Diversity inhibits foliar fungal diseases in grasslands: Potential mechanisms and temperature dependence

Abstract A long‐standing debate exists among ecologists as to how diversity regulates infectious diseases (i.e., the nature of diversity‐disease relationships); a dilution effect refers to when increasing host diversity inhibits infectious diseases (i.e., negative diversity‐disease relationships). However, the generality, strength, and potential mechanisms underlying negative diversity‐disease relationships in natural ecosystems remain unclear. To this end, we conducted a large‐scale survey of 63 grassland sites across China to explore diversity‐disease relationships. We found widespread negative diversity‐disease relationships that were temperature‐dependent; non‐random diversity loss played a fundamental role in driving these patterns. Our study provides field evidence for the generality and temperature dependence of negative diversity‐disease relationships in grasslands, becoming stronger in colder regions, while also highlighting the role of non‐random diversity loss as a mechanism. These findings have important implications for community ecology, disease ecology, and epidemic control.