Pathogen nutrient acquisition strategy mediates the strength of diversity–disease relationships in natural grasslands
Tianyun Li, Peng Zhang, Junsheng Ke, Kui Hu, Xiang LiuSummary
The relationship between biodiversity and disease risk is a cornerstone of disease ecology, yet predicting its direction and strength remains challenging. Pathogen nutrient acquisition strategies may be key to resolving this context dependency, but their roles in mediating diversity–disease relationships are poorly understood. Here, we combine a large‐scale survey spanning 2000 km in natural grasslands with advanced statistical modeling to demonstrate that pathogen nutrient acquisition strategy is a critical mediator. We show that diseases caused by biotrophic pathogens (e.g. rusts and powdery mildews), which depend on living host tissues, exhibit a significantly negative diversity–disease relationship, whereas diseases caused by necrotrophic pathogens (e.g. leaf spots and blights) show no significant relationship. Furthermore, the strength of this negative relationship for biotrophic pathogens is amplified in regions with higher disease severity. Bayesian structural equation modeling reveals that plant species richness directly reduces biotrophic disease severity, while for necrotrophic pathogens, precipitation is the primary driver of severity, with no direct effect of richness. Our findings provide a trait‐based framework linking climatic drivers, pathogen nutrient acquisition strategies, and the strength of diversity–disease relationships. These results enhance our ability to predict disease dynamics under biodiversity loss and inform biodiversity‐based disease management strategies.