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

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.

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

“…This suggests that grazing reduces the stability of soil bacterial communities compared to grasslands without grazing treatment (Mougi & Kondoh, 2012). Our findings indicate that grazing exclusion promotes higher bacterial network complexity, which differs from studies in temperate grasslands and could be a result of the harsh climate of the Tibetan Plateau, where microorganisms require complex linkages to optimize limited resources (Marcos et al, 2019; Wang, Li, et al, 2022).…”

Heavy grazing reduces soil bacterial diversity by increasing soil pH in a semi-arid steppe

“…Previous studies have reported that grazing may affect soil microbial diversity ( Zhang et al, 2016 ; Wang et al, 2022a ; Jing et al, 2023 ), however, findings have been mixed. Wu et al (2022) conducted a regional-scale grazing experiment on the Mongolian Plateau (covered three typical vegetation types) and showed that grazing increased the diversity of both bacterial and fungal compared with enclosure.…”

“…Soil microorganisms ( e.g. , bacteria and fungi) are the vital component of biodiversity and play important roles in the grassland ecosystem, such as litter decomposition, soil nutrient supply, the elements’ biogeochemical cycle, which regulate the plant nutrient availability ( Bardgett, 2005 ; Yao, Bowman & Shi, 2011 ; Zhang et al, 2016 ; Zhao et al, 2020 ; Wang et al, 2022a ). The loss of microbial diversity leads to the decline in ecosystem functions, which negatively impacts on primary production, nutrient cycling and climate regulation ( Delgado-Baquerizo et al, 2016 ).…”

Effect of isolated lactic acid bacteria on the quality and bacterial diversity of native grass silage

“…Generally, native grass hay is the traditional method of native grass; however, because the quality and palatability of natural hay is sensitive to environmental factors, it is not feasible to address the seasonal and annual imbalances through hay preparation techniques ( Li et al., 2015 ). Ensiling, a traditional method of preserving animal feed and fresh fodder crops, provides feed for animals all year round, effectively reducing nutritional losses and extending storage time ( Wang et al., 2022 ). Silage was mainly lactic acid bacteria (LAB) in the anaerobic environment using soluble carbohydrates for fermentation, produce lactic acid (LA), leading to low pH, inhibit aerobic bacteria, effective preservation of nutrients and improves feed palatability ( Cai et al., 2020 ).…”