The Innovation Team of Grassland Ecology and Remote Sensing at the Institute of Agricultural Resources and Regional Planning (IARRP) of the Chinese Academy of Agricultural Sciences (CAAS) has made significant progress in revealing the ecological strategy regulatory mechanism of soil microbial interactions and network structures in response to nitrogen enrichment. This finding, titled "Long-term nitrogen input reduces soil bacterial network complexity by shifts in life-history strategy in temperate grassland", has been published in "iMeta" (IF = 23.7).

Nitrogen deposition can alter soil microbial community structure and composition, affecting interactions among microbial species and microbial network the complexity, thereby exerting profound impacts on ecosystem stability and functions. While many studies have demonstrated that nitrogen deposition reduces soil microbial diversity, it remains unclear how nitrogen deposition influences microbial interactions and  networks, as well as the underlying mechanisms.

By comparing soil microbial network structure and microbial traits at community level along nitrogen input gradients, it was found that nitrogen enrichment reduced the network complexity of soil bacterial communities but promoted cooperation among bacterial taxa. The network complexity of soil fungal communities remained unchanged under  nitrogen enrichment. By elucidating soil bacterial traits at the genetic level, it was observed that soil bacteria shifted toward copiotrophic life-history strategy. Further modeling results suggested that this shift in bacterial life-history strategy was the direct driver of the reduction in co-occurrence network complexity. This study refutes the direct relationship between reduced microbial species diversity and simplified network complexity under nitrogen deposition, demonstrating the key role of trait-based changes in life-history strategy in regulating microbial interactions and reshaping co-occurrence networks, providing theoretical support for predicting ecosystem functions under global change.

Dr. Chao Wang, a postdoctoral researcher at IARRP, is the first author of the paper, with Researcher Weixing Liu as the corresponding author. This research was supported by the National Natural Science Foundation of China (42141006, 32171595, 31770530).

[Citation and original link]:

Wang Chao, Ziyue Shi, Aogui Li, Tianyi Geng, Lingli Liu, Weixing Liu. 2024. Long-term nitrogen input reduces soil bacterial network complexity by shifts in life-history strategy in temperate grassland. iMeta 3: e194. https://doi.org/10.1002/imt2.194