Genetic variation of Viola calaminaria, an endemic metallophyte

The zinc violet, Viola calaminaria (DC) Lej., is a rare threatened species in Belgium which is endemic to metalliferous sites. Yours aims were to assess the genetic structure of the species at the scale of its distribution range, including differentiation with related taxa Viola guesphalica and to examine the influence of population size and recent colonisation events on population genetic structure in order to identify conservation priorities.
The analysis of genetic variation (Amova) showed a strong population differentiation (Fst = 0.26) with a regional group differentiation. The V. guestfalica population exhibits the larger differentiation (Fst = 0.19). The levels of population genetic diversity (Hs) varied from 0.21 to 0.29. Mean genetic differentiation among ancient populations (Fst =0.26) is higher than genetic differentiation among recent populations (Fst =0.18) while any difference appears on genetic diversity.
This strong population differentiation suggests a low gene flow between populations but sufficient within population to maintain high level of diversity. For management, the result implies a hierarchical conservation strategy including small population. New populations had as much genetically importance than old populations.
No foundation effects were detected in the recent populations. These populations probably result from multiple colonization effects from more than one source population.
Finally, even if some V. calaminaria populations exhibit a similar level of genetic differentiation of V. guestfalica population, this one appeared as a particular genetic pool.