Trade‐off between seed dispersal in space and time.

Abstract

• Seed movement and delayed germination have long been thought to represent alternative risk‐spreading strategies, but current evidence covers limited scales and yields mixed results. Here we present the first global‐scale test of a negative correlation between dispersal and dormancy. The result demonstrates a strong and consistent pattern that species with dormant seeds have reduced spatial dispersal, also in the context of life‐history traits such as seed mass and plant lifespan. Long‐lived species are more likely to have large, non‐dormant seeds that are dispersed far. Our findings provide robust support for the theoretical prediction of a dispersal trade‐off between space and time, implying that a joint consideration of risk‐spreading strategies is imperative in studying plant life‐history evolution. The bet‐hedging patterns in the dispersal–dormancy correlation and the associated reproductive traits have implications for biodiversity conservation, via prediction of which plant groups would be most impacted in the changing era.