Global change alters ecosystems and their functioning, and biotic interactions can either buffer or amplify such changes. We utilized a long-term nitrogen (N) addition and species removal experiment in the Front Range of Colorado, USA to determine whether a codominant forb and a codominant grass, with different effects on nutrient cycling and plant community structure, would buffer or amplify the effects of simulated N deposition on soil bacterial and fungal communities. While the plant community was strongly shaped by both the presence of dominant species and N addition, we did not find a mediating effect of the plant community on soil microbial response to N. In contrast to our hypothesis, we found a decoupling of the plant and microbial communities such that the soil microbial community shifted under N independently of directional shifts in the plant community. These findings suggest there are not strong cascading effects of N deposition across the plant–soil interface in our system.

中文翻译：

---

植物与土壤的相互作用会影响微生物群落对环境变化的反应吗？

全球变化改变了生态系统及其功能，生物相互作用可以缓冲或放大这些变化。我们在美国科罗拉多州弗兰特山脉进行了一项长期的氮 (N) 添加和物种去除实验，以确定对养分循环和植物群落结构具有不同影响的共显杂草和共显草是否会缓冲或放大模拟氮沉降对土壤细菌和真菌群落的影响。虽然植物群落受到优势物种的存在和 N 添加的强烈影响，但我们没有发现植物群落对土壤微生物对 N 的反应的中介作用。与我们的假设相反，我们发现植物和微生物群落的脱钩使得土壤微生物群落在 N 下发生变化，而与植物群落的方向变化无关。这些发现表明，在我们的系统中，跨植物-土壤界面的 N 沉积没有强烈的级联效应。