Two-way migration ofLychnis wilfordiicaused by the circular landform of Japan-Korea-northeast China-Russian Far East region and its suggestion for conservation in northeast Asia

Abstract

In northeast Asia, substantial portion of the floras, including endangered species, are shared among its component countries in the continental, peninsula, and island parts largely through Quaternary migration. To effectively conserve nationally endangered plants in Northeast Asia, transnational conservation studies are vitally needed. Lychnis wilfordii (Caryophyllaceae) has disjunct distribution in Russian Far East (Primorsky Krai), northeast China (Jilin), Korea (Gangwon-do) and Japan (Hokkaido, Aomori, Nagano), surrounding the sea, and this is designated as an endangered species in Japan and Korea. Population genetic and molecular dating analyses were conducted 1) to elucidate geographic genetic structure covering the species range, 2) to test possible scenarios of migration, and 3) to develop logical plans for effective conservation. Population genetic analyses indicated the continent and peninsula parts (north and south Primorsky Krai, Jilin, and Gangwon-do) had higher genetic diversity compared to those in the Japanese Archipelago (Hokkaido and Nagano). Five genetically distinct groups were recognized, namely, Nagano, Gangwon-do, Jilin, north and south Primorsky Krai plus Aomori, and Hokkaido. Genetic distance between Hokkaido and Nagano was larger than between Hokkaido and north Primorsky Krai, and between Nagano and Gangwon-do, crossing national borders and the natural barrier of the sea. Considering these results, L. wilfordii likely migrated from the Asian continent to the Japanese Archipelago using two routes: north route from Russian Far East to Hokkaido and Aomori, and south route from the Korean Peninsula to Nagano. Based on molecular dating, migration from the continent to the islands likely occurred from the middle Pleistocene to the Holocene. For effective conservation of L. wilfordii, Hokkaido and Nagano populations should be distinguished as different evolutionary significant units, although these two regions belong to the same country, because Hokkaido and Nagano populations are at the different ends of the two migratory routes based on the migration scenario.

Circular genetic structure of the Abies nephrolepis species complex shaped by the circular landform of Northeast Asia

“…The high species diversity in northeast Asia is due to repeated contacts and isolations according to species range shifts in response to drastic environmental changes during climate fluctuations (Qian & Ricklefs, 2000). However, despite the exponential growth of phylogeographic research over the past two decades, few phylogeographic studies have extensively covered northeast Asia (Aizawa et al., 2007, 2009; Tamura et al., 2020), while most phylogeographic studies in East Asia have focused on the southern parts, namely, the central and southern parts of China and southern and central Japan (Jin et al., 2016; Lee et al., 2014; Li et al., 2008; Park et al., 2019; Qiu et al., 2009, 2011). The results of this study provide an empirical example of high plant species diversity affected by a complex phylogeographic history due to climate change and sea‐level fluctuations combined with physiographical complexities in northeast Asia.…”

“…The high species diversity in northeast Asia is due to repeated contacts and isolations according to species range shifts in response to drastic environmental changes during climate fluctuations (Qian & Ricklefs, 2000). However, despite the exponential growth of phylogeographic research over the past two decades, few phylogeographic studies have extensively covered northeast Asia (Aizawa et al, 2007(Aizawa et al, , 2009Tamura et al, 2020), while most phylogeographic studies in East Asia have focused on the…”