冀北山地绣线菊灌丛的土壤种子库特征

为了了解冀北山地退化植被--绣线菊（Spiraea pubescens）灌丛的生态恢复潜力，采用种子萌发法对其可萌发土壤种子库进行了研究，并与其他群落类型进行了比较。结果表明，绣线菊灌丛种子库的种子密度为4 013.33 粒/m²，低于华北落叶松（Larix gmelinii）人工林（4 646.67 粒/m²），但高于榛子（Corylus heterophylla）灌丛（1 713.33 粒/m²）和天然次生白桦（Betula platyphylla）林（746.67 粒/m²）；绣线菊灌丛土壤种子库以草本植物为主，没有发现乔木和灌木种子。各群落类型土壤种子库的种子密度有随土壤深度的增加以及坡位的上升而下降的趋势。绣线菊灌丛土壤种子库的物种组成与其他3 种群落类型具有一定的相似性，但低于其他三种群落之间的相似程度。由此得出结论，绣线菊灌丛具有数量庞大的草本植物种子库，群落草本层恢复潜力巨大，但木本植物，尤其是乔木较少，这是限制绣线菊灌丛向森林群落演替的主要限制因素，需要通过人工的方法引入乔木树种，加速群落的演替，促进森林植被的恢复。

The Characteristics of Soil Seed Banks of Degraded Spiraea pubescens Shrubs in the Northern Mountain Region of Hebei Province

In order to understand the restoration potential of Spiraea pubescens shrubs which is a degraded vegetation widely distributed in the Northern Mountain Region of Hebei Province, the soil germination seed banks of Spiraea pubescens shrub and other communities were studied by seed germination. The results show that the seed density of Spiraea pubescens shrub soil seed bank was 4013.33 seed·m^-2,which was lower than that of Larix gmelinii planation (4646.67 seed·m^-2), but higher than that of Corylus heterophylla shrub (1713.33 seed·m^-2) and Betula platyphylla natural secondary forest (746.67 seed·m^-2). In the soil seed bank of Spiraea pubescens shrubs, only herbaceous plants were founded, without arbor plants and shrub plants, and the other three communities were similar to Spiraea pubescens shrub. The seed density of soil seed bank in both Spiraea pubescens shrubs and the other communities decreased with increasing soil depth and along gradients from lower slope to upslope. There were some similarities to some extent between Spiraea pubescens shrub and the other three communities, but the similarity degree was lower than that of between any two among the other three communities due to the difference between Spiraea pubescens shrub and the other three communities in ecological factors and vegetation characteristics. It was concluded that Spiraea pubescens shrub has significant ecological restoratin potential because of the huge herbaceous soil seed bank in it, but the absence of woody plants seeds, especial arbor plants, hampers the succession process from shrub to forest and that it is necessary for the degraded vegetation like Spiraea pubescens shrub to introduce some trees by artificial measures to promote the ecological restoration process.