Abstract:The soil microbial community plays an important role in grassland ecosystem dynamics and has a crucial influence upon plant ecophysiological traits (Andres et al., 2017; Ford, Rousk, Garbutt, Jones, & Jones, 2013). A major challenge in applied ecology is to understand response mechanisms of those complex microbial communities to grazing, especially for those associated with grass species tolerant of grazing. Many studies have demonstrated that herbivores largely determine aboveground biomass, and also directly… Show more
“…However, HIS increased nitrogen consumption, which was the same as in HIM and HII. Although the nutrient consumption of HIS did not cause significant between-group differences in our study, the relationship between soil nitrogen content and bacterial communities involved in nitrogen cycling indicated that HIS exhibited oligotrophic status and increased nitrogen consumption [14,[48][49][50][51][52]. The reason may be that forage grass enhances nitrogen cycling and causes nitrogen loss via nitrite reduction [69].…”
Section: The Risks and Benefits Of Planting Forage Grass On Lacontrasting
confidence: 55%
“…In 2016 and 2017, HIS had significant effects on some oligotrophic bacteria, including Acidobacteria Gp3, Gemm-4, NB1-I, Polaromonas, and Novosphingobium (LDA score > 2, K-W test P < 0.05) [14,[48][49][50]. In 2018, some bacteria involved in nitrogen cycling and plantgrowth promotion increased in the HIS, including Solibacteres, Planctomycetia, Sva0725, Rubrivivax, and Nitrospira (LDA score > 2, K-W test P < 0.05) [51][52][53].…”
Section: The Effects Of Management Scenarios On Microbial Communitiesmentioning
Although agricultural land abandonment (LA) is accompanied by land degradation, it could be considered a kind of self-rehabilitation. Studies have shown that long-term LA has profound ecological and environmental benefits, whereas few studies have compared LA with human intervention (HI), which involves planting and fertilization in agroecosystem restoration. Here, we established four different scenarios based on local livestock husbandry, including LA without HI, LA with slight human intervention (HIS), medium human intervention (HIM), and intensive human intervention (HII). LA experiments were conducted for 3 years and repeatedly sampled three times. The soil bacterial and fungal communities were determined to present the ecological impacts. In this study, LA and HIS could save soil inorganic carbon and total calcium (Ca) contents and benefit soil mycorrhizal fungi and plant growth-promoting rhizobacteria. LA and HIM benefited some microbial communities associated with complicated organic compounds. Human interference methods did not significantly increase soil nutrients after 3 years of farmland abandonment. However, indigenous vegetation increased the risk of plant diseases based on soil microbial communities. Forage grass may control the risk, and HIS was a cost-effective scenario in our study. Moreover, we should maintain a cautious attitude toward HII to prevent excessive intervention.
“…However, HIS increased nitrogen consumption, which was the same as in HIM and HII. Although the nutrient consumption of HIS did not cause significant between-group differences in our study, the relationship between soil nitrogen content and bacterial communities involved in nitrogen cycling indicated that HIS exhibited oligotrophic status and increased nitrogen consumption [14,[48][49][50][51][52]. The reason may be that forage grass enhances nitrogen cycling and causes nitrogen loss via nitrite reduction [69].…”
Section: The Risks and Benefits Of Planting Forage Grass On Lacontrasting
confidence: 55%
“…In 2016 and 2017, HIS had significant effects on some oligotrophic bacteria, including Acidobacteria Gp3, Gemm-4, NB1-I, Polaromonas, and Novosphingobium (LDA score > 2, K-W test P < 0.05) [14,[48][49][50]. In 2018, some bacteria involved in nitrogen cycling and plantgrowth promotion increased in the HIS, including Solibacteres, Planctomycetia, Sva0725, Rubrivivax, and Nitrospira (LDA score > 2, K-W test P < 0.05) [51][52][53].…”
Section: The Effects Of Management Scenarios On Microbial Communitiesmentioning
Although agricultural land abandonment (LA) is accompanied by land degradation, it could be considered a kind of self-rehabilitation. Studies have shown that long-term LA has profound ecological and environmental benefits, whereas few studies have compared LA with human intervention (HI), which involves planting and fertilization in agroecosystem restoration. Here, we established four different scenarios based on local livestock husbandry, including LA without HI, LA with slight human intervention (HIS), medium human intervention (HIM), and intensive human intervention (HII). LA experiments were conducted for 3 years and repeatedly sampled three times. The soil bacterial and fungal communities were determined to present the ecological impacts. In this study, LA and HIS could save soil inorganic carbon and total calcium (Ca) contents and benefit soil mycorrhizal fungi and plant growth-promoting rhizobacteria. LA and HIM benefited some microbial communities associated with complicated organic compounds. Human interference methods did not significantly increase soil nutrients after 3 years of farmland abandonment. However, indigenous vegetation increased the risk of plant diseases based on soil microbial communities. Forage grass may control the risk, and HIS was a cost-effective scenario in our study. Moreover, we should maintain a cautious attitude toward HII to prevent excessive intervention.
“…Among the identified keystone species in our study, the taxa of Udeniomyces , Podospora , Lasiobolidium , Dioszegia , Dothiora , Thyrostroma and Sporormiella were first reported in the desert ecosystem and exhibited specificity to our host plants. In addition, Alternaria was general isolated as the most dominant fungal genera in desert plants as well as other symptomless halophytes [ 9 , 26 , 114 , 115 ]. Although Alternaria is known as a phytopathogen of several plant species, this species was frequently reported as a dominant member of desert ecosystems and displayed a greater adaptive potential [ 71 , 76 ].…”
Despite desert ecosystem being crucial to our understanding of natural geography, species evolution and global climate change, there is limited information on the dynamics of their composition and the diversity of endophytic fungi communities driven by plant identity and organ differentiation. Here, an extensive investigation of endophytic fungal microbiome in root, stem, and leaf organs associated with five xerophyte shrubs in an extremely arid desert, Northwest China, were examined. The fungal community dominated by Dothideomycetes and Pleosporales. Shrub species strongly drive the niche-based processes of endophytic fungi across the root, stem and leaf compartments. The diversity and composition of endophytic fungi in stem showed higher variability among plant species than leaf and root. The fungal communities in root libraries were more diverse and exhibited a remarkable differentiation of community composition. We further demonstrated the significant host preferences and tissue specificity of desert endophytic fungi, and unique specific taxa were also observed. The co-occurrence network revealed the coexistence of fungal endophytes in arid desert, and the root fungal network harbored the highest interspecies connectivity. Members of Pleosporales were the most common keystone species in the root fungal network. This is the first report of mycobiota in both plant species and organ differentiation in an extremely arid desert ecosystem.
“…This result may be attributed to the reduction of litter mass, due to the decrease of vegetation coverage and plant biomass caused by livestock grazing [48]. In contrast, the impacts of grazing on TN and TP from different studies were more variable: positive [49], negative [50], and neutral [51] effects were equally common and varied considerably with grassland ecosystem, grazing intensity, and plant diversity. NH 4 + -N and NO 3 − -N are the two main inorganic N sources from soil that can be taken up and utilized by most plants.…”
Section: Grazing-induced Changes In Soil Properties and Plant Characteristicsmentioning
Plant-associated endophytic microorganisms are essential to developing successful strategies for sustainable agriculture. Grazing is an effective practice of grassland utilization through regulating multitrophic relationships in natural grasslands. This study was conducted for exploring the effects of grazing on the diversities and communities of bacteria and fungi presented in rhizosphere soils, roots, stems, and leaves of Leymus chinensis (L. chinensis), based on high-throughput sequencing. Grazing increased bacterial diversity but reduced fungal diversity in plant leaves. Further analysis confirmed that the abundance of Chloroflexi, Gemmatimonadota, Nitrospirota, Sordariales, and Pezizales in plant leaves was increased by grazing. The Bray–Curtis similarities of microbial communities in the endosphere were higher under grazing plots than non-grazing plots. Moreover, the bacterial communities were significantly correlated with ions, while the nutrient and negative ions exhibited strong influence on fungal communities. We concluded that grazing-induced changes of microbial diversities and communities in different compartments of a dominant perennial grass (L. chinensis) could be attributed to the nutrient and ion distribution in host plant. The current study highlights the importance of livestock in mediating diversities and communities of endophytic microbes, and will be useful for better understanding the complexity of multitrophic interactions in a grassland ecosystem.
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