Extra-Mediterranean refugia: The rule and not the exception?

Abstract

Some decades ago, biogeographers distinguished three major faunal types of high importance for Europe: (i) Mediterranean elements with exclusive glacial survival in the Mediterranean refugia, (ii) Siberian elements with glacial refugia in the eastern Palearctic and only postglacial expansion to Europe and (iii) arctic and/or alpine elements with large zonal distributions in the periglacial areas and postglacial retreat to the North and/or into the high mountain systems. Genetic analyses have unravelled numerous additional refugia both of continental and Mediterranean species, thus strongly modifying the biogeographical view of Europe. This modified notion is particularly true for the so-called Siberian species, which in many cases have not immigrated into Europe during the postglacial period, but most likely have survived the last, or even several glacial phases, in extra-Mediterranean refugia in some climatically favourable but geographically limited areas of southern Central and Eastern Europe. Recently, genetic analyses revealed that typical Mediterranean species have also survived the Last Glacial Maximum in cryptic northern refugia (e.g. in the Carpathians or even north of the Alps) in addition to their Mediterranean refuge areas.

Mitochondrial genetic diversity and structuring of northernwhite-breasted hedgehogs from the Central Balkans

“…In order to completely support the present phylogeographic routes, wider sampling is necessary, specifically in eastern Europe and the region north of the Black Sea. This proposed wider sampling would also contribute to a better understanding of the influence of extra-Mediterranean refugia on phylogeographic patterns of hedgehogs, especially those in the Carpathian Basin, since recent studies have indicated its importance in ice age survival of European temperate species (Schmitt and Varga, 2012).…”

“…The glacial survival in the southern refugia (Iberian, Apennine, and Balkan peninsulas), followed by postglacial recolonization of northern Europe, seems to be a general model (Hewitt, 2001), suggesting that populations from different refugia responded individually to habitat availability during the interglacial periods, as well as at the end of the last glaciations, therefore expanding their distribution ranges and different genetic lineages northwards (Taberlet et al, 1998;Hewitt, 1999Hewitt, , 2004. It is noteworthy that recent genetic analyses revealed that typical Mediterranean species could also survive glacial phases in extra-Mediterranean refugia in some climatically favorable but geographically limited areas, such as the Carpathians or even north of the Alps (Schmitt and Varga, 2012). In the Balkan Peninsula, which is recognized as one of the hotspots of biodiversity, genetic studies of several mammal species (wild boars, gray wolves, brown hares) have proved the existence of high genetic diversity and provided signs of population structuring, with southerly biased gene pools (Djan et al, 2014;Veličković et al, 2015).…”

Studies on the Glacial Refugia of Forest Trees on Balkan Peninsula

“…This can be explained first, as a consequence of the admixture of divergent lineages colonizing the continent from separate refugia, and second, with admixture of the main recolonization routes with more northern ones, even coming from smaller refugia [3,9]. The last studies showed that glacial refugia for tree species existed northward from the Alps, although patchily distributed at low densities due to low atmospheric CO2 concentrations and high wind-speeds [17,18].…”

Biology and biogeography of the chalk-hill blue Polyommatus coridon – insect of the year 2015 for Germany, Austria and Switzerland

“…Hence, the chalk-hill blue shows biogeographical traits of a species that is much more cold-tolerant than previously thought and which was thus able, at least additionally, to survive glacial periods in so called extra-Mediterranean refugia north of the classical Mediterranean refugia (cf. Schmitt and Varga 2012).…”