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Sequential fragmentation of Pleistocene forests in an East Africa biodiversity hotspot: chameleons as a model to track forest history
Sequential fragmentation of Pleistocene forests in an East Africa biodiversity hotspot: chameleons as a model to track forest history
- Source :
- PLoS ONE, Vol 6, Iss 10, p e26606 (2011), PLoS ONE
- Publication Year :
- 2011
- Publisher :
- Public Library of Science (PLoS), 2011.
-
Abstract
- Background: The Eastern Arc Mountains (EAM) is an example of naturally fragmented tropical forests, which contain one of the highest known concentrations of endemic plants and vertebrates. Numerous paleo-climatic studies have not provided direct evidence for ancient presence of Pleistocene forests, particularly in the regions in which savannah presently occurs. Knowledge of the last period when forests connected EAM would provide a sound basis for hypothesis testing of vicariance and dispersal models of speciation. Dated phylogenies have revealed complex patterns throughout EAM, so we investigated divergence times of forest fauna on four montane isolates in close proximity to determine whether forest break-up was most likely to have been simultaneous or sequential, using population genetics of a forest restricted arboreal chameleon, Kinyongia boehmei. Methodology/Principal Findings: We used mitochondrial and nuclear genetic sequence data and mutation rates from a fossil-calibrated phylogeny to estimate divergence times between montane isolates using a coalescent approach. We found that chameleons on all mountains are most likely to have diverged sequentially within the Pleistocene from 0.93–0.59 Ma (95% HPD 0.22–1.84 Ma). In addition, post-hoc tests on chameleons on the largest montane isolate suggest a population expansion ,182 Ka. Conclusions/Significance: Sequential divergence is most likely to have occurred after the last of three wet periods within the arid Plio-Pleistocene era, but was not correlated with inter-montane distance. We speculate that forest connection persisted due to riparian corridors regardless of proximity, highlighting their importance in the region’s historic dispersal events. The population expansion coincides with nearby volcanic activity, which may also explain the relative paucity of the Taita’s endemic fauna. Our study shows that forest chameleons are an apposite group to track forest fragmentation, with the inference that forest extended between some EAM during the Pleistocene 1.1–0.9 Ma.
- Subjects :
- Evolutionary Genetics
Plant Phylogenetics
Arboreal locomotion
Atmospheric Science
Time Factors
Biodiversity
Population Modeling
lcsh:Medicine
Plant Science
Animal Phylogenetics
Social and Behavioral Sciences
Coalescent theory
Trees
Molecular Systematics
lcsh:Science
Phylogeny
Conservation Science
Climatology
education.field_of_study
Multidisciplinary
Geography
Ecology
Nucleotides
Lizards
Africa, Eastern
Phylogenetics
Biogeography
Research Article
Gene Flow
Conservation of Natural Resources
Pleistocene
Climate Change
Population
Molecular Sequence Data
Biology
Models, Biological
Vicariance
Genetics
Animals
Evolutionary Systematics
education
Evolutionary Biology
Population Biology
Herpetology
lcsh:R
Genetic Variation
Paleontology
Biodiversity hotspot
Haplotypes
Evolutionary Ecology
Earth Sciences
Biological dispersal
lcsh:Q
Paleoecology
Animal Genetics
Zoology
Population Genetics
Subjects
Details
- Language :
- English
- ISSN :
- 19326203
- Volume :
- 6
- Issue :
- 10
- Database :
- OpenAIRE
- Journal :
- PLoS ONE
- Accession number :
- edsair.doi.dedup.....fb76e16bc55cdff475837bbb730af7db