Grazing intensity alters soil microbial diversity and networks complexity in a typical steppe

Livestock grazing alters soil properties and microbial communities, which are critical for maintaining the biodiversity and functioning of grassland ecosystems. However, the effects of long-term and continuous grazing intensity on the soil microbiome (diversity, composition, and network complexity) remain unclear. In this study, we examined the responses of soil microbial composition, diversity, and network structure to different grazing intensities through a well-controlled 10-year grazing experiment on a typical steppe. Our results showed that grazing altered the structure and composition (beta-diversity) of soil microbes and enhanced the alpha-diversity of bacteria and fungi. Soil multifunctionality and microbial network complexity (bacteria and fungi) gradually decreased with increasing grazing intensity. Furthermore, bacterial communities were more sensitive than fungal communities to different grazing intensities, as reflected by the microbial diversity and network complexity. Moreover, the correlation between microbial diversity and soil environmental factors was stronger than that of the fungal community. Overall, this study enhances our understanding of the effects of grazing intensity on microbial communities and provides useful pointers for grassland management and ecological restoration in typical steppes.