Populations restored using regional seed are genetically diverse and similar to natural populations in the region.
Abstract
Ecological restoration and plant re-introductions aim to create plant populations that are genetically similar to natural populations to preserve the regional gene pool, yet genetically diverse to allow adaptation to a changing environment. For this purpose, seeds for restoration are increasingly sourced from multiple populations in the target region. However, it has only rarely been tested whether using regional seed indeed leads to genetically diverse restored populations which are genetically similar to natural populations. We used single nucleotide polymorphism (SNP) markers to investigate genetic diversity within and differentiation among populations of Centaurea jacea and Betonica officinalis on restored and natural meadows in the White Carpathians, Czech Republic. The restoration took place 20 years ago using regional seeds propagated from a mix of multiple regional source populations. We included original regional seeds in our analysis to compare the restored populations with their origin (only in C. jacea). Additionally, we analysed conventional seeds without certified origin because these would have constituted a common alternative for restoration seeding in the absence of regional seeds. The differentiation between restored and natural populations (mean pairwise FST = 0.018 in Centaurea and 0.021 in Betonica) was similar to the differentiation among natural populations (FST = 0.023 and 0.021), and the restored populations were slightly more genetically diverse than the natural populations. In addition, restored populations were relatively similar to their origin, the regional seeds (FST = 0.015). In contrast, conventional seeds were strongly differentiated from all regional populations (FST = 0.100 and 0.059, in Centaurea and Betonica respectively) and harboured substantially lower genetic diversity. We also found signs of gene flow via pollen or seed dispersal from natural to restored populations but not vice versa. Policy implications. Regionally sourced seeds can produce genetically diverse populations at natural levels of genetic differentiation.