Phylogeography of North African Atlas cedar (Cedrus atlantica, Pinaceae): Combined molecular and fossil data reveal a complex Quaternary history

Abstract

Northwest Africa is a major hotspot of plant biodiversity, but very little is known about the Quaternary range dynamics of plant species in this region. Here we investigate the range-wide population structure and phylogeography of Atlas cedar (Cedrus atlantica), an emblematic forest tree endemic to Morocco and Algeria. We genotyped 261 individuals from 11 populations using AFLP markers. Data were analyzed using both conventional F(ST)-based techniques and Bayesian clustering. Overall population differentiation was high (F(ST) = 0.25). Two major groups of populations were identified, one distributed through the Rif and Middle Atlas mountains in Morocco and the other through the Algerian Tell Atlas and Aurès mountains as well as the Middle Atlas. Combined molecular and fossil data indicate that C. atlantica survived the Last Glacial Maximum in at least three disjunct refugia along the coast of the Mediterranean Sea, whereas the Middle Atlas, today the core of the species range, has been colonized relatively recently (<10000 yr BP). The colonization history of individual populations has left clear imprints in their present-day diversity, which may vary greatly even between nearby stands. Our study illustrates how integrating different data sources and analytical approaches can help elucidate complex range dynamics that would otherwise remain undeciphered.

Divergent Selection and Local Adaptation in Disjunct Populations of an Endangered Conifer, Keteleeria davidiana var. formosana (Pinaceae)

“…formosana was also much lower than that in other Pinaceae species such as the disjunctly distributed Ced. atlantica ( F ST  = 0.25) [66] and A. ziyuanensis ( F ST  = 0.482, Φ ST  = 0.55) [67]; but was higher than the level of genetic differentiation in the widespread P. contorta ( F ST <0.02, Φ ST  = 0.016) [68]. Nevertheless, the level of genetic differentiation in K. davidiana var.…”

“…The average U H E was also higher in K. davidiana var. formosana compared to the average U H E of other Pinaceae species such as Cedrus atlantica (average U H E  = 0.129) endemic to Morocco and Algeria [66] and the endangered Abies ziyuanensis (average U H E  = 0.136) that occurs in China [67]. However, the average H E of K. davidiana var.…”

Relationships among Cedrus libani, C. brevifolia and C. atlantica as revealed by the morphological and anatomical needle characters

“…The studies on genetic diversity and phylogeography of C. atlantica (Terrab et al 2006(Terrab et al , 2008, genetic diversity of C. libani (Semaan and Dodd 2008) and C. brevifolia (Eliades et al 2011) described the high level of genetic variation and significant differences among studied populations of compared species. The Mediterranean cedars differ in respect to the length, width and shape of the male and female cones and in the length of the needles (e.g., Gaussen 1964;Krüssmann 1985;Vidaković 1991;Farjon 2010).…”

“…The increasing isolation between the west-, east-Mediterranean and central-Asiatic populations of the cedars was probably a reason for formation of remnant taxa (Gaussen 1964;Pons and Quézel 1985;Pons 1998;Qiao et al 2007). The Pleistocene climate oscillations were responsible for further reduction of the genus range (Elenga et al 2000;Svenning 2003;Fady et al 2008;Terrab et al 2008;Cheddadi et al 2009;Postigo-Mijarra et al 2010). The contemporary distribution of Mediterranean species reflects the overexploitation ( Fig.…”

Review of the cedar and oak forest-associated <i>Epuraea latipes</i> species group (Coleoptera: Nitidulidae, Epuraeinae), with description of a new species from southern Turkey

“…At that time Cedrus was known from the Rabat area in central-western Morocco (Feddi et al 2011). However, cedars may have marginally reached Spain via the Gibraltar Strait from northern Morocco during one of the last glacial periods at a time with markedly lower sea levels, thereby allowing a limited Wurmian presence of C. atlantica in extreme southern Spain (Cortes-Sanchez et al 2008, Terrab et al 2008). The presence of coastal cedar forests in northern Morocco and northern Algeria during the last glacial maximum has been demonstrated (Cheddadi et al 2009), and was followed by postglacial local extinction of low altitude cedar populations.…”