Patterns and drivers of soil microbial communities in Tibetan alpine and global terrestrial ecosystems

Abstract

Aim Soil microorganisms play key roles in regulating many important ecosystem processes. However, our understanding of the patterns and drivers of soil microbial communities remains limited. This study aims to test the hypothesis that edaphic factors are more important in explaining variations in soil microbial communities than climatic and biotic factors, as soils directly provide substrates and environment for soil microbial communities. Location Tibetan alpine grasslands and global terrestrial biomes. Methods On the basis of phospholipid fatty acid (PLFA) analysis, we investigated large‐scale patterns and drivers of soil microbial communities using data obtained from 196 sites within two major grassland types (alpine steppe and alpine meadow) on the Tibetan Plateau. We also explored global patterns of soil microbial communities by analysing published data from around the world. Results Soil microbial PLFAs in Tibetan alpine grasslands were positively associated with mean annual temperature and mean annual precipitation (MAP), contradicting patterns previously observed across global biomes. A combined stepwise regression and variation partitioning analysis revealed that soil microbial community variations in Tibetan alpine grasslands were mainly explained by edaphic factors, such as soil organic carbon, C : N ratio, pH and soil texture, then by biotic factors, such as aboveground biomass and plant species richness, and further by climatic factors, such as MAP. The global analysis confirmed that edaphic factors accounted for a greater portion of the variation in soil microbial communities than did climatic and biotic variables. Main conclusions These results provide strong support for the hypothesis that edaphic factors are the dominant drivers of spatial variations in soil microbial communities across regional and global scales.

Linking temperature sensitivity of soil CO2 release to substrate, environmental, and microbial properties across alpine ecosystems

“…It has been demonstrated that precipitation was a key limiting factor regulating vegetation production [ Yang et al ., ] and soil organic C density [ Yang et al ., ]. The spatial variations of microbial biomass and microbial community composition in Tibetan alpine grasslands were also reported to be regulated by the precipitation [ Chen et al ., ]. Our additional analyses found significant effects of precipitation on soil C:N ratio (Figure S8a) and the stoichiometric imbalance between microbial decomposers and their resources ( S C:N / M C:N ; Figure S8b).…”

Fungal community demonstrates stronger dispersal limitation and less network connectivity than bacterial community in sediments along a large river

“…Chen et al . () also found that environmental variations accounted for a greater portion of the variation in soil microbial community in Tibetan alpine grasslands than did biotic factor.…”

Linking microbial C:N:P stoichiometry to microbial community and abiotic factors along a 3500‐km grassland transect on the Tibetan Plateau

“…b,c), supporting our second hypothesis. The alpine steppe was reported to have a lower GPB biomass, GNB biomass, fungal biomass, AMF biomass and Act biomass but a higher F:B ratio than the alpine meadow (Chen et al ., ). Thus, an interesting question arose concerning how changes in the soil microbial communities between these two grassland systems could induce microbial C:N:P stoichiometric flexibility over a broad geographical scale.…”

“…Specifically, we tested the following hypotheses: (1) microbial C:N:P stoichiometry is larger in the alpine steppe than in the alpine meadow, whereas soil C:N:P stoichiometry is lower in the alpine steppe than in the alpine meadow because the alpine meadow has better environmental conditions (e.g. in terms of soil organic carbon, soil moisture, soil acidity and soil texture) (Yang et al ., ) than the alpine steppe, which benefit the growth of soil microbes (Chen et al ., ); and (2) variations in the microbial C:N:P stoichiometry are primarily related to shifts in soil microbial communities and are less related to abiotic factors over a broad geographical scale because microcosm studies have demonstrated that plasticity in microbial biomass stoichiometry is related to changes in the structure of soil microbial communities (Fanin et al ., ; Heuck et al ., ).…”