Genetic and fitness consequences of using wildflower seed mixtures in ecological restoration

Wildflower seed mixtures are widely used for restoration in areas with impoverished species pools. However, the genetic and fitness consequences of using seed mixtures are often not considered in practical restoration. We studied the genetic characteristics of sown and naturally occurring populations of the grassland plant Lychnis flos-cuculi in an agricultural landscape in the Oberaargau region in Switzerland. Furthermore, we examined various fitness parameters of these populations, and carried out experiments in the study area, in an experimental garden and in climate chambers, in order to study the effect of genetic diversity, origin and environmental conditions on the viability of plants. Sown and natural populations were characterized by similar genetic diversity. Inbreeding coefficients, by contrast, were significantly higher in sown populations. Sown populations were genetically different from natural populations. Experiments revealed that plants originating from sown populations and from seed companies were less likely to produce flowers and tended to flower later than plants from natural populations. We conclude that there was no substantial influence of origin and genetic diversity on plant fitness. However, seed mixtures used for restoration should originate from genetically diverse sources to avoid potential negative consequences for fitness. Wherever possible, natural recolonization should be favoured.