【作者】 詹学明； 李凌浩； 李鑫；

【Author】 Zhan Xue-Ming, Li Ling-Hao, Li Xin(Laboratory of Quantitative Vegetation Ecology, Institute of Botany, the Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Beijing 100093, China)

【机构】 中国科学院植物研究所植被数量生态学重点实验室；

【摘要】 应用幼苗萌发法研究了农牧交错区一块克氏针茅草地的土壤种子库在围栏内外的变化。在总共32个土样里记录了分属于19个物种的1593株幼苗,其中禾草类6种,非禾草13种;若以生活型划分,则一二年生植物1种,多年生植物18种;以单子叶或双子叶来划分,则单子叶植物为10种,双子叶植物为9种。围栏内的土壤种子库中共有16个物种,全部为多年生植物,其中禾草类6种,单子叶植物9种;围栏外的土壤种子库中共有13个物种,其中多年生植物12种,禾草类4种,单子叶植物5种。围栏内的土壤种子库的平均密度为5139粒/m2,围栏外的土壤种子库的平均密度是3664粒/m2,两者的差异达到了显著性水平(df=1/30,F=7.574,P=0.010)。采用Sorensen指数计算的土壤种子库与地上植被的相似性为0.7111(围栏内)和0.6111(围栏外)。研究结果表明,由于土壤种子库中一些重要物种的缺失和极不均匀的分布,可能会降低退化的克氏针茅草地的恢复速度。我们建议采取播种或者其它恢复措施来加快退化的克氏针茅草地的恢复进程。更多还原

【Abstract】 We studied the seed bank of a Stipa krylovii steppe in two sites with different landuse history: grazed pasture, which was continuously grazed site over at least 50 years and enclosed pasture, which has been continuously grazed and fenced in 2001.Altogether 1593 seedlings belonging to 19 species germinated from 32 samples. The total seed bank flora included 6 grasses vs. 13 forbs, 10 monocotyledons vs. 9 dicotyledons, and 18 perennials vs. 1 annuals + biennials. There were 16 perennials, 6 grasses and 9 monocotyledons of the total 16 species in the seed bank of enclosed pasture, while 12 perennials, 4 grasses and 5 monocotyledons of the total 13 species in the seed bank of grazed pasture. Mean number of viable seeds per square meter was higher (df = 1/30, F = 7.574, P = 0.010) at enclosed pasture (5 139 seeds/m2) than that at continuous grazed pasture (3 664 seeds/m2). 0.6111 and 0.7111 was the Sorensen’s index for the grazed pasture and enclosed pasture. Fifteen species were found only in the established vegetation. 81.0 % of the seeds recorded belonged to only five species (Artemisia frigida, S. krylovii, Potentilla acaulis, Cleistogenes squarrosa, Allium bidentatum), however, the total number of seeds belonged to nine species (Poa angustifolia, A. tenuissimum, Heteropappus altaicus et al.) made up only 2.8 % of the seeds recorded.Our results showed that the scarcity of seeds of many important steppe species maybe inhibit the speed of the restoration of the S. krylovii steppe, reseeding and some other managements should be used to restore the degraded S. krylovii steppe.更多还原