Patterns of grassland community composition and structure along an elevational gradient on the Qinghai-Tibet Plateau

2021 ◽  
Author(s):  
Xin Wang ◽  
Jiangling Zhu ◽  
Shitao Peng ◽  
Tianli Zheng ◽  
Zhaoyu Qi ◽  
...  
Keyword(s):  
Community Composition ◽  
Elevation Gradient ◽  
Elevational Gradient ◽  
Tibet Plateau ◽  
Equation Modeling ◽  
Grassland Community ◽  
Β Diversity ◽  
Composition And Structure ◽  
Α Diversity ◽  
Qinghai Tibet Plateau

Abstract Aims Grasslands in the Qinghai-Tibet Plateau play an important role in preserving ecological security and high biodiversity in this region. However, the distribution of the composition and structure of plant community and the mechanism by which it maintains itself in this region is still poorly understood. Methods Here, we designed 195 grassland plots in 39 grassland sites along an approximately 1700-m elevation gradient on the Northeastern Qinghai-Tibet Plateau. Important findings We found that the grassland community height decreased significantly with the increase of elevation, while community coverage did not demonstrate significant changes. With the increase of elevation, the plant species richness (α diversity) increased significantly, but the community variability (β diversity) decreased significantly. The constrained clustering analysis suggested that the α- and β-diversity in the grasslands transformed gradually with elevation, and three discontinuous points (based on community structure) were observed at elevation of 3640, 4252 and 4333 m. Structural equation modeling (SEM) indicated that the increase of precipitation and the decrease of temperature significantly positively influenced α diversity, which was negatively correlated with β diversity. These results demonstrate that the community composition and structure presented a quantitative-to-qualitative change along this elevational gradient on the Qinghai-Tibet Plateau.

scholarly journals Abundant and rare bacterial taxa structuring differently in sediment and water in thermokarst lakes in the Yellow River Source area, Qinghai-Tibet Plateau

2021 ◽  
Author(s):  
Ze Ren ◽  
Cheng Zhang ◽  
Xia Li ◽  
Kang Ma ◽  
Kexin Feng ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Yellow River ◽  
Source Area ◽  
Tibet Plateau ◽  
The Yellow River ◽  
Thermokarst Lakes ◽  
Β Diversity ◽  
Α Diversity ◽  
Yellow River Source ◽  
Qinghai Tibet Plateau

Thermokarst lakes are forming from permafrost thaw and severely affected by accelerating climate change. Sediment and water in these lakes are distinct habitats but closely connected. However, our understanding of the differences and linkages between sediment and water in thermokarst lakes remain largely unknow, especially from the perspective of bacterial community patterns and underlying mechanisms. In this study, we examined bacterial communities in sediment and water in thermokarst lakes in the Yellow River Source area, Qinghai-Tibet Plateau. Bacterial taxa were divided to abundant and rare according to their relative abundance, and the Sorensen dissimilarity (βsor) was partitioned into turnover (βturn) and nestedness (βnest). The results showed that the whole bacterial communities as well as the abundant and rare subcommunities differed substantially between sediment and water, in terms of taxonomical composition, α-diversity, and β-diversity. Sediment had significantly lower α-diversity indexes but higher β-diversity than water. Abundant taxa had significantly higher relative abundances but lower α-diversity and β-diversity than rare taxa. Moreover, bacterial communities are predominantly governed by strong turnover processes (βturn/βsor ratio of 0.925). Abundant subcommunities were significantly lower in βturn/βsor ratio compared to rare subcommunities. Bacterial communities in sediment had a significantly higher βturn/βsor ratio than in water. The results suggest that the bacterial communities of thermokarst lakes, especially rare subcommunities or particularly in sediment, might be strongly structured by environmental filtering and geographical isolation, leading to compositional distinct. By revealing bacterial communities in sediment and water, this integral study increased our current knowledge of thermokarst lakes, enhancing our understanding of the community assembly rules and ecosystem structures and processes of these rapid changing and vulnerable ecosystems.

scholarly journals Single-Species Artificial Grasslands Decrease Soil Multifunctionality in a Temperate Steppe on the Qinghai–Tibet Plateau

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2092
Author(s):  
Kelu Chen ◽  
Huakun Zhou ◽  
Bingbing Lu ◽  
Yang Wu ◽  
Jie Wang ◽  
...  
Keyword(s):  
Community Composition ◽  
Soil Ph ◽  
Abiotic Factors ◽  
Soil Microbial Communities ◽  
Single Species ◽  
Tibet Plateau ◽  
Temperate Steppe ◽  
Negatively Associated ◽  
Grass Production ◽  
Qinghai Tibet Plateau

Artificial grasslands have been regarded as an effective method to improve grass production and quality, especially on the Qinghai–Tibet Plateau. Soil ecosystem multifunctionality (EMF) plays an important role in sustainable regional development. However, few studies have investigated the impacts of artificial grasslands on soil EMF. Here, we constructed single-species artificial grasslands in a natural temperate steppe and investigated soil microbial communities, abiotic factors (soil moisture and pH), and functions related to biogeochemical cycles to explore (1) how the transformation from temperate steppe to artificial grasslands affected soil EMF and (2) the roles of species and phylogenetic microbial diversities, microbial community composition, and abiotic factors in driving differences in soil EMF. Our results showed that artificial grasslands decreased soil EMF regardless of planting species; that the bacterial and fungal community composition contributed more to soil EMF prediction than species and phylogenetic diversities; and that microbial phylogenetic diversities were negatively associated with soil EMF. Soil pH played an important role in the effects of artificial grasslands on soil EMF—artificial grasslands increased soil pH, which was negatively associated with soil EMF. Overall, the benefits of establishing artificial grasslands, for example, higher grass production and quality, might be at the expense of soil EMF. Further studies should explore mixed-species artificial grasslands.

Evapotranspiration and its dominant controls along an elevation gradient in the Qinghai Lake watershed, northeast Qinghai-Tibet Plateau

2019 ◽  
Vol 575 ◽  
pp. 257-268 ◽  
Author(s):  
Yu-Jun Ma ◽  
Xiao-Yan Li ◽  
Lei Liu ◽  
Xiao-Fan Yang ◽  
Xiu-Chen Wu ◽  
...  
Keyword(s):  
Elevation Gradient ◽  
Tibet Plateau ◽  
Qinghai Lake ◽  
Qinghai Tibet Plateau

scholarly journals Diversity Patterns of Different Life Forms of Plants along an Elevational Gradient in Crete, Greece

Diversity ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 200 ◽  
Author(s):  
Maria Lazarina ◽  
Athanasios Charalampopoulos ◽  
Maria Psaralexi ◽  
Nikos Krigas ◽  
Danai-Eleni Michailidou ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Large Scale ◽  
Regional Scale ◽  
Elevational Gradient ◽  
Life Forms ◽  
Species Pool ◽  
Diversity Patterns ◽  
Β Diversity ◽  
Α Diversity

Elevational gradients provide a unique opportunity to explore species responses to changing environmental conditions. Here, we focus on an elevational gradient in Crete, a climate-vulnerable Mediterranean plant biodiversity hotspot and explore the diversity patterns and underlying mechanisms of different plant life forms. We found that the significant differences in life forms’ elevational and environmental ranges are reflected in α- diversity (species richness at local scale), γ-diversity (species richness at regional scale) and β-diversity (variation in species composition). The α- and γ-diversity decreased with elevation, while β-diversity followed a hump-shaped relationship, with the peak varying between life forms. However, β-deviation (deviation from null expectations) varied significantly with elevation but was life formindependent. This suggests that species composition is shaped by the size of the available species pool which depends on life form, but also by other deterministic or stochastic processes that act in a similar way for different life forms. The strength of these processes varies with elevation, with hotter–drier conditions and increased human activities filtering species composition at lowlands and large-scale processes determining the species pool size overriding local ecological processes at higher elevations.

scholarly journals Dietary Fiber Influences Bacterial Community Assembly Processes in the Gut Microbiota of Durco × Bamei Crossbred Pig

2021 ◽  
Vol 12 ◽  
Author(s):  
Xianjiang Tang ◽  
Liangzhi Zhang ◽  
Chao Fan ◽  
Lei Wang ◽  
Haibo Fu ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Dietary Fiber ◽  
Community Assembly ◽  
Cecal Content ◽  
High Fiber ◽  
Β Diversity ◽  
Composition And Structure ◽  
Α Diversity ◽  
Deterministic Processes ◽  
Crossbred Pigs

Several studies have shown that dietary fiber can significantly alter the composition and structure of the gut bacterial community in humans and mammals. However, few researches have been conducted on the dynamics of the bacterial community assembly across different graded levels of dietary fiber in different gut regions. To address this, 24 Durco × Bamei crossbred pigs were randomly assigned to four experimental chows comprising graded levels of dietary fiber. Results showed that the α-and β-diversity of the bacterial community was significantly different between the cecum and the jejunum. Adding fiber to the chow significantly increased the α-diversity of the bacterial community in the jejunum and cecum, while the β-diversity decreased. The complexity of the bacterial network increased with the increase of dietary fiber in jejunal content samples, while it decreased in cecal content samples. Furthermore, we found that stochastic processes governed the bacterial community assembly of low and medium dietary fiber groups of jejunal content samples, while deterministic processes dominated the high fiber group. In addition, deterministic processes dominated all cecal content samples. Taken together, the variation of gut community composition and structure in response to dietary fiber was distinct in different gut regions, and the dynamics of bacterial community assembly across the graded levels of dietary fiber in different gut regions was also distinct. These findings enhanced our knowledge on the bacterial community assembly processes in gut ecosystems of livestock.

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