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High levels of effective long-distance dispersal may blur ecotypic divergence in a rare terrestrial orchid.

ABSTRACT: BACKGROUND: Gene flow and adaptive divergence are key aspects of metapopulation dynamics and ecological speciation. Long-distance dispersal is hard to detect and few studies estimate dispersal in combination with adaptive divergence. The aim of this study was to investigate effective long-distance dispersal and adaptive divergence in the fen orchid (Liparis loeselii (L.) Rich.). We used amplified fragment length polymorphism (AFLP)-based assignment tests to quantify effective long-distance dispersal at two different regions in Northwest Europe. In addition, genomic divergence between fen orchid populations occupying two distinguishable habitats, wet dune slacks and alkaline fens, was investigated by a genome scan approach at different spatial scales (continental, landscape and regional) and based on 451 AFLP loci. RESULTS: We expected that different habitats would contribute to strong divergence and restricted gene flow resulting in isolation-by-adaptation. Instead, we found remarkably high levels of effective long-distance seed dispersal and low levels of adaptive divergence. At least 15% of the assigned individuals likely originated from among-population dispersal events with dispersal distances up to 220 km. Six (1.3%) 'outlier' loci, potentially reflecting local adaptation to habitat-type, were identified with high statistical support. Of these, only one (0.22%) was a replicated outlier in multiple independent dune-fen population comparisons and thus possibly reflecting truly parallel divergence. Signals of adaptation in response to habitat type were most evident at the scale of individual populations. CONCLUSIONS: The findings of this study suggest that the homogenizing effect of effective long-distance seed dispersal may overwhelm divergent selection associated to habitat type in fen orchids in Northwest Europe.

SUBMITTER: Vanden Broeck A

PROVIDER: S-EPMC4099500 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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High levels of effective long-distance dispersal may blur ecotypic divergence in a rare terrestrial orchid.

Vanden Broeck An A Van Landuyt Wouter W Cox Karen K De Bruyn Luc L Gyselings Ralf R Oostermeijer Gerard G Valentin Bertille B Bozic Gregor G Dolinar Branko B Illyés Zoltán Z Mergeay Joachim J

BMC ecology 20140707

<h4>Background</h4>Gene flow and adaptive divergence are key aspects of metapopulation dynamics and ecological speciation. Long-distance dispersal is hard to detect and few studies estimate dispersal in combination with adaptive divergence. The aim of this study was to investigate effective long-distance dispersal and adaptive divergence in the fen orchid (Liparis loeselii (L.) Rich.). We used amplified fragment length polymorphism (AFLP)-based assignment tests to quantify effective long-distanc ...[more]

PMID: 24998243

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High levels of effective long-distance dispersal may blur ecotypic divergence in a rare terrestrial orchid.

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High levels of effective long-distance dispersal may blur ecotypic divergence in a rare terrestrial orchid.

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