Climate change impacts the dispersal of annual plants: a mechanistic approach

Abstract Anthropogenic climate change (ACC) significantly impacts plant populations, biodiversity, and ecosystem services. The survival of plant species hinges on their ability to adapt or migrate in pace with shifting climate niches, which is key for maintaining gene flow and habitat colonization in changing environments. This study investigates the mechanistic basis of how ACC affects seed dispersal. Here, we specifically model how elevated atmospheric CO2 levels, temperature, and drought collectively influence dispersal trait plasticity and potential across multiple species. We identified essential diaspore dispersal predictors using climate chamber experiments, fluid dynamic modelling, and wind tunnel assays. Our findings indicate a predicted dispersal distance reduction of 40% for temperate annual plants in warmer, drier, and CO2-rich conditions. Our results highlight the importance of inherent limits of plasticity in multiple traits for facing environmental change and the need to consider multiple environmental factors to understand dispersal in future climates.