Abstract: Gahai Salt Lake, which is situated in the Qaidam Basin of the Qinghai-Tibet Plateau at an elevation of 2849.6 m above sea level, is a saline lake with high salinity and abundant biological resources of Artemia (brine shrimp). An investigation on the characteristics of community diversity of plankton with relation to salinity was conducted in the summer of 1997. Forty-six species of phytoplankton and twelve species of zooplankton have been identified in the major body of water in the in-lake area with 22 sampling sites at 5 sections. The differences of the species composition, richness , individual abundance and biomass of plankton were compared between two sampling area with a big change of salinity in the waters. The results show that the salinity is an important limiting factor in determining the structure of biological communities in the inland saline lakes.

Key words: Torreya jackii, biodiversity protection