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Ecological speciation in Nolina parviflora (Asparagaceae): lacking spatial connectivity along of the Trans-Mexican Volcanic Belt.

Ruiz-Sanchez E, Specht CD - PLoS ONE (2014)

Bottom Line: Using species distribution models, climatic analyses, spatial connectivity and morphological comparisons, we found significant differences in climatic and morphological variables between populations of N. parviflora in two distinct Trans-Mexican Volcanic Belt regions (east vs. west).Spatial connectivity analysis revealed no connectivity between these regions under the present or last glacial maximum climate models, indicating a lack of gene flow between the populations of the two regions.The results imply that these populations may encompass more than a single species.

View Article: PubMed Central - PubMed

Affiliation: Red de Biodiversidad y Sistemática, Centro Regional de Bajío, Instituto de Ecología AC, Pátzcuaro, Michoacán, Mexico.

ABSTRACT
The hypothesis of ecological speciation states that as populations diverge in different niches, reproductive isolation evolves as a by-product of adaptation to these different environments. In this context, we used Nolina parviflora as a model to test if this species evolved via ecological speciation and to explore current and historical gene flow among its populations. Nolina parviflora is a montane species endemic to Mexico with its geographical distribution restricted largely to the Trans-Mexican Volcanic Belt. This mountain range is one of the most complex geological regions in Mexico, having undergone volcanism from the mid-Miocene to the present. Ecologically, the Trans-Mexican Volcanic Belt possesses different types of vegetation, including tropical dry forest; oak, pine, pine-oak, and pine-juniper forests; and xerophytic scrub--all of which maintain populations of N. parviflora. Using species distribution models, climatic analyses, spatial connectivity and morphological comparisons, we found significant differences in climatic and morphological variables between populations of N. parviflora in two distinct Trans-Mexican Volcanic Belt regions (east vs. west). This could mean that the geographically isolated populations diverged from one another via niche divergence, indicating ecological speciation. Spatial connectivity analysis revealed no connectivity between these regions under the present or last glacial maximum climate models, indicating a lack of gene flow between the populations of the two regions. The results imply that these populations may encompass more than a single species.

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Related in: MedlinePlus

Geographical distribution of Nolina parviflora along the Trans-Mexican Volcanic Belt.Population numbers are those given in Table 1. The bottom tree shows the results of the Bayesian molecular dating analysis of N. parviflora, numbers inside each clade indicate the populations included in the analysis, and node numbers indicate divergence time and its 95% highest posterior density (HPD) intervals (adapted from Ruiz-Sanchez & Specht, 2013).
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pone-0098754-g001: Geographical distribution of Nolina parviflora along the Trans-Mexican Volcanic Belt.Population numbers are those given in Table 1. The bottom tree shows the results of the Bayesian molecular dating analysis of N. parviflora, numbers inside each clade indicate the populations included in the analysis, and node numbers indicate divergence time and its 95% highest posterior density (HPD) intervals (adapted from Ruiz-Sanchez & Specht, 2013).

Mentions: Nolina parviflora (Kunth) Hemsl., is an excellent model to test if ecological speciation occurred via niche conservatism or niche divergence, and to explore current and historic gene flow among populations. Nolina parviflora (Nolinoideae, Asparagaceae) is a montane species endemic to Mexico, with its geographical distribution mainly along the Trans-Mexican Volcanic Belt (TMVB) in central Mexico (Fig. 1), where it inhabits tropical dry, oak, pine, pine-oak, pine-juniper forests and xerophytic scrub from 1700 to 2800 m above sea level [22]. The TMVB is a complex geological region with a high degree of topographic complexity due to its volcanic activity from the mid-Miocene to the present [23], [24]. Recent phylogenetic and phylogeographic studies show that the geological complexity of the TMVB is correlated with the diversification and speciation of various plant and animal lineages [20], [22], [25]–[27].


Ecological speciation in Nolina parviflora (Asparagaceae): lacking spatial connectivity along of the Trans-Mexican Volcanic Belt.

Ruiz-Sanchez E, Specht CD - PLoS ONE (2014)

Geographical distribution of Nolina parviflora along the Trans-Mexican Volcanic Belt.Population numbers are those given in Table 1. The bottom tree shows the results of the Bayesian molecular dating analysis of N. parviflora, numbers inside each clade indicate the populations included in the analysis, and node numbers indicate divergence time and its 95% highest posterior density (HPD) intervals (adapted from Ruiz-Sanchez & Specht, 2013).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4048214&req=5

pone-0098754-g001: Geographical distribution of Nolina parviflora along the Trans-Mexican Volcanic Belt.Population numbers are those given in Table 1. The bottom tree shows the results of the Bayesian molecular dating analysis of N. parviflora, numbers inside each clade indicate the populations included in the analysis, and node numbers indicate divergence time and its 95% highest posterior density (HPD) intervals (adapted from Ruiz-Sanchez & Specht, 2013).
Mentions: Nolina parviflora (Kunth) Hemsl., is an excellent model to test if ecological speciation occurred via niche conservatism or niche divergence, and to explore current and historic gene flow among populations. Nolina parviflora (Nolinoideae, Asparagaceae) is a montane species endemic to Mexico, with its geographical distribution mainly along the Trans-Mexican Volcanic Belt (TMVB) in central Mexico (Fig. 1), where it inhabits tropical dry, oak, pine, pine-oak, pine-juniper forests and xerophytic scrub from 1700 to 2800 m above sea level [22]. The TMVB is a complex geological region with a high degree of topographic complexity due to its volcanic activity from the mid-Miocene to the present [23], [24]. Recent phylogenetic and phylogeographic studies show that the geological complexity of the TMVB is correlated with the diversification and speciation of various plant and animal lineages [20], [22], [25]–[27].

Bottom Line: Using species distribution models, climatic analyses, spatial connectivity and morphological comparisons, we found significant differences in climatic and morphological variables between populations of N. parviflora in two distinct Trans-Mexican Volcanic Belt regions (east vs. west).Spatial connectivity analysis revealed no connectivity between these regions under the present or last glacial maximum climate models, indicating a lack of gene flow between the populations of the two regions.The results imply that these populations may encompass more than a single species.

View Article: PubMed Central - PubMed

Affiliation: Red de Biodiversidad y Sistemática, Centro Regional de Bajío, Instituto de Ecología AC, Pátzcuaro, Michoacán, Mexico.

ABSTRACT
The hypothesis of ecological speciation states that as populations diverge in different niches, reproductive isolation evolves as a by-product of adaptation to these different environments. In this context, we used Nolina parviflora as a model to test if this species evolved via ecological speciation and to explore current and historical gene flow among its populations. Nolina parviflora is a montane species endemic to Mexico with its geographical distribution restricted largely to the Trans-Mexican Volcanic Belt. This mountain range is one of the most complex geological regions in Mexico, having undergone volcanism from the mid-Miocene to the present. Ecologically, the Trans-Mexican Volcanic Belt possesses different types of vegetation, including tropical dry forest; oak, pine, pine-oak, and pine-juniper forests; and xerophytic scrub--all of which maintain populations of N. parviflora. Using species distribution models, climatic analyses, spatial connectivity and morphological comparisons, we found significant differences in climatic and morphological variables between populations of N. parviflora in two distinct Trans-Mexican Volcanic Belt regions (east vs. west). This could mean that the geographically isolated populations diverged from one another via niche divergence, indicating ecological speciation. Spatial connectivity analysis revealed no connectivity between these regions under the present or last glacial maximum climate models, indicating a lack of gene flow between the populations of the two regions. The results imply that these populations may encompass more than a single species.

Show MeSH
Related in: MedlinePlus