Distribution characteristics and its influencing factors of surface soil pollen in the marginal monsoon region of China
Studying the distribution characteristics of surface soil pollen in the marginal monsoon region of China and the factors influencing this distribution improves the reliability of reconstructing regional vegetation and pa-leo-monsoon evolution based on fossil pollen data.Through surface soil pollen analysis of 38 sampling sites with annual precipitation ranging from 30-650 mm in the marginal monsoon region of China,this study investigates the relationships among surface pollen assemblages,climate,and human activities.The results reveal that:(1)In low-altitude temperate steppe regions with a relatively warm and dry climate,Amaranthaceae and Artemisia domi-nate the pollen assemblages,and the ratio of Artemisia/Chenopodiaceae(A/C ratio)generally aligns with average annual precipitation.(2)In high-altitude alpine steppe and meadow regions with a relatively cold and humid cli-mate,pollen assemblages are dominated by Cyperaceae,Asteraceae,and Poaceae.The summed percentages of Ar-temisia and Amaranthaceae pollen average 25.8%,and no distinctive correlation exists between the A/C ratio and average annual precipitation in these regions.(3)The total tree and shrub pollen percentages exhibit a stronger correlation with average annual temperature and the temperature of the warmest month compared to average an-nual precipitation.(4)These pollen assemblage characteristics reflect the vegetation distribution and hydrother-mal conditions at varying altitudes in the marginal monsoon region of China.Redundancy analysis(RDA)of the pollen data also reveals the distribution of pollen assemblages and major pollen types along gradients of the warmest month temperature and altitude.In addition,the high abundance of fungal spores on the soil surface in the alpine region reflects environmental characteristics associated with significant grazing intensity and a subse-quent high soil erosion rate.
万方数据
维普
