Phylogeography of xerothermic Carlina acanthifolia subsp. utzka in Central Europe

Abstract

Phylogeographic studies of grassland plants with broad Eurasian ranges point to the importance of northern refuges in shaping genetic patterns in populations across species distribution ranges in Central Europe. Carlina acanthifolia subsp. utzka is a common inhabitant of xerothermic sites in Central European dry grasslands. The aim of this study was to test hypotheses regarding some of the main phylogeographical patterns proposed for European grassland plants, in particular the locations of glacial refugia, the re-colonization routes, and genetic affinities between Southern, Eastern and Central European populations. We analyzed the genetic diversity of Carlina acanthifolia subsp. utzka based on distribution-wide sampling of 39 populations (Southern, Central and Eastern Europe) and compiled data obtained using different markers (AFLP, cpDNA, ETS region). The results for AFLP and the ETS region split the populations into two groups: from Central and Eastern Europe with the northern part of the Balkan Peninsula; and from its southern part. The segregation visible both in the distribution of particular haplotypes and in the variation level of the southern group of populations (AFLP) points to local processes that were taking place independently in the northern and the southern parts of the range. Populations from the southern part of the range have likely served as the core of the Central European part during their colonization, while re-colonization of glacial areas in Central Europe took place from local refugia in the central and western parts of Eastern Europe. The southern areas did not participate in this process. The observed variation of the frequency of haplotypes indicates that Eastern Europe populations dominant in the northern Balkan Peninsula got in contact with those from Central Europe. On the other hand, the presence of a separate line of haplotypes and ribotypes in populations from the southern part of the Balkan Peninsula indicates the absence of continuous connectivity of these areas with disjunct areas in Central Europe.