中文摘要：

对三江源地区不同剥蚀退化高寒草甸群落生物量、群落组成及多样性分析。结果表明，群落地上、地下与总的生物量随退化加剧而降低，群落总生物量的变化受地下生物量的变化影响较大。群落地上生物量的变化主要由群落功能群组成的变化引起，随着剥蚀退化的加剧，群落中各功能群生物量均降低，莎草科和禾本科植物相对生物量降低最为明显，而杂类草相对生物量随退化的加剧而增加。不同剥蚀退化程度下，群落多样性指数和均匀度指数的变化趋势与物种丰富度变化趋势基本一致，均呈先降低后增加的趋势，在群落中度退化时各指数最低。物种多样性与功能群多样性指数表现为相同的变化趋势。

英文摘要：

The changes in plant productivity, composition and biodiversity were studied on the plateau meadow steppe denuded to different levels by erosion in the Three River Headwater region. Aboveground, belowground and total biomasses decreased with an increase in denudation, with the reduction of belowground biomass being the most important change. Changes of aboveground biomass related to changes of functional groups. Biomass of all functional groups decreased with increased denudation. Relative biomass of sedges, grasses and legumes decreased whereas the relative biomass of forbs increased with increased denudation. Changes of richness, diversity and evenness indices showed similar trends in relation to denudation, initially decreasing but then increasing, with the lowest values at moderate levels of denudation. Species and functional diversity indices showed similar response trends in relation to the level of denudation.