Palaearctic biogeography revisited: evidence for the existence of a North African refugium for Western Palaearctic biota

Abstract

Aim In contrast to the attention given to southern Europe both as a centre of speciation and differentiation and as a Pleistocene refugium of Western Palaearctic taxa, North Africa has been relatively neglected. In this paper, we set out to address this shortfall.Location North-West Africa and the Mediterranean.Methods We reviewed the existing literature on the biogeography of North Africa, and carried out analyses of species distribution data using parsimony, nestedness and co-occurrence methods.Results In many cases, distribution patterns of non-flying mammals, bats, amphibians, reptiles, butterflies, zygaenid moths and odonates demonstrated important biogeographical affinities between Europe and North Africa at the species level. On the other hand, species co-occurrence, nestedness and parsimony analysis also revealed some deep splits between the Maghreb and Europe; yet even in these cases the closest affinities were found between the Iberian Peninsula and the Maghreb. Furthermore, North Africa harbours the highest proportion of endemic taxa (13.7%) across all groups analysed. Many molecular studies demonstrated a strong genetic cohesiveness between North Africa and Europe despite the potential barrier effect of the Mediterranean Sea. In other taxa, however, remarkable splits were detected. In addition, southern European genetic lineages were often nested within North African clades, and many taxa showed exceptionally high genetic variability and differentiation in this region. Main conclusionsThe Maghreb was an important differentiation and speciation centre for thermophilic organisms during the Pliocene and Pleistocene with high relevance as a colonization source for Europe. The regions around the sea straits of Gibraltar and Sicily have acted as important biogeographical links between North Africa and Europe at different times.

A new species of Charinus Simon, 1892 (Arachnida: Amblypygi: Charinidae) from Israel and new records of C. ioanniticus (Kritscher, 1959)

“…Despite being a Pleistocene refugium for several taxa and having a high degree of endemism (Husemann et al 2014), the eastern Mediterranean counts thus far only one known species of Charinus, the parthenogenetic C. ioanniticus. This species is recorded from Greece (Kritscher 1959), Turkey (Kovařík & Vlasta 1996;Weygoldt 2005;Seyyar & Demir 2007), Egypt (El-Hennawy 2002) and Israel (Kraus 1961;Rosin & Shulov 1960).…”

Role of the Mediterranean Sea in differentiating European and North African woodland bird assemblages

“…Studies done with different animal groups found that for most of them this barrier has been of major biogeographic importance (Husemann et al 2014). Our comparison between bird assemblages of the same habitat on opposite sides of the Mediterranean contributes to the understanding of its potential role structuring forest bird communities.…”

“…While it seems clear that the Mediterranean is more permeable to birds than to most other groups of animals so far studied (Husemann et al 2014), this barrier could also have an indirect impact on bird assemblages by acting on the distribution of species that are important for birds, as either resources or predators. For example, tree diversity is lower on the southern side of the Strait, and part of that difference has been attributed to historical biogeographic processes (Rodríguez-Sánchez et al 2008).…”

“…The bird fauna of cork oak woodlands essentially mirrors that of natural Mediterranean woodlands, which is known to harbour mostly the same species in Europe and North Africa (Blondel 1995). Palaeoecological evidence indicates that during the Pliocene and Pleistocene parts of southern Europe and North Africa had comparable climatic and ecological conditions, leading to similarities in the faunas of the two regions (Husemann et al 2014). Comparable conditions persisted even during the Pleistocene glacial periods and in fact southern Iberia and the adjacent areas of North Africa have been classically merged in the same glacial refuge, the Atlantic-Mediterranean centre (De Lattin 1949).…”

“…The role of the Mediterranean Sea as a barrier to gene flow within species is relatively well studied (e.g., Broderic et al 2003, García-Mudarra et al 2009, Husemann et al 2014), but its effects on the structure of species assemblages across the region remain somewhat unexplored. Indeed, such an extensive barrier to dispersal of biota may cause the differentiation of assemblages by limiting colonization across the barrier, and by facilitating speciation of isolated populations.…”