In grassland biodiversity experiments the positive biodiversity–ecosystem functioning relationship generally increases over time. The mechanisms underlying this observation, however, are unclear. Recent research has shown that within one species, differential selection in monoculture and mixed-species communities can lead to the rapid emergence of monoculture and mixture types (Zuppinger-Dingley et al., 2014). We hypothesize that in large biodiversity experiments pre-adapted genotypes or epigenetic variants could be selected from the standing genetic or epigenetic variation by a sorting-out process (Bossdorf et al., 2008).
We used eight plant species selected for twelve years in such a biodiversity experiment to test whether selection for monoculture and mixture types had occurred. In a glasshouse experiment we assessed complementarity between species grown in mixtures of either monoculture types or mixture types. We further assessed genetic and epigenetic variation between monoculture and mixture types of the same species using a novel reference-free reduced representation bisulfite sequencing technique (epiGBS). Using epiGBS it is possible to conduct a comparative analysis of DNA methylation and genetic variation in a large number of sample (van Gurp et al., 2016).
Results/Conclusions
We found that twelve years of different community history could select for monoculture and mixture types. In newly assembled mixed communities, plants with a mixtures selection history performed better than plants with a monoculture selection history. Furthermore, we demonstrated that plants without community history produced the lowest aboveground biomass in both mixed communities and monocultures.
EpiGBS output classified plants within a species correctly into monoculture or mixture types based on their methylation pattern in a representative part of the genome. Our results indicate that in perennial grassland species it may be selection from epigenetic standing variation that drives the rapid emergence of monoculture and mixture types.
These novel findings indicate possible mechanisms that explain the rapid evolution of plant types adapted to their surrounding biodiversity in grasslands. Uncovering these mechanisms contributes to our understanding of the biodiversity–ecosystem functioning relationship, which has the potential to influence modern-day agricultural practice.