Abstract

Aim Mediterranean refugial areas are generally underrepresented in large-scalegenetic surveys of forest trees. In the case of silver fir (Abies alba Mill.), thishas led to divergent hypotheses about the exact location of glacial refugia andthe trajectory of recolonization routes. Based on the comprehensive samplingof Apennine populations, we aimed to reconcile discrepancies about the numberand location of refugia for silver fir in the Apennines and test alternativedemographic scenarios developed from palaeobotanical and genetic data.Location Mediterranean Basin; the Apennines and surrounding areas.Methods 1167 individuals from 16 Apennine populations, extensively coveringthe species' distribution along the Italian Peninsula, and eight populationsfrom the Alps and Eastern Europe were genotyped at 16 nuclear and threechloroplast microsatellite markers. The geographical distribution of geneticvariation was explored using Bayesian clustering and multivariate methods.Based on the inferred genetic structure, the demographic history of A. alba wasassessed by the approximate Bayesian computation (ABC) analysis.Results Two unexpected characteristics of genetic structure emerged: a sharpgenetic boundary in the central Apennines and a tight genetic connectionbetween southern Apennine and Eastern European gene pools. Two Apennineareas, corresponding precisely with refugial areas hypothesized in most recentpalaeobotanical syntheses, have high genetic diversity on a par with EasternEuropean populations. ABC analysis showed an ancient separation betweenApennine and Eastern European gene pools followed by an admixture eventthat, mainly through directional gene flow via pollen, might have establishedthe genetic similarity between southern Apennine and Eastern European populations.In addition, there was evidence that the central Apennines acted as asmall-scale, isolated refugium during the Last Glacial Maximum.Main conclusions Silver fir rear edge populations have experienced a complexdemographic history across several glacial-interglacial cycles, leading tounexpected genetic structure. Our study provides new insights into forest treedynamics in the Mediterranean, showing the putative presence of multiplerefugia for silver fir in the Apennines and a trans-Adriatic connection betweensilver fir populations in the southern Italy and the Balkans.

Autore Pugliese

• Vendramin Giovanni Giuseppe

Tutti gli autori

• A. Piotti ; C. Leonarduzzi; D. Postolache F. Bagnoli; I. Spanu; L. Brousseau; C.Urbinati;S. Leonardi; G.G. Vendramin

Titolo volume/Rivista

Journal of biogeography

Anno di pubblicazione

2017

ISSN

0305-0270

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

Ultimo Aggiornamento Citazioni

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Numero di citazioni Scopus

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Ultimo Aggiornamento Citazioni

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Settori ERC

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Codici ASJC

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