Population dynamics linked to glacial cycles in Cercis chuniana F. P. Metcalf (Fabaceae) endemic to the montane regions of subtropical China

Abstract

The mountains of subtropical China are an excellent system for investigating the processes driving the geographical distribution of biodiversity and radiation of plant populations in response to Pleistocene climate fluctuations. How the major mountain ranges in subtropical China have affected the evolution of plant species in the subtropical evergreen broadleaved forest is an issue with long‐term concern. Here, we focused on Cercis chuniana, a woody species endemic to the southern mountain ranges in subtropical China, to elucidate its population dynamics. We used genotyping by sequencing (GBS) to investigate the spatial pattern of genetic variation among 11 populations. Geographical isolation was detected between the populations located in adjacent mountain ranges, thought to function as geographical barriers due to their complex physiography. Bayesian time estimation revealed that population divergence occurred in the middle Pleistocene, when populations in the Nanling Mts. separated from those to the east. The orientation and physiography of the mountain ranges of subtropical China appear to have contributed to the geographical pattern of genetic variation between the eastern and western populations of C. chuniana. Complex physiography plus long‐term stable ecological conditions across glacial cycles facilitated the demographic expansion in the Nanling Mts., from which contemporary migration began. The Nanling Mts. are thus considered as a suitable area for preserving population diversity and large population sizes of C. chuniana compared with other regions. As inferred by ecological niche modeling and coalescent simulations, secondary contact occurred during the warm Lushan–Tali Interglacial period, with intensified East Asia summer monsoon and continuous habitat available for occupation. Our data support the strong influence of both climatic history and topographic characteristics on the high regional phytodiversity of the subtropical evergreen broadleaved forest in subtropical China.

High genetic diversity and low population differentiation of a medical plant Ficus hirta Vahl., uncovered by microsatellite loci: implications for conservation and breeding

“…The correlation between the geographical distance and genetic divergence of F. hirta populations were further supported by an IBD analysis with Mantel test ( R 2 = 0.281, P < 0.001). This may be related to the geographical isolation barrier of Luoxiao Mountains and Nanling Mountains between the mid-south and northeast populations, diminishing the gene flow between the above two clusters (which can also be found in other species like Gynostemma pentaphyllum [ 21 ], Eomecon chionantha [ 31 ] and Cercis chuniana [ 32 ]. Although there was a significant IBD patterns of F. hirta , we found a relatively low genetic differentiation in F. hirta ( G’ ST = 0.147) (Table 3 ).…”

Genomic insights into differentiation and adaptation of Amorphophallus yunnanensis in the mountainous region of Southwest China

“…Due to the diverse topography and ecology, this region has long been regarded as a global hotspot of biodiversity (López‐Pujol et al., 2011 ). These characteristics make Southwest China an excellent system for studying processes that drive the geographical distribution of biodiversity (Liu et al., 2021 ). One important question is whether genetic differentiation is driven by complete geographical isolation or by environmental selection.…”