Abstract: According To the natural successive sequence from saline-alkali spot to Suaeda corniculata com munity to Chioris virgata community to Puccinellia tenuiflora community to Leymus chinense community in the north-east Leymus chinense grassland, the paper selected the former four successive stages covering with litter and studied the effect of litter on different stages of progressive succession.The result showed that the litter could improve every stage of succession.The effect on saline-alkali spot was most violent, litter made that the sequence from saline-alkali spot directly became Chloris virgata community , picked up the speed of succession.Litter accelerated the succession from Suaeda corniculate community to Chloris virgata communi ty.Litter acceierated the expansion speed of Leymus chinense and Puccinellia tenuiflora, Chloris virgata com munity gradually changed from annual to perennial.The successive speed of Leymus chinense replacing the su periority of Puccinellia tenuiflora was quickened by the litter.

Key words: Succession, Litter, Successive stage

摘要： 本文根据东北退化羊草草地自然恢复的演替系列,即从盐碱斑→角碱蓬(Suaeda corniculata)群落→虎尾草(Chloris virgata)群落→星星草(Puccinellia tenuiflora)群落→羊草(Leymus chinense)群落。从中选择代表前四个阶段的样地,探讨覆盖干草对草地群落在不同演替阶段中的作用。结果表明,枯枝落叶层对各演替阶段皆有明显的促进作用,对盐碱斑的作用尤为显著,促使其超越碱蓬群落直接演替为虎尾草群落阶段,从而加快了演替进程;盖草后碱蓬群落演替为虎尾草群落速度比对照区快;盖草后使虎尾草群落中的羊草、星星草的扩展速度加快,群落逐渐由一年生向多年生牧草发展;羊草在枯枝落叶层的作用下,加快了取代星星草优势地位的速度。

关键词: 演替, 枯枝落叶层, 演替阶段