J Syst Evol ›› 2020, Vol. 58 ›› Issue (3): 247-262.DOI: 10.1111/jse.12524

• Research Articles • Previous Articles     Next Articles

A complex pattern of post‐divergence expansion, contraction, introgression, and asynchronous responses to Pleistocene climate changes in two Dipelta sister species from western China

Bin Tian1,2, Yi Fu2, Richard I. Milne3, Kang‐Shan Mao4, Yong‐Shuai Sun5,6*, Xiang‐Guang Ma1, and Hang Sun1*   

  1. 1Key Laboratory for Plant Diversity and Biogeography, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, China
    2Key Laboratory of Biodiversity Conservation in Southwest China, State Forestry Administration, Southwest Forestry University, Kunming 650224, China
    3Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh EH9 3JH, UK
    4Key Laboratory of Bio‐Resource and Eco‐Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China
    5Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, Yunnan, China
    6Centre for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Mengla 666303, Yunnan, China
  • Received:2018-11-13 Accepted:2019-06-11 Online:2019-06-24 Published:2020-05-01

Abstract:

The well‐known vicariance and dispersal models dominate in understanding the allopatric pattern for related species and presume the simultaneous occurrence of speciation and biogeographic events. However, the formation of allopatry could postdate the species divergence. We examined this hypothesis using DNA sequence data from three chloroplast fragments and five nuclear loci of Dipelta floribunda Maxim. and D. yunnanensis Franch, two shrub species with the circum Sichuan Basin distribution, combining the climatic niche modeling approach. The best‐fit model supported by the approximate Bayesian computation analysis indicated that D. floribunda and D. yunnanensis diverged during the mid‐Pleistocene period, consistent with the largest glacial period in the Qinghai–Tibet Plateau. The historically interspecific gene flow was identified, but seemed to have ceased after the last interglacial period, when the range of D. floribunda moved northward from the south of the Sichuan Basin. Furthermore, populations of D. floribunda had expanded obviously in the north of the Sichuan Basin after the last glacial maximum (LGM). Relatively, the range of D. yunnanensis expanded before the LGM, and reduced during the post‐LGM especially in the north of the Sichuan Basin, reflecting the asynchronous responses of related species to contemporary climate changes. Our results suggested that complex topography should be considered in understanding distributional patterns, even for closely related species and their demographic responses.

Key words: allopatric pattern, asynchronous demographic response, hABC, introgression, Pleistocene climate change, Sichuan Basin