Abstract: The seasonal dynamics and grazing responsiveness of modular populations of Kobresia humilis were studied at the fourth year (1991) of grazing under different stock intensities and after resting for 1 year (1993) in alpine meadow. The results showed that the number of tillers and leaves per ramet of modular populations of Kobresia humilis increased and the time for which the number of cumulative surviving leaves reaching its maximum was delayed with the increase of stock intensity. The seasonal dynamics of tiller, flowering tiller and total cumulative leave of the populations displayed similar variations with the change of grazing intensities. Two peaks of growth rate of tiller population were observed at the middle and last ten days of May and at the last ten days of August respectively. The peak of death rate of tiller population was at the end of season of growth. The cycle of initiation and death of leaf was nearly synchronous with that of tiller. The greatest risk of leaf death was also in concert with the highest rate birth. The pattern of survival curves was of the “Deevey type Ⅰ” for tiller populations and of the “stepwise” type for leaf populations respectively. And different stock intensities had no effect on the patterns of survival curves, however, their im-pacts on the differences in the number of tiller and leaf populations of Kobresia humilis remained 1 year after stop grazing.

Key words: Modular population, Grazing responses, Population dynamics, Kobresia humilis, Alpine meadow