Species and community-level responses to warming are well documented, with plants and invertebrates known to alter their range, phenology or composition as temperature increases. The effects of warming on biotic interactions are less clearly understood, but can have consequences that cascade through ecological networks. Here, we used a natural soil temperature gradient of 5–35°C in the Hengill geothermal valley, Iceland, to investigate the effects of temperature on plant community composition and plant–invertebrate interactions. We quantified the level of invertebrate herbivory on the plant community across the temperature gradient and the interactive effects of temperature, plant phenology (i.e. development stage) and vegetation community composition on the probability of herbivory for three ubiquitous plant species, Cardamine pratensis, Cerastium fontanum and Viola palustris. We found that the percentage cover of graminoids and forbs increased, while the amount of litter decreased, with increasing soil temperature. Invertebrate herbivory also increased with soil temperature at the plant community level, but this was underpinned by different effects of temperature on herbivory for individual plant species, mediated by the seasonal development of plants and the composition of the surrounding vegetation. This illustrates the importance of considering the development stage of organisms in climate change research given the variable effects of temperature on susceptibility to herbivory at different ontogenetic stages.

中文翻译：

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自然变暖实验中土壤温度、物候和植物群落组成对无脊椎动物食草动物的影响

物种和社区对变暖的反应有据可查，已知植物和无脊椎动物会随着温度升高而改变它们的范围、物候或组成。变暖对生物相互作用的影响不太清楚，但可能会通过生态网络产生级联效应。在这里，我们使用冰岛 Hengill 地热谷 5-35°C 的自然土壤温度梯度来研究温度对植物群落组成和植物-无脊椎动物相互作用的影响。我们量化了无脊椎动物在整个温度梯度下对植物群落的食草水平，以及温度、植物物候（即发育阶段）和植被群落组成对三种普遍存在的植物物种食草概率的交互影响，Cardamine pratensis、Cerastium fontanum和Viola palustris。我们发现，随着土壤温度的升高，禾本科和杂草的覆盖百分比增加，而凋落物的数量减少。无脊椎动物食草动物也随着植物群落水平的土壤温度而增加，但这是由温度对单个植物物种的食草动物的不同影响所支持的，这是由植物的季节性发育和周围植被的组成所介导的。鉴于温度对不同个体发育阶段的食草易感性的不同影响，这说明在气候变化研究中考虑生物体的发育阶段的重要性。