大通河上游高寒草甸植物群落的退化特征

采用样方法对祁连山区大通河上游不同退化程度高寒草甸植物群落进行调查，分析了该草地群落结构、物种多样性和草地生产力。结果表明，该类草地由24科51属60多种植物组成；随着草地退化程度的加重，草地优势种由高山嵩草（Kobresia pygmaea）向细叶亚菊（Ajania tenuifolia）过渡；中度退化草地的Shannon Wiener指数和Simpson指数均最高（P<0.05）；随草地退化程度的加剧，草地总盖度降低，禾本科和莎草科优良牧草生物量显著下降（P<0.05），杂类草和毒草生物量上升，草地质量下降，生产力明显降低。

Community characteristics of alpine meadow under different degrees of degradation in the upper area of Daitong River

A study on the community structure and productivity, and plant composition and diversity of alpine meadow under different degrees of degradation, including non degradation, light degradation, moderate degradation, heavy degradation and over degradation in the upper area of Daitong river. Results indicated that there were more than 60 plant species, which are belong to 24 families and 51 genus, in study ared. The dominant species in was conduced non degradation and over degradation grasslands were Kobresia pygmaea and Saussurea pulchra, respectively. The Shannon Wiener index and Simpson index in moderate degradation (P<0.05) were the highest. With the increasing of degradation, the biomass of weeds increased(P<0.05), and the vegetation coverage, biomass of high quality forages, total aboveground biomass and grassland quality decreased.