plant height.(4)Change in FD of five traits explained 19%and 28%of variation in soil bacterial richness and Shannon index,respectively.Soil bacterial diversity was positively associated with FD of plant height and leaf specific area.FD of five traits explained 33%of variation in soil fungal richness,which increased with FD of leaf nitrogen and leaf phosphorus,but decreased with FD of plant height and leaf dry matter content.In sum,locally change in soil microbial diversity was associated not only with soil attributes but also with functional characteristics of plant community.In plots with fertile soil at benign sites,plants tend to grow fast and tall with higher diversity of trait and soil bacteria,but lower in soil fungal diversity.In plots with infertile soil at harsh sites,plants with conservative strategy tend to grow slow and short with lower diversity of trait and soil bacteria,but higher soil fungal diversity.In short,plant community functional composition and structure significantly affected soil microbial diversity and in turn influenced by microbial diversity.This study provide new sights to understand the assembly and maintaining of soil microbial diversity in alpine meadows.