Mycorrhizal fungi maintain plant community stability by mitigating the negative effects of nitrogen deposition on subordinate species in Central Asia

Abstract Questions Plant community stability is threatened by increasing numbers of simultaneously changing factors such as increased precipitation and nitrogen (N) deposition. Despite the pivotal roles of arbuscular mycorrhizal fungi (AMF) for plant community dynamics, only few studies have paid attention to their roles in maintaining plant community stability under global change. We therefore assessed the interactive effects of a realistic N deposition and AMF on plant community temporal stability under future increased precipitation scenarios. Location Gurbantunggut desert, China. Methods We conducted a four‐year field experiment simulating a realistic N deposition and with/without AMF treatments in one typical ephemeral plant community, dynamically monitoring the changes in plant community biomass and composition. Results We found that suppression of AMF significantly reduced Shannon–Wiener diversity and evenness while the realistic N deposition only marginally reduced the Shannon–Wiener diversity. Suppression of AMF and increased N deposition highly increased the species turnover. Particularly, the stability of subordinate plant species significantly correlated to the community‐level stability. AMF were able to buffer the negative effects of increased N deposition on plant community diversity, to maintain community‐level stability. Conclusions Our study supports the subordinate insurance hypothesis, highlighting the considerable roles of subordinate plant species in maintaining community stability. Furthermore, our results indicate the joint roles of AMF and N deposition in regulating plant community stability, and point to the importance of taking AMF and the realistic N deposition into account for understanding the responses of community stability to multiple global change scenarios.