Nunatak survival vs. tabula rasa in the Central Pyrenees: a study on the endemic plant species Borderea pyrenaica (Dioscoreaceae).
Segarra-Moragues, J.G.; Palop-Esteban, M.; González-Candelas, F.; Catalán, P.. Nunatak survival vs. tabula rasa in the Central Pyrenees: a study on the endemic plant species Borderea pyrenaica (Dioscoreaceae).. Journal of Biogeography. 2007, Vol. 34(11), p. 1893-2007.
Aim Borderea pyrenaica (Dioscoreaceae) is a Tertiary relict plant endemic to the
Central Pyrenees. Because of its narrow distribution in a small geographical area
and the fact that it is restricted to high alpine habitats, it constitutes an ideal
model species for inferring the historical dynamics of population survival and
migration during and after Quaternary glaciations in the Pyrenees.
Location Central Pyrenees and pre-Pyrenees, Spain–France.
Methods Eleven primer pairs were used to amplify 18 microsatellite loci in this
allotetraploid species in a sample of 804 individuals from 15 populations,
revealing a total of 77 alleles. Genotypic data of individuals and populations were
analysed using clustering and Bayesian methods of analysis of population
structure.
Results A higher number of private alleles and a significantly higher allelic
richness (A*) were found in the southern area (21, A* ¼ 2.295) than in the
northern area (5, A* ¼ 1.791). Furthermore, the allelic composition of the
northern area represented a subset of that from the southern area.
Main conclusions The hypothesis of in situ survival in northern Pyrenean
nunataks was rejected, while peripheral refugia were considered to be restricted to
the southern Pyrenees and pre-Pyrenees, where historical geographical
fragmentation probably caused the divergence among southern Pyrenean
populations. Molecular evidence indicates that these refugial populations
probably colonized the northern area after sheet-ice retreat. Borderea pyrenaica
lineages followed two migratory pathways in their northward colonization,
suggesting several founder events for the populations that eventually reached the
territory of the Gavarnie cirque.
Aim Borderea pyrenaica (Dioscoreaceae) is a Tertiary relict plant endemic to the
Central Pyrenees. Because of its narrow distribution in a small geographical area
and the fact that it is restricted to high alpine habitats, it constitutes an ideal
model species for inferring the historical dynamics of population survival and
migration during and after Quaternary glaciations in the Pyrenees.
Location Central Pyrenees and pre-Pyrenees, Spain–France.
Methods Eleven primer pairs were used to amplify 18 microsatellite loci in this
allotetraploid species in a sample of 804 individuals from 15 populations,
revealing a total of 77 alleles. Genotypic data of individuals and populations were
analysed using clustering and Bayesian methods of analysis of population
structure.
Results A higher number of private alleles and a significantly higher allelic
richness (A*) were found in the southern area (21, A* ¼ 2.295) than in the
northern area (5, A* ¼ 1.791). Furthermore, the allelic composition of the
northern area represented a subset of that from the southern area.
Main conclusions The hypothesis of in situ survival in northern Pyrenean
nunataks was rejected, while peripheral refugia were considered to be restricted to
the southern Pyrenees and pre-Pyrenees, where historical geographical
fragmentation probably caused the divergence among southern Pyrenean
populations. Molecular evidence indicates that these refugial populations
probably colonized the northern area after sheet-ice retreat. Borderea pyrenaica
lineages followed two migratory pathways in their northward colonization,
suggesting several founder events for the populations that eventually reached the
territory of the Gavarnie cirque.