• 研究报告 •

### 北疆表土花粉组合及其与植被和气候的关系

1. (1中国科学院地球环境研究所黄土与第四纪地质国家重点实验室， 西安 710061；2天津大学表层地球系统科学研究院， 天津 300072；3中国科学院大学， 北京 100049)
• 出版日期:2018-12-10 发布日期:2018-12-10

### Pollen assemblages in surface soil and their relationships with vegetation and climate in northern Xinjiang.

WU Hui-xian1,3, XU Hai2*, LAN Jiang-hu1, ZHANG Ji-xiao1,3, YAN Dong-na1,3, ZHOU Kang-en1,3, WANG Tian-li1,3, YE Yuan-da1,3

1. (1State Key Laboratory ofLoess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710061, China; 2Institute of SurfaceEarth System Science, Tianjin University, Tianjin 300072, China; 3University of Chinese Academy of Sciences, Beijing 100049, China).
• Online:2018-12-10 Published:2018-12-10

Abstract: By comparing pollen assemblages in surface soil and cow dung samples in the dessert steppe and typical steppe in northern Xinjiang, we found similar pollen assemblages in both types of samples. The concentrations of tree pollen for most samples were lower than 10%, those of shrubs were on average 5.6%, and those of herbs were generally higher than 70%. Chenopodiaceae and Artemisia were the most important components of the pollen assemblages. The species number of pollen in cow dung samples was lower than that of surface soil samples. The pollen content of trees in cow dung (2.04%) was lower than that of surface soil (3.78%). The cow dung samples were produced in most recent months while the formation time of the surface soil samples was uncertain. It is likely that the pollen assemblages of cow dung should be more relevant to the modern vegetation types. We thus proposed that the cow dung could be used as a new archive of modern vegetation types in the dessert steppe and typical steppe. Furthermore, the pollen concentration of trees increased and that of the shrubs and herbs decreased in surface soil from dessert steppe to typical steppe. However, the pollen assemblages of cow dung showed an opposite trend, which is probably related to the diet of cows. Moreover, the principal component analysis of the main pollen assemblages (Rosaceae, Poaceae, Umbelliferae, and Leguminosae) and environmental factors revealed that the pollen assemblages had the strongest correlation with the mean precipitation during June-August and the mean annual precipitation, and the secondary strong correlation with the mean temperatures of the coldest and warmest months, but weak correlation with the mean annual temperature. Our results suggest that precipitation is likely the most important factor controlling vegetation distribution in northern Xinjiang.