放牧季节及放牧强度对高寒草地植物多样性的影响

在海北高寒草地进行了7年轻度放牧、中度放牧和重度放牧试验,并用围栏控制放牧进行对照.试验显示,物种丰富度和均匀度在夏季牧场和冬季牧场出现不同的变化.在夏季牧场,物种丰富度随着放牧强度的增强而增强,而均匀度则随着放牧强度的增强而下降;在冬季牧场,物种丰富度和放牧之间呈现驼峰反应模式,说明植物的丰富度在中度放牧强度时达到最大.不同牧场生物多样性变化的模式说明夏季牧场放牧强度不足.

Effects of grazing intensity and grazing season on plant species diversity in alpine meadow

For seven years, alpine meadow in an experiment in Haibei of Qinghai, China, has been lightly, moderately, or heavily grazed by cattle, or fenced off from grazing. Plant species richness and evenness showed different changes in summer and winter meadows. In summer meadow, species richness increased with grazing intensity, but species evenness reduced. In winter meadow, a "hump" model reflects the change in species richness that occurred with increase in grazing intensity, showing species richness was greatest at the moderate grazing intensity. Models of biodiversity change for the different meadows show that the summer meadow grazing intensity is too light.