Effects of grazing in different intensities and 10‐year grazing exclusion on soil bacterial community composition and interaction complexity in alpine grasslands of the Qinghai‐Tibet Plateau

Abstract

To decrease the detrimental consequences of overgrazing on the sustainability of grassland ecosystems, many countries have developed policies on grazing exclusions. However, compared with grazing, how grazing exclusion modifies soil bacterial community and the associated environmental drivers is inadequately understood. Here, we studied the effects of grazing in different intensities (no grazing, light, moderate, and heavy grazing) and 10 years' grazing exclusion on soil bacteria community and associated environmental factors in the grassland of the Qinghai‐Tibet Plateau. The results showed significant changes in soil bacterial composition among all the treatments. After 10 years' grazing exclusion, the composition of the bacterial community rather than bacterial diversity was significantly different from that in grassland without grazing treatment. Under grazing exclusion, bacterial community composition was regulated by the total nitrogen and nitrate nitrogen. Grazing treatments decreased the complexity of the bacterial co‐occurrence network, but 10 years' grazing exclusion increased the complexity. This study found that grazing in different intensities substantially affected bacterial community structure and diversity, but 10 years' grazing exclusion hardly alleviated the historical grazing effects on the bacterial community structure. The findings of the study extended the understanding of how bacterial communities in grasslands respond to grazing in different intensities and grazing exclusion, providing a crucial scientific foundation for evaluating sustainable grazing management.