Short-Term Grazing Exclusion Alters Soil Bacterial Co-occurrence Patterns Rather Than Community Diversity or Composition in Temperate Grasslands

Fangfang Wang; Zongming Li; Bojie Fu; Yihe Lü; Guoping Liu; Dongbo Wang; Xing Wu

doi:10.3389/fmicb.2022.824192

Short-Term Grazing Exclusion Alters Soil Bacterial Co-occurrence Patterns Rather Than Community Diversity or Composition in Temperate Grasslands

Front Microbiol. 2022 Mar 29:13:824192. doi: 10.3389/fmicb.2022.824192. eCollection 2022.

Authors

Fangfang Wang^{1

2}, Zongming Li^{2

3}, Bojie Fu^{1

2

4}, Yihe Lü^{1

2}, Guoping Liu⁵, Dongbo Wang⁶, Xing Wu^{1

2}

Affiliations

¹ State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.
² College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China.
³ Key Laboratory of Agro-Ecological Processes in Subtropical Region and Changsha Research Station for Agricultural & Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China.
⁴ State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, China.
⁵ College of Animal Science, Yangtze University, Jingzhou, China.
⁶ Hulunbuir Eco-environmental Monitoring Center of Inner Mongolia, Hulunbuir, China.

Abstract

Grazing exclusion is one of the most common practices for degraded grassland restoration worldwide. Soil microorganisms are critical components in soil and play important roles in maintaining grassland ecosystem functions. However, the changes of soil bacterial community characteristics during grazing exclusion for different types of grassland remain unclear. In this study, the soil bacterial community diversity and composition as well as the co-occurrence patterns were investigated and compared between grazing exclusion (4 years) and the paired adjacent grazing sites for three types of temperate grasslands (desert steppe, typical steppe, and meadow steppe) in the Hulunbuir grassland of Inner Mongolia. Our results showed that short-term grazing exclusion decreased the complexity and connectivity of bacterial co-occurrence patterns while increasing the network modules in three types of temperate grasslands. The effects of grazing exclusion on soil bacterial α-diversity and composition were not significant in typical steppe and meadow steppe. However, short-term grazing exclusion significantly altered the community composition in desert steppe, indicating that the soil bacteria communities in desert steppe could respond faster than those in other two types of steppes. In addition, the composition of bacterial community is predominantly affected by soil chemical properties, such as soil total carbon and pH, instead of spatial distance. These results indicated that short-term grazing exclusion altered the soil bacterial co-occurrence patterns rather than community diversity or composition in three types of temperate grasslands. Moreover, our study suggested that soil bacterial co-occurrence patterns were more sensitive to grazing exclusion, and the restoration of soil bacterial community might need a long term (>4 years) in our study area.

Keywords: bacterial composition; bacterial diversity; co-occurrence network; grazing exclusion; temperate grassland.