J Syst Evol

• Research Article •    

Species boundaries and conservation implications of Cinnamomum japonicum, an endangered plant in China

Han‐Yang Lin1,2†, Yue Yang1†, Wen‐Hao Li1, Yu‐Xin Luo1, Xiao‐Hua Bai1, Tetsuo Ohi‐Toma3, Changkyun Kim4, Joo‐Hwan Kim5*, and Yun‐Peng Zhao1*   

  1. 1 Laboratory of Systematic and Evolutionary Botany and Biodiversity, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
    2 School of Advanced Study, Taizhou University, Taizhou 318000, Zhejiang, China
    3 Nature Fieldwork Center, Okayama University of Science, Okayama 700‐0005, Japan
    4 Division of Botany, Honam National Institute of Biological Resources, Mokpo 58762, South Korea
    5 Department of Life Science, Gachon University, Seongnam 13120, South Korea
    Han‐Yang Lin and Yue Yang contributed equally to this study.
    *Authors for correspondence. Yun‐Peng Zhao. E‐mail: ypzhao@zju.edu.cn; Joo‐Hwan Kim. E‐mail: kimjh2009@gachon.ac.kr
  • Received:2022-08-01 Accepted:2023-02-06 Online:2023-03-22

Abstract: Clear species boundaries are crucial for plans and actions on biodiversity conservation. However, morphological similarities among allied species can result in taxonomic difficulties, thus impeding conservation efforts. In China, Cinnamomum japonicum Siebold is a well-known endangered plant, yet suffers from longstanding taxonomic issues. Here, we explicitly evaluate whether C. japonicum, C. chenii, and C. chekiangense are the same phylogenetic species on the basis of a multi-individual sampling strategy. We identified three sets of low-copy orthologous genes from 19 Lauraceae taxa for phylogenetic inferences. Both the concatenation and coalescent-based phylogenies supported that C. chenii individuals were embedded in the C. japonicum clade, indicating these two taxa are conspecific. Meanwhile, C. chekiangense accessions formed a monophyly which was not sister to C. japonicum. This result, together with the morphological differences that the leaves of C. japonicum are glabrous with a faveolate pattern of venation while those of C. chekiangense have trichomes and inevident lateral veins, led us to consider both as two distinct species. Based on 17 728 neutral single nucleotide polymorphisms (SNPs), the ADMIXTURE analysis suggested that the Chinese C. japonicum populations in Zhoushan Archipelago (=C. chenii) were genetically differentiated from the Japanese and Korean ones. Furthermore, ecological niche modeling predicted that the present distribution area of Chinese C. japonicum is likely to be unsuitable under global warming scenarios. Together with its limited distribution and genetic uniqueness, we recommend that Chinese C. japonicum deserves conservation priorities.

Key words: Cinnamomum chekiangense, Cinnamomum chenii, Cinnamomum japonicum, ecological niche modeling, integrative taxonomy, species delimitation