Genetic consequences of long-term isolation for the last French population of Eryngium viviparum (Apiaceae)

Abstract

Eryngium viviparum (Apiaceae) is an endangered endemic plant of the Atlantic region of Europe, growing in seasonally flooded sites, and is characterized by a highly disjunct distribution. It occurs in just a few sites in the north-western part of the Iberian Peninsula and in a single locality in France. To improve the conservation status of E. viviparum in France, a conservation programme has been implemented to reintroduce the species. Before considering such an operation, genetic studies were conducted to determine the genetic status of the last French population and to identify the genetic source that should be considered for the best reintroduction strategy. Using microsatellite markers, we documented the genetic structure of the last French population and compared its genetic diversity with that of ten Iberian populations, which cover the three geographical regions where the species occurs. As expected, the French population of E. viviparum shows low genetic diversity due to a bottleneck and geographical isolation. The evolutionary potential appears low, with no private alleles in this population. Furthermore, this population is highly differentiated from the Iberian populations in terms of genetic variation and ecological niche. These results bring new questions regarding the conservation of E. viviparum in France, especially for management and reintroduction aimed at favouring genetic diversity and avoiding extinction.