Glacial refuge areas are expected to harbor a large fraction of the intraspecific biodiversity of the temperate biota. To test this hypothesis, we studied chloroplast DNA variation in 22 widespread European trees and shrubs sampled in the same forests. Most species had genetically divergent populations in Mediterranean regions, especially those with low seed dispersal abilities. However, the genetically most diverse populations were not located in the south but at intermediate latitudes, a likely consequence of the admixture of divergent lineages colonizing the continent from separate refugia.

http://www.as.wvu.edu/~sdifazio/molececol/Oct11a.pdf

Glacial Refugia: Hotspots But Not Melting Pots of Genetic Diversity

An Atlas of Past and Present Pollen Maps for Europe: 0-13000 Years Ago, and The Overlay Maps.

The main aim of DNA barcoding is to establish a shared community resource of DNA sequences that can be used for organismal identification and taxonomic clarification. This approach was successfully pioneered in animals using a portion of the cytochrome oxidase 1 (CO1) mitochondrial gene. In plants, establishing a standardized DNA barcoding system has been more challenging. In this paper, we review the process of selecting and refining a plant barcode; evaluate the factors which influence the discriminatory power of the approach; describe some early applications of plant barcoding and summarise major emerging projects; and outline tool development that will be necessary for plant DNA barcoding to advance.

https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0019254&type=printable

Choosing and Using a Plant DNA Barcode

The glacial episodes of the Quaternary (2.6 million years ago–present) were a major factor in shaping the present-day distributions of extant flora and fauna, with expansions and contractions of the ice sheets rendering large areas uninhabitable for most species. Fossil records suggest that many species survived glacial maxima by retreating to refugia, usually at lower latitudes. Recently, phylogeographic studies have given support to the existence of previously unknown, or cryptic, refugia. Here we summarise many of these insights into the glacial histories of species in cryptic refugia gained through phylogeographic approaches. Understanding such refugia might be important as the Earth heads into another period of climate change, in terms of predicting the effects on species distribution and survival.

/pdf/phylogeographic-insights-into-cryptic-glacial-refugia-1ephre68rp.pdf

Phylogeographic insights into cryptic glacial refugia.

Aim The aims of this study were to assess the distribution of putative Mediterranean refugia of plants, to compare the locations of refugia and those of regional hotspots of plant biodiversity, and to provide a critical analysis of the Mediterranean refugium paradigm. Furthermore, we consider how biogeographical and genetic results can be combined to guide global conservation strategies. Location The Mediterranean region. Methods We started from a detailed analysis of the scientific literature (1993-2007) in order to identify refugia in the Mediterranean region, based on intraspecific phylogeographical studies of plant species. We used population locations together with gene-pool identity to establish the database, comparing patterns of phylogeographical concordance with the locations of Mediterranean refugia. We then tested the biogeographical congruence between two biodiversity components, namely phylogeographical refugia and regional hotspots. Results We identified 52 refugia in the Mediterranean bioclimatic region and confirmed the role played by the three major peninsulas, with a shared total of 25 refugia. We emphasize the importance of areas that have previously been attributed a lesser role (large Mediterranean islands, North Africa, Turkey, Catalonia). Of the 52 refugia identified, 33 are situated in the western Mediterranean Basin and 19 in the eastern part. The locations of the phylogeographically defined refugia are significantly associated with the 10 regional hotspots of plant biodiversity, with 26 of these refugia (i.e. 50%) occurring within the hotspots. Main conclusions The locations of refugia are determined by complex historical and environmental factors, the cumulative effects of which need to be considered because they have occurred since the Tertiary, rather than solely during the last glacial period. Refugia represent climatically stable areas and constitute a high conservation priority as key areas for the long-term persistence of species and genetic diversity, especially given the threat posed by the extensive environmental change processes operating in the Mediterranean region. The refugia defined here represent 'phylogeographical hotspots'; that is, significant reservoirs of unique genetic diversity favourable to the evolutionary processes of Mediterranean plant species.

/pdf/glacial-refugia-influence-plant-diversity-patterns-in-the-rp01uam2ol.pdf

Glacial refugia influence plant diversity patterns in the Mediterranean Basin

http://www.pierroton.inra.fr/Fairoak/Papers2001/fem156_1_3.pdf

Identification of refugia and post-glacial colonisation routes of European white oaks based on chloroplast DNA and fossil pollen evidence

http://www.pierroton.inra.fr/Fairoak/Papers2001/fem156_1_1.pdf

Chloroplast DNA variation in European white oaks phylogeography and patterns of diversity based on data from over 2600 populations

http://www.pierroton.inra.fr/Fairoak/Papers2001/fem156_2_9.pdf

Izabela Glaz

Papers

Identification of refugia and post-glacial colonisation routes of European white oaks based on chloroplast DNA and fossil pollen evidence

Chloroplast DNA variation in European white oaks phylogeography and patterns of diversity based on data from over 2600 populations

Chloroplast DNA variation of white oak in the Baltic countries and Poland