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 Spring frost controls spring tree phenology along elevational gradients on the southeastern Tibetan Plateau

2017 ◽  
Author(s):  
Yafeng Wang ◽  
Bradley Case ◽  
Sergio Rossi ◽  
Liping Zhu ◽  
Eryuan Liang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Driving Forces ◽  
Climate Extremes ◽  
The Tibetan Plateau ◽  
Spring Phenology ◽  
Altitudinal Gradients ◽  
Leaf Unfolding ◽  
Spring Frost ◽  
Southeastern Tibetan Plateau ◽  
Spring Frosts

AbstractTemperature is considered to be a main driver of spring phenology, whereas the role of climate extremes (such as spring frosts) has long been neglected. A large elevational gradient of mature forests on the Tibetan Plateau provides a powerful space-for-time ‘natural experiment’ to explore driving forces of spring phenology. Combining 5-yr of in situ phenological observations of Smith fir (Abies georgei var. smithii) with concurrent air temperature data along two altitudinal gradients on the southeastern Tibetan Plateau, we tested the hypothesis that spring frost was a major factor regulating the timing of spring phenology. Onset of bud swelling and leaf unfolding in the study years occurred ≈ 18 or 17 days earlier, respectively, at the lowest (3800 m a.s.l.) elevation relative to upper treelines (4360 or 4380 m a.s.l.). The frequency of freezing events and last freezing date were critical factors in determining the timing of bud swelling along two altitudinal gradients, whereas onset of leaf unfolding was primarily controlled by the onset of bud swelling. This finding provides evidence for detrimental impacts of spring frost on spring phenology, which have been underappreciated in research on phenological sensitivity to climate but should be included in phenology models. It contributes to explain the declining global warming effects on spring phenophases, because climatic extreme events (e.g. spring frosts) tend to increase with warming.

scholarly journals Distribution of PCBs and PBDEs in soils along the altitudinal gradients of Balang Mountain, the east edge of the Tibetan Plateau

2012 ◽  
Vol 161 ◽  
pp. 101-106 ◽  
Author(s):  
Xiaoyan Zheng ◽  
Xiande Liu ◽  
Guibin Jiang ◽  
Yawei Wang ◽  
Qinghua Zhang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
The Tibetan Plateau ◽  
Altitudinal Gradients

scholarly journals Tree growth and its climate signal along latitudinal and altitudinal gradients: comparison of tree rings between Finland and the Tibetan Plateau

2017 ◽  
Vol 14 (12) ◽  
pp. 3083-3095 ◽  
Author(s):  
Lixin Lyu ◽  
Susanne Suvanto ◽  
Pekka Nöjd ◽  
Helena M. Henttonen ◽  
Harri Mäkinen ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Tree Ring ◽  
Tree Growth ◽  
Latitudinal Gradient ◽  
Ring Width ◽  
Growing Season ◽  
The Tibetan Plateau ◽  
Climate Variables ◽  
Climate Data ◽  
Altitudinal Gradients

Abstract. Latitudinal and altitudinal gradients can be utilized to forecast the impact of climate change on forests. To improve the understanding of how these gradients impact forest dynamics, we tested two hypotheses: (1) the change of the tree growth–climate relationship is similar along both latitudinal and altitudinal gradients, and (2) the time periods during which climate affects growth the most occur later towards higher latitudes and altitudes. To address this, we utilized tree-ring data from a latitudinal gradient in Finland and from two altitudinal gradients on the Tibetan Plateau. We analysed the latitudinal and altitudinal growth patterns in tree rings and investigated the growth–climate relationship of trees by correlating ring-width index chronologies with climate variables, calculating with flexible time windows, and using daily-resolution climate data. High latitude and altitude plots showed higher correlations between tree-ring chronologies and growing season temperature. However, the effects of winter temperature showed contrasting patterns for the gradients. The timing of the highest correlation with temperatures during the growing season at southern sites was approximately 1 month ahead of that at northern sites in the latitudinal gradient. In one out of two altitudinal gradients, the timing for the strongest negative correlation with temperature at low-altitude sites was ahead of treeline sites during the growing season, possibly due to differences in moisture limitation. Mean values and the standard deviation of tree-ring width increased with increasing mean July temperatures on both types of gradients. Our results showed similarities of tree growth responses to increasing seasonal temperature between latitudinal and altitudinal gradients. However, differences in climate–growth relationships were also found between gradients due to differences in other factors such as moisture conditions. Changes in the timing of the most critical climate variables demonstrated the necessity for the use of daily-resolution climate data in environmental gradient studies.

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.

scholarly journals Different patterns of belowground fungal diversity along altitudinal gradients with respect to microhabitat and guild types

2021 ◽  
Author(s):  
Ki Hyeong Park ◽  
Shinnam Yoo ◽  
Myung Soo Park ◽  
Chang Sun Kim ◽  
Young Woon Lim
Keyword(s):  
Mycorrhizal Fungi ◽  
Pinus Densiflora ◽  
Illumina Miseq ◽  
Fungal Communities ◽  
Its2 Region ◽  
Plant Host ◽  
Saprotrophic Fungi ◽  
Altitudinal Gradients ◽  
Ecological Roles ◽  
Ecm Fungi

Abstract Background Fungi are key components of belowground ecosystems with various ecological roles in forests. Although the changes in the richness and composition of belowground fungi across altitudinal gradients have been widely reported, only a few studies have focused on the microhabitat types along altitudinal gradients. Results Here, we analyzed the effect of altitudinal gradients on the fungal communities of belowground microhabitats (roots and soil) and their different ecological roles. Root and nearby soil samples were collected from 80 Pinus densiflora trees in 16 localities at various altitudes across the country, and their community composition was analyzed using DNA metabarcoding of the ITS2 region on the Illumina MiSeq platform. We found that ectomycorrhizal (ECM) fungi and ericoid mycorrhizal fungi were more abundant in the soil, whereas the relative abundance of endophytic and saprotrophic fungi was higher in the roots. Altitude negatively affected the species richness of root-inhabiting and ECM fungi but did not influence that of non-ECM fungi. However, the composition of ECM fungi was less influenced by altitude than that of non-ECM fungi.Conclusion Our results demonstrate that microhabitat types and altitudinal gradients affect the diversity, composition, and function of fungal communities associated with a single plant host and contribute to a better understanding of plant-associated fungal communities.

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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