The Quaternary evolutionary history, potential distribution dynamics, and conservation implications for a Qinghai-Tibet Plateau endemic herbaceous perennial, Anisodus tanguticus (Solanaceae).
Various hypotheses have been proposed about the Quaternary evolutionary history of plant species on the Qinghai-Tibet Plateau (QTP), yet only a handful of studies have considered both population genetics and ecological niche context. In this study, we proposed and compared climate refugia hypotheses based on the phylogeographic pattern of Anisodus tanguticus (three plastid DNA fragments and nuclear internal transcribed spacer regions from 32 populations) and present and past species distribution models (SDMs). We detected six plastid haplotypes in two well-differentiated lineages. Although all haplotypes could be found in its western (sampling) area, only haplotypes from one lineage occurred in its eastern area. Meanwhile, most genetic variations existed between populations (F ST = 0.822). The SDMs during the last glacial maximum and last interglacial periods showed range fragmentation in the western area and significant range contraction in the eastern area, respectively, in comparison with current potential distribution. This species may have undergone intraspecific divergence during the early Quaternary, which may have been caused by survival in different refugia during the earliest known glacial in the QTP, rather than geological isolation due to orogenesis events. Subsequently, climate oscillations during the Quaternary resulted in a dynamic distribution range for this species as well as the distribution pattern of its plastid haplotypes and nuclear genotypes. The interglacial periods may have had a greater effect on A. tanguticus than the glacial periods. Most importantly, neither genetic data nor SDM alone can fully reveal the climate refugia history of this species. We also discuss the conservation implications for this important Tibetan folk medicine plant in light of these findings and SDMs under future climate models. Together, our results underline the necessity to combine phylogeographic and SDM approaches in future investigations of the Quaternary evolutionary history of species in topographically complex areas, such as the QTP.
State Key Laboratory of Grassland Agro-Ecosystem School of Life Sciences Lanzhou University Lanzhou 730000 Gansu China.
Dong-Shi
DS
Wan
College of Plant Sciences Xinjiang Production & Construction Corps Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin Tarimu University Alar Xinjiang China.
Jian-Ju
JJ
Feng
State Key Laboratory of Grassland Agro-Ecosystem School of Life Sciences Lanzhou University Lanzhou 730000 Gansu China.
De-Chun
DC
Jiang
State Key Laboratory of Grassland Agro-Ecosystem School of Life Sciences Lanzhou University Lanzhou 730000 Gansu China; Key Laboratory for Bio-resources and Eco-environment of Ministry of Education College of Life Science Sichuan University Chengdu 610064 China.
Kang-Shan
0000-0002-0071-1844
KS
Mao
Key Laboratory of Biodiversity and Biogeography Kunming Institute of Botany Chinese Academy of Sciences Lanhei Road 132, Heilongtan Kunming 650204 Yunnan China.
Yuan-Wen
YW
Duan
Faculty of Biology and Geology University of Marburg 35032 Marburg Germany.
Georg
G
Miehe
Faculty of Biology and Geology University of Marburg 35032 Marburg Germany.
Lars
L
Opgenoorth
Glacial refugia; nuclear internal transcribed spacer; phylogeographic pattern; plastid DNA; species distribution modeling