Species decline under nitrogen fertilization increases community-level competence of fungal diseases

The artificial fertilization of soils can alter the structure of natural plant communities and exacerbate pathogen emergence and transmission. Although the direct effects of fertilization on disease resistance in plants have received some research attention, its indirect effects of altered community structure on the severity of fungal disease infection remain largely uninvestigated. We designed manipulation experiments in natural assemblages of Tibetan alpine meadow vegetation along a nitrogen-fertilization gradient over 5 years to compare the relative importance of direct and indirect effects of fertilization on foliar fungal infections at the community level. We found that species with lower proneness to pathogens were more likely to be extirpated following fertilization, such that community-level competence of disease, and thus community pathogen load, increased with the intensity of fertilization. The amount of nitrogen added (direct effect) and community disease competence (indirec...土壤人工施肥可改变天然植物群落结构，并加剧病原物的出现与传播。尽管施肥对植物抗病性的直接效应已获得一定研究关注，但其通过改变群落结构间接影响真菌病害侵染严重程度的途径，迄今仍未得到充分探究。我们在5年周期内，沿氮素施肥梯度对青藏高原高山草甸植被的天然群落开展控制实验，以对比群落水平上施肥对叶片真菌侵染的直接与间接效应的相对重要性。研究发现，对病原物易感程度较低的物种在施肥后更易从群落中局部灭绝，因此群落病害承载能力，进而群落病原负荷，随施肥强度升高而增强。氮肥施用量（直接效应）与群落病害承载能力（间接……