彝海沉积物孢粉记录的西南地区近千年植被与气候演化  

VEGETATION AND CLIMATE CHANGES IN SOUTHWEST CHINA DURING THE LAST MILLENNIUMREVEALEDBY A PALYNOLOGICAL RECORDFROMLAKE YIHAI

作　　者：崔凯 王永波 胡柏盈 CUI Kai;WANG Yongbo;HU Baiying(College of Resource Environment and Tourism,Capital Normal University,Beijing 100048)

机构地区：[1]首都师范大学资源环境与旅游学院,北京100048

出　　处：《第四纪研究》2024年第3期727-741,共15页Quaternary Sciences

基　　金：国家自然科学基金项目(批准号:42277444和41877282)资助。

摘　　要：亚洲夏季风强度变化及相应的气候波动对区域生态环境演化和社会经济发展具有重要影响,其近千年演化特征及影响因素备受关注。在精确定年的基础上,利用彝海71 cm沉积物序列孢粉分析结果,恢复了川西地区过去1000年植被与气候演化历史。根据花粉组合特征划分为5个阶段:阶段1(公元1050~1320年)以木本花粉为主,反映中世纪时期区域暖湿的气候环境特征,亚洲夏季风较强;阶段2(公元1320~1570年)和阶段3(公元1570~1680年)桤木属、青冈属等乔木花粉含量降低,以蒿属为代表的草本花粉含量上升,指示进入相对冷干的小冰期,夏季风衰退;阶段4(公元1680~1950年)由于外来移民迁入导致区域人口增加,人类活动增强造成森林选择性砍伐,桤木属等花粉含量显著上升,人类活动开始叠加于自然气候背景上对区域植被造成显著影响;阶段5(公元1950年至今)中云南松、桤木属等花粉含量显著升高,指示人工飞播造林工程对区域植被的影响。基于孢粉组合的主成分分析结果进一步揭示区域环境演变趋势,与西南地区已有气候记录呈现出较为一致的时间变化特征,而太阳活动波动和热带辐合带迁移被认为是驱动近千年西南地区气候变化和夏季风演化的关键因素。The variations in Asian Summer Monsoon and corresponding climate fluctuations are essentially importation for regional ecosystem composition and socioeconomic development,especially for the period of last millennium which has attracted wide attentions.Fossil pollen preserved in lake sediments can effectively reflect the evolution history of regional vegetation and reveal the evolution history of regional climate and environment.Lake Yihai(28.73°N,102.24°E;2280 m a.s.l.)is located in the Hengduan Mountain region of Southwest China and affected by the southwest monsoon.In this study,we conducted palynological analysis of sediment core from Lake Yihai in the Hengduan Mountainous region.A total of 151 terrestrial pollen species were identified from 36 samples in a 71 cm long sediment core,among which 13 types with proportions of over 1%in at least 2 samples were selected for data analysis.Combining with 210Pb/137Cs and radiocarbon dating results,the history of vegetation and environment changes in Southwest China during the past 1000 years were reconstructed.Based on the numerical analysis of pollen composition,including CONISS cluster analysis and principal component analysis(PCA),the environmental evolution of the study area was divided into five stages.In stage YH-1(1050~1320 A.D.),the pollen assemblage was dominated by arboreal pollen species,which indicated a briefly warm and wet medieval climate condition with strong Asian summer monsoon.In stages YH-2(1320~1570 A.D.)and YH-3(1570~1680 A.D.),the decrease in broad-leaved forest components(such as Alnus and Cyclobalanopsis),along with the gradual increase in herbaceous pollen taxa dominated by Artemisia,indicated increased landscape openness following the decline in regional moisture during the Little Ice Age(LIA).In stage YH-4(1680~1950 A.D.),the migration during the Qing Dynasty led to a great increase in regional population and corresponding human activities.Accordingly,selective deforestation process has possibly caused the significant increase in the propo

关 键 词：湖泊沉积物 孢粉组成 气候变化 彝海 近千年 

分 类 号：P534.632[天文地球—第四纪地质学] Q944.571[天文地球—古生物学与地层学] Q948.112.4[天文地球—地质学]