Abstract: Hongjiannao Lake is the largest desert freshwater lake in China and the largest breeding and habitat of relict gulls in the world. In 2012, it was listed as a national key protected lake. Protection of Hongjiannao Lake contributes great significance to the local ecological environment and provides a good ecological environment for birds breeding. Based on remote sensing and observational data, this paper constructed a high-precision long-time continuous monitoring data set of water area from 1986 to 2018, and summarized spatio-temporal evolution combined natural factors and human activities. At the same time, this study showed significance of the protection process since 2012. The results show:The water protection activities implemented since 2012, which had achieved evident preliminary results. It is contributed by mainly artificial precipitation enhancement and increase water supply by upstream reservoirs, which caused the first increase in 2016 in the past decade. Based on the comprehensive analysis, it is recommended to keep the artificial precipitation enhancement and water supplement constantly to inhibit the shrinkage of the water area of Hongjiannao Lake, and to achieve long-term sustainable restoration of the wetland ecology.

Key words: Hongjiannao Lake, spatio-temporal evolution, protection measures