Genotypic selection shapes patterns of within-species diversity in experimental plant populations

1. An increasing body of evidence suggests that within-species diversity plays an important role for community and ecosystem functioning, alters complex trophic interactions and affects patterns of species diversity and coexistence. Nonetheless, we lack a good understanding of how genotypic trait variation translates into shifts in the relative abundance of genotypes within populations. 2. In this study, we show that genotypic selection strongly alters dominance relationships among genotypes over a period of 5 years. This resulted in remarkably consistent changes in the proportional representation of genotypes, and in a concomitant decline of diversity and evenness in our experimental populations. 3. High growth rates and the production of large offspring were positively associated with genotypic performance. Vegetative abundances of genotypes translated monotonically into flowering frequencies. 4. Synthesis. We conclude that genotypic selection markedly affects patterns of diversity and consistently alters genotypic abundance and mean trait distributions in plant populations over a relatively short period of time