High and distinct range-edge genetic diversity despite local bottlenecks. | - CCMAR -

Journal Article

TítuloHigh and distinct range-edge genetic diversity despite local bottlenecks.
Publication TypeJournal Article
AuthorsAssis, J, Coelho, NCastilho, Alberto, F, Valero, M, Raimondi, P, Reed, D, Serrão, EA
Year of Publication2013
JournalPLoS One
Volume8
Questão7
Date Published2013
Paginatione68646
ISSN1932-6203
Palavras-chaveBiodiversity, Europe, Genetic Variation, Microsatellite Repeats, Phaeophyta, Phylogeography, Population Density, Population Dynamics
Abstract

The genetic consequences of living on the edge of distributional ranges have been the subject of a largely unresolved debate. Populations occurring along persistent low latitude ranges (rear-edge) are expected to retain high and unique genetic diversity. In contrast, currently less favourable environmental conditions limiting population size at such range-edges may have caused genetic erosion that prevails over past historical effects, with potential consequences on reducing future adaptive capacity. The present study provides an empirical test of whether population declines towards a peripheral range might be reflected on decreasing diversity and increasing population isolation and differentiation. We compare population genetic differentiation and diversity with trends in abundance along a latitudinal gradient towards the peripheral distribution range of Saccorhiza polyschides, a large brown seaweed that is the main structural species of kelp forests in SW Europe. Signatures of recent bottleneck events were also evaluated to determine whether the recently recorded distributional shifts had a negative influence on effective population size. Our findings show decreasing population density and increasing spatial fragmentation and local extinctions towards the southern edge. Genetic data revealed two well supported groups with a central contact zone. As predicted, higher differentiation and signs of bottlenecks were found at the southern edge region. However, a decrease in genetic diversity associated with this pattern was not verified. Surprisingly, genetic diversity increased towards the edge despite bottlenecks and much lower densities, suggesting that extinctions and recolonizations have not strongly reduced diversity or that diversity might have been even higher there in the past, a process of shifting genetic baselines.

DOI10.1371/journal.pone.0068646
Sapientia

http://www.ncbi.nlm.nih.gov/pubmed/23967038?dopt=Abstract

Alternate JournalPLoS ONE
PubMed ID23967038
PubMed Central IDPMC3744244
CCMAR Authors