High levels of effective long-distance dispersal may blur ecotypic divergence in a rare terrestrial orchid.
BMC Ecol
; 14: 20, 2014 Jul 07.
Article
in En
| MEDLINE
| ID: mdl-24998243
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.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Genetic Variation
/
Orchidaceae
/
Gene Flow
/
Seed Dispersal
/
Ecotype
Type of study:
Prognostic_studies
Country/Region as subject:
Europa
Language:
En
Journal:
BMC Ecol
Journal subject:
SAUDE AMBIENTAL
Year:
2014
Type:
Article
Affiliation country:
Belgium