11000年以来太湖地区的植被与气候变化

根据太湖盆地３个钻孔、约自１１０００年以来的孢粉分析结果将其划分为３个阶段：１）１１０００—９０００ａＢ．Ｐ，该段虽以Ｐｉｎｕｓ为主的针叶植物占有一定的优势，但起主导作用的仍以壳斗科为主的阔叶乔木种类，尤其是其间尚含有不少的亚热带成分，推测当时该区地带性植被已为亚热带落叶常绿阔叶林，鉴于植被中尚含有少量耐寒的Ａｂｉｅｓ和Ｐｉｃｅａ，推测当时气温可能较今略低；２）９０００—５０００（５４００）ａＢ．Ｐ，该段为常绿阔叶林大发展时期，气候温暖适宜，为全新世最佳期，气温约较今高１—２Ｃ；３）５０００？ａＢ．Ｐ．－现在，孢粉组合特征显示，阔叶木本植物就总的来说呈下降趋势，尤其是亚热带成分，与其相反，针叶和一些暖温带成分的含量则略有上升，表明该段气温较前一阶段有所下降，但该阶段的植被受人类活动的影响较大。

CHANGES IN VEGETATION AND CLIMATE IN THE TAIHULAKE BASIN DURING THE LAST 11 000 YEARS

This study uses three sediment profiles collected from Taihu Lake to determine the relationship between vegetation cover and climate in the lake basin. Three major periods canbe defined using the pollen assemblages from the sediment profiles.(1)From11 000-9 000 aB.P.,broad leaf deciduous species especially Fagaceae predominate,whileconifer species mainly Pinus had a strong presence.The Taihu Lake Basin was alreadydominated by subtropical evengreen broad leaf deciduous species 1 but the presence of Ablesand Picea indicate that the temperatures were lower than the present ones.(2From9 000-5 000(5 400)aB.P.was the peak period for evergreen broad leaf plant species.The climate was warm and wet, providing a suitable environment for these species. Thetemperature is about I-2 C higher than the present ones.(3)From 5 000 aB.P.present,subtropical broad leaf woody plants, subtropical elements in particular, declined andconifer species and warm-temperate species increased. This reflects lower temperaturesand the increasing impacts of human activities.This article includes the following sections:(1)introduction,(2)materials and methods,(3)results of pollen analyses,(4)interpretation of the sudden in increases in Pinus,Cardamine,and MI'crolepia.