The effect of genotype richness and genomic dissimilarity ofAndropogon gerardiion invasion resistance and productivity

Background: The genetic diversity within populations has been shown to affect ecosystem functions, including productivity and invasion resistance. To date most experiments have focused on manipulation of genotypic richness and have ignored other measures of genetic diversity.Aims: In the present study we aimed to establish whether manipulated genotypic richness and genomic dissimilarity of Andropogon gerardii affect productivity and invasion resistance.Methods: We created experimental mesocosms with three levels of genotypic richness: one-, three-, and nine-genotypes. In the three-genotype treatment, we manipulated a range of genomic dissimilarity values (genetic relatedness among individuals). At the end of one growing season we measured above-ground, below-ground and total biomass of the mesocosms, and invasion resistance to Andropogon bladhii.Results: Overall, we found no significant effect of genotypic richness on any measure of ecosystem function, although there tended to be more root biomass (due to...