So those small small seeds produced by plants have actually big effects on plant demography. Read more in the Early View paper “Non-native conditions favor non-native populations of invasive plant: demographic consequences of seed size variation?” by José L. Hierro et al.
Or be quicly updated by Josés own short summary:
We conducted a reciprocal common garden in part of the native (southwestern Turkey) and introduced (central Argentina) range of a globally distributed plant invader, Centaurea solstitialis (yellow starthistle, Asteraceae) to explore the idea that the demographic success of the species in Argentina relates to differences between native and introduced populations. Unusual among common gardens, our experimental design included seed additions to explicitly evaluate population level responses. We found that seed mass was two times larger for Argentinean than Turkish populations. Similarly, plant establishment at the end of the experiment was greater for Argentinean than Turkish populations, but only in the common garden in Argentina. In Turkey, we detected no differences in plant establishment between population origins. Our results suggest that increased seed size in Argentinean populations may have demographic consequences under central Argentina conditions that can contribute to the invasive success of C. solstitialis. Our study offers the most complete evaluation to date to the idea that variation in seed size can contribute to differences in plant density between native and non-native distributions of invasive plant species.