Invertebrate herbivory is a crucial process contributing to the cycling of nutrients and energy in terrestrial ecosystems. While the function of herbivory can decrease with land-use intensification, the underlying mechanisms remain unclear. We hypothesize that land-use intensification impacts invertebrate leaf herbivory rates mainly through changes in characteristics of plants and insect herbivores. We investigated herbivory rates (i.e., damaged leaf area) on the most abundant plant species in forests and grasslands and along land-use intensity gradients on 297 plots in three regions of Germany. To evaluate the contribution of shifts in plant community composition, we quantified herbivory rates at plant species level and aggregated at plant community level. We analyzed pathways linking land-use intensity, plant and insect herbivore characteristics, and herbivory rates. Herbivory rates at plant species and community level decreased with increasing land-use intensity in forests and grasslands. Path analysis revealed strong direct links between land-use intensity and herbivory rates. Particularly at the plant community level, differences in plant and herbivore composition also contributed to changes in herbivory rates along land-use intensity gradients. In forests, high land-use intensity was characterized by a larger proportion of coniferous trees, which was linked to reduced herbivory rates. In grasslands, changes in the proportion of grasses, plant fiber content, as well as the taxonomic composition of herbivore assemblages contributed to reduced herbivory rates. Our study highlights the potential of land-use intensification to impair ecosystem functioning across ecosystems via shifts in plant and herbivore characteristics. De-intensifying land use in grasslands and reducing the share of coniferous trees in temperate forests can help to restore ecosystem functionality in these systems.

中文翻译：

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土地利用导致的无脊椎食草动物减少只能部分用植物和昆虫特征的变化来解释

无脊椎动物食草是促进陆地生态系统中养分和能量循环的关键过程。虽然食草动物的功能会随着土地利用的集约化而降低，但其潜在机制仍不清楚。我们假设土地利用集约化主要通过改变植物和昆虫食草动物的特征来影响无脊椎动物的叶食草率。我们在德国三个地区的 297 个地块上调查了森林和草原中最丰富的植物物种以及土地利用强度梯度的食草率（即受损叶面积）。为了评估植物群落组成变化的贡献，我们量化了植物物种水平的食草动物率并在植物群落水平上进行了汇总。我们分析了连接土地利用强度、植物和昆虫食草动物特征的途径，和食草率。随着森林和草地土地利用强度的增加，植物物种和群落水平的食草率下降。路径分析揭示了土地利用强度与食草率之间的密切直接联系。特别是在植物群落层面，植物和食草动物组成的差异也导致食草率随土地利用强度梯度的变化。在森林中，高土地利用强度的特点是针叶树比例较大，这与食草率降低有关。在草原上，草的比例、植物纤维含量以及食草动物组合的分类组成的变化导致食草率下降。我们的研究强调了土地利用集约化可能通过改变植物和食草动物特征来损害整个生态系统的生态系统功能。减少草地的土地利用和减少温带森林中针叶树的份额可以帮助恢复这些系统中的生态系统功能。