1. A dramatic insect decline has been documented on the grasslands and forests of European or North American mainland. Yet, other parts of the world and other ecosystems remain much less studied with unknown patterns.
2. Using a unique time‐series dataset, we investigate recent trends on abundance and richness of arthropods sampled in Azorean native forest over 6 years (2013–2018).
3. We test the hypothesis that biodiversity erosion drivers are changing the diversity and relative species abundance structure (species abundance distribution, SAD) of endemics, native non‐endemics and exotic species over time. We also examine temporal trends in abundance for each individual species.
4. In contrast with mainland studies, we observed no decline in overall arthropod diversity, but a clear increase in the diversity of exotic arthropods and some evidence of a tendency for decreasing abundance for some endemic species. We also document stronger species turnover for exotic species, but no specific changes in the SAD.
5. We argue that many changes, particularly in unique systems such as islands, will be noticed not at the richness but mostly at compositional level. Special attention should be given to exotic species which are known to be one of the major drivers of biodiversity erosion on islands.

中文翻译：

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岛屿外来节肢动物多样性的增加是当前生物多样性危机的一个基本方面

1. 在欧洲或北美大陆的草原和森林上，昆虫的数量急剧下降。但是，对于世界其他地区和其他生态系统，人们仍然缺乏以未知模式研究的知识。
2. 使用独特的时间序列数据集，我们调查了6年（2013-2018年）在亚速尔群岛原生林中采样的节肢动物的丰富度和丰富度的最新趋势。
3. 我们检验了以下假设：生物多样性侵蚀驱动因素随着时间的推移正在改变特有物种，本地非特有物种和外来物种的多样性和相对物种丰富度结构（物种丰富度分布，SAD）。我们还检查了每个物种的丰富度的时间趋势。
4. 与大陆的研究相比，我们没有观察到整体节肢动物的多样性下降，但是外来节肢动物的多样性明显增加，并且有证据表明某些地方性物种的丰度有降低的趋势。我们还记录了外来物种的更强物种周转率，但SAD没有特定变化。
5. 我们认为，许多变化，特别是在诸如岛屿之类的独特系统中，将不会在富人身上注意到，而主要是在成分层面上注意到。应特别注意外来物种，外来物种是已知的岛屿生物多样性侵蚀的主要驱动力之一。