中文摘要：

研究了四川省红原县境内4个不同放牧强度下高寒草甸植物群落的物种组成、生物量及其分配特征。随放牧强度的增加，植物群落表现出由垂穗鹅冠草（Roegneria nutans）和垂穗披碱草（Elymus nutans）等禾草为优势种的群落向以川嵩草（Kobresia setchwanensis）和高山嵩草（Kobresia pygmaea）等莎草为优势种的群落演替的趋势。生长季节6—9月，草甸植物地上生物量以不放牧为最高，重度放牧显著小于不放牧；地下生物量随放牧强度的增加而呈增加趋势，重度和中度放牧显著高于不放牧和轻度放牧。不放牧、轻度、中度和重度放牧草地6—9月4个月植物总生物量平均值分别为1543．3、1621．6、2294．7和2448．5g·m^-2，地下生物量占总生物量比例大小排序为重牧（87．8％）〉中牧（81．8％）〉轻牧（76．2％）〉不放牧（69．2％）。草甸植物生物量的变化主要是由于放牧作用下植物群落优势种的变化而引起的，其分配比例的变化反映了草甸植物对放牧干扰的适应。

英文摘要：

A study was carried out on seasonal variation of species composition, biomass and distribution of alpine meadow plant communities with different grazing intensity in Hongyuan County, Sichuan Province. With increasing grazing intensity, dominancy of the plant community shifted from grasses （ Roegneria nutans and Elymus nutans） to sedges （ Kobresia pygmaea and K. setchwanensis）. Over the growing season from June to September, aboveground biomass was the highest in Treatment NG （non-grazing plot） and the lowest in Treatment HG （heavily grazed plot） , while belowground biomass showed an rising trend with increasing grazing intensity and it was significantly higher in Treatment HG and Treatment MG （moderately grazed plot） than in Treatment NG and Treatment LG （lightly grazed plot）. Total plant biomass averaged over the growing season was 1 543.3, 1 621.6, 2 294.7, and 2 448.5 g·m^-2 in Treatments NG, LG, MG and HG, respectively. The proportion of belowground biomass to total plant biomass was 87.8% , 81.8% , 76.2% , and 69.2% , in Treatments HG, MG, LG and NG, respectively, which shows adaptation of the plants in the meadow to grazing.