Spatial patterns of vegetation and climate on the Chinese Loess Plateau since the Last Glacial Maximum
Spatial patterns of vegetation and climate on the Chinese Loess Plateau since the Last Glacial Maximum
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末次盛冰期以来中国黄土高原植被与气候的空间格局
DOI：
10.1016/j.quaint.2013.10.039
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发表时间：
2014-06-17
影响因子：
2.2
通讯作者：
Cheng, Yufen
中科院分区：
文献类型：
--
作者：
Jiang, Wenying;Yang, Xiaoxiao;Cheng, Yufen
为揭示末次盛冰期以来黄土高原植被和气候的空间格局，对黄土高原南北和东西两条样带的7个样点的黄土沉积物进行了孢粉分析。结果表明，在末次盛冰期和全新世最佳期，草原都占主导地位。末次盛冰期，西北部植被以蒿属、松果菊属、蒲公英属和藜科植物为主，东南部植被以蒿属、松果菊属、蒲公英属和藜科植物为主，但禾本科植物略有增加。在全新世最佳时期，植被更加多样化，西北部以禾本科、蒿属、Echinops-type和藜科为主，东南部以松属、榛属、禾本科、蒿属和卷柏为主。我们的记录还表明，从末次盛冰期到全新世最佳时期，Echinops型和蒲公英型花粉的存在减少，而禾本科花粉变得更加普遍。由于大多数禾本科植物对湿润环境的适应性较强，且在荒漠植被中，Echinops型和蒲公英型植物的丰度增加，因此提出了一个新的代用指标，即禾本科I（松果菊型+蒲公英型）比例（P/（E + T）），用以比较末次盛冰期和全新世最佳期气候的空间差异，高P/（E + T）值表示相对温暖和潮湿的条件。P/（E + T）比值在末次盛冰期和全新世最佳期均表现出向南和向东的总体增加趋势。此外，它表现出显着的南北和东西梯度在全新世最佳，但显示一个平坦的在末次冰期，表明更明显的空间差异，在全新世比末次冰期的气候。这可能与黄土高原独特的地理位置有关，在间冰期，黄土高原处于东亚夏季风的边缘地带，而在冰期，由于气候带南移，黄土高原受冬季风的控制。(C)2013 Elsevier Ltd和INQUA。All rights reserved.
In order to identify the spatial patterns of vegetation and climate on the Chinese Loess Plateau since the Last Glacial Maximum (LGM), pollen analysis was conducted for loess deposits from seven sites, which constitute two north south and west east transects across the Plateau. Results show that steppe prevailed both in the LGM and the Holocene Optimum. During the LGM, vegetation in the northwest mainly consisted of Artemisia, Echinops-type, Taraxacum-type, and Chenopodiaceae, and vegetation in the southeast was characterized by the same types but with a slight increase in Poaceae. During the Holocene Optimum, vegetation was more diverse, with Poaceae, Artemisia, Echinops-type, and Chenopodiaceae dominant in the northwest, and Pinus, Corylus, Poaceae, Artemisia, and Selaginella sinensis dominant in the southeast. Our records also show that from the LGM to the Holocene Optimum, the presence of Echinops-type and Taraxacum-type pollen decreased, while Poaceae pollen became more prevalent. As it has been found that most species of Poaceae prefer relatively humid conditions and abundances of Echinops-type and Taraxacum-type increase in desert vegetation, a new proxy, Poaceae I(Echinops-type + Taraxacum-type) ratio (P/(E + T)), was thus developed to compare the spatial differences in climate between the LGM and the Holocene Optimum, with high P/(E + T) values indicating relatively warm and wet conditions. The P/(E + T) ratio shows an overall southward and eastward increase for both the LGM and the Holocene Optimum. Furthermore, it exhibits a prominent north south and west east gradient during the Holocene Optimum but displays a flat one during the LGM, indicating more pronounced spatial contrasts in climate during the Holocene than in the LGM. This phenomenon may be attributed to the unique geographic location of the Loess Plateau, which was located in the marginal zone of the East Asian summer monsoon during interglacials but was dominated by the winter monsoon during glacials due to a southward displacement of climate zones. (C) 2013 Elsevier Ltd and INQUA. All rights reserved.