Characteristics of the modern pollen distribution and their relationship to vegetation in the Xinjiang region, northwestern China

Luo, Chao; Zheng, Zhuo; Tarasov, Pavel E.; Pan, Anding; Huang, Kangyou; Beaudouin, Célia; Fang-zhou, AN

doi:10.1016/j.revpalbo.2008.08.007

Cited by 78 publications

(47 citation statements)

References 29 publications

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“…However, the percentage never exceeds 20 % except in the spruce forest samples, implying that [20 % of Picea can represent the local presence of spruce trees in the study region. This result agrees with previous studies in arid regions of China Luo et al 2009). …”

Section: Discussion Pollen Representation Of Modern Vegetationsupporting

confidence: 94%

“…discussed the distribution of Picea pollen in topsoil in different vegetation zones. Luo et al (2009) presented a modern pollen-vegetation dataset based on surface soil samples in the Altay Mountains, the Junggar Basin, the eastern Tianshan Mountains, the Tarim Basin and the Kunlun Mountains. Their results indicated that Chenopodiaceae and Artemisia pollen was dominant and was well correlated with the dominant vegetation community in these regions.…”

Section: Introductionmentioning

confidence: 99%

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Surface pollen and its relationships with modern vegetation and climate in the Tianshan Mountains, northwestern China

Wei

Zhao

2015

Veget Hist Archaeobot

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A dataset consisting of 70 surface pollen samples from forest, alpine meadow, alpine steppe, temperate steppe, desert steppe, shrub/semi-shrub steppe and desert sites in the Tianshan Mountains, northwestern China provides an opportunity to study the relationships between surface pollen assemblages and modern vegetation and climate in this region. Redundancy analysis (RDA), the human influence index (HII) and pollen ratios were used to facilitate analysis of the pollen data. The modern pollen assemblages are primarily composed of Picea, Artemisia, Chenopodiaceae, Poaceae, Asteraceae, Nitraria and Ephedra. The results suggest that the surface pollen assemblages of different vegetation types largely represent the modern vegetation in terms of the primary taxa and dominant types. The RDA indicates that the mean annual precipitation (MAP) and the July temperature (T July ) are the major climate variables that control the modern pollen assemblages. Picea, Artemisia, Poaceae, Cyperaceae, Fabaceae, Asteraceae, Polygonaceae and Apiaceae pollen assemblages are positively correlated with MAP and negatively correlated with T July , while the pollen ratios for certain other types, such as Chenopodiaceae, Ephedra and Nitraria, are negatively correlated with MAP and positively correlated with T July . The arboreal/non-arboreal ratios are notably high in the forest samples, indicating a sensitive response to forest vegetation. Moreover, the Artemisia/Chenopodiaceae pollen ratios are generally correlated with the vegetation type and annual precipitation change, suggesting that these factors could be useful indicators of moisture variability in arid regions. However, it is difficult to distinguish between steppe and steppe desert based on this ratio, due partly to human disturbance. The HII is significantly correlated with certain pollen taxa, including Poaceae, Plantago, Polygonaceae and Elaeagnaceae, particularly in the alpine meadow and steppe samples. Our results have implications for interpreting the available fossil pollen data in the study region and other arid and semi-arid regions.

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Section: Discussion Pollen Representation Of Modern Vegetationsupporting

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Surface pollen and its relationships with modern vegetation and climate in the Tianshan Mountains, northwestern China

Wei

Zhao

2015

Veget Hist Archaeobot

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“…Xinjiang is situated in the arid area of central Asia, which has been a hot spot for paleovegetation and paleoclimate research given its fragile ecology and sensitive response to climate change [6][7][8][9]. Modern pollen rain studies in Xinjiang have generated much attention over the past several decades [10][11][12][13][14][15][16][17][18]. Yan and Xu [12] reported the characteristics of modern pollen distribution in different vegetation zones in the Altai Mountains.…”

mentioning

confidence: 99%

“…Yan et al [16] and Yang et al [17] studied the distribution of surface pollen from the source area of the Urumqi River at the Tianshan Mountains. Luo et al [18] examined the modern pollen distribution and its relationship to vegetation communities in the Xinjiang region, and suggested that the different vegetation formations have unique assemblages that can be statistically distinguished.…”

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confidence: 99%

Modern pollen and vegetation relationships in the Yili Basin, Xinjiang, NW China

Zhao

2013

Chin. Sci. Bull.

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Fifty-six surface pollen samples from different vegetation zones in the Yili Basin, western Tianshan Mountains, Xinjiang were analyzed to examine the relationships between the surface pollen assemblages and the original vegetation. A pollen analysis and a vegetation investigation with a discriminant analysis show that the pollen assemblages greatly differ across disparate vegetation zones. Twelve pollen taxa can be used as significant types for vegetation reconstruction in the basin. These taxa were the most abundant in the surface pollen samples. Cupressaceae pollen percentages were greater than 1% in Cupressaceae shrubs. More than 5% of Picea pollen indicates the growth of a Picea forest within 5 km. The subalpine meadow that is distributed widely in the basin is characterized by high content of Artemisia, Chenopodiaceae, Poaceae, Picea, Asteraceae, Taraxacum and Arenaria pollen types. The Artemisia-Chenopodiaceae-Poaceae-Cannabaceae pollen assemblages indicate the presence of montane steppe in the area. Artemisia and Chenopodiaceae pollen dominate the desert steppe and Populus forest. Artemisia pollen percentages were greater than 60% in the Artemisia desert, whereas Chenopodiaceae pollen percentages exceeded 65% in the Chenopodiaceae desert. The Artemisia/Chenopodiaceae (A/C) ratios reflect the vertical moisture changes in the Yili Basin. The mean A/C ratios were greater than 1.2 in the subalpine meadow and montane steppe that occupy the humid zone in the basin. These ratios were between 1 and 1.2 in the Cupressaceae shrubs, desert steppe, Populus forest and floodplain meadow. The ratios were less than 0.5 in the Chenopodiaceae desert, which is an arid environment. Tianshan Mountains, Yili Basin, modern pollen and vegetation, discriminant analysis, A/C ratios Citation:Zhao K L, Li X Q. Modern pollen and vegetation relationships in the Yili Basin,

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“…In the past 2 decades, a number of modern pollen studies have been conducted in China to investigate regional pollenvegetation-climate relationships Li et al, 2009;Lu et al, 2011;Luo et al, 2009;Shen et al, 2006;Xu et al, 2007;Zheng et al, 2008) and human impact on vegetation Wang et al, 2009;Yang et al, 2012;Zhang et al, 2014Zhang et al, , 2010. At the same time, representative modern reference datasets Xu et al, 2010a;Yu et al, 2000;Zheng et al, 2008Zheng et al, , 2014 and fossil pollen datasets (Cao et al, 2013;Ren and Beug, 2002;Sun et al, 1999) have been assembled, which make it possible to reconstruct the vegetation and climate for individual sites, regions, or the of whole China Ni et al, 2014;Tian et al, 2016;Wang et al, 2014;Xu et al, 2010b).…”

Section: Introductionmentioning

confidence: 99%

Examining bias in pollen-based quantitative climate reconstructions induced by human impact on vegetation in China

Ding

Tarasov

2017

Clim. Past

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Abstract. Human impact is a well-known confounder in pollen-based quantitative climate reconstructions as most terrestrial ecosystems have been artificially affected to varying degrees. In this paper, we use a "human-induced" pollen dataset (H-set) and a corresponding "natural" pollen dataset (N-set) to establish pollen-climate calibration sets for temperate eastern China (TEC). The two calibration sets, taking a weighted averaging partial least squares (WA-PLS) approach, are used to reconstruct past climate variables from a fossil record, which is located at the margin of the East Asian summer monsoon in north-central China and covers the late glacial Holocene from 14.7 ka BP (thousands of years before AD 1950). Ordination results suggest that mean annual precipitation (P ann ) is the main explanatory variable of both pollen composition and percentage distributions in both datasets. The P ann reconstructions, based on the two calibration sets, demonstrate consistently similar patterns and general trends, suggesting a relatively strong climate impact on the regional vegetation and pollen spectra. However, our results also indicate that the human impact may obscure climate signals derived from fossil pollen assemblages. In a test with modern climate and pollen data, the P ann influence on pollen distribution decreases in the H-set, while the human influence index (HII) rises. Moreover, the relatively strong human impact reduces woody pollen taxa abundances, particularly in the subhumid forested areas. Consequently, this shifts their model-inferred P ann optima to the arid end of the gradient compared to P ann tolerances in the natural dataset and further produces distinct deviations when the total tree pollen percentages are high (i.e. about 40 % for the Gonghai area) in the fossil sequence. In summary, the calibration set with human impact used in our experiment can produce a reliable general pattern of past climate, but the human impact on vegetation affects the pollen-climate relationship and biases the pollen-based climate reconstruction. The extent of human-induced bias may be rather small for the entire late glacial and early Holocene interval when we use a reference set called natural. Nevertheless, this potential bias should be kept in mind when conducting quantitative reconstructions, especially for the recent 2 or 3 millennia.

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Characteristics of the modern pollen distribution and their relationship to vegetation in the Xinjiang region, northwestern China

Cited by 78 publications

References 29 publications

Surface pollen and its relationships with modern vegetation and climate in the Tianshan Mountains, northwestern China

Surface pollen and its relationships with modern vegetation and climate in the Tianshan Mountains, northwestern China

Modern pollen and vegetation relationships in the Yili Basin, Xinjiang, NW China

Examining bias in pollen-based quantitative climate reconstructions induced by human impact on vegetation in China

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