e-journal

Phylogeography sheds light on the central–marginal hypothesis in a Mediterranean narrow endemic plant

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† Background and Aims:
Understanding the factors that shape variation in genetic diversity across the geographic ranges of species is an important challenge in the effort to conserve evolutionary processes sustaining biodiversity. The historical influences leading to a central–marginal organization of genetic diversity have been explored
for species whose range is known to have expanded from refugia after glacial events. However, this question
has rarely been addressed for Mediterranean endemic plants of azonal habitats such as rocky slopes or screes.
In this context, this comprehensive study examined molecular and field data from Arenaria provincialis
(Caryophyllaceae), a narrow endemic plant of south-eastern France.

† Methods:
Across the whole geographic range, an investigation was made of whether high levels of abundance and genetic diversity (estimated from amplified fragment length polymorphism markers) are centrally distributed, to
evaluate the relevance of the central–marginal hypothesis. Phylogeographic patterns inferred from chloroplast
DNA (cpDNA) were used, applying Bayesian methods to test the influence of past biogeographic events.
Multivariate analysis combining phylogeographic and ecological datawas used to reveal the historical and ecological distinctiveness of populations.

† Key Results:
Despite the narrow distribution of A. provincialis, a high level of nucleotide variation is found within
cpDNA loci, supporting its persistence throughout the Pleistocene period. The area characterized by the highest genetic diversity is centrally located. Structured phylogeography and Bayesian factor analysis supported the hypothesis that the central area of the distribution was the source of both west ward and eastward migrations, probably during arid periods of the Pleistocene, and more recentlywas a crossroads of backward migrations. By contrast, the two areas located today at the range limits are younger, have reduced genetic diversity and are marginal in the ecological gradients.

†Conclusions:
This study highlights a case of strong population distinctiveness within a narrow range. Phylogeography sheds light on the historical role of the areas centrally situated in the distribution. The current range size and abundance patterns are not sufficient to predict the organization of genetic diversity.

Key words: Arenaria provincialis, Caryophyllaceae, central–marginal hypothesis, genetic diversity, geographic
range, ecological niche, Pleistocene, Provence, conservation, migration, population distinctiveness.

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Informasi Detail

Judul Seri

Annals of Botany

No. Panggil

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Penerbit

Oxford : Oxford University Press on behalf of the Annals of Botany Company., 2013

Deskripsi Fisik

Annals of Botany 112: 1409–1420, 2013

Bahasa

English

ISBN/ISSN

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Klasifikasi

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Tipe Isi

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Tipe Media

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Tipe Pembawa

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Edisi

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Subjek

PERSEBARAN TANAMAN

Info Detail Spesifik

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Pernyataan Tanggungjawab

agus

Versi lain/terkait

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