Abstract: Desmids, which are a group of Chlorophyta with diverse species and complex morpha, play important roles in water quality monitoring, protection, and nutritional analysis because they are highly sensitive to environmental changes. Desmids in Nansi Lake and Dongping Lake from May 2010 to May 2013 were collected monthly at a depth of 0.5 m below the surface. Three genera, 12 species were identified in Nansi Lake and 4 genera, 15 species in Dongping Lake. The abundance of desmids in summer and autumn (from June to November) was higher than that in other months, with the maximum of 50.0×10⁴ cells·L^-1 and 55.9×10⁴ cells·L^-1, respectively. Species of Cosmarium were dominant in both lakes. The results of redundancy analysis (RDA) and Pearson correlation analysis showed that the major environmental factors influencing the distribution of desmids in Nansi Lake were pH and TN, and those in Dongping Lake were temperature, dissolved oxygen, and chemical oxygen demand. Desmids identified in both lakes were mainly indicative species of oligotrophic water, with a low detection frequency.

Key words: atmospheric warming, seed reproduction, adaptation., Northwestern Yunnan Plateau, Napahai wetland