Unique postglacial evolution of the hornbeam (Carpinus betulus L.) in the Carpathians and the Balkan Peninsula revealed by chloroplast DNA Dragoş Postolache a , Flaviu Popescu b, ⁎, Ladislav Paule c , Dalibor Ballian d,e , Peter Zhelev f , Sorina Fărcaş g , Juraj Paule h , Ovidiu Badea i,j a National Institute for Research and Development in Forestry “Marin Drăcea”, Cluj-Napoca Research Station, 400275 Cluj-Napoca, Romania b National Institute for Research and Development in Forestry “Marin Drăcea”, Simeria Research Station, 335900 Simeria, Romania c Faculty of Forestry, Technical University in Zvolen, 96053 Zvolen, Slovakia d Faculty of Forestry, University of Sarajevo, 71000 Sarajevo, Bosnia and Herzegovina e Slovenian Forest Institute, 1000 Ljubljana, Slovenia f University of Forestry, 1797 Sofia, Bulgaria g National Institute of Research and Development for Biological Sciences – Institute of Biological Research, 400015 Cluj-Napoca, Romania h Department Botany and Molecular Evolution, Senckenberg Research Institute and Natural History Museum, 60325 Frankfurt/Main, Germany i National Institute for Research and Development in Forestry “Marin Drăcea”, 077190 Voluntari, Ilfov, Romania j Transilvania University of Braşov, Faculty of Silviculture and Forest Engineering, 500123 Braşov, Romania HIGHLIGHTS • Refugia within refugia pattern revealed in Carpinus betulus • Three distinct effective glacial refugia found in the Balkan Peninsula • Inference of three postglacial re- colonization routes from effective refugia • A “suture zone” observed in the Ukraini- an Carpathians GRAPHICAL ABSTRACT abstract article info Article history: Received 27 February 2017 Received in revised form 5 May 2017 Accepted 6 May 2017 Available online xxxx Editor: Elena Paoletti The Balkan Peninsula is one of the largest and most important European glacial refugia. However, the evolution- ary history and phylogeographic pattern of temperate tree species that survived in the Balkans glacial refugia and their contribution to the genetic structure of the current population in the Carpathian Mountains remains poorly understood. Using polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP), and extensive popula- tion sampling, we explored the phylogeographic pattern of Carpinus betulus in both the Balkan Peninsula and the Carpathian region. We aimed to determine the locations of potential glacial refugia, in order to delineate post- glacial colonization routes, and also to test if northern cryptic refugia had persisted during the Last Glacial Max- imum (LGM). Our results provide strong support for the existence of multiple refugia similar to the ‘refugia-within-refugia’ sce- nario, which would suggest that Carpinus betulus has experienced a complex evolutionary history. Keywords: cpDNA Genetic diversity Hornbeam forests Science of the Total Environment 599–600 (2017) 1493–1502 ⁎ Corresponding author. E-mail address: flaviu.popescu@icashd.ro (F. Popescu). http://dx.doi.org/10.1016/j.scitotenv.2017.05.062 0048-9697/© 2017 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv