Soil-borne pathogens structure plant communities, shaping their diversity, and through these effects may mediate plant responses to climate change and disturbance. Little is known, however, about the environmental determinants of plant pathogen communities. Therefore, we explored the impact of climate gradients and anthropogenic disturbance on root-associated pathogens in grasslands. We examined the community structure of two pathogenic groups—fungal pathogens and oomycetes—in undisturbed and anthropogenically disturbed grasslands across a natural precipitation and temperature gradient in the Midwestern USA. In undisturbed grasslands, precipitation and temperature gradients were important predictors of pathogen community richness and composition. Oomycete richness increased with precipitation, while fungal pathogen richness depended on an interaction of precipitation and temperature, with precipitation increasing richness most with higher temperatures. Disturbance altered plant pathogen composition and precipitation and temperature had a reduced effect on pathogen richness and composition in disturbed grasslands. Because pathogens can mediate plant community diversity and structure, the sensitivity of pathogens to disturbance and climate suggests that degradation of the pathogen community may mediate loss, or limit restoration of, native plant diversity in disturbed grasslands, and may modify plant community response to climate change.

土壤传播的病原体构建植物群落，塑造它们的多样性，并通过这些影响可能介导植物对气候变化和干扰的反应。然而，关于植物病原体群落的环境决定因素知之甚少。因此，我们探讨了气候梯度和人为干扰对草原根系相关病原体的影响。我们在美国中西部的自然降水和温度梯度下，在未受干扰和人为干扰的草原上检查了两个致病菌群（真菌病原体和卵菌）的群落结构。在未受干扰的草原中，降水和温度梯度是病原体群落丰富度和组成的重要预测因子。随着降水的增加，卵菌的丰富度增加，而真菌病原体的丰富度取决于降水和温度的相互作用，随着温度的升高，降水的丰富度增加最多。干扰改变了植物病原体组成，降水和温度对受干扰草原病原体丰富度和组成的影响降低。由于病原体可以调节植物群落的多样性和结构，病原体对干扰和气候的敏感性表明病原体群落的退化可能会介导受干扰草原中原生植物多样性的丧失或限制恢复，并可能改变植物群落对气候变化的反应. 干扰改变了植物病原体组成，降水和温度对受干扰草原病原体丰富度和组成的影响降低。由于病原体可以调节植物群落的多样性和结构，病原体对干扰和气候的敏感性表明病原体群落的退化可能会介导受干扰草原中原生植物多样性的丧失或限制恢复，并可能改变植物群落对气候变化的反应. 干扰改变了植物病原体组成，降水和温度对受干扰草原病原体丰富度和组成的影响降低。由于病原体可以调节植物群落的多样性和结构，病原体对干扰和气候的敏感性表明病原体群落的退化可能会介导受干扰草原中原生植物多样性的丧失或限制恢复，并可能改变植物群落对气候变化的反应.