Herbivore assemblages affect soil microbial communities by altering root biomass and available nutrients in an alpine meadow

Abstract

Three different herbivore grazing assemblages, namely, yak grazing (YG), Tibetan sheep grazing (SG) and yak and Tibetan sheep co-grazing (MG), are practiced in alpine meadows on the Qinghai-Tibetan Plateau (QTP), but the effects of the different herbivore assemblages on soil microbes are relatively unknown. The microbial community plays an important role in the functional stability of alpine grassland ecosystems. Therefore, it is important to understand how the microbial community structure of grassland ecosystems changes under different herbivore grazing assemblages to ensure their sustainable development. To fill this gap, a field study was carried out to investigate the effects of YG, SG, and MG on plant communities, soil physico-chemical properties and microbial communities under moderate grazing intensity in alpine meadows. Grazing increased the β-diversity of the bacteria community and decreased the β-diversity of the fungal community. The herbivore assemblage affected the microbial community diversity, but not the plant community diversity. Total phosphorus, soil bulk density, root biomass, and plant α-diversity were correlated with both the bacterial and fungal community composition, available phosphorus and soil moisture were correlated only with the bacterial community composition, while available potassium and above-ground net primary production (ANPP) were correlated only with the fungal community composition. Soil available nitrogen, soil available phosphorus and soil bulk density were highest in SG, while ANPP was highest in MG. It was concluded that MG can improve ANPP and stabilize the soil microbial community, suggesting that MG is an effective method for sustainable use and conservation of alpine meadows on the QTP.

Legume-grass mixtures increase forage yield by improving soil quality in different ecological regions of the Qinghai-Tibet Plateau

“…At the same time, differences in the biological nitrogen fixation capacity of leguminous crops in different ecological regions make soil nitrogen cycling and utilization different, indirectly affecting soil bacterial microbial diversity( Kennedy and Tchan, 1992 ; Rahman, 2013 ). In addition, we found that the bacterial a-diversity was significantly higher in HZ and GN than in MY, possibly due to different initial microbial communities and different responses of soil microbes in different ecological zones to cropping patterns ( Liu et al., 2023 ). We also found that Proteobacteria were the most abundant phylum in the studied flora in different ecological zones, followed by Actinobacteria, which is in line with previous findings ( Jing et al., 2018 ).…”

“…Soil bacterial b-diversity varies between cropping patterns. It is due to the fact that bacterial b-diversity is mainly driven by plant diversity and dominant species of bacteria ( Liu et al., 2023 ). Whereas mixed seeding increases plant diversity, different plant characteristics and soil environments produce different ecological niches ( Hamid et al., 2021 ), which in turn affect specific soil microbial communities.…”

“…Differences in the composition and amount of root secretions of different species can lead to alterations in the metabolism of soil microorganisms, which in turn affects the composition of soil microorganisms ( Nayyar et al., 2010 ). In addition to this, different plant communities have different apoplasts, which can affect the living environment of soil microorganisms and indirectly influence the composition of soil microbial communities ( Liu et al., 2023 ).…”

Interplay of soil characteristics and arbuscular mycorrhizal fungi diversity in alpine wetland restoration and carbon stabilization

“…The alpine wetlands situated on the Qinghai-Tibetan Plateau, represent one of the largest alpine wetland ecosystems, offering a striking illustration of the profound influence of livestock grazing on these fragile ecosystems ( Sun et al, 2022 ; Wang et al, 2023 ; Zhang et al, 2023 ). The practice of grazing is deeply integrated into the local socio-economic practices, brings about significant alterations to various ecological aspects, including soil properties, rates of litter decomposition, and soil microbes ( Sun et al, 2018 ; Ji et al, 2020 ; Qin et al, 2021 ; Wang et al, 2022 ; Liu Y. et al, 2023 ). These changes have cascading effects on the C cycle, for instance, grazing-induced disturbances can disrupt soil structure and nutrient dynamics, impacting both the quantity and quality of organic matter decomposition and subsequent soil C stabilization ( Sun et al, 2018 ; Ji et al, 2020 ).…”

“…These changes have cascading effects on the C cycle, for instance, grazing-induced disturbances can disrupt soil structure and nutrient dynamics, impacting both the quantity and quality of organic matter decomposition and subsequent soil C stabilization ( Sun et al, 2018 ; Ji et al, 2020 ). Furthermore, grazing modifies the diversity and functionality of soil microbial communities, which are crucial for organic matter breakdown and C cycling, thereby influencing soil respiration rates and the overall C storage capacity of the soil ( Qin et al, 2021 ; Liu Y. et al, 2023 ).…”