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Thriving in the Cold: Glacial Expansion and Post-Glacial Contraction of a Temperate Terrestrial Salamander (Plethodon serratus).

Newman CE, Austin CC - PLoS ONE (2015)

Bottom Line: Phylogenetic results show that P. serratus is comprised of multiple genetic lineages, and the four regions are not reciprocally monophyletic.The Appalachian salamanders form a clade sister to all other P. serratus.Niche and paleodistribution modeling results suggest that P. serratus expanded from the Appalachians during the cooler Last Glacial Maximum and has since been restricted to its current disjunct distribution by a warming climate.

View Article: PubMed Central - PubMed

Affiliation: Museum of Natural Science, Louisiana State University, Baton Rouge, Louisiana, United States of America; Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America.

ABSTRACT
The dynamic geologic history of the southeastern United States has played a major role in shaping the geographic distributions of amphibians in the region. In the phylogeographic literature, the predominant pattern of distribution shifts through time of temperate species is one of contraction during glacial maxima and persistence in refugia. However, the diverse biology and ecology of amphibian species suggest that a "one-size-fits-all" model may be inappropriate. Nearly 10% of amphibian species in the region have a current distribution comprised of multiple disjunct, restricted areas that resemble the shape of Pleistocene refugia identified for other temperate taxa in the literature. Here, we apply genetics and spatially explicit climate analyses to test the hypothesis that the disjunct regions of these species ranges are climatic refugia for species that were more broadly distributed during glacial maxima. We use the salamander Plethodon serratus as a model, as its range consists of four disjunct regions in the Southeast. Phylogenetic results show that P. serratus is comprised of multiple genetic lineages, and the four regions are not reciprocally monophyletic. The Appalachian salamanders form a clade sister to all other P. serratus. Niche and paleodistribution modeling results suggest that P. serratus expanded from the Appalachians during the cooler Last Glacial Maximum and has since been restricted to its current disjunct distribution by a warming climate. These data reject the universal applicability of the glacial contraction model to temperate taxa and reiterate the importance of considering the natural history of individual species.

No MeSH data available.


Related in: MedlinePlus

Maximum-likelihood phylogeny of mitochondrial cytb.Nodal support: grey dots: Bayesian PP > 0.9; black dots: ML bootstrap > 0.75 and Bayesian PP > 0.9. Shapes on the phylogeny correspond to map. Inset: Ouachita region.
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pone.0130131.g002: Maximum-likelihood phylogeny of mitochondrial cytb.Nodal support: grey dots: Bayesian PP > 0.9; black dots: ML bootstrap > 0.75 and Bayesian PP > 0.9. Shapes on the phylogeny correspond to map. Inset: Ouachita region.

Mentions: The mitochondrial cyt b alignment was 728 bp long and contained 48 haplotypes. Average pairwise JC sequence divergence between geographic regions ranged from 4.4%-7.2%. Average JC sequence divergence within regions ranged from 0%-4.5% (Table 2). The ML phylogeny revealed 10 geographically concordant clades with strong support from ML bootstraps (≥ 75) and Bayesian posterior probabilities (≥ 0.9) (Fig 2, S2 Fig). The Appalachians and Ozarks each form strongly supported clades (Fig 2). Surprisingly, the two allopatric sites in Louisiana (Kisatchie, Sicily Island; Fig 1, Table 1) are not sister clades; rather, Sicily Island falls out sister to a clade comprised of samples from the Ouachitas. The Ouachita region as a whole also does not form a clade. To some extent, the spatial distribution of mitochondrial clades is concordant with geography at the population level, as populations that are closer together geographically tend to be more closely related. But this pattern does not hold at the larger scale, among regions, as only two of the four regions are represented by monophyletic clades.


Thriving in the Cold: Glacial Expansion and Post-Glacial Contraction of a Temperate Terrestrial Salamander (Plethodon serratus).

Newman CE, Austin CC - PLoS ONE (2015)

Maximum-likelihood phylogeny of mitochondrial cytb.Nodal support: grey dots: Bayesian PP > 0.9; black dots: ML bootstrap > 0.75 and Bayesian PP > 0.9. Shapes on the phylogeny correspond to map. Inset: Ouachita region.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4488858&req=5

pone.0130131.g002: Maximum-likelihood phylogeny of mitochondrial cytb.Nodal support: grey dots: Bayesian PP > 0.9; black dots: ML bootstrap > 0.75 and Bayesian PP > 0.9. Shapes on the phylogeny correspond to map. Inset: Ouachita region.
Mentions: The mitochondrial cyt b alignment was 728 bp long and contained 48 haplotypes. Average pairwise JC sequence divergence between geographic regions ranged from 4.4%-7.2%. Average JC sequence divergence within regions ranged from 0%-4.5% (Table 2). The ML phylogeny revealed 10 geographically concordant clades with strong support from ML bootstraps (≥ 75) and Bayesian posterior probabilities (≥ 0.9) (Fig 2, S2 Fig). The Appalachians and Ozarks each form strongly supported clades (Fig 2). Surprisingly, the two allopatric sites in Louisiana (Kisatchie, Sicily Island; Fig 1, Table 1) are not sister clades; rather, Sicily Island falls out sister to a clade comprised of samples from the Ouachitas. The Ouachita region as a whole also does not form a clade. To some extent, the spatial distribution of mitochondrial clades is concordant with geography at the population level, as populations that are closer together geographically tend to be more closely related. But this pattern does not hold at the larger scale, among regions, as only two of the four regions are represented by monophyletic clades.

Bottom Line: Phylogenetic results show that P. serratus is comprised of multiple genetic lineages, and the four regions are not reciprocally monophyletic.The Appalachian salamanders form a clade sister to all other P. serratus.Niche and paleodistribution modeling results suggest that P. serratus expanded from the Appalachians during the cooler Last Glacial Maximum and has since been restricted to its current disjunct distribution by a warming climate.

View Article: PubMed Central - PubMed

Affiliation: Museum of Natural Science, Louisiana State University, Baton Rouge, Louisiana, United States of America; Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America.

ABSTRACT
The dynamic geologic history of the southeastern United States has played a major role in shaping the geographic distributions of amphibians in the region. In the phylogeographic literature, the predominant pattern of distribution shifts through time of temperate species is one of contraction during glacial maxima and persistence in refugia. However, the diverse biology and ecology of amphibian species suggest that a "one-size-fits-all" model may be inappropriate. Nearly 10% of amphibian species in the region have a current distribution comprised of multiple disjunct, restricted areas that resemble the shape of Pleistocene refugia identified for other temperate taxa in the literature. Here, we apply genetics and spatially explicit climate analyses to test the hypothesis that the disjunct regions of these species ranges are climatic refugia for species that were more broadly distributed during glacial maxima. We use the salamander Plethodon serratus as a model, as its range consists of four disjunct regions in the Southeast. Phylogenetic results show that P. serratus is comprised of multiple genetic lineages, and the four regions are not reciprocally monophyletic. The Appalachian salamanders form a clade sister to all other P. serratus. Niche and paleodistribution modeling results suggest that P. serratus expanded from the Appalachians during the cooler Last Glacial Maximum and has since been restricted to its current disjunct distribution by a warming climate. These data reject the universal applicability of the glacial contraction model to temperate taxa and reiterate the importance of considering the natural history of individual species.

No MeSH data available.


Related in: MedlinePlus