The Convention on Biological Diversity (CBD) aims at the conservation of all three levels of biodiversity, that is, ecosystems, species and genes. Genetic diversity represents evolutionary potential and is important for ecosystem functioning. Unfortunately, genetic diversity in natural populations is hardly considered in conservation strategies because it is difficult to measure and has been hypothesised to co-vary with species richness. This means that species richness is taken as a surrogate of genetic diversity in conservation planning, though their relationship has not been properly evaluated. We tested whether the genetic and species levels of biodiversity co-vary, using a large-scale and multi-species approach. We chose the high-mountain flora of the Alps and the Carpathians as study systems and demonstrate that species richness and genetic diversity are not correlated. Species richness thus cannot act as a surrogate for genetic diversity. Our results have important consequences for implementing the CBD when designing conservation strategies.

We used four potentially unlinked nuclear DNA regions from the gene family encoding the second largest subunit of the RNA polymerases, as well as the psbE-petG spacer and the rps16 intron from the chloroplast genome, to evaluate the origin of and relationships within Heliosperma (Sileneae, Caryophyllaceae). Relative dates of divergence times are used to discriminate between hybridization and gene duplication/loss as alternative explanations for topological conflicts between gene trees. The observed incongruent relationships among the three major lineages of Heliosperma are better explained by homoploid hybridization than by gene duplication/losses because species branching events exceed gene coalescence times under biologically reasonable population sizes and generation times, making lineage sorting an unlikely explanation. The origin of Heliosperma is complex and the gene trees likely reflect both reticulate evolution and sorting events. At least two lineages have been involved in the origin of Heliosperma, one most closely related to the ancestor of Viscaria and Atocion and the other to Eudianthe and/or Petrocoptis.

The leafy spurges, Euphorbia subg. Esula, make up one of four main lineages in Euphorbia. The subgenus comprises about 480 species, most of which are annual or perennial herbs, but with a small number of dendroid shrubs and nearly leafless, pencil–stemmed succulents as well. The subgenus constitutes the primary northern temperate radiation in Euphorbia. While the subgenus is most diverse from central Asia to the Mediterranean region, members of the group also occur in Africa, in the Indo–Pacific region, and in the New World. We have assembled the largest worldwide sampling of the group to date (273 spp.), representing most of the taxonomic and geographic breadth of the subgenus. We performed phylogenetic analyses of sequence data from the nuclear ribosomal ITS and plastid ndhF regions. Our individual and combined analyses produced well–resolved phylogenies that confirm many of the previously recognized clades and also establish a number of novel groupings and placements of previously enigmatic species. Euphorbia subg. Esula has a clear Eurasian center of diversity, and we provide evidence for four independent arrivals to the New World and three separate colonizations of tropical and southern Africa. One of the latter groups further extends to Madagascar and New Zealand, and to more isolated islands such as Réunion and Samoa. Our results confirm that the dendroid shrub and stem–succulent growth forms are derived conditions in E. subg. Esula. Stem–succulents arose twice in the subgenus and dendroid shrubs three times. Based on the molecular phylogeny, we propose a new classification for E. subg. Esula that recognizes 21 sections (four of them newly described and two elevated from subsectional rank), and we place over 95% of the accepted species in the subgenus into this new classification.

Summary The mosaic distribution of interbreeding taxa with contrasting ecology and morphology offers an opportunity to study microevolutionary dynamics during ecological divergence. We investigate here the evolutionary history of an alpine and a montane ecotype of Heliosperma pusillum (Caryophyllaceae) in the south‐eastern Alps.From six pairs of geographically close populations of the two ecotypes (120 individuals) we obtained a high‐coverage restriction site associated DNA sequencing (RADseq) dataset that was used for demographic inference to test the hypothesis of parallel evolution of the two ecotypes.The data are consistent with repeated ecological divergence in H. pusillum, uncovering up to five polytopic origins of one ecotype from the other. A complex evolutionary history is evidenced, with local isolation‐with‐migration in two population pairs and intra‐ecotype migration in two others. In all cases, the time of divergence or secondary contact was inferred as postglacial. A metagenomic analysis on exogenous contaminant RAD sequences suggests divergent microbial communities between the ecotypes.The lack of shared genomic regions of high divergence across population pairs illustrates the action of drift and/or local selection in shaping genetic divergence across repeated cases of ecological divergence.

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The European steppes and their biota have been hypothesized to be either young remnants of the Pleistocene steppe belt or, alternatively, to represent relicts of long-term persisting populations; both scenarios directly bear on nature conservation priorities. Here, we evaluate the conservation value of threatened disjunct steppic grassland habitats in Europe in the context of the Eurasian steppe biome. We use genomic data and ecological niche modelling to assess pre-defined, biome-specific criteria for three plant and three arthropod species. We show that the evolutionary history of Eurasian steppe biota is strikingly congruent across species. The biota of European steppe outposts were long-term isolated from the Asian steppes, and European steppes emerged as disproportionally conservation relevant, harbouring regionally endemic genetic lineages, large genetic diversity, and a mosaic of stable refugia. We emphasize that conserving what is left of Europe's steppes is crucial for conserving the biological diversity of the entire Eurasian steppe biome.

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The evolution of species or ecotypes can occur gradually through neutral and adaptive genetic changes. To explore the influence of natural selection during early phases of divergence, morphological and ecological discontinuity and its adaptive significance were investigated in six pairs of alpine and independently evolved montane populations of Heliosperma pusillum s.l.; the latter are usually taxonomically recognised at the species rank in spite of their highly debatable taxonomic value. We tested whether environmental conditions – characterised by Landolt indicator values from vegetation surveys and temperature measurements – and morphology of alpine and montane populations differ discretely and in parallel across six population pairs. By reciprocal transplantation experiments in natural environments in two population pairs and in climate chambers for five population pairs we compared fitness of native versus non‐native individuals. Alpine and montane populations differed in environmental conditions and morphology within each pair. Morphological differentiation occurred in parallel and correlated with environmental, but not with genetic distances. In both environments, native individuals had higher establishment success and plant size. Differentiation of the independently evolved montane populations is driven by natural selection and parallel, independent adaptation in response to drought, lower irradiance and higher, less fluctuating temperatures in montane populations. Our study system exemplifies rapid, parallel evolution leading to morphologically and ecologically strongly divergent, though fully interfertile, ecotypes.