不同干扰对高寒草原群落物种多样性和生物量的影响

通过对新疆巴音布鲁克高寒草原天然草地进行灌溉、围栏(2年、7年、13年)和自由放牧处理,探讨不同干扰类型对草地植物多样性和生物量的影响。结果表明:灌溉使草地植物群落的高度、盖度和地上、地下生物量达到较高的水平,物种多样性也有一定程度的增加;而在自由放牧制度下,由于干扰过于剧烈,草地已呈退化趋势,物种多样性和生物量均较低;在围栏草地中,随着围封年限的增加,群落高度、盖度、地上、地下生物量逐渐增加,物种丰富度、多样性指数、均匀度指数呈现先增加后减小的趋势。在5种干扰类型中,物种丰富度、Shannon-W iener指数(H′)的排列顺序为:放牧草地<围栏2年草地<灌溉草地<围栏13年草地<围栏7年草地;P ielou均匀度指数的排列顺序为:围栏2年<放牧<灌溉<围栏13年<围栏7年;地上生物量的变化趋势为:放牧草地<围栏2年草地<围栏7年草地<围栏13年草地<灌溉草地;地下生物量的变化趋势为:放牧草地<围栏2年草地<灌溉草地<围栏7年草地<围栏13年草地。

Effects of Different Disturbances on the Diversity and Biomass of the Phytobiocoenoses in Alpine Steppes

The main purpose of this study is to research the effects of different disturbances including irrigation,enclosure(for 2 years,7 years and 13 years) and free grazing on the biodiversity and biomass of the phytobiocoenoses in alpine steppes.The results show that irrigation leads to a significant increase in species diversity,vegetation coverage,mean plant height,aboveground biomass and underground biomass.Under free-grazing system,however,the phytobiocoenoses have been seriously degenerated due to the severe disturbance,and both the species diversity and biomass of the phytobiocoenoses are low.In the enclosure steppes,the vegetation coverage,mean plant height,aboveground biomass and underground biomass are gradually increased with prolonging the enclosure time,and the species richness index,diversity index and evenness index are increased at first and then decreased.Under 5 kinds of disturbances,the species richness index and Shannon-Wiener index of steppes are in an order of grazing steppe <2-year enclosure steppe