中文摘要：

云南亚热带高原湖泊在过去几十年内面临着工业污染、富营养化、滩地围垦、极端干旱等多重环境压力的影响.本研究以大屯海为研究对象,结合沉积物硅藻、粒度、碳氮同位素以及年代序列等数据进行了多指标分析,重建并识别了大屯海近百年来生态环境变化的历史和硅藻群落变化的特征.结果表明：近百年来硅藻群落组合出现了较大的转变,优势种由连接脆杆藻转变为极细微曲壳藻.结合多指标环境记录（如碳氮同位素）和现代监测记录,采用排序分析以及方差分解发现,工业污染和湖泊营养盐富集是大屯海硅藻群落结构长期变化的主要驱动因子.此外,沉积物粒度分析结果与气象数据显示,由于大屯海受到修建大坝以及多次干旱事件的影响,湖泊水动力与水体交换能力减弱,从而使沉积物硅藻群落结构也发生了相应的变化.

英文摘要：

Subtropical plateau lakes in Southeast Yunnan are known to have experienced multiple environmental stressors（ lake pollution,eutrophication,land reclamation and droughts） during the past decades. Here,we applied multi-proxy analyses（ i. e.,diatom,grain size,C and N isotopic and chronology） of lake sediments,aiming to track the history of lake environment change and the characteristics of diatom community responses in Datun Lake for the past century. The results proved that the sedimentary diatom community records showed significant changes with the replacement of Fragilaria construens by Achnanthes minutissima. Combining with multiple-proxy records（ i.e.,isotopic data） and modern monitoring records,the ordination analyses and variation partitioning further suggested that industrial pollution and eutrophication were the major driving factors that led to the long-term shift of diatom community. In addition,the grain size results and meteorological data revealed that the reductions in hydrodynamic and water exchange intensity associated with damming and the occurrence of extreme droughts,thus led to the corresponding diatom community change.