The ongoing wide-scale introduction of nonnative plants across the world may negatively influence native invertebrate fauna, due to a lack of coevolved traits related to the novel plants, e.g., unique phytochemicals or shifted phenology. Nonnative plants, specifically trees, are common in urban environments, areas that already pose novel habitats to plants and wildlife through a wide array of anthropogenic factors. For example, impervious surfaces contribute to increased ambient temperatures, the so-called urban heat island effect (UHI), which can affect local plant phenology. Yet, few studies have simultaneously studied the effects of urbanization and tree species origin on urban invertebrate communities. We measured the city-level UHI and phenology of nine native and seven nonnative tree species in five city-center parks in southern Sweden, as well as four common native species in a rural control forest. We quantified the abundance of invertebrates on a subset of native and nonnative tree species through shake sampling, sticky traps, and frass collection. In the urban environment, nonnative trees hosted significantly fewer invertebrates compared to native trees. Furthermore, the nonnative trees had a delayed phenology compared to native species, while the peak of caterpillars associated with the subset of trees surveyed for this measure was significantly earlier compared to that of the native species studied. The effect of tree species origin on urban invertebrate abundance was of a greater magnitude (effect size) than the effect of urbanization on invertebrate abundance in native tree hosts. Hence, the results indicate that the impact of nonnative vegetation may be a stronger driver of invertebrate declines in urban areas than other factors. As the effect of species origin on tree phenology was at a level comparable to the urban effect, increasing prevalence of nonnative vegetation can potentially obscure effects of urbanization on phenology in large-scale studies, as well as induce mismatches to invertebrate populations. Since parks harbor a large proportion of urban biodiversity, native trees play a crucial role in such habitats and should not be considered replaceable by nonnative species in terms of conservation value.

中文翻译：

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树木起源和城市化对无脊椎动物丰度和树木物候的对比影响

由于缺乏与新型植物相关的共同进化特征，例如独特的植物化学物质或变化的物候学，全球范围内正在进行的大规模引入非本地植物可能会对本地无脊椎动物群产生负面影响。非本地植物，特别是树木，在城市环境中很常见，这些地区已经通过各种人为因素为植物和野生动物提供了新的栖息地。例如，不透水表面会导致环境温度升高，即所谓的城市热岛效应 (UHI)，它会影响当地植物物候。然而，很少有研究同时研究城市化和树种起源对城市无脊椎动物群落的影响。我们测量了瑞典南部五个城市中心公园中九种本地树种和七种非本地树种的城市级 UHI 和物候，以及农村控制森林中的四种常见本地物种。我们通过摇采样、粘性陷阱和碎片收集来量化本地和非本地树种子集上无脊椎动物的丰度。在城市环境中，与原生树木相比，非原生树木所承载的无脊椎动物要少得多。此外，与本地物种相比，非本地树木的物候学有所延迟，而与该措施调查的树木子集相关的毛虫峰值明显早于所研究的本地物种的峰值。树种起源对城市无脊椎动物丰度的影响比城市化对本地树木宿主中无脊椎动物丰度的影响更大（影响大小）。因此，结果表明，与其他因素相比，非本地植被的影响可能是城市地区无脊椎动物减少的更大驱动力。由于物种起源对树木物候的影响与城市效应相当，非本地植被的增加可能会在大规模研究中掩盖城市化对物候的影响，并导致与无脊椎动物种群的不匹配。由于公园拥有大部分城市生物多样性，本地树木在这些栖息地中发挥着至关重要的作用，在保护价值方面不应被认为可以被非本地物种取代。在大规模研究中，越来越多的非本地植被可能会掩盖城市化对物候学的影响，并导致与无脊椎动物种群的不匹配。由于公园拥有大部分城市生物多样性，本地树木在这些栖息地中发挥着至关重要的作用，在保护价值方面不应被认为可以被非本地物种取代。在大规模研究中，越来越多的非本地植被可能会掩盖城市化对物候学的影响，并导致与无脊椎动物种群的不匹配。由于公园拥有大部分城市生物多样性，本地树木在这些栖息地中发挥着至关重要的作用，在保护价值方面不应被认为可以被非本地物种取代。