Geographical speciation related to Pleistocene range shifts in the western Mediterranean mountains (Reseda sect. Glaucoreseda, Resedaceae)

Abstract

Reseda sect. Glaucoreseda is a monophyletic group composed of five endemic tetraploid species with a disjunct distribution in the high mountains and plateaus of the Iberian Peninsula and Morocco. It was previously suggested that range shifts induced by Quaternary glaciations played an important role in the speciation of the group. We studied the evolution of R. sect. Glaucoreseda in order to infer historical range dynamics and speciation processes, and to understand current distributional patterns. Phylogeographic analyses were performed using nuclear ribosomal ITS and plastid trnL-F and rps16 sequences. Cloning of additive ITS sequences was carried out to elucidate the origin of intra-individual polymorphisms. A dated phylogeny based on ITS and cpDNA (rbcL, matK, trnL-F) sequences was used to estimate divergence times of R. sect. Glaucoreseda. Time estimates using Penalized Likelihood analyses indicate a late Pleistocene diversification of R. sect. Glaucoreseda. Incomplete lineage sorting of ancestral polymorphisms due to recent divergence, rather than rampant hybridisation, is suggested as the main cause of the phylogenetic incongruence detected between nuclear and plastid datasets. Our results support the vicariance hypothesis for population disjunctions in the Iberian Peninsula, in which an ancestral, widespread species could have undergone differentiation by Quaternary interglacial fragmentation. In contrast, long-distance dispersal across the Strait of Gibraltar may have been involved in the colonisation of North African plateaus by R. battandieri.

Diversification, Biogeographic Pattern, and Demographic History of Taiwanese Scutellaria Species Inferred from Nuclear and Chloroplast DNA

“…Although the Taiwanese topography is ragged, the vicariance hypothesis of speciation is untenable because the divergent times of species occurred much later than the geographic events (e.g., orogenesis). In contrast, species divergence during the warm interglacial periods was probably caused by long-distance dispersal followed by geographic isolation [68], [69]. Such scenarios were also proved with S-DIVA (see Figure 4).…”

Genetically diverse but with surprisingly little geographical structure: the complex history of the widespread herb Carex nigra (Cyperaceae)

“…, 2001; Kropf et al. , 2006; Martín‐Bravo et al. , 2010), promoted by populations being split among different mountains during warmer periods and by subsequent isolation.…”

Population Genetics Methods Applied to a Species Delimitation Problem: Endemic Trumpet Daffodils (NarcissusSectionPseudonarcissi) from the Southern Iberian Peninsula

“…These factors have significantly enhanced the diversification and speciation of plants in the region (Martín-Bravo et al 2010), which has resulted in an exceptionally rich flora comprising a large proportion of narrowly endemic taxa (Gó mez-Campo 1985;Sainz-Ollero and Moreno-Saiz 2002). Another factor contributing to the outstanding diversity of Mediterranean floras is environmental heterogeneity, which has promoted ecological specialization and the natural fragmentation and isolation of conspecific populations (Thompson 2005;Hughes et al 2006;Frajman and Oxelman 2007;Martín-Bravo et al 2010).…”

“…These factors have significantly enhanced the diversification and speciation of plants in the region (Martín-Bravo et al 2010), which has resulted in an exceptionally rich flora comprising a large proportion of narrowly endemic taxa (Gó mez-Campo 1985;Sainz-Ollero and Moreno-Saiz 2002). Another factor contributing to the outstanding diversity of Mediterranean floras is environmental heterogeneity, which has promoted ecological specialization and the natural fragmentation and isolation of conspecific populations (Thompson 2005;Hughes et al 2006;Frajman and Oxelman 2007;Martín-Bravo et al 2010). The diversifying role of plant specialization on specific substrates and its consequences for ecological speciation in the Baetic Ranges has often been emphasized in relation to dolomitic outcrops (Mota et al 2002(Mota et al , 2008, but the contribution of other similarly fragmented, infrequent habitat types to the high endemism rates characterizing the region has been infrequently considered (Medrano et al 2006;Medrano and Herrera 2008).…”

“…that are exclusively distributed throughout the Baetic Ranges of the southeastern Iberian Peninsula, one of the most prominent plant biodiversity hotspots of the Mediterranean Basin (Médail and Quézel 1997;Melendo et al 2003;Thompson 2005). Mediterranean mountains have been the site of a significantly high number of speciation events (Martín-Bravo et al 2010), which have resulted in a high number of endemic species and an exceptionally rich flora (Gó mezCampo 1985;Sainz-Ollero and Moreno-Saiz 2002). The genus Narcissus is also a remarkable example of Mediterranean lineage with a complex evolutionary history (Graham and Barrett 2004;Santos-Gally et al 2012).…”