Relationship analysis between topsoil pollen assemblages and vegetation and environmental factors in Dalaoling, Yichang
WANG Xiumei1, 2, CHENG Bo1, 2, WAN Jinhong3
(1.Hubei Province Laboratory for Geographical Process Analyzing & Modeling, Central China Normal University, Wuhan 430079, China;2.College of Urban and Environmental Sciences, Central China Normal University, Wuhan 430079, China; 3.Water History Department of China Institute of Water Resources and Hydropower Research, Beijing 100048,China)
Abstract:The relationship between modern topsoil pollen assemblages and vegetation was investigated by analysing pollen samples at different elevations in Yichang Dalaoling Nature Reserve in combination with vegetation surveys. The results showed that among the pollen assemblages of evergreen and deciduous broad-leaved mixed forest and coniferous broad-leaved mixed forest in Dalaoling, the coniferous trees pollen of Pinus was over-representative and Tsuga was moderately representative. The deciduous broad-leaved tree pollen was dominated by Quercus with high representation, Rosaceae, Betula, Carpinus, Juglans and Fagus with moderate representation. The evergreen broad-leaved tree pollen of Cyclobalanopsis was moderately representative, Ericaceae and Caprifoliaceae showed low representation. The herbaceous Gramineae and Artemisia differ significantly in their representation in the mountains. Ferns were generally over-representative. The pollen assemblages generally reflected the main vegetation characteristics of the mixed coniferous and broad-leaved forests in the mountains of the northern edge of the present subtropics. Pollen assemblages deviated somewhat from vegetation types due to pollen's own characteristics, microhabitats and human activities. The results of principal component analysis (PCA) indicated that the main environmental factor influencing the variation of pollen taxa in Dalaoling was temperature. The E/D value of topsoil pollen (evergreen broad-leaved trees/deciduous broad-leaved trees) decreased with increasing altitude, reflecting the trend of decreasing evergreen broad-leaved trees and increasing deciduous broad-leaved trees in montane vegetation.