Phylogeography and paleodistribution models of a widespread birch (Betula platyphylla Suk.) across East Asia: Multiple refugia, multidirectional expansion, and heterogeneous genetic pattern

Abstract

Widespread tree species cover large geographical areas and play important roles in various vegetation types. Understanding how these species responded to historical climatic changes is important for understanding community assembly mechanisms with evolutionary and conservation implications. However, the location of refugial areas and postglacial history of widespread trees in East Asia remain poorly known. We combined microsatellite data (63 populations, 1756 individuals) and ecological niche modeling to examine the range‐wide population diversity, genetic structure, and historical demography of a pioneer tree species, Asian white birch ( Betula platyphylla Suk.) across East Asia. We found a north‐to‐south trend of declining genetic diversity and five clusters, corresponding to geographical regions. Different clusters were inferred to have diverged through Pleistocene climatic oscillations and have different expansion routes, leading to genetic admixture in some populations. Ecological niche models indicated that the distribution of B. platyphylla during the last glacial maximum still had a large latitude span with slight shifts toward southeast, and northern populations had more variable distribution ranges than those in the south during later climatic oscillations. Our results reflect the relatively stable distribution through the last glacial–interglacial cycles and recent multidirectional expansion of B. platyphylla , providing new hypotheses for the response pattern of widespread tree species to climate change. The gradual genetic pattern from northeast to southwest and alternative distribution dynamics possibly resulted from environmental differences caused by latitude and topographic heterogeneity.

Prediction of the potential geographical distribution of Betula platyphylla Suk. in China under climate change scenarios

“…platyphylla were mainly concentrated in the Changbai Mountains, Xiaoxing’an Mountains, Greater Khingan Mountains, Yanshan Mountains, Taihang Mountains, Lvliang Mountains, Qinling Mountains, Qilian Mountains, Hengduan Mountains, central and southern Shandong Mountains, and Funiu Mountains. This range is consistent with the results of Chen et al [ 29 ]. The potential geographical distribution of B .…”

“…It can still perform well with either incomplete data or presence-only data [ 24 , 25 ]. It has been widely used to simulate forest geographical distribution [ 26 ], assess flower habitat protection [ 27 ], evaluate the habitat suitability of wild protected animals [ 28 ], speculate species refuges [ 29 ], and simulate the distribution of suitable areas of medicinal materials [ 30 ].…”

“…platyphylla multi-sanctuaries, multi-directional expansion, heterogeneous genetic models, etc. [ 29 ]. However, few scholars have predicted the potential geographical distribution pattern of B .…”

Genome‐scale phylogeography resolves the native population structure of the Asian longhorned beetle, Anoplophora glabripennis (Motschulsky)

“…Temperate forests and their associated communities experienced repeated fragmentation and range shifts due to historic changes in climate and sea levels, combined with diverse topography in the region. These biogeographic processes created ideal conditions for the evolution of high inter‐ and intraspecific diversity (Bai et al, 2010 ; Chen & Lou, 2019 ), which can result, at least partially, from the biogeographic history of the area. We observed some distinct phylogeographic patterns within ALB consistent with earlier publications and patterns seen in other forest species (Carter et al, 2009 ; Du et al, 2019 , 2021 ).…”

Are Cenozoic relict species also climatic relicts? Insights from the macroecological evolution of the giant sedges ofCarexsect.Rhynchocystis(Cyperaceae)

“…Thus, the progressively harsher conditions resulted in the disappearance of most of the Paleotropical vegetation from the WP before the beginning of the Pleistocene glaciation cycles (Mai, 1989; Milne and Abbott, 2002; Kovar‐Eder et al, 2006). Nonetheless, some Paleotropical elements were able to survive by retreating to refugia in southeastern Asia (Ye et al, 2016; Chen and Lou, 2019) and southwestern Europe (Valcárcel et al, 2017; Vitelli et al, 2017; Benítez‐Benítez et al, 2018), including locations in the Mediterranean and Black Sea basins (Rodríguez‐Sánchez and Arroyo, 2008; Médail and Diadema, 2009; Miguez et al, 2017) and the Macaronesian archipelagos (Valiente‐Banuet et al, 2006; Alarcón et al, 2013; Chen et al, 2014).…”