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Genetic Connectivity of the Moth Pollinated Tree Glionnetia sericea in a Highly Fragmented Habitat

Long-distance gene flow is thought to be one prerequisite for the persistence of plant species in fragmented environments. Human influences have led to severe fragmentation of native habitats in the Seychelles islands, with many species surviving only in small and isolated populations. The endangere...

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Autores principales: Finger, Aline, Kaiser-Bunbury, Christopher N., Kettle, Chris J., Valentin, Terence, Ghazoul, Jaboury
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4210268/
https://www.ncbi.nlm.nih.gov/pubmed/25347541
http://dx.doi.org/10.1371/journal.pone.0111111
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author Finger, Aline
Kaiser-Bunbury, Christopher N.
Kettle, Chris J.
Valentin, Terence
Ghazoul, Jaboury
author_facet Finger, Aline
Kaiser-Bunbury, Christopher N.
Kettle, Chris J.
Valentin, Terence
Ghazoul, Jaboury
author_sort Finger, Aline
collection PubMed
description Long-distance gene flow is thought to be one prerequisite for the persistence of plant species in fragmented environments. Human influences have led to severe fragmentation of native habitats in the Seychelles islands, with many species surviving only in small and isolated populations. The endangered Seychelles endemic tree Glionnetia sericea is restricted to altitudes between 450 m and 900 m where the native forest vegetation has been largely lost and replaced with exotic invasives over the last 200 years. This study explores the genetic and ecological consequences of population fragmentation in this species by analysing patterns of genetic diversity in a sample of adults, juveniles and seeds, and by using controlled pollination experiments. Our results show no decrease in genetic diversity and no increase in genetic structuring from adult to juvenile cohorts. Despite significant inbreeding in some populations, there is no evidence of higher inbreeding in juvenile cohorts relative to adults. A Bayesian structure analysis and a tentative paternity analysis indicate extensive historical and contemporary gene flow among remnant populations. Pollination experiments and a paternity analysis show that Glionnetia sericea is self-compatible. Nevertheless, outcrossing is present with 7% of mating events resulting from pollen transfer between populations. Artificial pollination provided no evidence for pollen limitation in isolated populations. The highly mobile and specialized hawkmoth pollinators (Agrius convolvuli and Cenophodes tamsi; Sphingidae) appear to promote extensive gene flow, thus mitigating the potential negative ecological and genetic effects of habitat fragmentation in this species. We conclude that contemporary gene flow is sufficient to maintain genetic connectivity in this rare and restricted Seychelles endemic, in contrast to other island endemic tree species with limited contemporary gene flow.
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spelling pubmed-42102682014-10-30 Genetic Connectivity of the Moth Pollinated Tree Glionnetia sericea in a Highly Fragmented Habitat Finger, Aline Kaiser-Bunbury, Christopher N. Kettle, Chris J. Valentin, Terence Ghazoul, Jaboury PLoS One Research Article Long-distance gene flow is thought to be one prerequisite for the persistence of plant species in fragmented environments. Human influences have led to severe fragmentation of native habitats in the Seychelles islands, with many species surviving only in small and isolated populations. The endangered Seychelles endemic tree Glionnetia sericea is restricted to altitudes between 450 m and 900 m where the native forest vegetation has been largely lost and replaced with exotic invasives over the last 200 years. This study explores the genetic and ecological consequences of population fragmentation in this species by analysing patterns of genetic diversity in a sample of adults, juveniles and seeds, and by using controlled pollination experiments. Our results show no decrease in genetic diversity and no increase in genetic structuring from adult to juvenile cohorts. Despite significant inbreeding in some populations, there is no evidence of higher inbreeding in juvenile cohorts relative to adults. A Bayesian structure analysis and a tentative paternity analysis indicate extensive historical and contemporary gene flow among remnant populations. Pollination experiments and a paternity analysis show that Glionnetia sericea is self-compatible. Nevertheless, outcrossing is present with 7% of mating events resulting from pollen transfer between populations. Artificial pollination provided no evidence for pollen limitation in isolated populations. The highly mobile and specialized hawkmoth pollinators (Agrius convolvuli and Cenophodes tamsi; Sphingidae) appear to promote extensive gene flow, thus mitigating the potential negative ecological and genetic effects of habitat fragmentation in this species. We conclude that contemporary gene flow is sufficient to maintain genetic connectivity in this rare and restricted Seychelles endemic, in contrast to other island endemic tree species with limited contemporary gene flow. Public Library of Science 2014-10-27 /pmc/articles/PMC4210268/ /pubmed/25347541 http://dx.doi.org/10.1371/journal.pone.0111111 Text en © 2014 Finger et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Finger, Aline
Kaiser-Bunbury, Christopher N.
Kettle, Chris J.
Valentin, Terence
Ghazoul, Jaboury
Genetic Connectivity of the Moth Pollinated Tree Glionnetia sericea in a Highly Fragmented Habitat
title Genetic Connectivity of the Moth Pollinated Tree Glionnetia sericea in a Highly Fragmented Habitat
title_full Genetic Connectivity of the Moth Pollinated Tree Glionnetia sericea in a Highly Fragmented Habitat
title_fullStr Genetic Connectivity of the Moth Pollinated Tree Glionnetia sericea in a Highly Fragmented Habitat
title_full_unstemmed Genetic Connectivity of the Moth Pollinated Tree Glionnetia sericea in a Highly Fragmented Habitat
title_short Genetic Connectivity of the Moth Pollinated Tree Glionnetia sericea in a Highly Fragmented Habitat
title_sort genetic connectivity of the moth pollinated tree glionnetia sericea in a highly fragmented habitat
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4210268/
https://www.ncbi.nlm.nih.gov/pubmed/25347541
http://dx.doi.org/10.1371/journal.pone.0111111
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