Nunatak survival vs. tabula rasa in the Central Pyrenees: a study on the endemic plant species Borderea pyrenaica (Dioscoreaceae)

• Published in: Journal of biogeography Vol. 34; no. 11; pp. 1893 - 1906
• Main Authors: Segarra-Moragues, José Gabriel, Palop-Esteban, Marisa, González-Candelas, Fernando, Catalán, Pilar
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.11.2007; Blackwell Publishing Ltd; Blackwell Publishing; Blackwell
• Subjects: Alleles; Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; Dioscoreaceae; Ecological genetics; Fundamental and applied biological sciences. Psychology; General aspects; Genetic loci; microsatellite repeats; Microsatellites; Nunataks; palaeopolyploids; Plant Distributions, Associations and Dynamics; plant phylogeography; Plants; Population genetics; Population geography; Population structure; postglacial colonization; Pyrenees; Refuge habitats; refugia; Synecology; Europe; Pyrenees; Monocotyledones; Endemic species; Phylogeography; Biogeography; Population structure; post- glacial colonization; palaeopolyploids; Survival; refugia; Dioscoreaceae; microsatellites; Plant; Angiospermae; Spermatophyta; Pyrenees; plant phylogeography; Colonization
• ISSN: 0305-0270; 1365-2699
• DOI: 10.1111/j.1365-2699.2007.01740.x

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. Central Pyrenees and pre-Pyrenees, Spain-France. 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. A higher number of private alleles and a significantly higher allelic richness (A*) were found in the southern area (21, A* = 2.295) than in the northern area (5, A* = 1.791). Furthermore, the allelic composition of the northern area represented a subset of that from the southern area. 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.