The change in nutrient availability in the soil can affect key functions of forest ecosystems, such as insect herbivory. Although insect herbivory is particularly relevant because it can impact on the growth and mortality of forest plant species, the evidence of the impacts of fertilizers addition on herbivory patterns is limited. In this study, we specifically evaluated how herbivory frequency on the timber species is affected by the addition of nitrogen (N), phosphorus (P), potassium (K) and their combinations to the soil, using a long term full-factorial field experiment in a North-Patagonian Forest (Argentina). Our study investigated the effects of fertilizers (N, P, and K) on herbivory frequency and leaf nutrient concentrations of the studied species. We found that the addition of fertilizers to the soil increased herbivory frequency, which was mediated by increases in leaf nutrient concentrations. Furthermore, we observed that interactions between fertilizers in leaf nutrient concentrations generally produced increases in herbivory, both in the amount of leaf consumed and in the foliar damage percentage. These findings suggest that fertilization can have complex effects on plant-herbivore interactions, and that the specific effects may depend on the identity of the nutrients that combined, the plant species, and the level of nutrient availability. Our results provide evidence that changes in soil nutrient availability are important in forest ecosystems, and that should be considered to develop effective management strategies for the sustainable use of natural resources in Patagonian forests.

中文翻译：

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营养物质的添加增加了北巴塔哥尼亚森林中南极黄毛榉的昆虫食草性

土壤养分有效性的变化会影响森林生态系统的关键功能，例如昆虫食草。尽管昆虫食草特别重要，因为它可以影响森林植物物种的生长和死亡率，但肥料添加对食草模式影响的证据有限。在这项研究中，我们通过长期全因子田间实验，专门评估了向土壤中添加氮 (N)、磷 (P)、钾 (K) 及其组合对木材树种的食草频率的影响在北巴塔哥尼亚森林（阿根廷）。我们的研究调查了肥料（氮、磷和钾）对所研究物种的食草频率和叶片养分浓度的影响。我们发现，向土壤中添加肥料会增加食草频率，这是通过叶子养分浓度的增加来调节的。此外，我们观察到，肥料之间在叶子养分浓度方面的相互作用通常会导致草食性的增加，无论是在叶子消耗量还是叶损伤百分比方面。这些发现表明，施肥会对植物与草食动物的相互作用产生复杂的影响，具体影响可能取决于所结合的营养物质的特性、植物种类和营养物质的可用性水平。我们的研究结果证明，土壤养分有效性的变化对森林生态系统很重要，在制定有效的管理策略以可持续利用巴塔哥尼亚森林自然资源时应考虑这一点。