Coalescent and biophysical models of stepping-stone gene flow in neritid snails

Crandall, Eric D., Treml, Eric A. and Barber, Paul H. (2012) Coalescent and biophysical models of stepping-stone gene flow in neritid snails. Molecular Ecology, 21 22: 5579-5598. doi:10.1111/mec.12031

Author Crandall, Eric D.
Treml, Eric A.
Barber, Paul H.
Title Coalescent and biophysical models of stepping-stone gene flow in neritid snails
Journal name Molecular Ecology   Check publisher's open access policy
ISSN 0962-1083
Publication date 2012-11
Sub-type Article (original research)
DOI 10.1111/mec.12031
Volume 21
Issue 22
Start page 5579
End page 5598
Total pages 20
Place of publication Oxford, United Kingdom
Publisher Wiley-Blackwell Publishing
Collection year 2013
Language eng
Abstract Marine species in the Indo-Pacific have ranges that can span thousands of kilometres, yet studies increasingly suggest that mean larval dispersal distances are less than historically assumed. Gene flow across these ranges must therefore rely to some extent on larval dispersal among intermediate ‘stepping-stone’ populations in combination with long-distance dispersal far beyond the mean of the dispersal kernel. We evaluate the strength of stepping-stone dynamics by employing a spatially explicit biophysical model of larval dispersal in the tropical Pacific to construct hypotheses for dispersal pathways. We evaluate these hypotheses with coalescent models of gene flow among high-island archipelagos in four neritid gastropod species. Two of the species live in the marine intertidal, while the other two are amphidromous, living in fresh water but retaining pelagic dispersal. Dispersal pathways predicted by the biophysical model were strongly favoured in 16 of 18 tests against alternate hypotheses. In regions where connectivity among high-island archipelagos was predicted as direct, there was no difference in gene flow between marine and amphidromous species. In regions where connectivity was predicted through stepping-stone atolls only accessible to marine species, gene flow estimates between high-island archipelagos were significantly higher in marine species. Moreover, one of the marine species showed a significant pattern of isolation by distance consistent with stepping-stone dynamics. While our results support stepping-stone dynamics in Indo-Pacific species, we also see evidence for nonequilibrium processes such as range expansions or rare long-distance dispersal events. This study couples population genetic and biophysical models to help to shed light on larval dispersal pathways.
Keyword Amphidromy
Habitat preference
Isolation by distance
Model selection
South Pacific
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2013 Collection
School of Biological Sciences Publications
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Created: Wed, 05 Dec 2012, 10:32:18 EST by Dr Eric Treml on behalf of School of Biological Sciences