Genetic structure and diversity in carnations of Dianthus plumarius subsp. blandus in the eastern Alps

Knowledge on the habitats, life history traits and genetic structure of rare and possibly endangered species is fundamental for the conservation of biodiversity. Especially rare taxa with fragmented and isolated populations, like the narrow endemic Dianthus plumarius subsp. blandus thriving on open habitats over stabilised scree, are expected to suffer from loss of genetic diversity and increasing differentiation between the populations due to genetic drift. This study aims at resolving the genetic structure within and among the populations of this taxon in the Gesäuse Mts. (Austria) and two adjacent regions. Using Amplified Fragment Length Polymorphism (AFLP) we found moderate genetic differentiation between the regions and between the Gesause populations with one exception showing higher differentiation to all others. While in general landscape features were of low importance we found that a broad stream of mobile screee provided a substantial barrier to gene flow between two subpopulations despite spatial proximity. Patterns of genetic diversity were not related to population size and habitat features. Based on earlier demographic studies on these populations we discuss reproductive features and last but not least human impact in provoking the idiosyncratic patterns we have observed.