Evolutionary history of the angiosperm flora of China

Li Min Lu, Institute of Botany Chinese Academy of Sciences
Ling Feng Mao, Nanjing Forestry University
Tuo Yang, Nanjing Forestry University
Jian Fei Ye, Institute of Botany Chinese Academy of Sciences
Bing Liu, Institute of Botany Chinese Academy of Sciences
Hong Lei Li, Chongqing University of Arts and Science
Miao Sun, University of Florida
Joseph T. Miller, Commonwealth Scientific and Industrial Research Organization
Sarah Mathews, Commonwealth Scientific and Industrial Research Organization
Hai Hua Hu, Institute of Botany Chinese Academy of Sciences
Yan Ting Niu, Institute of Botany Chinese Academy of Sciences
Dan Xiao Peng, Institute of Botany Chinese Academy of Sciences
You Hua Chen, Chengdu Institute of Biology Chinese Academy of Sciences
Stephen A. Smith, University of Michigan, Ann Arbor
Min Chen, Institute of Botany, Jiangsu Province and Chinese Academy of Science
Kun Li Xiang, Institute of Botany Chinese Academy of Sciences
Chi Toan Le, Institute of Botany Chinese Academy of Sciences
Viet Cuong Dang, Institute of Botany Chinese Academy of Sciences
An Ming Lu, Institute of Botany Chinese Academy of Sciences
Pamela S. Soltis, Florida Museum of Natural History
Douglas E. Soltis, University of Florida
Jian Hua Li, Hope College
Zhi Duan Chen, Institute of Botany Chinese Academy of Sciences

Abstract

© 2018 Macmillan Publishers Limited, part of Springer Nature. All rights reserved. High species diversity may result from recent rapid speciation in a 'cradle' and/or the gradual accumulation and preservation of species over time in a 'museum'. China harbours nearly 10% of angiosperm species worldwide and has long been considered as both a museum, owing to the presence of many species with hypothesized ancient origins, and a cradle, as many lineages have originated as recent topographic changes and climatic shifts - such as the formation of the Qinghai-Tibetan Plateau and the development of the monsoon - provided new habitats that promoted remarkable radiation. However, no detailed phylogenetic study has addressed when and how the major components of the Chinese angiosperm flora assembled to form the present-day vegetation. Here we investigate the spatio-temporal divergence patterns of the Chinese flora using a dated phylogeny of 92% of the angiosperm genera for the region, a nearly complete species-level tree comprising 26,978 species and detailed spatial distribution data. We found that 66% of the angiosperm genera in China did not originate until early in the Miocene epoch (23 million years ago (Mya)). The flora of eastern China bears a signature of older divergence (mean divergence times of 22.04-25.39 Mya), phylogenetic overdispersion (spatial co-occurrence of distant relatives) and higher phylogenetic diversity. In western China, the flora shows more recent divergence (mean divergence times of 15.29-18.86 Mya), pronounced phylogenetic clustering (co-occurrence of close relatives) and lower phylogenetic diversity. Analyses of species-level phylogenetic diversity using simulated branch lengths yielded results similar to genus-level patterns. Our analyses indicate that eastern China represents a floristic museum, and western China an evolutionary cradle, for herbaceous genera; eastern China has served as both a museum and a cradle for woody genera. These results identify areas of high species richness and phylogenetic diversity, and provide a foundation on which to build conservation efforts in China.