The historical biogeography of Scabiosa (Dipsacaceae): implications for Old World plant disjunctions

Abstract

Aim To reconstruct the temporal and biogeographical history of Old World disjunctions in Scabiosa (Dipsacaceae) and the timing of diversification in the Mediterranean Basin, in order to evaluate the importance of biogeographical and climatological history (particularly the onset of a mediterranean climate) in shaping Scabiosa distributions. Location Europe and the Mediterranean Basin, southern Africa and eastern Asia. Methods This study uses maximum‐likelihood and Bayesian phylogenetic analyses of chloroplast DNA (atpB–rbcL, trnL–trnF, trnS–trnG, psbA–trnH) and nuclear ribosomal DNA [internal transcribed spacer (ITS) and external transcribed spacer (ETS)] from 24 out of c. 37 ingroup taxa, beast molecular dating, and the dispersal–extinction–cladogenesis method (Lagrange) to reconstruct ancestral geographical ranges and the timing of diversification of the major clades of Scabiosa. Results Biogeographical and divergence time reconstructions showed that Scabiosa originated during the Miocene and diversified in Europe, followed by independent movements into Asia and Africa. Several of the major clades were inferred to have radiated sometime between the late Miocene and early Pleistocene, a timeframe that encompasses the onset of the mediterranean climate in Europe. More recent middle–late Pleistocene radiations in the Mediterranean Basin and southern Africa have played a large role in Scabiosa diversification. Main conclusions Members of Scabiosa appear to have capitalized on adaptations to montane and/or dry conditions in order to colonize similar habitats in different biogeographical regions. The formation of the East African Rift mountains is potentially of great importance in explaining the southward migration of Scabiosa. The initial diversification of Scabiosa in Europe during the Miocene is not consistent with the initiation of the mediterranean climate, but may instead be associated with increased aridity and the retreat of subtropical lineages during this time. However, the radiation of some of the major subclades within Scabiosa may have been associated with an emerging mediterranean climate. More recent and rapid radiations in both the Mediterranean Basin and southern Africa highlight the probable importance of Pleistocene climate fluctuations in Scabiosa diversification.

Phylogeography ofSyringa josikaea(Oleaceae): Early Pleistocene divergence from East Asian relatives and survival in small populations in the Carpathians

“…While the broader time frame of the confidence interval spans from the Pliocene to the Pleistocene, 1.88 Mya falls in the Gelasian (2.56‐1.81 Mya), the opening epoch of the Pleistocene. Previous studies of other taxa had found that disjunctions in Eurasian lineages took place in the Late Miocene, Pliocene or Early Pleistocene (Yokohama et al ., ; Zhang et al ., ; Tu et al ., ; Carlson et al ., ), and had hypothesized that climatic changes may have been the cause for the disruption of formerly wide distribution areas of ancestral taxa. On this background, it seems reasonable to postulate that S. josikaea separated from its East Asian relatives in a cooler and drier period in the Early Pleistocene (Huntley, ; Svenning, ).…”

“…Such disjunctions may reach continental scales (Thorne, ; Milne, ; Wen & Ickert‐Bond, ; Kadereit & Baldwin, ). Disjunct distributions of plant taxa between eastern and western Eurasia originated over a long time period from the Oligocene and Early Miocene (Xiang et al ., , ; Donoghue, Bell & Li, ) to the Late Miocene and Pliocene (Zhang, Uhink & Kadereit, ; Tu et al ., ; Carlson, Linder & Donoghue, ). While the origin of older disjunctions may be associated with continental movements, e.g., those resulting in the uplift of the Tibetan Plateau, more recent disjunctions may have been caused by climatic changes especially in the Pliocene and Pleistocene (Zhang et al ., ; Tu et al ., ).…”

Evolutionary diversifications of plants on the Qinghai-Tibetan Plateau

“…The Pliocene climatic changes have been suggested to be a more plausible explanation for more recent disjunctions between Europe and Asia (Fiz-Palacios et al, 2010; Tu et al, 2010; Carlson et al, 2012). The genus Pistacia represents an example of a widespread ancestral area of the Old World clade of Pistacia in MEA and eastern Asia (Yi et al, 2008; Xie et al, 2014).…”

Long‐distance dispersal or postglacial contraction? Insights into disjunction between Himalaya–Hengduan Mountains and Taiwan in a cold‐adapted herbaceous genus, Triplostegia

“…To estimate the crown age of Triplostegia, we downloaded sequences of three cpDNA regions (trnH-psbA, trnL-F, and trnS-trnG) for 41 Dipsacales species (including five Adoxaceae species as outgroups) from GenBank (Table S4) that represent all major lineages of Dipsacales (Bell & Donoghue, 2005;Carlson, Linder, & Donoghue, 2012;Wang, Landrein et al, 2015). Sequences were assembled, with 16 Triplostegia haplotypes identified from the same three cpDNA regions, to represent all 20 cpDNA haplotypes identified in the phylogeographic analyses.…”