Effects of plant community diversity on soil microbial functional groups in permafrost peatlands of Greater Khingan Mountains, Northeast China

Permafrost thaw will likely change plant communities and their relationship with soil microbial communities in northern peatlands under climate change. Understanding the linkage response of plant communities and soil microbial communities in boreal peatlands to permafrost thaw is needed to better forecast future functioning of permafrost peatlands. Here, we investigated soil microbial abundance and bacterial community diversity and determined their relationship with soil carbon and nitrogen contents in five typical peatlands with different dominant plant species. The dominant plant species were Eriophorum vaginatum ( E. vaginatum ), Betula fruticosa ( B. fruticosa ), Ledum palustre ( L. palustre ), Betula fruticosa–Vaccinium uliginosum ( B. fruticosa + V. uliginosum ) and Betula platyphylla ( B. platyphylla ), respectively. Results showed that soil methanogen and methanotroph abundance were higher in B. fruticosa , E. vaginatum , and L. palustre dominant peatlands than in B. platyphylla and B. fruticosa + V. uliginosum dominant peatlands. Nir S-type denitrifying bacteria abundance in the superficial layer of the soil (0–15 cm) was lower in B. fruticosa + V. uliginosum dominant plants than in other sites. Plant species richness index was positively correlated with methanogen and methanotroph abundances in the superficial layer of the soil. Plant species diversity index was significantly positively correlated with total bacteria and methanotroph abundance in subsoil (15–30 cm). Soil bacterial diversity was positively related to soil pH. The bacterial community differences in the soil depths of 0–15 and 15–30 cm were driven by different main factors. Our findings verify that plant community diversity is linked to the soil microbial functional group involved by soil carbon and nitrogen nutrient and pH in permafrost peatlands. This study is critical to better understanding the biodiversity maintenance mechanism in permafrost peatland under climate warming.