Recent similarity in distribution ranges does not mean a similar postglacial history: a phylogeographical study of the boreal tree species Alnus incana based on microsatellite and chloroplast DNA variation

Abstract

SummaryWe reconstructed the historical pattern of postglacial biogeographic range expansion of the boreal tree species Alnus incana in Europe.To assess population genetic structure and diversity, we performed a combined analysis of nuclear microsatellite loci and chloroplast DNA sequences (65 populations, 1004 individuals).Analysis of haplotype and microsatellite diversity revealed that southeastern refugial populations situated in the Carpathians and the Balkan Peninsula did not spread north and cannot be considered as important source populations for postglacial recolonization of Europe; populations in Eastern Europe did not establish Fennoscandian populations; populations in Fennoscandia and Eastern Europe have no unique genetic cluster, but represent a mix with a predominant cluster typical for Central Europe; and that colonization of Fennoscandia and Eastern Europe took place from Central Europe.Our findings highlight the importance of an effective refugium in Central Europe located outside classical southern refugia confirming the existence of northern refugia for boreal trees in Europe. The postglacial range expansion of A. incana did not follow the model established for Picea abies. Fennoscandian populations are not derived from Eastern European ones, but from Central European ones.

Raznolikost i strukturiranost hrvatskih kontinentalnih i alpsko-dinarskih populacija bijele johe (Alnus incana /L./ Moench subsp. incana); geografska i okolišna izolacija kao uzrok fenotipske divergencije

“…However, we cannot exclude the possibility that adaptive differentiation and historical migration processes acted in combination to produce the observed pattern of morphological variation in the studied populations (Temunović et al 2012;DeWoody et al 2015). Although the main refugium during the last glacial period was located in Central Europe (Huntley and Birks 1983;Douda et al 2014;Mandák et al 2016), A. incana probably survived in situ in river canyons and protected valleys along the north-western Dinaric Alps, while north-eastern populations from the continental biogeographical region could represent newly colonised populations from the refugium in Central Europe.…”

“…The distribution of subsp. incana in the southern part of the range is linked with a patchy mountain occurrence (in the Alps, the northern Apennines, the Hercynian mountains, the Carpathians, the Bulgarian mountains, the Dinaric Alps, the Caucasus, and mountains in Turkey) and continues eastward across European Russia to western Siberia (Mandák et al 2016). Grey alder is represented by two subspecies in North America: subsp.…”

“…incana (hereafter Alnus incana), family Betulaceae, is a diploid (2n = 2x = 28), monoecious and wind-pollinated, relatively short-lived, small to medium-sized deciduous tree (Tallantire 1974;Mandák et al 2016;Vít et al 2017). It is a light-demanding, hygromesophilous species which tolerates low winter temperatures.…”

“…Microsatellite primers specific for the A. glutinosa (L.) Gaertn and A. incana, developed by Lepais and Bacles (2011), were used to evaluate the population genetic structure and diversity of 65 populations, and to reconstruct the historical pattern of postglacial biogeographical range expansion of the boreal tree species A. incana in Europe (Mandák et al 2016). Furthermore, genetic diversity and clonal structure of 24 populations covering the Central European part of the species range from the Scandinavian Peninsula to the Balkans were analysed utilizing four nuclear microsatellite markers (Dering et al 2016).…”

Could clonality contribute to the northern survival of grey alder [Alnus incana (L.) Moench] during the Last Glacial Maximum?

“…Palaeobotanical studies on the genus Alnus support the idea of northern refugia formed by the species [14]. Recent reconstruction of the postglacial history of grey alder made with genetic markers indicated that the species was able to survive beyond the classic southern refugia in areas of Central Europe [15]. Those populations were the main source for subsequent colonization of Fennoscandia and Eastern Europe.…”