An 850-year tree-ring-based reconstruction of drought history in the western Qilian Mountains of northwestern China

2014 ◽  
Vol 35 (11) ◽  
pp. 3308-3319 ◽  
Author(s):  
Xiaohua Gou ◽  
Linlin Gao ◽  
Yang Deng ◽  
Fahu Chen ◽  
Meixue Yang ◽  
...  
Keyword(s):  
Tree Ring ◽  
Qilian Mountains ◽  
Northwestern China

scholarly journals Tree-Ring Based Drought Reconstruction (A.D. 1855–2001) for the Qilian Mountains, Northwestern China

2007 ◽  
Vol 63 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Qinhua Tian ◽  
Xiaohua Gou ◽  
Yong Zhang ◽  
Jianfeng Peng ◽  
Jinsong Wang ◽  
...  
Keyword(s):  
Tree Ring ◽  
Qilian Mountains ◽  
Northwestern China ◽  
Drought Reconstruction ◽  
The Qilian Mountains

A 1232-YEAR TREE-RING RECORD OF CLIMATE VARIABILITY IN THE QILIAN MOUNTAINS, NORTHWESTERN CHINA

IAWA Journal ◽  
2009 ◽  
Vol 30 (4) ◽  
pp. 407-420 ◽  
Author(s):  
Yong Zhang ◽  
Xiaohua Gou ◽  
Fahu Chen ◽  
Qinhua Tian ◽  
Meilin Yang ◽  
...  
Keyword(s):  
Tree Ring ◽  
Asian Monsoon ◽  
East Asian Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Ring Width ◽  
Qilian Mountains ◽  
Northwestern China ◽  
The Past ◽  
The Qilian Mountains

A millennium-long tree-ring width chronology for the middle Qilian Mountains in northwestern China has been developed back to A.D. 775. Correlation analysis indicates that the tree-ring width reflects growingseason moisture variability. Our chronology reveals three distinct periods based on the prevailing moisture anomalies: A.D. 775–1101 (wetness persistence), 1101–1831 (dryness persistence) and 1831–2006 (wetness persistence). A 31-year running mean through the tree-ring index series clearly shows seven obvious dry spells and eight wet spells. Compared with the proxies associated with the East Asian monsoon and the westerlies in the past millennium, our moisture-sensitive tree-ring chronology revealed that the East Asian summer monsoon had a strong influence on tree growth before A.D. 1300. From about A.D. 1450–1750, the westerlies strongly affected the Qilian Mountains. After A.D. 1750, a combined influence of both East Asian monsoon and westerlies was apparent. In the past century, the effect of westerlies has become stronger. Our results suggest that tree rings can preserve the information on the advance and retreats of the westerlies and the East Asian summer monsoon. Additionally, this research is helpful for understanding the driving mechanism of the Asian monsoon and the westerlies in northwestern China over the past thousand years.

scholarly journals High diversity of nitrogen-fixing bacteria in the upper reaches of the Heihe River, northwestern China

2013 ◽  
Vol 10 (8) ◽  
pp. 5589-5600 ◽  
Author(s):  
X. S. Tai ◽  
W. L. Mao ◽  
G. X. Liu ◽  
T. Chen ◽  
W. Zhang ◽  
...  
Keyword(s):  
Water Conservation ◽  
Bacterial Communities ◽  
Nifh Gene ◽  
Qilian Mountains ◽  
Northwestern China ◽  
Heihe River ◽  
Meadow Soil ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
Gene Copies

Abstract. Vegetation plays a key role in water conservation in the southern Qilian Mountains (northwestern China), located in the upper reaches of the Heihe River. Nitrogen-fixing bacteria are crucial for the protection of the nitrogen supply for vegetation in the region. In the present study, nifH gene clone libraries were established to determine differences between the nitrogen-fixing bacterial communities of the Potentilla parvifolia shrubland and the Carex alrofusca meadow in the southern Qilian Mountains. All of the identified nitrogen-fixing bacterial clones belonged to the Proteobacteria. At the genus level, Azospirillum was only detected in the shrubland soil, while Thiocapsa, Derxia, Ectothiorhodospira, Mesorhizobium, Klebsiella, Ensifer, Methylocella and Pseudomonas were only detected in the meadow soil. The phylogenetic tree was divided into five lineages: lineages I, II and III mainly contained nifH sequences obtained from the meadow soils, while lineage IV was mainly composed of nifH sequences obtained from the shrubland soils. The Shannon–Wiener index of the nifH genes ranged from 1.5 to 2.8 and was higher in the meadow soils than in the shrubland soils. Based on these analyses of diversity and phylogeny, the plant species were hypothesised to influence N cycling by enhancing the fitness of certain nitrogen-fixing taxa. The number of nifH gene copies and colony-forming units (CFUs) of the cultured nitrogen-fixing bacteria were lower in the meadow soils than in the shrubland soils, ranging from 0.4 × 107 to 6.9 × 107 copies g−1 soil and 0.97 × 106 to 12.78 × 106 g−1 soil, respectively. Redundancy analysis (RDA) revealed that the diversity and number of the nifH gene copies were primarily correlated with aboveground biomass in the shrubland soil. In the meadow soil, nifH gene diversity was most affected by altitude, while copy number was most impacted by soil-available K. These results suggest that the nitrogen-fixing bacterial communities beneath Potentilla were different from those beneath Carex.

A 3585-YEAR RING-WIDTH DATING CHRONOLOGY OF QILIAN JUNIPER FROM THE NORTHEASTERN QINGHAI-TIBETAN PLATEAU

IAWA Journal ◽  
2009 ◽  
Vol 30 (4) ◽  
pp. 379-394 ◽  
Author(s):  
Xuemei Shao ◽  
Shuzhi Wang ◽  
Haifeng Zhu ◽  
Yan Xu ◽  
Eryuan Liang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Tree Ring ◽  
Tree Species ◽  
Qaidam Basin ◽  
Ring Width ◽  
Northwestern China ◽  
Tree Ring Width ◽  
Living Tree ◽  
Qilian Juniper

This article documents the development of a precisely dated and wellreplicated long regional tree-ring width dating chronology for Qilian juniper (Juniperus przewalskii Kom.) from the northeastern Qinghai- Tibetan Plateau. It involves specimens from 22 archeological sites, 24 living tree sites, and 5 standing snags sites in the eastern and northeastern Qaidam Basin, northwestern China. The specimens were cross-dated successfully among different groups of samples and among different sites. Based on a total of 1438 series from 713 trees, the chronology covers 3585 years and is the longest chronology by far in China. Comparisons with chronologies of the same tree species about 200 km apart suggest that this chronology can serve for dating purposes in a region larger than the study area. This study demonstrates the great potential of Qilian juniper for dendrochronological research.

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