Abstract: Xiarxili Nature Reserve which maintains an original intact ecosystem is an ideal area for studying the relationship between vegetation and environmental change in Xinjiang,China. In this paper,we collected 33 surface pollen samples from the mountain steppe desert zone,mountain steppe zone to mountain forest zone in this nature reserve area covering the elevation from 1 042 m to 2 426 m,and each sampling site was surveyed.The clustering analysis (CA) and redundancy analysis (RDA) based on the palynology data were carried out,and the relationship among palynology characteristics of surface samples and vegetation survey was discussed.The results show that there was a good fit between the characteristics of the three surface pollen assemblage zones,which were accomplished according to the results of CA and RDA,and the modern vegetation zones.The pollen contents of Chenopodiaceae and Ephedra were not significantly associated with the vegetation coverage,thus Chenopodiaceae and Ephedra presented a super-representative distribution characteristic,indicating that the pollen was transmitted from the lowerelevation region to the higherelevation region with the airflow,and Chenopodiaceae and Ephedra were the exogenous-originated pollen. Betula and Leguminosae pollen had good correspondence with birch grove and Caragana bush. A/C ratio and pollen total concentration had important significance in distinguishing forest zone and steppe desert zone.The RDA results showed that fern spores were positively correlated with precipitation and elevation,and Leguminous pollen was positively correlated with temperature.Because of the difference of soil,moisture and illuminance caused by the variation of mountain topography, different type of vegetation zone formed on the sunny and shady slopes at the same elevation, the forest zone and meadow zone occurred alternately. Influenced by mountain airflow and waterflow, the pollen composition was mixed with things coming from the two vegetation zones, thus the correlation between the pollen content of Picea and Betula and the vegetation coverage was decreased. Therefore, the quantitative relation between pollen and vegetation became more complex, which is universal in the scope of phytoecology. But it has a great impact on the quantitative reconstruction of vegetation and climate when using the surface pollen data, though the mechanism should be further studied. Hence, when using the surface pollen data from the mountain region for quantitative reconstruction, it is necessary to investigate the vegetation status of sampling sites in detail and analyze the characteristics of sedimentary environment, and should correct and filter the surface pollen data.

Key words: font-size:10.5pt, Xarxili')">">Xarxili, surface sporopollen, cluster analysis, redundancy analysis, Xinjiang