Driving mechanisms of soil bacterial α and β diversity under long-term nitrogen addition: Subtractive heterogenization based on the environment selection

• Published in: Geoderma Vol. 445; p. 116886
• Main Authors: Yang, Zhu, Dai, Handan, Huang, Yongtao, Dong, Biao, Fu, Shenglei, Zhang, Chenlu, Li, Xiaowei, Tan, Yuhua, Zhang, Xiaoxin, Zhang, Xiao
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2024; Elsevier
• Subjects: Local assembly processes; long-term N addition; Soil bacterial diversity; Subtractive heterogenization; Ubiquitous species; Soil bacterial diversity; long-term N addition; Local assembly processes; Ubiquitous species; Subtractive heterogenization
• ISSN: 0016-7061; 1872-6259
• DOI: 10.1016/j.geoderma.2024.116886

•N addition decreased ubiquitous species, resulting in lower α diversity.•N addition promoted heterogeneous selection, resulting in higher β diversity.•N addition decreased γ diversity via reducing ubiquitous species.•The subtractive heterogenization based on environment selection predicts diversity. Soil bacterial α and β diversity patterns under nitrogen (N) addition have been intensively examined, but γ diversity patterns remain largely unknown, especially, the mechanisms that concurrently control changes in α, β and γ diversity remain elusive. Therefore, we formulated a conceptual framework that simultaneously considers candidate drivers including ubiquitous species, rare species, and community assembly processes to elucidate the driving mechanisms of α, β and γ diversity under N addition. The conceptual framework was tested by compiling the sequence data of seven studies published from January 1997 to May 2022 and following the same analysis as our own two long-term multilevel N addition experiments. We demonstrate that subtractive heterogenization based on environment selection simultaneously predicts the changes in α, β and γ diversity under long-term N addition. That is, long-term N addition led to the decline of ubiquitous species (subtractive processes) through low soil pH, and promoted the strength of heterogeneous selection (heterogeneous processes) via enhancing environmental heterogeneity, subsequently causing lower α diversity and γ diversity but higher β diversity. These results mean that N addition may lead to a significant loss of soil bacterial diversity around the world. Together, these findings offer a way to simultaneously predict soil bacterial α, β and γ diversity responses to the ongoing atmospheric nitrogen deposition.