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Independent Demographic Responses to Climate Change among Temperate and Tropical Milksnakes (Colubridae: Genus Lampropeltis).

Ruane S, Torres-Carvajal O, Burbrink FT - PLoS ONE (2015)

Bottom Line: In addition, we determine whether range sizes are correlated with effective population sizes for milksnakes.Results indicate that there are no identifiable trends with respect to demographic response based on location, and that species responded to changing climates independently, with tropical taxa showing greater instability.There is also no correlation between range size and effective population size, with the largest population size belonging to the species with the smallest geographic distribution.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, College of Staten Island, 2800 Victory Blvd., Staten Island, NY, 10314, United States of America; The Graduate Center, City University of New York, 365 5th Avenue, New York, NY, 10016, United States of America.

ABSTRACT
The effects of Late Quaternary climate change have been examined for many temperate New World taxa, but the impact of Pleistocene glacial cycles on Neotropical taxa is less well understood, specifically with respect to changes in population demography. Here, we examine historical demographic trends for six species of milksnake with representatives in both the temperate and tropical Americas to determine if species share responses to climate change as a taxon or by area (i.e., temperate versus tropical environments). Using a multilocus dataset, we test for the demographic signature of population expansion and decline using non-genealogical summary statistics, as well as coalescent-based methods. In addition, we determine whether range sizes are correlated with effective population sizes for milksnakes. Results indicate that there are no identifiable trends with respect to demographic response based on location, and that species responded to changing climates independently, with tropical taxa showing greater instability. There is also no correlation between range size and effective population size, with the largest population size belonging to the species with the smallest geographic distribution. Our study highlights the importance of not generalizing the demographic histories of taxa by region and further illustrates that the New World tropics may not have been a stable refuge during the Pleistocene.

No MeSH data available.


Map showing sampling, and estimated full ranges of three tropical milksnakes, Lampropeltis polyzona (red), L. abnorma (yellow), and L. micropholis (pink).Ranges of all species are based on Ruane et al. [62].
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pone.0128543.g002: Map showing sampling, and estimated full ranges of three tropical milksnakes, Lampropeltis polyzona (red), L. abnorma (yellow), and L. micropholis (pink).Ranges of all species are based on Ruane et al. [62].

Mentions: We selected six milksnake species for our analyses of demographic change; L. triangulum, L. gentilis, L. elapsoides, L. polyzona, L. abnorma, and L. micropholis, following the revised taxonomy of Ruane et al. [62] and using GenBank sequences from accession series KF214996–KF216452. These six taxa, with an abundance of populations previously sampled, have extensive distributions throughout the Nearctic and portions of Neotropics (Figs 1 and 2). The three temperate species included L. triangulum (n = 34), L. gentilis (n = 30), and L. elapsoides (n = 32), occurring in the USA and Canada. The tropical species included L. polyzona (n = 31), L. abnorma (n = 11), and L. micropholis (n = 16), rangeing from Western/Central Mexico to Ecuador (see S1 Table in supporting information for details of samples). All six species originated between 1.1 and 3.6 Ma [62] and so would have experienced Late Pleistocene climate change. For L. triangulum, L. elapsoides, and L. gentilis, three genes were used, the mitochondrial gene cytochrome b (Cytb) and two anonymous nuclear loci, 2CL8 and CL4. For L. polyzona, L. abnorma, and L. micropholis, the same three genes were used; additional nuclear loci were available for the tropical taxa as well and so we also included the protein coding genes NT3 and PRLR, the introns SPTBN intron 1, Vimenton intron 5, NAV intron 5, and Z-chromosome GAD intron 15, and the anonymous loci 2CL3, 2CL4, and LATCL (S2 Table). Nuclear loci heterozygosities were previously resolved with PHASE v2.1.1 [72] in Ruane et al. [62], and so we used the most probable pair of resulting alleles for analyses.


Independent Demographic Responses to Climate Change among Temperate and Tropical Milksnakes (Colubridae: Genus Lampropeltis).

Ruane S, Torres-Carvajal O, Burbrink FT - PLoS ONE (2015)

Map showing sampling, and estimated full ranges of three tropical milksnakes, Lampropeltis polyzona (red), L. abnorma (yellow), and L. micropholis (pink).Ranges of all species are based on Ruane et al. [62].
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4470684&req=5

pone.0128543.g002: Map showing sampling, and estimated full ranges of three tropical milksnakes, Lampropeltis polyzona (red), L. abnorma (yellow), and L. micropholis (pink).Ranges of all species are based on Ruane et al. [62].
Mentions: We selected six milksnake species for our analyses of demographic change; L. triangulum, L. gentilis, L. elapsoides, L. polyzona, L. abnorma, and L. micropholis, following the revised taxonomy of Ruane et al. [62] and using GenBank sequences from accession series KF214996–KF216452. These six taxa, with an abundance of populations previously sampled, have extensive distributions throughout the Nearctic and portions of Neotropics (Figs 1 and 2). The three temperate species included L. triangulum (n = 34), L. gentilis (n = 30), and L. elapsoides (n = 32), occurring in the USA and Canada. The tropical species included L. polyzona (n = 31), L. abnorma (n = 11), and L. micropholis (n = 16), rangeing from Western/Central Mexico to Ecuador (see S1 Table in supporting information for details of samples). All six species originated between 1.1 and 3.6 Ma [62] and so would have experienced Late Pleistocene climate change. For L. triangulum, L. elapsoides, and L. gentilis, three genes were used, the mitochondrial gene cytochrome b (Cytb) and two anonymous nuclear loci, 2CL8 and CL4. For L. polyzona, L. abnorma, and L. micropholis, the same three genes were used; additional nuclear loci were available for the tropical taxa as well and so we also included the protein coding genes NT3 and PRLR, the introns SPTBN intron 1, Vimenton intron 5, NAV intron 5, and Z-chromosome GAD intron 15, and the anonymous loci 2CL3, 2CL4, and LATCL (S2 Table). Nuclear loci heterozygosities were previously resolved with PHASE v2.1.1 [72] in Ruane et al. [62], and so we used the most probable pair of resulting alleles for analyses.

Bottom Line: In addition, we determine whether range sizes are correlated with effective population sizes for milksnakes.Results indicate that there are no identifiable trends with respect to demographic response based on location, and that species responded to changing climates independently, with tropical taxa showing greater instability.There is also no correlation between range size and effective population size, with the largest population size belonging to the species with the smallest geographic distribution.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, College of Staten Island, 2800 Victory Blvd., Staten Island, NY, 10314, United States of America; The Graduate Center, City University of New York, 365 5th Avenue, New York, NY, 10016, United States of America.

ABSTRACT
The effects of Late Quaternary climate change have been examined for many temperate New World taxa, but the impact of Pleistocene glacial cycles on Neotropical taxa is less well understood, specifically with respect to changes in population demography. Here, we examine historical demographic trends for six species of milksnake with representatives in both the temperate and tropical Americas to determine if species share responses to climate change as a taxon or by area (i.e., temperate versus tropical environments). Using a multilocus dataset, we test for the demographic signature of population expansion and decline using non-genealogical summary statistics, as well as coalescent-based methods. In addition, we determine whether range sizes are correlated with effective population sizes for milksnakes. Results indicate that there are no identifiable trends with respect to demographic response based on location, and that species responded to changing climates independently, with tropical taxa showing greater instability. There is also no correlation between range size and effective population size, with the largest population size belonging to the species with the smallest geographic distribution. Our study highlights the importance of not generalizing the demographic histories of taxa by region and further illustrates that the New World tropics may not have been a stable refuge during the Pleistocene.

No MeSH data available.