Abstract:

In order to reveal the compensatory mechanism and grazing-tolerance ability of the 4 species plants at the Haibei Research Station of the Chinese Academy of Sciences. The experiment used a split-pot design with clipping treatment on the whole plot (stubbled 1 cm, 3 cm and unclipped control) and both fertilizer (fertilized and unfertilized Urea+DAP) and water (watered and unwatered) treatments in subplots. Our objectives were to examine how the compensatory growth of Elymus nutans, Stipa aliena, Kobresia humilis and Carex scabrirostris (including compensatory height, ramet density, compensatory abovegroud biomass per ramet and relative growth rate (RGR) varies with different levels of clipping, fertilizing and watering. The results showed that the responses of compensatory height and compensatory abovegroud biomass to clipping were more sensitive for the two Gramineous plants than the two Cyperaceae plants. Ramet density of S. aliena, K. humilis and C. scabrirostris were appeared overcompensatory after defoliation damage. RGR of ramet height of the 4 species were increased by clipping treatment; RGR of compensatory biomass were different among species. The order of the tolerance ability of they was K. humilis>C. scabrirostris>E. nutans>S. aliena. Fertilizing can induce obvious increasing in compensatory height, compensatory biomass, RGR of ramet height and tolerance to grazing for the 4 species. It was suggested that the grazing-tolerance of the 4 species plants depended on the resource availability in soil in alpine meadow.