[Long-term pattern of diatom community structure changes in response to multiple environmental stressors at Datun...

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.