Ecological and evolutionary role of a persistent soil seed bank in perennial herbaceous plant species

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Plants have developed two risk reduction mechanisms, dispersal and dormancy, to cope with the unpredictability of their habitats. Theoretical models suggest a number of specific effects of dormant seeds in a soil seed bank on plant demography, genetic structure and evolutionary biology. Thus, seed banks may increase or conserve genetic diversity and reduce population differentiation. However, empirical data on genetic relationships between seed bank and above-ground population are scarce. This project will consist of field and common garden studies. Based on information of previous own studies, it will focus on Viola elatior Fries, a perennial herb occurring along an environmental gradient from floodplain meadows to alluvial forests. The main aims are to test the hypotheses that (1) a persistent soil seed bank in a perennial plant serves as a reservoir of genotypes that are not longer present in the above-ground population, (2) variation in seed dormancy and germination in response to different selection regimes depends on the genetic diversity of the parent population and (3) that naturally and enforced germinating seeds differ in post-germination traits and fitness. We will do an AFLP genome scan to identify potentially adaptive loci in the seed bank and the above-ground population and along an environmental gradient. Additionally, we will address the question whether and how genetic diversity and differentiation of Viola elatior populations are related to the surrounding landscape structure using a landscape genetic approach based on different landscape metrics.