scholarly journals Ecological processes underlying community assembly of aquatic bacteria and macroinvertebrates under contrasting climates on the Tibetan Plateau

2020 ◽  
Vol 702 ◽  
pp. 134974 ◽  
Author(s):  
Annika Vilmi ◽  
Wenqian Zhao ◽  
Félix Picazo ◽  
Mingjia Li ◽  
Jani Heino ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Community Assembly ◽  
The Tibetan Plateau ◽  
Ecological Processes ◽  
Aquatic Bacteria

scholarly journals Distinct assembly mechanisms underlie similar biogeographical patterns of rare and abundant bacteria in Tibetan Plateau grassland soils

2020 ◽  
Author(s):  
Mukan Ji ◽  
Weidong Kong ◽  
James Stegen ◽  
Linyan Yue ◽  
Fei Wang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Community Assembly ◽  
Climatic Factors ◽  
Variation Partitioning ◽  
Terrestrial Ecosystems ◽  
The Tibetan Plateau ◽  
Grassland Soils ◽  
Ecological Processes ◽  
Local Factors ◽  
Grassland Types

Abstract Background: Bacteria in low abundance represent the majority of Earth’s biodiversity and perform vital ecological functions, but little is known about their biogeography nor the ecological processes that drive their community assembly in terrestrial ecosystems. Here, we investigated the community compositions and phylogenies of rare (relative abundance < 0.1%) and abundant (> 1%) soil bacteria along a transect containing three alpine grassland types (meadow, steppe, and desert) on the Tibetan Plateau. Results: Our results revealed similar biogeographical patterns of rare and abundant bacteria, with their community compositions and phylogenies shifting gradually along the transect. The similar patterns, however, were driven by contrasting community assembly processes, with rare subcommunity being more heavily influenced by stochasticity (72%) than abundant (57%). The composition of abundant subcommunity (80%) was better explained by local (including soil and vegetation factors), geospatial and climatic factors than that of rare subcommunity (41%), while the phylogeny of the rare one (36%) was better explained than that of the abundant one (29%). Variation partitioning analysis indicated that pure local factors consistently explained a higher proportion of the community composition than geospatial factors in both rare (12.3% and 8.7%, respectively) and abundant bacteria (18.3% and 14.1%, respectively). In contrast, the phylogeny of rare subcommunity was explained by local and geospatial factors equally (11.5% and 11.9%, respectively), while that of abundant subcommunity was more explained by geospatial (22.1%) than local factors (11.3%). Furthermore, our results revealed a tighter connection between the community phylogeny and composition in rare than in abundant bacteria. Conclusions: Our results revealed consistent biogeographical patterns of rare and abundant bacteria in grassland soils, but their assembly processes were distinct. We further demonstrated that rare subcommunity was less predictable than the abundant subcommunity by environmental and geospatial factors. Rare and abundant bacteria responded differentially to factors, which was attributed to the distinct life strategies. Our study provides novel insights into the assembly processes and biographical patterns of rare and abundant bacteria in terrestrial ecosystems.

The effects of land degradation on plant community assembly: Implications for the restoration of the Tibetan Plateau

2020 ◽  
Vol 31 (18) ◽  
pp. 2819-2829
Author(s):  
Jiufu Luo ◽  
Li Ma ◽  
Guijing Li ◽  
Dongzhou Deng ◽  
Dechao Chen ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Plant Community ◽  
Land Degradation ◽  
Community Assembly ◽  
The Tibetan Plateau ◽  
Plant Community Assembly

scholarly journals Distribution and Assembly Processes of Soil Fungal Communities along an Altitudinal Gradient in Tibetan Plateau

2021 ◽  
Vol 7 (12) ◽  
pp. 1082
Author(s):  
Sarfraz Hussain ◽  
Hao Liu ◽  
Senlin Liu ◽  
Yifan Yin ◽  
Zhongyuan Yuan ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Null Model ◽  
Illumina Miseq ◽  
Fungal Communities ◽  
The Tibetan Plateau ◽  
Ecological Processes ◽  
Altitudinal Gradients ◽  
Community Model ◽  
Α Diversity ◽  
Dispersal Limitations

In soil ecosystems, fungi exhibit diverse biodiversity and play an essential role in soil biogeochemical cycling. Fungal diversity and assembly processes across soil strata along altitudinal gradients are still unclear. In this study, we investigated the structure and abundance of soil fungal communities among soil strata and elevational gradients on the Tibetan Plateau using Illumina MiSeq sequencing of internal transcribed spacer1 (ITS1). The contribution of neutral and niche ecological processes were quantified using a neutral community model and a null model-based methodology. Our results showed that fungal gene abundance increased along altitudinal gradients, while decreasing across soil strata. Along with altitudinal gradients, fungal α-diversity (richness) decreased from surface to deeper soil layers, while β-diversity showed weak correlations with elevations. The neutral community model showed an excellent fit for neutral processes and the lowest migration rate (R2 = 0.75). The null model showed that stochastic processes dominate in all samples (95.55%), dispersal limitations were dominated at the surface layer and decreased significantly with soil strata, while undominated processes (ecological drift) show a contrary trend. The log-normal model and the null model (βNTI) correlation analysis also neglect the role of niche-based processes. We conclude that stochastic dispersal limitations, together with ecological drifts, drive fungal communities.

scholarly journals Community assembly and functional leaf traits mediate precipitation use efficiency of alpine grasslands along environmental gradients on the Tibetan Plateau

2016 ◽  
Author(s):  
Shaowei Li ◽  
Jianshuang Wu
Keyword(s):  
Climate Change ◽  
Tibetan Plateau ◽  
Community Assembly ◽  
Environmental Gradients ◽  
Diversity Index ◽  
Regional Scale ◽  
The Tibetan Plateau ◽  
Alpine Grasslands ◽  
Moisture Index ◽  
Use Efficiency

The alpine grasslands on the Tibetan Plateau are sensitive and vulnerable to climate change. However, it is still unknown how precipitation use efficiency (PUE), the ratio of ANPP to precipitation, is related to community assembly of plant species, functional groups or traits for the Tibetan alpine grasslands along actual environmental gradients. We conducted a multi-site field survey at grazing-excluded pastures across meadow, steppe and desert-steppe to measure aboveground biomass in August, 2010. We used species richness, the Shannon diversity index, and cover-weighted functional group composition (FGC) of 1-xerophytes, 2-mesophytes, and 3-hygrophytes to describe community assembly at the species level; and chose community-level leaf area index (LAIc ), specific leaf area (SLAc ), and species-mixed foliar δ13C to quantify community assembly at the functional trait level. Our results showed that PUE decreased with increasing accumulated active temperatures (AccT) when daily temperature average is higher than 5°C, but increased with increasing climatic moisture index, which was demined as the ratio of growing season precipitation (GSP) to AccT. We also found that PUE increased with increasing species richness, the Shannon diversity index, FGC and LAIc ,decreased with increasing foliar δ13C, and had no relation with SLAc at the regional scale. Neither soil total nitrogen nor organic carbon has no influence on PUE at the regional scale. The community assembly of the Shannon index, LAIc and SLAc together accounted for 46.3 % of variance in PUE, whilst climatic moisture index accounted for 47.9 % of variance in PUE at the regional scale. This implies that community structural properties and plant functional traits can mediate the sensitivity of alpine grassland productivity in response to climate change. Thus, a long-term observation on community structural and functional changes is recommended for better understanding the response of alpine ecosystems to regional climate change on the Tibetan Plateau.

scholarly journals Community assembly and functional leaf traits mediate precipitation use efficiency of alpine grasslands along environmental gradients on the Tibetan Plateau

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2680 ◽  
Author(s):  
Shaowei Li ◽  
Jianshuang Wu
Keyword(s):  
Climate Change ◽  
Tibetan Plateau ◽  
Community Assembly ◽  
Environmental Gradients ◽  
Diversity Index ◽  
Regional Scale ◽  
The Tibetan Plateau ◽  
Alpine Grasslands ◽  
Use Efficiency ◽  
Precipitation Use Efficiency

The alpine grasslands on the Tibetan Plateau are sensitive and vulnerable to climate change. However, it is still unknown how precipitation use efficiency (PUE), the ratio of aboveground net primary productivity (ANPP) to precipitation, is related to community assembly of plant species, functional groups or traits for the Tibetan alpine grasslands along actual environmental gradients. We conducted a multi-site field survey at grazing-excluded pastures across meadow, steppe and desert-steppe to measure aboveground biomass (AGB) in August, 2010. We used species richness (SR), the Shannon diversity index, and cover-weighted functional group composition (FGC) of 1-xerophytes, 2-mesophytes, and 3-hygrophytes to describe community assembly at the species level; and chose community-level leaf area index (LAIc), specific leaf area (SLAc), and species-mixed foliar δ13C to quantify community assembly at the functional trait level. Our results showed that PUE decreased with increasing accumulated active temperatures (AccT) when daily temperature average is higher than 5 °C, but increased with increasing climatic moisture index (CMI), which was demined as the ratio of growing season precipitation (GSP) to AccT. We also found that PUE increased with increasing SR, the Shannon diversity index, FGC and LAIc, decreased with increasing foliar δ13C, and had no relation with SLAcat the regional scale. Neither soil total nitrogen (STN) nor organic carbon has no influence on PUE at the regional scale. The community assembly of the Shannon index, LAIcand SLActogether accounted for 46.3% of variance in PUE, whilst CMI accounted for 47.9% of variance in PUE at the regional scale. This implies that community structural properties and plant functional traits can mediate the sensitivity of alpine grassland productivity in response to climate change. Thus, a long-term observation on community structural and functional changes is recommended for better understanding the response of alpine ecosystems to regional climate change on the Tibetan Plateau.

scholarly journals Community assembly and functional leaf traits mediate precipitation use efficiency of alpine grasslands along environmental gradients on the Tibetan Plateau

2016 ◽  
Author(s):  
Shaowei Li ◽  
Jianshuang Wu
Keyword(s):  
Climate Change ◽  
Tibetan Plateau ◽  
Community Assembly ◽  
Environmental Gradients ◽  
Diversity Index ◽  
Regional Scale ◽  
The Tibetan Plateau ◽  
Alpine Grasslands ◽  
Moisture Index ◽  
Use Efficiency

The alpine grasslands on the Tibetan Plateau are sensitive and vulnerable to climate change. However, it is still unknown how precipitation use efficiency (PUE), the ratio of ANPP to precipitation, is related to community assembly of plant species, functional groups or traits for the Tibetan alpine grasslands along actual environmental gradients. We conducted a multi-site field survey at grazing-excluded pastures across meadow, steppe and desert-steppe to measure aboveground biomass in August, 2010. We used species richness, the Shannon diversity index, and cover-weighted functional group composition (FGC) of 1-xerophytes, 2-mesophytes, and 3-hygrophytes to describe community assembly at the species level; and chose community-level leaf area index (LAIc ), specific leaf area (SLAc ), and species-mixed foliar δ13C to quantify community assembly at the functional trait level. Our results showed that PUE decreased with increasing accumulated active temperatures (AccT) when daily temperature average is higher than 5°C, but increased with increasing climatic moisture index, which was demined as the ratio of growing season precipitation (GSP) to AccT. We also found that PUE increased with increasing species richness, the Shannon diversity index, FGC and LAIc ,decreased with increasing foliar δ13C, and had no relation with SLAc at the regional scale. Neither soil total nitrogen nor organic carbon has no influence on PUE at the regional scale. The community assembly of the Shannon index, LAIc and SLAc together accounted for 46.3 % of variance in PUE, whilst climatic moisture index accounted for 47.9 % of variance in PUE at the regional scale. This implies that community structural properties and plant functional traits can mediate the sensitivity of alpine grassland productivity in response to climate change. Thus, a long-term observation on community structural and functional changes is recommended for better understanding the response of alpine ecosystems to regional climate change on the Tibetan Plateau.

Terrestrial-aquatic ecosystem links on the Tibetan Plateau inferred from sedaDNA shotgun sequencing

2021 ◽  
Author(s):  
Sisi Liu ◽  
Kathleen R. Stoof-Leichsenring ◽  
Luise Schulte ◽  
Heike H. Zimmermann ◽  
Steffen Mischke ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Species Interactions ◽  
Shotgun Sequencing ◽  
Ice Age ◽  
The Tibetan Plateau ◽  
Ecological Communities ◽  
Submerged Plants ◽  
Ecological Processes ◽  
Large Herbivores ◽  
The Past

&lt;p&gt;Climate change and associated species interactions are responsible for many vital mechanisms governing the dynamics of ecological communities. However, the long-term contribution of environmental conditions and species connections to community assembly remain mostly unknown. Here, we present changes of terrestrial and freshwater communities based on metagenomic shotgun data retrieved from lacustrine sediments of an alpine freshwater lake on the south-eastern Tibetan Plateau (Hengduan Mountains) covering the past 15,100 thousand years (ka). Terrestrial assemblages between 15.1-14 ka are explained by the harsh environment and facilitative interactions due to diverse cushion plants, while the abundant ice-age algae (&lt;em&gt;Nannochloropsis&lt;/em&gt; and &lt;em&gt;N. limnnetica&lt;/em&gt;) indicate dominance of glacial meltwaters. A sharp decrease in alpine herbs (e.g Asteraceae, &lt;em&gt;Carex&lt;/em&gt; and Poaceae) corresponded to competitive interactions with the colonization of woody plants (Salicaceae, &lt;em&gt;Salix&lt;/em&gt;, &lt;em&gt;Rhododendron&lt;/em&gt; and &lt;em&gt;R. delavayi&lt;/em&gt;) since 14 ka, leading to a decline of large herbivores (Bovidae and &lt;em&gt;Bos mutus&lt;/em&gt;) that predominated. Meanwhile, the disappearance of ice-age algae and the expansion of submerged plants (e.g., &lt;em&gt;Potamogeton&lt;/em&gt;, &lt;em&gt;P. perfoliatus&lt;/em&gt;, &lt;em&gt;Myriophyllum&lt;/em&gt;, and &lt;em&gt;M. spicatum&lt;/em&gt;) are consistent with an increase in temperature and a plentiful supply of nutrients due to weathering and soil erosion. The loss of submerged plants during the late Holocene (~3.6 ka) is probably related to environmental deterioration; however, it could also be related to the Cyanobacteria boom. Our study highlights that shotgun sequencing of lake sediments is an important tool for exploring ecological processes of communities in the past.&lt;/p&gt;

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