不同放牧强度对矮嵩草草甸群落返青的影响

对青海省海北地区矮嵩草草甸植物群落不同放牧强度下返青时的特征进行了调查。结果表明，不同放牧强度对群落返青时的植物种类组成影响明显，种丰富度随放牧强度的增大而减少，莎草科植物类群的重要值增加，禾本科与杂类草的重要值无明显变化，细叶亚菊、棘豆等杂毒草的重要值减少，同时各类群内植物密度、频度、盖度、地上生物量以及重要值等数量指标随放牧的变化比较复杂，与群落处于季节稳定状态时（7－8月份）的特征并不完全相同，说明尚不能简单地对该群落不同时期的特征进行了相互推证。

Effects of different grazing intensity on green-up of Kobresia humilis meadow

In this paper, the regenerative features of Kobresia humilis were examined under different grazing intensities in Haibei region of Qinghai province The effects of different grazing intensities on plant species component among communities was obvious in regenerative period Species richness was decreased with increasing of grazing intensity The important value was increased for sedge group, decreased for poisonous group and no obviously changed for grass and forb group Simultaneously, some quantitative indices such as density, frequency, coverage, aboveground biomass and important value of every plant group had complicatedly changed These were incompletely consisted with the community features at the seasonal stable state every year,and suggested that we couldn't simply infer the nature of community from one period to another in same season