Impact of life history traits on gene flow: A multispecies systematic review across oceanographic barriers in the Mediterranean Sea

Marta Pascual,Borja Rives,Celia Schunter,Enrique Macpherson,Tzen-Yuh Chiang

doi:10.1371/journal.pone.0176419

Abstract

BackgroundMarine species can demonstrate strong genetic differentiation and population structure despite the hypothesis of open seas and high connectivity. Some suggested drivers causing the genetic breaks are oceanographic barriers and the species’ biology. We assessed the relevance of seven major oceanographic fronts on species connectivity while considering their dispersal capacity and life strategy.MethodsWe systematically reviewed the scientific articles reporting population genetic differentiation along the Mediterranean Sea and across the Atlantic-Mediterranean transition. We retained those considering at least one sampling locality at each side of an oceanographic front, and at least two localities with no-front between them to correctly assess the effect of the front. To estimate the impact of life history characteristics affecting connectivity we considered the planktonic larval duration (PLD) and adult life strategy.ResultsOceanographic barriers in the Mediterranean Sea seem to reduce gene flow globally; however, this effect is not homogeneous considering the life history traits of the species. The effect of the oceanographic fronts reduces gene flow in highly mobile species with PLD larger than 2–4 weeks. Benthic sessile species and/or with short PLD (< 2 weeks) have more significant genetic breaks between localities than species with higher motility; however, genetic differentiation occurs independently of the presence of a front.ConclusionGenetic connectivity is important for populations to recover from anthropogenic or natural impacts. We show that species with low mobility, mostly habitat-formers, have high genetic differentiation but low gene flow reduction mediated by the front, therefore, considering the importance of these species, we emphasize the vulnerability of the Mediterranean ecosystems and the necessity of protection strategies based on the whole ecosystem.

Highlights

The Mediterranean Sea displays one of the world’s richest diversity [1]
We show that species with low mobility, mostly habitat-formers, have high genetic differentiation but low gene flow reduction mediated by the front, considering the importance of these species, we emphasize the vulnerability of the Mediterranean ecosystems and the necessity of protection strategies based on the whole ecosystem
We evaluated the impact of life history traits (PLD, life strategy (LIFE) strategy and the two of them combined to integrate the whole life-history) on the connectivity reduction mediated by fronts using Wilcoxon matched pairs tests (Table 1)

Summary

Introduction

The Mediterranean Sea displays one of the world’s richest diversity [1]. This basin contains more than 20,000 species of fish, cetaceans, invertebrates, sea turtles, algae and seaweeds, with a large proportion of endemism (ca. 20%). The Mediterranean Sea displays one of the world’s richest diversity [1] This basin contains more than 20,000 species of fish, cetaceans, invertebrates, sea turtles, algae and seaweeds, with a large proportion of endemism Modelling studies have indicated the great importance of spatial configurations of MPAs and stock identification units to promote population and ecosystem persistence [4,5]. Marine species can demonstrate strong genetic differentiation and population structure despite the hypothesis of open seas and high connectivity. We assessed the relevance of seven major oceanographic fronts on species connectivity while considering their dispersal capacity and life strategy

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