四川若尔盖县不同退化程度高寒草地群落比较研究

于2008年、2009年在若尔盖县沿高寒草地退化梯度进行物种多样性和生物量等方面的群落监测,以期探讨不同退化程度高寒草地群落结构特征,并提出引起退化的原因.结果表明:(1)随着退化加剧,草地群落盖度、群落物种丰富度、Shannon-Wiener指数和Pielou指数均递减.未退化群落以鹅绒委陵菜、无脉苔草为优势种,群落...

Comparative study of the alpine grassland communities in varying degradation in Zoige County, Sichuan Province

The monitoring of species diversity and evenness of alpine grassland along the degradation gradient was conducted to characterize changes of the community structure in varying degradation and suggest possible causes in Zoige County in both 2008 and 2009.The results showed that:(1)the coverage,species richness,Shannon-Wiener and Pielou indexes of species diversity of communities were decreasing from the non-degradation to the highest degradation;(2)The aboveground biomass was decreasing from the non-degradation to the highest degradation,with 836.78 g/m2,726.37 g/m2,and 542.78 g/m2 in fresh weight for non-degraded,moderate degraded and heavy degraded communities.The weight of dry biomass of moderate degraded communities was quite close to non-degraded communities and obviously higher than heavy degraded communities;(3)Excavating discharge ditches in 1965-1973 might be the main driving factor of community degradation.Other driving factors included overgrazing,highway construction and tourism.