松嫩草原不同时间火烧后群落特征的变化

松嫩草原早春火烧后，种类密度、物种多样性和丰富度增高，均匀度降低；晚春火烧后则相反．无论是早春火烧还是晚春火烧．群落高度降低，但晚烧更低．火烧能刺激羊草生长活力，晚烧作用更明显．火烧后，羊草叶产量增高，叶茎比例以晚烧地为最高．早烧后，群落地下现存量增多，晚烧相反．

Community variation on Songnen grassland after different burning time.

After early spring burning,the density,diversity and richness of grass species are increased and their evenness is decreased.but it is the contrary after later spring burning.Whether early or later spring burning, the height of the community is decreased,especially in the later burned plot.Burning can promote the growth vigour of Aneurolapidium chinense,which is more significant in the later burned plot. After burning,the leaf production of A.chinense is increaed,and the ratio of leaf to stem is the maximum in the later burned plot.The underground biomass of the community is increased in early burned plot,but decreased in later burned one.