Soil temperature and fungal diversity jointly modulate soil heterotrophic respiration under short-term warming in the Zoige alpine peatland

Global warming has changed carbon cycling in terrestrial ecosystems, but it remains unclear how climate warming affects soil heterotrophic respiration (Rh). We conducted a field experiment in the Zoige alpine peatland to investigate the mechanism of how short-term warming affects Rh by examining the relationships between plant biomass, soil properties, soil microbial diversity, and functional groups and Rh. Our results showed that warming increased Rh after one growing season of warming. However, warming barely changed the bacterial functional groups involved in the carbon cycle predicted by the functional annotation analysis. According to the Mantel test, NO3- was found to be the primary determinant for bacterial and fungal communities. The results of the Structural Equation Model (SEM) indicate that soil temperature and fungal diversity jointly modulate Rh, suggesting that short-term warming may not affect Rh by altering the structural and functional composition of microorganisms, which provides new insight into the mechanisms of the effects of warming on Rh in terrestrial ecosystems.