In situglacial survival at the northern limit of tropical insular Asia by a lowland herbBegonia fenicis(Begoniaceae)

Abstract

Equatorward contraction and re‐expansion during and after the last glacial maximum has been reported for temperate plants, but little is known about latitudinal shifts of tropical plants in insular Asia. We used molecular methods to test the post‐glacial migration hypothesis for Begonia fenicis at the northern limit of tropical insular Asia, namely, the northern Philippines, southern Taiwan and the southern Ryukyus of Japan. Based on internal transcribed spacer sequences, analyses of phylogeographical structure suggested long‐term survival of island populations and negated recent northward migration; demographic analyses indicated spatial expansion in the early Pleistocene and subsequent stable demography. Based on nuclear microsatellites, Bayesian clustering and other spatial analyses indicated inter‐island differentiation, and coalescent analysis of migration indicated the lack of inter‐island migration during and after the last glacial maximum. Our results refuted the postglacial migration hypothesis for B. fenicis and suggest in situ survival through the last glacial maximum. The stable historical distribution and demography are probably attributable to the Kuroshio Current bringing warm and humid air, which washed these islands even during the glacial periods. Additionally, because these are low islands, absence of competition with montane plants descending to the lowlands during cooler periods may have mitigated the influence of temperature lowering and facilitated their survival. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174, 305–325.

The Miocene to Pleistocene colonization of the Philippine archipelago by Begonia sect. Baryandra (Begoniaceae)

“…Some of the phylogenetic incongruence may also be due to incomplete lineage sorting. Begonia species have been reported to exist as long‐term stable entities even through Pleistocene climatic cycles in Central America (Twyford et al, 2013) and the Ryuku Islands (Nakamura et al, 2014). Such isolated, long‐lived populations with poor gene flow may make Begonia species prone to harboring between‐population polymorphism and taking a relatively long time to reach monophyly.…”

Complex inter‐island colonization and peripatric founder speciation promote diversification of flightless Pachyrhynchus weevils in the Taiwan–Luzon volcanic belt

“…Nakamura et al, 2014). The current elevation of these islands ranges from several hundred metres in most islands to over a thousand metres in Batan (Yang et al, 1996) (Figure 1a).…”

“…Most of the islands of the Taiwan-Luzon volcanic belt were not connected to each other or to the Asian mainland during the Pleistocene glacial period (Voris, 2000), minimizing the effect of recent climatic changes on regional phylogeographical patterns (e.g. Nakamura et al, 2014). The current elevation of these islands ranges from several hundred metres in most islands to over a thousand metres in Batan (Yang et al, 1996) (Figure 1a).…”

Ecology and evolution on oceanic islands: broadening the botanical perspective

“…Nakamura et al . () provide a complementary view: islands as refuges of genetic diversity during climatic oscillations. In this case, the authors find evidence for long‐term survival of island populations of Begonia fenicis Merr., particularly at the limits (northern Philippines and southern Ryukyus) of its current distribution.…”

“…These observations suggest that distance to mainland (representing opportunities for island-mainland connection) is a significant factor in explaining patterns of genetic diversity and differentiation on islands. Nakamura et al (2014) provide a complementary view: islands as refuges of genetic diversity during climatic oscillations. In this case, the authors find evidence for long-term survival of island populations of Begonia fenicis Merr., particularly at the limits (northern Philippines and southern Ryukyus) of its current distribution.…”