Abstract

Non-native plants can have strong effects on the structure and functioning of ecosystems. Recently, the American pokeweed (Phytolacca americana), indigenous to east United States, has expanded its range in many regions all over the world. The species combines several traits that facilitate its invasiveness and its impact on ecosystems in its introduced range. The aim of this study was to analyse the effects of P. americana on multiple ground-dwelling arthropods by conducting a field survey in three forest sites in southwest Germany. Key findings were that P. americana invasion resulted in an altered arthropod community structure compared to native reference sites. Furthermore, the carabid species composition was influenced by the invasion, however this effect was dependent on the forest site. Contrasting effects of P. americana invasion on individual numbers of single ground-dwelling arthropod taxa were observed including positive (3 taxa), negative (1 taxa) and neutral effects (8 taxa). For 2 taxa (Carabidae and Formicidae) the effect of P. americana invasion was dependent on forest site. Reasons for the effects on the local fauna might be altered environmental conditions (reduced herbaceous plant cover) and biotic interactions. The study shows that P. americana induces shifts in the native faunal assemblages. Since responses depend on taxonomic groups and regions, the study highlights the importance for considering multiple taxonomic groups in evaluating the ecological impacts of invasive plants and that the evaluation of impacts must consider the regional context.

中文翻译：

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美洲商陆（Phytolacca americana）入侵对德国西南部地上森林节肢动物的影响

摘要

非本地植物会对生态系统的结构和功能产生重大影响。最近，美国东部原住民的美国商陆（Phytolacca americana）在全球许多地区扩大了业务范围。该物种结合了几个特性，可促进其入侵性及其对引进范围内的生态系统的影响。这项研究的目的是通过在德国西南部的三个林地进行实地调查，分析美洲假单胞菌对多种地面节肢动物节肢动物的影响。主要发现是美洲假单胞菌与本地参考站点相比，入侵导致节肢动物群落结构发生了变化。此外，腕甲物种的组成受到入侵的影响，但是这种影响取决于森林的位置。观察到美洲印第安人入侵对单个地面节肢动物类群数量的相反影响，包括正面影响（3个分类单元），负面影响（1个分类单元）和中性影响（8个分类单元）。对于2个分类单元（腕足科和蚁科），美洲假单胞菌入侵的影响取决于林地。影响当地动物的原因可能是环境条件的改变（草本植物的覆盖减少）和生物相互作用。研究表明美洲P.引起本地动物群落的变化。由于响应取决于分类群和地区，因此该研究强调了在评估入侵植物的生态影响时考虑多个分类群的重要性，并且影响的评估必须考虑区域背景。