The role of infectious disease in regulating host populations is increasingly recognized, but how environmental conditions affect pathogen communities and infection levels remains poorly understood. Over 3 y, we compared foliar disease burden, fungal pathogen community composition, and foliar chemistry in the perennial bunchgrass Stipa pulchra occurring in adjacent serpentine and nonserpentine grassland habitats with distinct soil types and plant communities. We found that serpentine and nonserpentine S. pulchra experienced consistent, low disease pressure associated with distinct fungal pathogen communities with high interannual species turnover. Additionally, plant chemistry differed with habitat type. The results indicate that this species experiences minimal foliar disease associated with diverse fungal communities that are structured across landscapes by spatially and temporally variable conditions. Distinct fungal communities associated with different growing conditions may shield S. pulchra from large disease outbreaks, contributing to the low disease burden observed on this and other Mediterranean grassland species.

传染病在调节宿主种群中的作用越来越被认识到，但环境条件如何影响病原体群落和感染水平仍然知之甚少。在 3 年多的时间里，我们比较了多年生丛草Stipa pulchra 的叶病负担、真菌病原体群落组成和叶化学，这些植物生长在相邻的蛇纹石和非蛇纹石草原栖息地，具有不同的土壤类型和植物群落。我们发现蛇纹石和非蛇纹石S. pulchra经历了与具有高年际物种周转率的独特真菌病原体群落相关的一致的低疾病压力。此外，植物化学因栖息地类型而异。结果表明，该物种经历了与不同真菌群落相关的最小叶面病害，这些真菌群落由空间和时间可变条件跨景观构成。与不同生长条件相关的不同真菌群落可能会保护S. pulchra免受大规模疾病爆发的影响，从而导致在这种和其他地中海草原物种上观察到的疾病负担较低。