Reintroduction of Armeria maritima ssp. elongata by sowing and planting in a 20-year restoration project: Is there an impact on genetic variation?

Reintroduction is a frequently used method to restore populations of endangered species. However, it has hardly been tested whether there is a pronounced genetic impact resulting from different propagule types used for restoration. To address this knowledge gap, we carried out a pilot study based on a 20-years practical experiment, in which new populations of the rare and endangered herb Armeria maritima ssp. elongata were founded using seeds and/or young plants. The experiment took place in a nature reserve protecting a declining nutrient-poor sand-dune habitat. To evaluate if there was an effect of propagule type on genetic variation of restored populations, we compared populations of A. maritima ssp. elongata started by direct seeding, planting of seedlings and both seeding & planting. Using molecular markers (AFLPs), we observed slightly higher levels of genetic diversity within restored compared to the source population. Genetic diversity was comparable in populations restored by different propagules, and genetic differentiation between the source and restored populations was absent. Our study provides a first piece of evidence that both seeds and young plants can be applied successfully in population restoration projects. We suggest to further test the impact of the reintroduction methods on restoration outcomes under different experimental settings, e.g. using species with different life history traits.