Data from: Historical divergence versus contemporary gene flow: evolutionary history of the calcicole Ranunculus alpestris group (Ranunculaceae) in the European Alps and the Carpathians

Although many species have similar total distributional ranges, they might
be restricted to very different habitats and might have different
phylogeographic histories. In the European Alps, our excellent knowledge
of the evolutionary history of silicate-dwelling plants is contrasted by a
virtual lack of data from limestone-dwelling plants. These two categories
are expected to differ strongly with respect to their glacial history. The
calcicole Ranunculus alpestris group comprises three diploid species of
alpine habitats. Analyses of AFLP fingerprints and matK sequences gave
incongruent results, indicative for reticulate evolution. Our data
highlight historical episodes of range fragmentation and expansion,
occasional long distance dispersal and on-going gene flow as important
processes shaping the genetic structure of the group. Genetic divergence
seems a better indicator of historical processes than patterns of genetic
diversity, which rather mirror contemporary processes as connectivity of
populations and population sizes. Three phylogeographical subgroups have
been found within the R. alpestris group, neither following taxonomy nor
geography. Genetic heterogeneity in the Southern Alps contrasts with
Northern Alpine uniformity. The Carpathians have been stepwise colonised
from the Eastern Alpine lineage resulting in a marked diversity loss in
the Southern Carpathians. The main divergence within the group, separating
the ancestor of the two endemic species from R. alpestris s. str.,
predates the Quaternary. Therefore, range shifts produced by paleoclimatic
oscillations seem to have acted on the genetic structure of R. alpestris
group on a more regional level, e.g. triggering an allopatric separation
of R. traunfellneri from R. bilobus.