哈拉湖流域表土花粉与植被关系研究

Relationship between Surface Pollen and Vegetation in Hala Lake Area

中文关键词:  哈拉湖  表土花粉  湖底表层沉积物

英文关键词:Hala lake  Surface pollen  Lake surface sediment

中文摘要:

      哈拉湖位于青海省境内祁连山系西部,属于高山内陆湖泊。对哈拉湖域进行了植被样方调查及表土、湖底表层沉积物花粉分析,结果显示该流域表土花粉组合能较好地反映样方植被群落特征,高寒荒漠草原植被样点花粉组合以蒿属、菊科、藜科花粉为主,高寒草甸样点莎草科花粉占绝对优势。R值分析结果显示藜科、莎草科和蒿属花粉具有超代表性,而禾本科、菊科、豆科花粉具有低代表性特征。湖底表层沉积物中的花粉分析结果显示湖泊沉积物花粉受控于湖泊近源植被,花粉组合能较好反映湖区整体植被特征,花粉分布具有均一性。沉积物表层花粉组合以蒿属、藜科为主,双气囊型花粉如云杉属、松属等少量出现,表明河流和风力是哈拉湖沉积物花粉输入的主要动力。该研究为在哈拉湖地区利用花粉重建古植被提供了重要的参考依据。

英文摘要:

      Hala Lake is an intermontane lake and located in the Qilian Mountains,Qinghai Province.We carried out vegetational investigation and surface pollen analysis in the study area.The result shows that the major vegetation communities in Hala Lake area can be well differentiated by their surface pollen assemblages.The surface pollen assemblages in Alpine desert steppe vegetation samples were dominated by Artemisia,Chenopodiaceae and Asteraceae while Cyperaceae pollen dominated in Alpine meadow samples.R values indicate that Chenopodiaceae,Cyperaceae and Artemisia pollen relatively show over-representation,while Poaceae,Asteraceae,Fabaceae have under-representation.Hala Lake surface sediment pollen analysis indicates that pollen in the lake mainly imported from the nearby vegetation zones,and pollen assemblages can well reflect vegetation communities around Hala Lake.The pollen assemblages in the different samples collected from the Lake tends to be similar.Chenopodiaceae and Artemisia dominated in the lake sediment surface samples,and Picea and Pinus appeared in low percentage,indicating rivers and wind are the main factors of the pollen input to the lake.This study provides theoretical bases for quantitative reconstructions of palaeoclimate and palaeovegetation based on fossil pollen spectra from lake sediments in the Hala Lake and surrounding area.