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Evolution on the Balkan Peninsula: Phylogeny and phylogeography of the genera Edraianthus and Heliosperma

Final Activity Report Summary - EVOBALK (Evolution on the Balkan Peninsula: Phylogeny and phylogeography of the genera Edraianthus and Heliosperma)

Numerous surveys of regional biodiversity patterns confirm that the Balkan Peninsula is indeed the hotspot of biodiversity and endemism in Europe. The Balkan flora is undoubtedly the richest in Europe, possessing not only the largest number of species of any comparable area in Europe, but also having the largest number of endemic species with an estimate of 2200 to 2500 taxa.

This is a result of number of conditions, the most important being:
(a) an old flora which have survived the Quaternary ice ages in many glacial refugia;
(b) a complex landscape with numerous geographically and ecologically highly structured and diverse areas;
(c) the spatial proximity of other floras, and
(d) an early and profound influence of Man creating new habitats and introducing species from outside the Balkan Peninsula. Strong biogeographic connections between the Balkans and Apennines exist in terms of disjunctions of many closely related taxa due to the vivid paleo-environmental past, i.e. the recurrent formation of land bridges across the Adriatic Sea. Investigations of disjunctions can provide insights into processes such as speciation, extinction, changes of distributional areas and colonisation.

The two genera Edraianthus (Campanulaceae) and Heliosperma (Caryophyllaceae) are excellent model groups for addressing such questions:
(a) What are the phylogeographical patterns of widely distributed but disjunct species? Are these disjunctions due to (ancient) range fragmentation or rather due to recent long-distance dispersal events?
(b) How deep are the major splits within widely but disjunctly distributed taxa compared to those between sister-taxa? Are there cryptic taxa to be discovered?

The main results of the project were:
(1) the genus Edraianthus (Campanulaceae) forms a monophyletic group, yet nested within Campanula (Campanulaceae);
(2) morphological (and thus taxonomic) differentiation often disagrees with the genetic differentiation as results of geographical and ecological differentiation, for instance the taxa of the Edraianthus serpyllifolius-group (among those newly described ones) or members of the Heliosperma pusillum group;
(3) different taxa responded differently to the climatic fluctuations in the Pleistocene, alpine taxa mostly by vertical movements, lowland taxa by horizontal range shifts;
(4) the Adriatic Sea did not represent a significant barrier between the Balkan and Appenine Peninsula, but instead colonisations from the Dinaric mountains towards the central Apennine Peninsula happened recurrently; the southern Apennine Peninsula was colonised from the central Appenines, without any detectable connections over the Ionian Sea; other peripheral regions (NW Dinaric mountains, Greece, Carpathians) were also colonised from the central Balkan Peninsula;
(5) floristically based hypotheses of biogeographic boundaries in the Dinaric Mts and the Balkans are only sparsely congruent with phylogenetic and phylogeographic results;
(6) speciation and intraspecific differentiation took mostly place in the Pleistocene.