高寒牧区中华羊茅人工草地退化演替的数量特征研究

对中华羊茅人工草地退化演替数量特征的研究表明，植物群落组分种的数量、丰富度指数、多样性指数和均匀度指数均随演替的进程而增加，生态优势度指数呈下降趋势。对25个组分种的重要值、生态位宽度及生态位重叠值计测的结果表明，一些阔叶杂草（如细叶亚菊、西伯利亚蓼等）是退化演替过程中入侵人工草地的先锋植物，比其他杂类草具有较大的生态位宽度值，其重要值在演替过程中呈逐年上升趋势。以中华羊茅为其中一个组分种的植物种对间的生态位重叠值，在大多数情况下小于两种阔叶杂草种对间的生态位重叠值。阔叶杂草入侵是导致人工草地退化的一个重要影响因素。

Quantitative characteristics of degenerative succession in Festuca sinensis sowing grassland in the alpine pastoral area

Quantitative characteristics of degenerative succession in Festuca sinensis sowing grassland in the alpine pastoral area were studied. The results showed that with the succession developing,number of species,richness index,diversity index,and evenness index were all increased,but ecological dominance was decreased. Analysis on important values,niche width,and niche overlaps proved that some herb species such as Ajania tenuifolia and Polygomum sibiricum were pioneer plants invading sowing grassland in the succession process. The pioneer plants had wider niche widths than other species,and their important values increased with the succession developing.Niche overlaps between Festuca sinensis and other species were smaller than that between two latifoliate herbs species in most case. The invasion of latifoliate herbs was one of the most important factors,which made the sowing grassland more degenerative.