Both temperature fluctuations and East Asian monsoons have driven plant diversification in the karst ecosystems from southern China

Karst ecosystems in southern China are species-rich and have high levels of endemism, yet little is known regarding the evolutionary processes responsible for the origin and diversification of karst biodiversity.

Hanghui Kong1, Fabien L. Condamine2, AJ Harris3,  Junlin Chen1,Bo Pan4, Michael M€oller5,  Van Sam Hoang6, Ming Kang1,7

1  Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China 

2  CNRS, UMR 5554 Institut des Sciences del’Evolution (Universite de Montpellier),Montpellier, France

3  Department of Botany, MRC 166,Smithsonian Institution, National Museum of Natural History, Washington, DC, USA

4  Guangxi Institute of Botany, GuangxiZhang Autonomous Region and the Chinese Academy of Sciences, Guilin, China

5  Royal Botanic Garden Edinburgh, Edinburgh, UK

6  Forest Plant Department, Vietnam National University of Forestry, Hanoi,Vietnam

7  Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences, Nay Pyi Taw, Myanmar 

Correspondence

Ming Kang, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou,China.

Email: mingkang@scbg.ac.cn

PubYear : 2017

Volume : online

Publication Name: Molecular Ecology

Page number :

DOI: 10.1111/mec.14367

Abstract: Karst ecosystems in southern China are species-rich and have high levels of endemism, yet little is known regarding the evolutionary processes responsible for the origin and diversification of karst biodiversity. The genus Primulina (Gesneriaceae) comprises ca. 170 species endemic to southern China with high levels of ecological (edaphic) specialization, providing an exceptional model to study the plant diversification in karsts. We used molecular data from nine chloroplast and 11 nuclear regions and macroevolutionary analyses to assess the origin and cause of species diversification due to palaeoenvironmental changes and edaphic specialization in Primulina. We found that speciation was positively associated with changes in past temperatures and East Asian monsoons through the evolutionary history of Primulina. Climatic change around the mid-Miocene triggered an early burst followed by a slowdown of diversification rate towards the present with the climate cooling. We detected different speciation rates among edaphic types, and transitions among soil types were infrequently and did not impact the overall speciation rate. Our findings suggest that both global temperature changes and East Asian monsoons have played crucial roles in floristic diversification within the karst ecosystems in southern China, such that speciation was higher when climate was warmer and wetter. This is the first study to directly demonstrate that past monsoon activity is positively correlated with speciation rate in East Asia. This case study could motivate further investigations to assess the impacts of past environmental changes on the origin and diversification of biodiversity in global karst ecosystems, most of which are under threat.

KEYWORDS: biodiversity hotspots, climate change, diversification analyses, East Asian monsoons, edaphic, specialization, Primulina