Microsatellites Reveal Clonal Growth and Genetically Distinct Groups in Cryptocarya chinensis in Fragmented Lower Subtropical Forest, China

The lower subtropical monsoon evergreen broadleaved forest in South China (about 22° ~ 24° N) has a high conservation status, because of its uniqueness and high biodiversity. During the last few decades, most of these forests have been destroyed, and the remaining are being degraded by fragmentation. However, genetic information concerning the effects of fragmentation is currently lacking for plant species in these forests. In this study, therefore, eight microsatellites were used to study six Cryptocaya chinensis fragmented populations in Guangdong Province South China, and the results revealed a complex pattern of genetic variation within and among C. chinensis populations. Firstly, genetic variations demonstrate hitherto undetected clonal growth in C. chinensis. Secondly, current population structure of C. chinensis reflects an interaction between ancient homogeneous level of genetic variation and contemporary bottleneck via fragmentation. Small populations maintain substantial genetic variation of the initial populations through clonal growth, and do not show genetic depauperation compared to larger populations. Finally, two genetically distinct groups (West and Middle- East groups) are found in this area, connected by highly mixed contact zone.