火烧对羊草草原植物群落组成的影响

在羊草草原正常能着火季节内，通过人为点烧的方法，对比研究了不同时间火烧对植物群落组成的影响．结果表明，羊草－杂类草草原早春火烧后，群落密度、种类丰富度和多样性提高，均匀性降低；羊草典型草原秋季火烧后，群落密度、多样性和均匀性降低，种类丰富度提高．连续２次火烧除羊草和几种１—２年生植物密度增加外，其它各种群密度降低，群落多样性也降低，一些种类退出群落．

Effect of fire on plant composition of Aneurolepidium chinense steppe

In normal season of grassland fire occurrence, the effect of different fire regimes on plant composition of Aneurolepidium chinense on Hulunber and Xilinguole grasslands is studied.The results show that on Hulunber grassland, the community density, species richness and diversity are increased, but the eveness is decreased after early spring burning. On Xilinguole grassland, the community density, species diversity and eveness are decreased, but the species richness is increased after Autumn burning. Continuous twice burning induces the increase of population density of A. chinense and several annual and biennial plant species, the decrease of community density and diversity of other populations, and the withdrawing of some species from the community.