Abstract: The effect of grazing intensity disturbance on plant diversity, soil chemical properties, and soil available microelements characteristics of Kobresia pygmaea meadow community in Qinghai-Tibet plateau was studied to provide scientific basis for Kobresia pygmaea meadow ecosystem protection and restoration. Results showed that vegetation coverage, number of species, plant diversity and aboveground biomass were significantly decreased along with the increasing of grazing intensity. There was significant difference between heavy grazing and control (P<0.05), while no significant difference between moderate grazing and control. The influence of grazing disturbance on soil chemical properties decreased soil organic matter, available nitrogen, total phosphorus and available phosphorus in 0~30 cm soil layers, but there was no significant difference between moderate grazing and control. Total phosphorus and available phosphorus contents of soil under moderate grazing was significantly increased in 10~20 cm soil layers. The contents of soil available microelements were obviously increased with the increasing of grazing intensity (P<0.05). The contents of soil available trace elements was ordered as Fe>Mn>Zn>Cu. These results suggested that moderate grazing was an effective way to protect plant biodiversity and improve grass productivity of Kobresia pygmaea meadow.

Key words: Qinghai-Tibet plateau, Alpine meadow, Plant diversity, Grazing intensity, Soil nutrient

摘要： 以青藏高原高山嵩草(Kobresia pygmaea)草甸为对象,研究不同放牧强度对草甸群落植物多样性、土壤化学性状及土壤有效态微量元素的影响,旨在为高山嵩草草甸生态系统保护和恢复提供科学依据。结果表明:随着放牧牦牛强度的增加,高山嵩草草甸群落的盖度、群落物种数、物种多样性、地上生物量均显著降低,重度放牧与对照间差异显著(P<0.05),而适度放牧与对照间差异不显著;放牧对土壤化学性状的影响主要表现为,随着放牧强度增加,0~30 cm土层中有机质、速效氮、全磷和速效磷含量减少,而适度放牧全氮含量与对照间差异不显著。适度放牧下10~20 cm土层中全磷和速效磷含量显著增加,与对照和重度放牧相比差异显著(P<0.05)。不同放牧强度下土壤有效态微量元素Fe,Mn,Cu和Zn的含量差异显著(P<0.05)。不同放牧强度对高山嵩草草甸的土壤有效态微量元素含量影响不同,从高到低依次为Fe>Mn>Zn>Cu。因此,适度放牧是保护高山嵩草草甸植物多样性、维护土壤养分以及提高草地生产力的有效途径。

关键词: 青藏高原, 高寒草甸, 植物多样性, 放牧强度, 土壤养分