中文摘要：

2005-2012年,进行了青藏高原高寒草甸主要分布地区草地状况的调查,禾草-矮嵩草群落是青藏高原高寒嵩草草甸的典型地带性植被,对处于不同退化程度的小嵩草群落采取封育或减牧后,均可恢复到禾草-矮嵩草群落,但由于退化程度的不同,恢复所需要的时间具有极大的差异。青海果洛地区高寒草甸多处于以小嵩草群落草毡表层剥蚀和杂类草-黑土型退化草地演替阶段,玉树地区处于矮嵩草群落向小嵩草群落的演替阶段,祁连山区处于禾草-矮嵩草群落,藏北高原则处于矮嵩草群落向小嵩草群落转化期或正常小嵩草群落时期。禾本科、莎草科等可食牧草逐渐减少和杂类草盖度急剧增加的趋势反映了高寒草甸退化演替过程植被变化的基本特征,草地退化造成了土壤容重增加,且表层土壤对放牧的敏感性高于底层,土壤0～10,10～20和20～40cm容重分别增加了（0.50±0.08）g/m3,（0.16±0.07）g/m3和（0.04±0.03）g/m3。同时,有机质大幅降低,其降低幅度高达19.3%～53.2%,并随着土层的加深,降幅趋于减小。

英文摘要：

The degradation succession characteristics of alpine meadow on Qinghai-Tibetan Plateau were studied comprehensively from 2005 to 2012.The results indicated that the typical zonal vegetation on Qinghai-Tibaten Plateau was Gramineae and Kobresia humilis community.The degraded grassland in Guoluo of Qinghai Province was characterized with large-scale erosion of mattic epipedon in Kobresia pygmaea community and forbs-black soil.It was at the stage of succession from K.humilis to K.pygmaea community in Yushu of Qinghai Province.The alpine meadow successes from K.humilis to K.pygmaea community,or it remains the normal K.pygmaea community in the north part of Tibetan Plateau.The reduced excellent edible forage of Gramineae and Cyperaceae,and the increased forbs coverage were the main characteristic of alpine meadow degradation.Meanwhile,this degradation caused the increased soil compaction and the topsoil was more sensitive.The bulk densities of different layers in 0 to 10 cm,10 to 20 cm and 20 to 40 cm were increased by（0.50±0.08） g/m3,（0.16±0.07） g/m3 and（0.04±0.03） g/m3 respectively.Meanwhile,The soil organic matter content was greatly reduced by 19.3% to 53.2% and the reduction slowed down with the soil depth.