Prof. ZHU Hua of Xishuangbanna Tropical Botanical Garden (XTBG) recently addresssed the issue of origin and evolution of biota in Hainan Island, China. Through comparative studies of biotic groups, geological structures and palaeomagnetism, it is suggested that Hainan Island was connected to Vietnam and Guangxi during the Eocene, and subsequently moved southeastward to its current position.

Related results were published in SCIENCE CHINA Earth Sciences.

The researcher mainly discussed the origin of biota in Hainan Island from the perspectives of molecular phylogeny and paleobotany, and identified the formation and evolutionary processes of biological groups in Hainan Island through genomic, phylogenetic and molecular biogeographic studies.

The results showed that the fauna and flora of Hainan had land connection with Vietnam and Guangxi during the Eocene–Oligocene, which explains the early occurrence and divergence of genera and species. In the Miocene (ca. 15 million years ago), Hainan Island moved to its current position, and the population and genetic divergence of late-diverged species could be explained by the close distance or land connection between Hainan Island and Leizhou Peninsula.

In the Eocene-Oligocene period, southwest China and Hainan Island had subtropical vegetation and flora. However, the fossil group in southeast China (in Maoming, near present-day Hainan Island) in the Late Eocene indicated a tropical rainforest vegetation and flora. This suggests that in the Paleogene, Hainan Island may have been located near or on the southwest border of Guangxi and northern Vietnam, rather than in its present location. Southwest China and Hainan Island during the Eocene–Oligocene, and fossil assemblages from Late Eocene Southeastern China (near today’s Hainan Island) indicate the presence of tropical rainforest vegetation and floras.

The distribution of the flora in Hainan Island basically presents a northeast-southwest tilting pattern, which can be explained by the counterclockwise rotation of Hainan Island during its southeastward movement.

“This study provides a basis for the in-depth exploration of the origin and evolution of the biota of Hainan Island,” said ZHU Hua.

Contact

ZHU Hua Ph.D

Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China                       

E-mail: zhuh@xtbg.ac.cn        

First published:  03 December 2024