Community characteristics study on alpine grassland in source regions of three rivers

Typical Stipa Breriflova steppe in Xinghai, S. purpurea grassland in Maduo and alpine meadows in Dari, Zaduo, Qumalai and Tanggulashan counties were selected for studying the community character in source regions of three rivers with quadrats investigation. The results showed that 1) the richness of alpine meadow in Dari and Qumalai counties were higher, and there were 20 and 15 species (P＜0.05).The species were 8 in Xinghai, Maduo and Tanggulashan, separately, but it was only 5 in Zaduo (P＞0.05). 2) The diversity was the highest in Dari and Qumalai at 2.74 and 2.27. Moreover it was the lowest in Tanggulashan and Zaduo, and it was about 1.5. The species diversity of Stipa steppe in Xinghai and Maduo both were 1.87. The Pielou index was lower in Tanggulashan and Qumalai at 0.76 and 0.84, then that were higher in other plots. The statistics showed that there was significant correlation between diversity and species(r=0.967, P＜0.01), the equation was y=1.130 1+ 0.079 5x (R2= 0.935 9, P＜0.01). 3) It was revealed that the alpine meadows of Zaduo and Qumalai were first classified into one group by clustering. Then alpine meadow of Tanggulashan was injected. After that the Stipa Breriflova steppe of Xinghai, alpine meadow of Dari were attributed to the group, and Stipa purpurea steppe in Maduo was clustered one group finally.