Climate and Plant Traits Alter the Relationship between Seed Dispersal and Seed Dormancy Capacity in the Alpine Environment

Abstract

Species employ seed dispersal and dormancy to mitigate competition and extinction risks in uncertain environments. Theoretical insights suggest a trade-off: efficiently dispersed species tend to exhibit lower seed dormancy. This tradeoff is hypothesized to be modified by life history traits and climatic factors. We collected data from 547 plants, encompassing dormancy, dispersal capacities, climatic conditions (temperature and wind speed), plant height, seed mass and shape from the Tibetan Plateau. We found that larger, non-spherical seeds favor strong dispersal and non-dormancy. Woody species demonstrate greater dispersal and lower dormancy compared to herbaceous species. A negative association between dispersal and dormancy was found, but the significance and magnitude of the tradeoff depended on traits and climate. This trade-off amplifies with higher temperatures and specific seed shapes. The trade-off strengthens as seed mass, plant height, and wind speed decrease in woody plants, but not in herbaceous. The interplay between climate factors and life-history traits affects the trade-off dynamics. Our results suggest that plants may not be inclined to invest in a single dispersal or dormancy strategy to adapt to cold alpine environments. Our findings provide new insights into species utilizing altered dispersal and dormancy relationships to adapt to alpine environments. If dormancy is necessary under altered climate, climate warming may increase the risk of extinction of certain species, alter species coexistence status and community structure in alpine vegetation.

Keywords: dormancy, dispersal, Trade-off, growth type, plant height, seed mass, seed shape, Climate change