TY - JOUR
T1 - Species replacement along a linear coastal habitat
T2 - Phylogeography and speciation in the red alga Mazzaella laminarioides along the south east pacific
AU - Montecinos, Alejandro
AU - Broitman, Bernardo R.
AU - Faugeron, Sylvain
AU - Haye, Pilar A.
AU - Tellier, Florence
AU - Guillemin, Marie Laure
N1 - Funding Information:
This research was supported by CONICYT, Comisión Nacional de Investigación Científica y Tecnológica, Gobierno de Chile (FONDECYT N° 1090360, FONDECYT N°1090488 and FONDECYT N°1090670). FT was partially supported by a FONDECYT grant N°3110051. We thank C. Destombe, C. Molinet and V. Oppliger for field support and sample collection and G. D’Elía for analyses using MrBayes.
PY - 2012
Y1 - 2012
N2 - Background: The Chilean shoreline, a nearly strait line of coast expanding across 35 latitudinal degrees, represents an interesting region to assess historical processes using phylogeographic analyses. Stretching along the temperate section of the East Pacific margin, the region is characterized by intense geologic activity and has experienced drastic geomorphological transformations linked to eustatic and isostatic changes during the Quaternary. In this study, we used two molecular markers to evaluate the existence of phylogeographic discontinuities and detect the genetic footprints of Pleistocene glaciations among Patagonian populations of Mazzaella laminarioides, a low-dispersal benthic intertidal red seaweed that inhabits along ∼3,700km of the Chilean coastal rocky shore. Results: Three main genetic lineages were found within M. laminarioides. They are distributed along the Chilean coast in strict parapatry. The deep divergence among lineages suggests that they could be considered putative genetic sibling species. Unexpectedly, genetic breaks were not strictly concordant with the biogeographic breaks described in the region. A Northern lineage was restricted to a broad transition zone located between 30°S and 33°S and showed signals of a recent bottleneck. The reduction of population size could be related to warm events linked to El Nĩo Southern Oscillation, which is known to cause massive seaweed mortality in this region. To the south, we propose that transient habitat discontinuities driven by episodic tectonic uplifting of the shoreline around the Arauco region (37°S-38°S); one of the most active forearc-basins in the South East Pacific; could be at the origin of the Central/South genetic break. The large beaches, located around 38°S, are likely to contribute to the lineages integrity by limiting present gene flow. Finally, the Southern lineage, occupies an area affected by ice-cover during the last glaciations. Phylogeny suggested it is a derived clade and demographic analyses showed the lineage has a typical signature of postglacial recolonization from a northern glacial refugium area. Conclusions: Even if environmental adaptation could have strengthened divergence among lineages in M. laminarioides, low dispersal capacity and small population size are sufficient to generate phylogeographic discontinuities determined by genetic drift alone. Interestingly, our results confirm that seaweed population connectivity over large geographic scales does not rely only on dispersal capacity but also seem to depend highly on substratum availability and population density of the receiving locality.
AB - Background: The Chilean shoreline, a nearly strait line of coast expanding across 35 latitudinal degrees, represents an interesting region to assess historical processes using phylogeographic analyses. Stretching along the temperate section of the East Pacific margin, the region is characterized by intense geologic activity and has experienced drastic geomorphological transformations linked to eustatic and isostatic changes during the Quaternary. In this study, we used two molecular markers to evaluate the existence of phylogeographic discontinuities and detect the genetic footprints of Pleistocene glaciations among Patagonian populations of Mazzaella laminarioides, a low-dispersal benthic intertidal red seaweed that inhabits along ∼3,700km of the Chilean coastal rocky shore. Results: Three main genetic lineages were found within M. laminarioides. They are distributed along the Chilean coast in strict parapatry. The deep divergence among lineages suggests that they could be considered putative genetic sibling species. Unexpectedly, genetic breaks were not strictly concordant with the biogeographic breaks described in the region. A Northern lineage was restricted to a broad transition zone located between 30°S and 33°S and showed signals of a recent bottleneck. The reduction of population size could be related to warm events linked to El Nĩo Southern Oscillation, which is known to cause massive seaweed mortality in this region. To the south, we propose that transient habitat discontinuities driven by episodic tectonic uplifting of the shoreline around the Arauco region (37°S-38°S); one of the most active forearc-basins in the South East Pacific; could be at the origin of the Central/South genetic break. The large beaches, located around 38°S, are likely to contribute to the lineages integrity by limiting present gene flow. Finally, the Southern lineage, occupies an area affected by ice-cover during the last glaciations. Phylogeny suggested it is a derived clade and demographic analyses showed the lineage has a typical signature of postglacial recolonization from a northern glacial refugium area. Conclusions: Even if environmental adaptation could have strengthened divergence among lineages in M. laminarioides, low dispersal capacity and small population size are sufficient to generate phylogeographic discontinuities determined by genetic drift alone. Interestingly, our results confirm that seaweed population connectivity over large geographic scales does not rely only on dispersal capacity but also seem to depend highly on substratum availability and population density of the receiving locality.
KW - COI
KW - Parapatric distribution
KW - Phylogeography
KW - Pleistocene glaciations
KW - Red seaweed
KW - Sister-species complex
KW - South East Pacific coast
KW - rbcL
UR - http://www.scopus.com/inward/record.url?scp=84862624423&partnerID=8YFLogxK
U2 - 10.1186/1471-2148-12-97
DO - 10.1186/1471-2148-12-97
M3 - Article
C2 - 22731925
AN - SCOPUS:84862624423
SN - 1471-2148
VL - 12
JO - BMC Evolutionary Biology
JF - BMC Evolutionary Biology
IS - 1
M1 - 97
ER -