Characteristics of Soil Extracellular Enzymes and Stoichiometry Along the Elevation Gradient and Their Controlling Factors in Qinghai-Tibet Plateau, China

2022 ◽  
Author(s):  
Yanxia Pan ◽  
Xinrong Li ◽  
Zengru Wang ◽  
Li Feng ◽  
Lei Huang ◽  
...  
2018 ◽  
Author(s):  
Bin Cao ◽  
Tingjun Zhang ◽  
Qinghai Wu ◽  
Yu Sheng ◽  
Lin Zhao ◽  
...  

Abstract. Many maps have been produced to estimate permafrost distribution over the Qinghai-Tibet Plateau, however, the evaluation and comparisons of them are poorly understood due to limited evidence. Using a large number data from various sources, we present the inventory of permafrost presence/absence with 1475 sites/plots over the QTP. Based on the in-situ measurements, our evaluation results showed a wide range of map performance with the overall accuracy of about 59–82 %, and the estimated permafrost region (1.42–1.84 × 106 km2) and area (0.76–1.25 × 106 km2) are extremely large. The low agreement in areas near permafrost boundary and fragile landscapes require improved method considering more controlling factors at both medium-large and local scales.


2021 ◽  
Author(s):  
Xin Wang ◽  
Jiangling Zhu ◽  
Shitao Peng ◽  
Tianli Zheng ◽  
Zhaoyu Qi ◽  
...  

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.


2019 ◽  
Vol 575 ◽  
pp. 257-268 ◽  
Author(s):  
Yu-Jun Ma ◽  
Xiao-Yan Li ◽  
Lei Liu ◽  
Xiao-Fan Yang ◽  
Xiu-Chen Wu ◽  
...  

2019 ◽  
Vol 13 (2) ◽  
pp. 511-519 ◽  
Author(s):  
Bin Cao ◽  
Tingjun Zhang ◽  
Qingbai Wu ◽  
Yu Sheng ◽  
Lin Zhao ◽  
...  

Abstract. Many maps have been produced to estimate permafrost distribution over the Qinghai–Tibet Plateau (QTP), but the errors and biases among them are poorly understood due to limited field evidence. Here we evaluate and inter-compare the results of six different QTP permafrost maps with a new inventory of permafrost presence or absence comprising 1475 field sites compiled from various sources. Based on the in situ measurements, our evaluation results showed a wide range of map performance, with Cohen's kappa coefficient from 0.21 to 0.58 and an overall accuracy between about 55 % and 83 %. The low agreement in areas near the boundary between permafrost and non-permafrost and in spatially highly variable landscapes highlights the need for improved mapping methods that consider more controlling factors at both medium–large and local scales.


2020 ◽  
Author(s):  
Yu Zhu ◽  
Shiyin Liu ◽  
Ying Yi ◽  
Miaomiao Qi ◽  
Wanqiu Li ◽  
...  

Abstract The nature of the heterogeneity of terrestrial water storage (TWS) in the Eastern Qinghai-Tibet Plateau (EQTP) is poorly understood because of the lack of validated datasets and the complex topographical conditions. In this study, monthly GRACE Level 2 Release 6 (RL06) products were employed to characterize TWS changes between April 2002 and August 2016 in the EQTP. Based on the observations and hydrological model output, the dominant factors contributing to the changes in TWS in sub-basins, and areas of TWS decrease and increase were analyzed systematically. We concluded that the TWS in the EQTP showed a slight decreasing trend from 2002 to 2016 with obvious spatial heterogeneity. The decrease in TWS may be attributed to the increase in evapotranspiration, which explains approximately 59% of the variations. In the region where a substantial decrease in TWS was observed, the trend primarily depended on evapotranspiration, and was certainly affected by glacial ablation. Moreover, the expansion of lakes supplemented by glaciers was the main cause of TWS change in the areas where TWS increased. A decrease in TWS mainly occurred in summer and was mainly due to the increase in evapotranspiration because of warming, an increase in wind speed, and a decrease in relative humidity.


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