干旱草原星毛委陵菜群落种子库与植被功能群结构的关系

以石羊河上游星毛委陵菜(Potentilla aclaulis)群落为研究对象,采取现场植物测定与土壤采样分析相结合的方法,对地上植被、种子库功能群结构组成及相互关系进行分析,探讨了植被演替过程中功能群的响应和群落稳定性的维持机理.结果表明:(1)不同植被梯度下多年生禾草和多年生杂草在植被群落中占据优势地位,优势度比例变化较小,而一、二年生杂草及豆科植物地位不突出,优势度比例较小.(2) 土壤种子库中,水平方向上,在植被梯度下多年生杂草优势度所占比例较高,变幅较小;多年生禾草、豆科植物则表现出由低到高再降低的变化过程,而一、二年生杂草的变化规律与之相反.垂直方向上,0-5 cm与0-15 cm层在植被梯度下,不同功能群优势度比例大小呈显著正相关,5-10 cm与10-15 cm层变化规律不明显.(3) 种子库具有比植被丰富的物种,系统稳定性较高,针对于扰,群落表现出明显的生存策略.

Relationship Between Soil Seed Banks and Vegetation Functional Group Structure of Potentill a Aca ulis Community in Arid Grassland

Taking the Potentilla acaulis community in the upstream of Shiyang River as an example and adop-ting soil seed bank analysis combined with vegetation restoration determination , the soil seed banks and vege-tation functional group structure,as well as their relationship,are analyzed and an discussion on the response of functional group,maintenance mechanisms of community stability during the vegetation succession are made. Results show that(1)the perennial grasses and the perennial weeds are dominant species under differ-ent vegetation gradient and their dominant state has not changed significantly. But the situation of annuals and biennials and the Legume plants are not so prominent.(2) In horizontal direction,the perennial weeds have a higher proportion with the smaller change in a small change range in the soil seed bank. The tendency of perennial grasses and Legume plants presents a single curve , while the annuals and biennials show the op-posite tendency. In vertical direction ,compared with the vegetation gradients in 0-5 and 0-15cm layers,dominance ratio of different functional groups presents a significant positive correlation,while the tendency is not obvious for the gradients in 5-10cm and 10-15cm layers.(3) Compared with the standing vegetation,the soil seed banks have more species with higher stability and for the same interference , its group shows a more significant state of survival strategy.