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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

A-C west lineage.A. Plant showing two branches. B. Primary inflorescence branch, showing fruits and seed, scale bar  =  1 cm. C. Panoramic image of the oak forest type in the locality of Río Los Patitos, Zacatecas, Mexico. D-F east lineage. D. Plant showing seven branches and inflorescences. E. Primary inflorescence branch, showing fruits and seeds, scale bar  = 1 cm. F. Panoramic image of xerophytic scrub habitat type with Pico de Orizaba in the background, Veracruz, Mexico. Photos by E. Ruiz-Sanchez.
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pone-0098754-g005: A-C west lineage.A. Plant showing two branches. B. Primary inflorescence branch, showing fruits and seed, scale bar  =  1 cm. C. Panoramic image of the oak forest type in the locality of Río Los Patitos, Zacatecas, Mexico. D-F east lineage. D. Plant showing seven branches and inflorescences. E. Primary inflorescence branch, showing fruits and seeds, scale bar  = 1 cm. F. Panoramic image of xerophytic scrub habitat type with Pico de Orizaba in the background, Veracruz, Mexico. Photos by E. Ruiz-Sanchez.

Mentions: Twelve vegetative and floral characters noted to vary among individuals within and between populations were scored (Table 4, Fig. 5). When clustered into separate groups, the most significant differences were detected between specimens of the east v. west clades in (1) plant height, (2) leaf length and (3) fruit size (Table 4).


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

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

A-C west lineage.A. Plant showing two branches. B. Primary inflorescence branch, showing fruits and seed, scale bar  =  1 cm. C. Panoramic image of the oak forest type in the locality of Río Los Patitos, Zacatecas, Mexico. D-F east lineage. D. Plant showing seven branches and inflorescences. E. Primary inflorescence branch, showing fruits and seeds, scale bar  = 1 cm. F. Panoramic image of xerophytic scrub habitat type with Pico de Orizaba in the background, Veracruz, Mexico. Photos by E. Ruiz-Sanchez.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0098754-g005: A-C west lineage.A. Plant showing two branches. B. Primary inflorescence branch, showing fruits and seed, scale bar  =  1 cm. C. Panoramic image of the oak forest type in the locality of Río Los Patitos, Zacatecas, Mexico. D-F east lineage. D. Plant showing seven branches and inflorescences. E. Primary inflorescence branch, showing fruits and seeds, scale bar  = 1 cm. F. Panoramic image of xerophytic scrub habitat type with Pico de Orizaba in the background, Veracruz, Mexico. Photos by E. Ruiz-Sanchez.
Mentions: Twelve vegetative and floral characters noted to vary among individuals within and between populations were scored (Table 4, Fig. 5). When clustered into separate groups, the most significant differences were detected between specimens of the east v. west clades in (1) plant height, (2) leaf length and (3) fruit size (Table 4).

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