Effect of seed origin on vegetative and floral performances of plants reintroduced into the wild

Translocation of rare plant species to their original habitat is an increasingly used conservation approach around the world. However, we lack information on the factors affecting translocation outcomes. Research on the influence of seed provenance on plant fitness is limited in the context of translocations using plug plants. This study aims at exploring the effect of seed origin on vegetative and floral performances of three species (Arnica montana L., Campanula glomerata L. and Helichrysum arenarium (L.) Moench) in eight populations (of 500 to 700 individuals each from two to five different origins) translocated in Belgium. We recorded for 4 to 8 years the survival of each plant, its fertility, the length of the longest flower stem or rosette diameter (depending on the species), the number of flower stems and the number of flowers (or flower heads) per flower stem. The results show that the origin of the seeds significantly impacted the three species studied for at least three performance variables, but no origin was superior to the others in all the measured variables. A combined effect of seed origin, site and year has also been observed. The seed origin effect persisted over the years, suggesting that this factor is at least as important as habitat suitability or environmental stochasticity. These results show the importance of the choice of the source population in the context of translocations and strongly support a multisource and multisite approach for future translocations of threatened species.