Does seed trait variability support preliminary seed transfer zones for Hungary?

Abstract

Maladaptation of populations can lead to a failed restoration when seeds are transferred to non-local target sites. Seed transfer zones (STZs) can guide transfer for restoration practices. In a previous study, we delineated STZs for Hungary based on biogeographic maps and potential natural vegetation models. The present aims were to compare the STZ with the pattern of seed trait variability of sand grasslands species (Festuca vaginata, Stipa borysthenica, Dianthus serotinus and Centaurea arenaria) from 34 localities. We assessed the effect of location as well as geographical, ecological, and environmental distances between locations on seed mass, germination, and emergence in a common garden. We detected that seed trait differentiation between the populations is a signal of local adaptation or phenotypic plasticity. Geographical distance did not affect the variability of seed traits, except on the emergence of C. arenaria. Ecological distance reflected in STZ delineation also did not explain seed trait variability except for the seed mass of C. arenaria. Aridity had a significant effect on the germination or emergence of the two forbs, but not on the grasses. In conclusion, we do not suggest restricting seed transfer among the populations over the sampled area. Further studies might complement these findings and lead to more general conclusions.