高寒草甸放牧扰动与两种植物的反应研究

Reponses of Two Plant Species to Grazing Practice in Alpine and Cold Meadow under Grazing and Grazing-suspension

对不同放牧强度下矮嵩草草甸植物垂穗披碱草和鹅绒委陵菜的生长和繁殖特性进行了5年研究。结果表明,垂穗披碱草株高、分蘖数、地上生物量、地下生物量、有性繁殖效力在不放牧或轻度放牧下最大,营养生长效力在重度放牧中最大,而贮藏效力在重度放牧中最小。鹅绒委陵菜叶数、匍匐茎长度、地上生物量、匍匐茎生物量、开花数、生殖生物量、有性繁殖效力及营养繁殖效力在放牧区显著高于不放牧的对照区。说明适当的放牧干扰有利于垂穗披碱草营养生长,但放牧过重会抑制其有性繁殖;由于放牧采食减少了种间竞争影响,从而提高了鹅绒委陵菜营养生长效力和有性繁殖效力。两物种地下贮藏物的比例随着放牧强度增加显著减少。放牧强度对高寒草甸的群落演替方向有显著影响。

Two meadow plants, Elymus nutans and Potentilla anserina of Kobresia humilis meadow were studied al different grazing intensity in consecutive five years. The results indicated that E. nutans appeared the highest in its planl height, tiller numbers, aboveground biomass, underground biomass and sexual reproductive effort without grazing or with light grazing, the highest in its vegetative growth effort with medium-intensity grazing, and the lowest in its storage effort with heavy grazing. P. anserina presented higher in its leaf number, stolon length, aboveground biomass, stolon biomass, flower number, reproductive biomass, sexual reproductive effort and vegetative growth effort with grazing than without grazing. Accordingly, proper grazing is conducive to the vegetative growth of E. nutans but heavy grazing was capable of inhibiting its sexual reproduction; because grazing reduced interspecific competition, grazing was favorable for improving the vegetative growth effort and sexual reproduction effort of P. anserina. The two species showed significantly decreased underground storages with intensified grazing. The grazing intensity significantly affected the evolution orientation of the populations in alpine and cold meadows.