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Aim The decomposition of plant residues is a fundamental process of soil organic matter accumulation. The loss of plant functional groups (PFGs) could affect this process by producing litter of different qualities in the soil. Microorganisms are one of the indispensable driving forces of ecological processes, but the mechanisms by microbial communities respond to aboveground PFG changes are still unclear, which limits our understanding of biogeochemical cycle changes under PFG loss.Methods We assessed the microbial taxonomic and functional composition of six typical single PFGs (evergreen conifer, evergreen shrubs, deciduous shrub, graminoid, forb and fern), random loss of a single PFG (SPFG) from litter mixtures and total mixture of six PFGs in a Tibetan fir forest by a high-throughput sequencing method.Results The microbial composition and function did not change with loss of a SPFG in litter, and microbial communities were mainly determined by the carbon and nitrogen ratio (C:N), carbon and phosphorus ratio (C:P), N and lignin, and bacterial functional pathways and fungal functional guilds were both determined by N, C:N and C:P ratios. Bacterial diversity was positively related while fungal diversity was negatively related to N and cellulose concentrations.Conclusion We speculated that the difference in initial litter qualities (especially C:N) between different PFGs, rather than a decreased number of PFGs, is a determinant of microbial composition and function. As the loss of PFG does not change litter quality, the microbial community can resist the loss of PFG, which maintains alpine ecosystem carbon and nutrient cycling stability. |
