Abstract

The diversity of aboveground vegetation of the herb–dwarf shrub layer and seedlings from the soil seed bank in the thickets of invasive shrub Sorbaria sorbifolia was evaluated in urbanized forests of the city of Yekaterinburg (the Middle Urals, Russia). Geobotanical relevés and identification of seedlings from the soil seed bank were performed in different forest communities: thickets of invasive S. sorbifolia, thickets of native Rubus idaeus, and in forest communities without S. sorbifolia and R. idaeus. The effect observed in the presence of S. sorbifolia was as follows: the abundance of aboveground vegetation in the herb–dwarf shrub layer was lower by a factor of 10–20 or more; the taxonomic richness of the herb–dwarf shrub layer in the relevé (α-diversity), by a factor of 6–8; and the total number of species recorded in the community group (γ-diversity), by a factor of 3. The disappearance of species under S. sorbifolia was selective. Relatively light-loving and relatively dry-loving species disappeared first, while more shade-loving and moisture-loving species were relatively resistant. The taxonomic richness and abundance of seedlings from the soil seed bank did not change depending on the abundance of S. sorbifolia. Approximately half of the identified seedling taxa were typical forest plants, while the others were only specific for the seed bank and did not occur in the vegetative state. It is concluded that the influence of S. sorbifolia on the vegetation of subordinate layers is due primarily to the direct competitive and habitat-transforming effect of the living S. sorbifolia phytomass.

中文翻译：

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外来入侵苦参的灌丛中植物的多样性：对地上植被和种子库的影响差异

摘要

在叶卡捷琳堡市（俄罗斯乌拉尔中部地区）的城市化森林中，对侵入性灌木Sorbaria sorbifolia灌丛中草本矮化灌木层和土壤种子库中地上植被的多样性进行了评估。在不同的森林群落中进行了土壤植物学相关性和从土壤种子库中鉴定幼苗的操作：入侵性沙门氏菌的灌丛，天然悬钩子的灌丛，以及没有沙门氏菌和R. idaeus的森林群落。在山梨链球菌存在下观察到的效果结果如下：在草本矮矮灌木层中，地上植被的丰富度降低了10-20倍或更多。相关区域中草本矮化灌木层的分类学丰富度（α多样性），为6-8倍；群落组中记录的物种总数（γ多样性）为3。在S. sorbifolia下物种的消失是选择性的。相对较喜欢光和比较干燥的物种首先消失了，而更偏爱阴影和耐湿的物种则相对具有抵抗力。土壤种子库中幼苗的分类学丰富度和丰度没有改变，这取决于山梨链球菌的丰度。。鉴定出的幼苗分类单元中大约有一半是典型的森林植物，而其他仅针对种子库而并非以植物状态出现。结论是：山梨链球菌对下层植被的影响主要是由于活的山梨链球菌植物的直接竞争和生境转化作用。