Long‐term nitrogen input reduces soil bacterial network complexity by shifts in life history strategy in temperate grassland

• Published in: iMeta Vol. 3; no. 3; pp. e194 - n/a
• Main Authors: Wang, Chao, Shi, Ziyue, Li, Aogui, Geng, Tianyi, Liu, Lingli, Liu, Weixing
• Format: Journal Article
• Language: English
• Published: Hoboken John Wiley and Sons Inc 01.06.2024; Wiley
• ISSN: 2770-596X; 2770-5986; 2770-596X
• DOI: 10.1002/imt2.194

We investigated soil bacterial and fungal communities, constructed co‐occurrence networks, and estimated bacterial traits along a gradient of nitrogen (N) input. The results showed that soil bacterial co‐occurrence networks complexity decreased with increasing N input. The ratio of negative to positive cohesion decreased with increasing N input, suggesting the declined competitive but strengthened cooperative interactions. However, soil fungal network complexity did not change under N enrichment. In addition, N input stimulated the copiotroph/oligotroph ratio, ribosomal RNA operon (rrn) copy number, and guanine‐cytosine (GC) content of soil bacteria, shifting bacterial life history strategy toward copiotroph with increased r‐/K‐strategy ratio. Piecewise structural equation modeling results further revealed that the reduction in bacterial co‐occurrence network complexity was directly regulated by the increased bacterial r‐/K‐strategy ratio, rather than reduced bacterial richness. Our study reveals the mechanisms through which microbial traits regulate interactions and shape co‐occurrence networks under global changes.