scholarly journals Asymmetrical Warming Between Elevations May Result in Similar Plant Community Composition Between Elevations in Alpine Grasslands

2021 ◽  
Vol 9 ◽  
Author(s):  
Jiangwei Wang ◽  
Chengqun Yu ◽  
Gang Fu
Keyword(s):  
Tibetan Plateau ◽  
Community Composition ◽  
Plant Species ◽  
Plant Community ◽  
Environmental Temperature ◽  
The Tibetan Plateau ◽  
Plant Community Composition ◽  
Alpine Grasslands ◽  
Phylogenetic Composition ◽  
Moisture Conditions

Asymmetrical warming between elevations is a common phenomenon and warming magnitude increases with increasing elevations on the Tibetan Plateau, which in turn may reduce temperature differences between elevations. However, it is still unclear how such phenomenon will affect plant community composition in alpine grasslands on the Tibetan Plateau. Therefore, in this study, we performed an experiment at three elevations (i.e., 4,300 m, 4,500 m, and 4,700 m) in alpine grasslands, the Northern Tibetan Plateau since May, 2010. Open top chambers were established at the elevations 4,500 m and 4,700 m. Plant species and phylogenetic composition were investigated in August, 2011–2019. There were no significant differences in plant species and phylogenetic composition, environmental temperature and moisture conditions between the elevation 4,300 m under non-warming conditions and the elevation 4,500 m under warming conditions in 2019. There were also no significant differences in plant species composition, environmental temperature and moisture conditions between the elevation 4,500 m under non-warming conditions and the elevation 4,700 m under warming conditions in 2019. Therefore, the narrowing temperature differences between elevations may result in plant community composition between elevations tending to be similar in alpine grasslands on the Tibetan Plateau under future elevational asymmetrical warming.

Above-and below-ground trait linkages of dominant species shape responses of alpine steppe composition to precipitation changes in the Tibetan Plateau

2021 ◽  
Author(s):  
Zhi Zheng ◽  
Yue Zhang ◽  
Shihu Zhang ◽  
Qun Ma ◽  
Dajie Gong ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Community Composition ◽  
Plant Community ◽  
Dominant Species ◽  
The Tibetan Plateau ◽  
Plant Community Composition ◽  
Alpine Steppe ◽  
Precipitation Regimes ◽  
Below Ground ◽  
Precipitation Changes

Abstract Aims Human activities and global changes have led to alterations in global and regional precipitation regimes. Despite extensive studies on the effects of changes in precipitation regimes on plant community composition across different types of grassland world-wide, few studies have specifically focused on the effects of precipitation changes on high-altitude alpine steppe at community and plant species levels in the Tibetan Plateau. Methods We investigated the effects of growing-season precipitation changes (reduced precipitation by 50%; ambient precipitation; enhanced precipitation by 50%) for 6 years on plant community composition in an alpine steppe of Tibetan Plateau by linking above-ground to below-ground traits of dominant species. Important Findings We found that reduced precipitation shifted community composition from dominance by bunchgrass (primarily Stipa purpurea) to dominance by rhizomatous grass (primarily Leymus secalinus). Roots and leaf traits of L. secalinus and S. purpurea differed in their responses to reduced precipitation. Reduced precipitation enhanced root vertical length and carbon (C) allocation to deep soil layers, and decreased the leaf width in L. secalinus, but it did not change the traits in S. purpurea. Moreover, reduced precipitation significantly enhanced rhizome biomass, length, diameter and adventitious root at the rhizome nodes in L. secalinus. These changes in traits may render rhizomatous grass greater competitive during drought stress. Therefore, our findings highlight important roles of above-ground and below-ground traits of dominant species in plant community composition of alpine steppe under precipitation change.

Variation in substrate chemistry along microtopographical and water-chemistry gradients in peatlands

1984 ◽  
Vol 62 (1) ◽  
pp. 142-153 ◽  
Author(s):  
E. F. Karlin ◽  
L. C. Bliss
Keyword(s):  
Water Chemistry ◽  
Community Composition ◽  
Plant Species ◽  
Plant Community ◽  
Biotic Interactions ◽  
Plant Community Composition ◽  
Parallel Increase ◽  
Substrate Moisture ◽  
Study Sites ◽  
Minerotrophic Peatland

A broad range of water chemistry (pH 3.5–8.2; Ca, 2–120 mg L−1) and substrate chemistry (pH 3.3–7.8; Ca, 4–138 mequiv. 100 g−1) exists among peatlands present in central Alberta. The six peatlands comprising the main study sites included strongly minerotrophic, moderately minerotrophic, and weakly minerotrophic systems. Variation in substrate chemistry along the hollow to hummock gradient in strongly and moderately minerotrophic peatlands was high (ranging from highly minerotrophic peats to ombrotrophic peats), while variation in substrate chemistry in weakly minerotrophic peatlands was slight (weakly minerotrophic peats to ombrotrophic peats) along the same gradient. Substrate chemistry and plant community composition of hollow and low-hummock communities varied considerably along the strongly minerotrophic to weakly minerotrophic peatland gradient. In contrast, the chemistry of the upper peat layers of the hummocks and hummock plant community composition were similar in all of the peatlands studied. Distributional patterns of plant species in weakly minerotrophic peatlands are not primarily in response to gradients in substrate chemistry but arise from gradients in substrate moisture and biotic interactions. This is not the case for strongly and moderately minerotrophic systems, where gradients in substrate chemistry may also strongly influence plant species distribution. The increase in complexity of the substrate environment in peatlands along the weakly minerotrophic to strongly minerotrophic gradient is reflected by a parallel increase in plant species diversity.

scholarly journals Temperature and Precipitation Drive Elevational Patterns of Microbial Beta Diversity in Alpine Grasslands

2021 ◽  
Author(s):  
Xiaoqin Yang ◽  
Yue Li ◽  
Bin Niu ◽  
Qiuyu Chen ◽  
Yilun Hu ◽  
...  
Keyword(s):  
Species Richness ◽  
Tibetan Plateau ◽  
Community Composition ◽  
Beta Diversity ◽  
Microbial Community Composition ◽  
Mean Annual Precipitation ◽  
Mean Annual Temperature ◽  
The Tibetan Plateau ◽  
Alpine Grasslands ◽  
Temperature And Precipitation

Abstract Understanding the mechanisms underlying biodiversity patterns is a central issue in ecology, while how temperature and precipitation jointly control the elevational patterns of microbes is understudied. Here, we studied the effects of temperature, precipitation and their interactions on the alpha and beta diversity of soil archaea and bacteria in alpine grasslands along an elevational gradient of 4,300-5,200 m on the Tibetan Plateau. Alpha diversity was examined on the basis of species richness and evenness, and beta diversity was quantified with the recently developed metric of local contributions to beta diversity (LCBD). Typical alpine steppe and meadow ecosystems were distributed below and above 4,850 m, respectively, which was consistent with the two main constraints of mean annual temperature (MAT) and mean annual precipitation (MAP). Species richness and evenness showed decreasing elevational patterns in archaea and nonsignificant or U-shaped patterns in bacteria. The LCBD of both groups exhibited significant U-shaped elevational patterns, with the lowest values occurring at 4,800 m. For the three diversity metrics, soil pH was the primary explanatory variable in archaea, explaining over 20.1% of the observed variation, whereas vegetation richness, total nitrogen and the K/Al ratio presented the strongest effects on bacteria, with relative importance values of 16.1%, 12.5% and 11.6%, respectively. For the microbial community composition of both archaea and bacteria, the moisture index showed the dominant effect, explaining 17.6% of the observed variation, followed by MAT and MAP. Taken together, temperature and precipitation exerted considerable indirect effects on microbial richness and evenness through local environmental and energy supply-related variables, such as vegetation richness, whereas temperature exerted a larger direct influence on LCBD and the community composition. Our findings highlighted the profound influence of temperature and precipitation interactions on microbial beta diversity in alpine grasslands on the Tibetan Plateau.

scholarly journals Shifts in plant community composition weaken the negative effect of nitrogen addition on community-level arbuscular mycorrhizal fungi colonization

2020 ◽  
Vol 287 (1927) ◽  
pp. 20200483
Author(s):  
Yawen Lu ◽  
Xiang Liu ◽  
Fei Chen ◽  
Shurong Zhou
Keyword(s):  
Community Composition ◽  
Plant Species ◽  
Plant Community ◽  
Direct Effect ◽  
Indirect Effect ◽  
Mycorrhizal Fungi ◽  
Nitrogen Addition ◽  
Community Level ◽  
Colonization Rate ◽  
Plant Community Composition

Nitrogen addition affects plant–arbuscular mycorrhizal fungi (AMF) association greatly. However, although the direct effect of nitrogen addition on AMF colonization has received investigation, its indirect effect through shifts in plant community composition has never been quantified. Based on a 7-year nitrogen addition experiment in an alpine meadow of Qinghai–Tibet Plateau, we investigated the effects of nitrogen addition on plant community, AMF diversity and colonization, and disentangled the direct and indirect effects of nitrogen addition on community AMF colonization. At plant species level, nitrogen addition significantly decreased root colonization rate and altered AMF community composition, but with no significant effect on AMF richness. At plant community level, plant species richness and AMF colonization rate decreased with nitrogen addition. Plant species increasing in abundance after nitrogen addition were those with higher AMF colonization rates in natural conditions, resulting in an increased indirect effect induced by alternation in plant community composition with nitrogen addition, whereas the direct effect was negative and decreased with nitrogen addition. Overall, we illustrate the effect of nitrogen addition and plant species in influencing the AMF diversity, demonstrate how shifts in plant community composition (indirect effect) weaken the negative direct effect of nitrogen addition on community-level AMF colonization rate, and emphasize the importance of plant community-mediated mechanisms in regulating ecosystem functions.

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