Data from: Rapid buildup of genetic diversity in founder populations of the gynodioecious plant species Origanum vulgare after semi-natural grassland restoration

In most landscapes the success of habitat restoration is largely dependent
on spontaneous colonization of plant species. This colonization process,
and the outcome of restoration practices, can only be considered
successful if the genetic makeup of founding populations is not eroded
through founder effects and subsequent genetic drift. Here we used 10
microsatellite markers to investigate the genetic effects of recent
colonization of the long-lived gynodioecious species Origanum vulgare in
restored semi-natural grassland patches. We compared the genetic diversity
and differentiation of fourteen recent populations with that of thirteen
old, putative source populations, and we evaluated the effects of spatial
configuration of the populations on colonization patterns. We did not
observe decreased genetic diversity in recent populations, or inflated
genetic differentiation among them. Nevertheless, a significantly higher
inbreeding coefficient was observed in recent populations, although this
was not associated with negative fitness effects. Overall population
genetic differentiation was low (FST = 0.040). Individuals of restored
populations were assigned to on average 6.1 different source populations
(likely following the ‘migrant pool’ model). Gene flow was, however,
affected by the spatial configuration of the grasslands, with gene flow
into the recent populations mainly originating from nearby source
populations. This study demonstrates how spontaneous colonization after
habitat restoration can lead to viable populations in a relatively short
time, overcoming pronounced founder effects, when several source
populations are nearby. Restored populations can therefore rapidly act as
stepping stones and sources of genetic diversity, likely increasing
overall metapopulation viability of the study species.