1. It is often assumed that there is a trade-off between maternal provisioning and dispersal capacity,
leading small-seeded species to disperse further than large-seeded species. However, this relationship
between dispersal distance and seed mass has only been quantified for species from particular
sites or with particular dispersal syndromes.
2. We provided the first large-scale, cross-species quantification of the correlations between dispersal
distance and both seed mass and plant height. Seed mass was positively related to mean dispersal
distance, with a 100-fold increase in seed mass being associated with a 4.5-fold increase in
mean dispersal distance (R
2 = 0.16; n = 210 species; P < 0.001). However, plant height had substantially
stronger explanatory power than did seed mass, and we found a 5-fold increase in height
was associated with a 4.6-fold increase in mean dispersal distance (R
2 = 0.54; n = 211 species;
P < 0.001).
3. Once plant height was accounted for, we found that small-seeded species dispersed further than
did large-seeded species (R
2 = 0.54; n = 181 species; slope = )0.130; P < 0.001); however, seed
mass only added 2% to the R
2
of the model. Within dispersal syndromes, tall species dispersed further
than did short species, while seed mass had little influence on dispersal distance.
4. Synthesis. These findings enhance our understanding of plant life-history strategies and improve
our ability to predict which species are best at colonizing new environments.