浑善达克沙地南缘沙化草地围封过程中土壤种子库与地上植被的耦合关系

The Coupling Relationship Between the Seed Bank and the Standing Vegetation on the Sandy Grassland in the Course of Fencing in the South Edge of Hunshandake Sand

在浑善达克沙地南缘,以围封不同年限的沙化草地(1年、4年、9年)为试验样地,并以未围封沙化草地作对照,深入研究了沙化草地围封过程中,土壤种子库与地上植被的耦合关系。结果表明,对沙化草地实施围栏封育,可显著提高土壤种子库与地上植被的物种丰富度;不同围封年限间,二者在植被群落组成上,均表现出较高的相似性,且相临阶段相似性较高,随围封年限差异的增加,相似性逐渐减小,但这一变化前者滞后于后者,表明草地在恢复演替中,前者较后者具有滞后性;4种类型样地之间,土壤种子库密度以及地上植被密度差异均极显著,且二者之间均存在显著正相关性,其关系均可用二次曲线描述。

The coupling relationship between the seed bank and the standing vegetation on the sandy grasstand samples which have been fenced for 1 year, 4 years, 9 years and opened as control were deeply researched in the south edge of Hunshandake sand. Results show that fencing can increase the species richness of the seed bank and the standing vegetation significantly. There is a high similarity on the seed bank and the standing vegetation among the grassland samples, especially between the samples which have a close fencing time. Then the similarity becomes smaller and smaller with the increasing differences of the enclosing time, which has a more remarkable representation on the standing vegetation than on the seed bank. So the later has a hysteresis quality in the recovery succession. The difference of seed bank density among the 4 samples is very remarkable, so it is the standing vegetation. There is a remarkable positive correlation between the seed bank and the standing vegetation density, which can be described by secondary curves.