The Quaternary evolutionary history, potential distribution dynamics, and conservation implications for a Qinghai–Tibet Plateau endemic herbaceous perennial, Anisodus tanguticus (Solanaceae)

Abstract

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 (FST = 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.

Phylogeography of Orinus (Poaceae), a dominant grass genus on the Qinghai-Tibet Plateau

“…In comparison with Europe and North America, the genetic structure and variation in Quaternary phylogeographic histories of plant species are much more pronounced in topographically complex regions of China, such as the Qinghai-Tibet Plateau (QTP) (e.g. Zhang et al, 2005;Meng et al, 2007;Wang et al, 2009aWang et al, , 2014Opgenoorth et al, 2010;Xu et al, 2010;Qiu et al, 2011;Zou et al, 2012;Wen et al, 2014;Liu et al, 2015;Zhang et al, 2015;Wan et al, 2016).…”

“…Recent studies have shown evidence for the importance of Quaternary climatic oscillations in explaining genetic variability, distributions and demographic patterns observed in modern populations of QTP species (Tang & Shen, 1996;Bawa et al, 2010;Jia et al, 2011;Liu et al, 2012Liu et al, , 2014bLiu et al, , 2015Wan et al, 2016). In particular, many alpine species retreated to eastern or south-eastern refugia during glacial periods and recolonized the central plateau platform during the interglacial or postglacial stages (e.g.…”

“…In particular, many alpine species retreated to eastern or south-eastern refugia during glacial periods and recolonized the central plateau platform during the interglacial or postglacial stages (e.g. Zhang et al, 2005;Meng et al, 2007;Chen et al, 2008;Yang et al, 2008;Wu et al, 2010;Tian et al, 2011;Jia et al, 2012;Liu et al, 2015;Wan et al, 2016). In contrast, some other cold-tolerant alpine species were able to survive in situ through glacial periods in multiple ice-free refugia or microrefugia (Wang et al, 2009b;Opgenoorth et al, 2010;Jia et al, 2011;Ma et al, 2014).…”

“…Although many phylogeographic studies of QTP plants have been performed, these have mostly focused on woody plants or herbaceous dicot lineages that occur in forested areas (e.g. Zhang et al, 2005;Meng et al, 2007;Chen et al, 2008;Tian et al, 2011;Jia et al, 2012;Wan et al, 2016). The grasslands comprise a significant portion of the QTP and are dominated by grasses (Poaceae).…”

Adapting to extreme environments: can coral reefs adapt to climate change?

“…These environments provide an ideal natural laboratory for studies on adaptive evolution. Organisms that live in the QTP must have undergone a series of significant adaptive evolutionary genetic changes to produce a wide range of ecologically adaptive characters [51,52]. Cyanobacteria can exist symbiotically in corals [53], and genome and transcriptome sequencing of cyanobacteria Trichormus sp.…”