Phylogeographic analyses suggest that a deciduous species (Ostryopsis davidiana Decne., Betulaceae) survived in northern China during the Last Glacial Maximum

Abstract

Aim Palaeontologial data suggest that all temperate forest species in northern China migrated southwards during the Last Glacial Maximum (LGM) and recolonized post‐glacially within the Holocene. We tested this assumption using phylogeographical studies of a temperate deciduous shrub species (Ostryopsis davidiana Decne., Betulaceae), which has a wide distribution in northern China. Location Northern China. Methods We sequenced two chloroplast DNA (cpDNA) fragments (trnL–trnF and psbA–trnH, together about 1300 bp in length) of 294 plants from 21 populations across the total distribution range of this species. We used maximum parsimony and haplotype network methods to construct phylogenetic relationships among haplotypes. Results The analysis of cpDNA variation identified eight haplotypes. A single haplotype was fixed in all populations except for one population that was polymorphic, having two haplotypes. The population subdivisions were extremely high (GST = 0.972 and NST = 0.974), suggesting very low gene flow between populations. Haplotypes clustered into two tentative clades, both of which occur in the southern region of the species’ range but only one of which occurs in the northern region. Across the sampled populations, the haplotype distributions were differentiated geographically. Main conclusions Our analyses suggest that multiple refugia were maintained across the range of O. davidiana in both northern (north of the Qing Mountains) and southern (south of the Qing Mountains) regions during the LGM rather than that the species survived only in the south and subsequently colonized northwards. The extremely low within‐population diversity of this species suggests strong bottleneck or founder effects within each fragmented region during the Quaternary climatic oscillations. These findings provide important clues for understanding range shifts and changes in within‐ and/or between‐population genetic diversity of temperate forests in response to past climatic oscillations in northern China.

Chloroplast View of the Population Genetics and Phylogeography of a Widely Distributed Shrub Species, <I>Rhododendron dauricum</I> (Ericaceae)

“…Phylogeographic Structure and Inference of Demographic Patterns -Our results on the phylogeographic structure of R. dauricum were consistent with previous studies of temperate montane flora in northeastern China, which were strongly structured phylogeographically (Chen et al 2008;Tian et al 2009;Chen et al 2012b). In this study, N ST was significantly …”

“…Similar phenomena have also been observed in Ostryopsis davidiana Decne. (Tian et al 2009), Fagus engleriana Seemen ex Diels (Lei et al 2012), Quercus variabilis Blume (Chen et al 2012a) and Juglans cathayensis Dode (Bai et al 2014). In addition, the results of the neutrality test suggested stable population dynamics recently, implying no spatial expansions in the post-glaciations.…”

Phylogeography of postglacial range expansion in Juglans mandshurica (Juglandaceae) reveals no evidence of bottleneck, loss of genetic diversity, or isolation by distance in the leading-edge populations

“…Initially, temperate forests in the Northern Hemisphere were thought to have retreated southward during the glacial periods and then to have re-colonized the previously uninhabitable northern regions at the warm and wet interglacials (Hewitt, 2000(Hewitt, , 2004. However, recent phylogeographic studies of cool-temperate trees in continental East Asia have clearly shown that this southern refuge model does not apply: cool-temperate trees survived the ice ages in situ rather than moved to the south (Bai et al, 2010;Hu et al, 2008;Liu et al, 2014;Tian et al, 2009;Zeng et al, 2011;Zeng et al, 2015). Consequently, postglacial range expansions of the eastern Asian temperate trees were necessarily spatially limited compared to the southern refuge model.…”

Species delimitation and biogeography of two fir species (Abies) in central China: cytoplasmic DNA variation

“…If this is correct, then the current distribution of populations is likely to have resulted from expansions from these different refugia, with secondary contact occurring in some areas giving rise to populations (for example, populations 2, 11, 23 and 24) polymorphic for mitotypes diagnostic of the different phylogeographic groups. Other surveys of molecular variation in different plant species occurring in central China, such as Taxus wallichiana (Gao et al, 2007), Pinus tabulaeformis (Chen et al, 2008), Ostryopsis davidiana (Tian et al, 2009), Eurycorymbus cavaleriei , have also indicated that multiple refugia existed in this region during the Quaternary.…”

“…These two species occur exclusively in central China where many indigenous species shifted their distribution ranges in response to Quaternary climatic oscillations even though the region was never covered by ice sheets during the Quaternary (Chen et al, 2008;Tian et al, 2009). The occurrence of range fragmentation and adaptation to new niches during this period may have promoted speciation in the region (Qian and Ricklefs, 2000).…”