Fungi are more sensitive than bacteria to drainage in the peatlands of the Zoige Plateau

The peatlands of the Zoige Plateau are an important global carbon source that is currently under threat as a result of drainage for grazing. How drainage affects the microbial diversity and activity in peatlands is unclear. This study examined the response of microbial communities at two sites to short-term drainage (3 years) and long-term drainage (48 years) in combination with three different water table treatments. Our objective was to examine the changes in the physicochemical properties of the soil, composition of bacterial and fungal communities, and microbial activity. Our results indicated that (1) both duration of drainage and water table drawdown had significant effects on the diversity and composition of the bacterial and fungal communities in the soil, and certain bacteria were replaced by fungal decomposers; (2) duration of drainage affected the structure of fungal communities more than that of bacterial communities, and interactions between microbial species were more complex in peatlands with long-term drainage; (3) drainage significantly altered concentrations of dissolved inorganic nitrogen (NH4+-N and NO3−-N), and these changes correlated with structure of bacterial and fungal communities as well as with changes in abundance of certain dominant microbial species; and (4) fungal communities explained a larger part of microbial activity than bacterial communities. Overall, these findings suggest that fungi play a much more important role than bacteria in microbial-mediated ecosystem functioning in peatlands undergoing drainage.