scholarly journals Insights Into the Significance of the Chinense Loess Plateau for Preserving Biodiversity From the Phylogeography of Speranskia tuberculata (Euphorbiaceae)

2021 ◽  
Vol 12 ◽  
Author(s):  
Jun-Wei Ye ◽  
Hai-Yang Wu ◽  
Meng-Jiao Fu ◽  
Pei Zhang ◽  
Bin Tian
Keyword(s):  
Genetic Diversity ◽  
Loess Plateau ◽  
Ecological Niche Modeling ◽  
Nuclear Dna ◽  
Demographic History ◽  
Haplotype Diversity ◽  
Northern China ◽  
Chinese Loess Plateau ◽  
Spatial Expansion ◽  
Chinese Loess

The significance of the Chinese Loess Plateau (CLP) in maintaining biodiversity for northern China has rarely been shown, as previous phylogeographic studies are mostly woody species and they have revealed that Quaternary refugia are mainly located in mountain regions. We selected a drought-enduring endemic herb, Speranskia tuberculata (Euphorbiaceae), to determine its glacial refugia and postglacial demographic history. To this end, we sampled 423 individuals from 38 populations covering its entire geographic distribution. Three chloroplast DNA (cpDNA) fragments, two low-copy nuclear genes, and six nuclear microsatellites (nSSRs) were used and supplemented with ecological niche modeling (ENM) to infer the phylogeographic history of this species. Populations with private haplotypes and high haplotype diversity of cpDNA are mainly located in the CLP or scattered around northeastern China and the coastal region. Spatial expansion, detected using a neutrality test and mismatch distribution, may have resulted in a widely distributed ancestral cpDNA haplotype, especially outside of the CLP. For nuclear DNA, private haplotypes are also distributed mainly in the CLP. In nSSRs, STRUCTURE clustering identified two genetic clusters, which are distributed in the west (western cluster) and east (eastern cluster), respectively. Many populations belonged, with little to no admixture, to the western cluster while (hardly) pure populations of the eastern cluster were barely found. Genetic differentiation is significantly correlated with geographic distance, although genetic diversity is uniformly distributed. ENM suggests that the distribution of S. tuberculata has recently expanded northwards from the southern CLP, whereas it has experienced habitat loss in the south. Thus, S. tuberculata populations probably survived the last glacial maximum (LGM) in the southern CLP and experienced post-glacial expansion. Wind-dispersed pollen could bring the majority of genotypes to the front during spatial expansion, resulting in uniformly distributed genetic diversity. Based on evidence from molecular data and vegetation and climate changes since the LGM, we conclude that drought-enduring species, especially herbaceous species, are likely to have persisted in the CLP during the LGM and to have experienced expansion to other regions in northern China.

scholarly journals Reconstruction of the March–August PDSI since 1703 AD based on tree rings of Chinese pine (<i>Pinus tabulaeformis</i> Carr.) in the Lingkong Mountain, southeast Chinese loess Plateau

2013 ◽  
Vol 9 (6) ◽  
pp. 6311-6344 ◽  
Author(s):  
Q. Cai ◽  
Y. Liu ◽  
Y. Lei ◽  
G. Bao ◽  
B. Sun
Keyword(s):  
Loess Plateau ◽  
Tree Ring ◽  
Asian Summer Monsoon ◽  
Ring Width ◽  
Northern China ◽  
Chinese Loess Plateau ◽  
Pinus Tabulaeformis ◽  
Drought Severity ◽  
Chinese Loess ◽  
Pdsi Reconstruction

Abstract. We utilized tree-ring cores, collected from three sites at Lingkong Mountain located in the southeast part of the Chinese Loess Plateau (CLP), to develop a regional ring-width chronology. Significant positive correlations between the tree-ring index and the monthly Palmer drought severity index (PDSI) were identified, indicating that the radial growth of trees in this region was moisture-limited. The March–August mean PDSI was quantitatively reconstructed from 1703 to 2008 with an explained variance of 46.4%. Seven dry periods during 1719–1726, 1742–1748, 1771–1778, 1807–1818, 1832–1848, 1867–1932 and 1993–2008 and six wet periods during 1727–1741, 1751–1757, 1779–1787, 1797–1805, 1853–1864 and 1934–1957 were revealed in our reconstruction. Among them, 1867–1932 and 1934–1957 were identified as the longest dry and wet periods, respectively. On the centennial scale, the 19th century was recognized as the driest century. The drying tendency since 1960s was evident, however, recent drought was still within the frame of natural climate variability based on the 306 yr PDSI reconstruction. The warm and dry phases of Lingkong Mountain were in accordance with changes in the East Asian summer monsoon (EASM) strength, they also showed strong similarity to other tree-ring based moisture indexes in large areas in and around the CLP, indicating the moisture variability in the CLP was almost synchronous and closely related with EASM variation. Spatial correlation analysis suggested that this PDSI reconstruction could represent the moisture variations for most parts of the CLP, even larger area of northern China and east Mongolia. Multi-taper spectral analysis revealed significant cycles at the inter-annual (2.0–7.8 yr), inter-decadal (37.9 yr) and centennial (102 yr) scales, suggesting the influence of ENSO and solar activity on moisture conditions in the CLP. Results of this study are very helpful for us to improve the knowledge of past climate change in the CLP and enable us to prevent and manage future natural disasters.

Geochemical and grain-size evidence for the provenance of loess deposits in the Central Shandong Mountains region, northern China

2016 ◽  
Vol 85 (2) ◽  
pp. 290-298 ◽  
Author(s):  
Shuzhen Peng ◽  
Qingzhen Hao ◽  
Luo Wang ◽  
Min Ding ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Grain Size ◽  
Loess Plateau ◽  
Major Element ◽  
Yellow River ◽  
Northern China ◽  
Chinese Loess Plateau ◽  
The Yellow River ◽  
Chinese Loess ◽  
Loess Deposits ◽  
The Chinese Loess Plateau

Widespread loess deposits in the Central Shandong Mountains yield valuable paleoclimatic records for this currently semi-humid monsoonal region of northern China. The grain-size distribution and major element composition for bulk samples and two grain-size fractions (< 20 and 20–63 μm) for the loess in the Central Shandong Mountains were compared with loess from the Chinese Loess Plateau and sediment from the Yellow River to help determine its provenance. The presence of a significant percentage of medium- and coarse-silt, and the difference in relatively immobile major element ratios of TiO2/Al2O3 and K2O/Al2O3 for the < 20 and 20–63 μm fractions, suggests that sediment that forms the loess deposits in the Central Shandong Mountains was not blown directly from the northern deserts of China as is the case for the loess deposits of the Chinese Loess Plateau. Rather, this suggests that sediments exposed during glacial times on the North China fluvial plain, including the floodplain of the Yellow River, were the major dust source for the loess in the Central Shangong Mountains. In addition, the wide distribution of perimontane loess in the Central Shandong Mountains region indicates the occurrence of strengthened local aridification during glacial times since the middle Pleistocene.

scholarly journals Reconstruction of the March–August PDSI since 1703 AD based on tree rings of Chinese pine (<i>Pinus tabulaeformis</i> Carr.) in the Lingkong Mountain, southeast Chinese loess Plateau

2014 ◽  
Vol 10 (2) ◽  
pp. 509-521 ◽  
Author(s):  
Q. Cai ◽  
Y. Liu ◽  
Y. Lei ◽  
G. Bao ◽  
B. Sun
Keyword(s):  
Loess Plateau ◽  
Tree Ring ◽  
Large Scale ◽  
Ring Width ◽  
Northern China ◽  
Chinese Loess Plateau ◽  
Pinus Tabulaeformis ◽  
Drought Severity ◽  
Chinese Loess ◽  
Pdsi Reconstruction

Abstract. We utilised tree-ring cores, collected from three sites at Lingkong Mountain located in the southeast part of the Chinese Loess Plateau (CLP), to develope a regional ring-width chronology. Significant positive correlations between the tree-ring index and the monthly Palmer drought severity index (PDSI) were identified, indicating that the radial growth of trees in this region was moisture-limited. The March–August mean PDSI was quantitatively reconstructed from 1703 to 2008 with an explained variance of 46.4%. Seven dry periods during 1719–1726, 1742–1748, 1771–1778, 1807–1818, 1832–1848, 1867–1932 and 1993–2008 and six wet periods during 1727–1741, 1751–1757, 1779–1787, 1797–1805, 1853–1864 and 1934–1957 were revealed in our reconstruction. Among them, 1867–1932 and 1934–1957 were identified as the longest dry and wet periods, respectively. On the centennial scale, the 19th century was recognised as the driest century. The drying tendency since 1960s was evident. However, recent drought in 1993–2008 was still within the frame of natural climate variability based on the 306 yr PDSI reconstruction. The dry and wet phases of Lingkong Mountain were in accordance with changes in the summer Asian-Pacific oscillation (IAPO) and sunspot numbers, they also showed strong similarity to other tree-ring based moisture indexes in large areas in and around the CLP, indicating the moisture variability in the CLP was almost synchronous and closely related with large-scale land–ocean–atmospheric circulation and solar activity. Spatial correlation analysis suggested that this PDSI reconstruction could represent the moisture variations for most parts of the CLP, and even larger area of northern China and east Mongolia. Multi-taper spectral analysis revealed significant cycles at the inter-annual (2–7 yr), inter-decadal (37.9 yr) and centennial (102 yr) scales. Results of this study are very helpful for us to improve the knowledge of past climate change in the CLP and enable us to prevent and manage future natural disasters.

Changes in Sand Content of Loess Deposits along a North–South Transect of the Chinese Loess Plateau and the Implications for Desert Variations

1999 ◽  
Vol 52 (1) ◽  
pp. 56-62 ◽  
Author(s):  
Zhongli Ding ◽  
Jimin Sun ◽  
Nat W. Rutter ◽  
Dean Rokosh ◽  
Tungsheng Liu
Keyword(s):  
Grain Size ◽  
Loess Plateau ◽  
Northern China ◽  
Transitional Zone ◽  
Chinese Loess Plateau ◽  
Transitional Region ◽  
Sand Content ◽  
The Loess Plateau ◽  
Chinese Loess ◽  
Helan Mountains

Geological records have shown that the deserts east of the Helan Mountains in northern China were covered by grass during the Holocene Optimum, whereas during marine oxygen isotope stages 2 and 4 distribution of the deserts was almost the same as at present. The wide advance–retreat cycles of the deserts may have exerted an important control on grain-size changes in the loess of the Loess Plateau by altering the distance between the source and the accumulation zone of the loess. This challenges the widely accepted model that winter monsoon winds were the sole factor responsible for spatial and temporal changes in loess texture. To observe spatial changes in sedimentological characteristics of loess during the last glacial–interglacial cycle, the texture of loess was measured along a north–south transect of the Loess Plateau. This transect consists of nine loess sections, starting at Yulin in the transitional region between the Loess Plateau and the Mu Us Desert and ending at Weinan in the southernmost part of the Loess Plateau. Southward changes in sand (>63 μm) content along the transect suggest that variations in desert extent have indeed played a significant role in loess grain-size distributions, particularly in the northern part of the Loess Plateau. It is proposed that sand content (>63 μm%) of loess in the loess–desert transitional zone may be used as a proxy indicator for proximity to the desert margin.

scholarly journals Spatially variable provenance of the Chinese Loess Plateau

Geology ◽  
2021 ◽  
Author(s):  
Haobo Zhang ◽  
Junsheng Nie ◽  
Xiangjun Liu ◽  
Alex Pullen ◽  
Guoqiang Li ◽  
...  
Keyword(s):  
Loess Plateau ◽  
Northern China ◽  
Source Model ◽  
Chinese Loess Plateau ◽  
Sediment Provenance ◽  
Chinese Loess ◽  
Atmospheric Circulation Patterns ◽  
Large N ◽  
Circulation Patterns ◽  
The Chinese Loess Plateau

Loess sequences of the Chinese Loess Plateau (CLP) compose one of the most complete Neogene–Quaternary terrestrial paleoclimatic archives. Understanding the CLP’s sediment sources is critical to tracing Asian aridification, atmospheric circulation patterns, and Asian monsoon evolution. Commonly, the sediments that compose the Quaternary strata of the CLP are considered largely homogeneous, and thus numerous studies have applied a uniform source model when attempting to use CLP-derived proxies as paleoclimate indicators. Here we present large-n detrital zircon U-Pb geochronology data from the Quaternary CLP. These data support spatial variability in sediment provenance across the CLP. At least three distinct provenance zones are recognized for Quaternary loess strata: central western, eastern, and northeastern. These zones received sediment primarily from their neighboring river systems. This finding conflicts with the classic views that attribute the Quaternary loess principally to the deserts north and west of the CLP. We conclude that fluvial processes, and thus precipitation, played an important and previously underemphasized role in Quaternary dust production in northern China. Furthermore, nonuniformity in CLP Quaternary sediment provenance raises questions about the validity of using paleoclimate information archived in the CLP to make sweeping regional interpretations.

scholarly journals Changes in soil water holding capacity and water availability following vegetation restoration on the Chinese Loess Plateau

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yong-wang Zhang ◽  
Kai-bo Wang ◽  
Jun Wang ◽  
Changhai Liu ◽  
Zhou-ping Shangguan
Keyword(s):  
Land Use ◽  
Soil Water ◽  
Loess Plateau ◽  
Soil Layer ◽  
Soil Physical Properties ◽  
Chinese Loess Plateau ◽  
Land Use Type ◽  
Chinese Loess ◽  
Water Holding ◽  
The Chinese Loess Plateau

AbstractChanges in land use type can lead to variations in soil water characteristics. The objective of this study was to identify the responses of soil water holding capacity (SWHC) and soil water availability (SWA) to land use type (grassland, shrubland and forestland). The soil water characteristic curve describes the relationship between gravimetric water content and soil suction. We measured the soil water characteristic parameters representing SWHC and SWA, which we derived from soil water characteristic curves, in the 0–50 cm soil layer at sites representing three land use types in the Ziwuling forest region, located in the central part of the Loess Plateau, China. Our results showed that the SWHC was higher at the woodland site than the grassland and shrubland, and there was no significant difference between the latter two sites, the trend of SWA was similar to the SWHC. From grassland to woodland, the soil physical properties in the 0–50 cm soil layer partially improved, BD was significantly higher at the grassland site than at the shrubland and woodland sites, the clay and silt contents decreased significantly from grassland to shrubland to woodland and sand content showed the opposite pattern, the soil porosity was higher in the shrubland and woodland than that in the grassland, the soil physical properties across the 0–50 cm soil layer improved. Soil texture, porosity and bulk density were the key factors affecting SWHC and SWA. The results of this study provide insight into the effects of vegetation restoration on local hydrological resources and can inform soil water management and land use planning on the Chinese Loess Plateau.

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