Effects of Pleistocene sea-level fluctuations on mangrove population dynamics: a lesson from Sonneratia alba

BMC Evolutionary Biology

Research Article

Cairong Zhong¹  Yuchen Yang²  Shuhuan Yang²  Suhua Shi²  Lu Fang²  Jianfang Li²  Renchao Zhou²  Xinnian Li²  Norman C. Duke³ 

[1] Hainan Dongzhai Harbor National Nature Reserve, 571129, Haikou, China;State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, Sun Yat-sen University, 510275, Guangzhou, China;Trop WATER, James Cook University, Townsville, Quennsland, Australia;

关键词: Gene flow;    Genetic diversity;    Indo-West Pacific;    Mangroves;    Pleistocene glaciations;   

DOI  :  10.1186/s12862-016-0849-z

 received in 2016-09-19, accepted in 2016-12-08,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundA large-scale systematical investigation of the influence of Pleistocene climate oscillation on mangrove population dynamics could enrich our knowledge about the evolutionary history during times of historical climate change, which in turn may provide important information for their conservation.ResultsIn this study, phylogeography of a mangrove tree Sonneratia alba was studied by sequencing three chloroplast fragments and seven nuclear genes. A low level of genetic diversity at the population level was detected across its range, especially at the range margins, which was mainly attributed to the steep sea-level drop and associated climate fluctuations during the Pleistocene glacial periods. Extremely small effective population size (Ne) was inferred in populations from both eastern and western Malay Peninsula (44 and 396, respectively), mirroring the fragility of mangrove plants and their paucity of robustness against future climate perturbations and human activity. Two major genetic lineages of high divergence were identified in the two mangrove biodiversity centres: the Indo-Malesia and Australasia regions. The estimated splitting time between these two lineages was 3.153 million year ago (MYA), suggesting a role for pre-Pleistocene events in shaping the major diversity patterns of mangrove species. Within the Indo-Malesia region, a subdivision was implicated between the South China Sea (SCS) and the remaining area with a divergence time of 1.874 MYA, corresponding to glacial vicariance when the emerged Sunda Shelf halted genetic exchange between the western and eastern coasts of the Malay Peninsula during Pleistocene sea-level drops. Notably, genetic admixture was observed in populations at the boundary regions, especially in the two populations near the Malacca Strait, indicating secondary contact between divergent lineages during interglacial periods. These interregional genetic exchanges provided ample opportunity for the re-use of standing genetic variation, which could facilitate mangrove establishment and adaptation in new habitats, especially in the context of global climate changes.ConclusionPhylogeogrpahic analysis in this study reveal that Pleistocene sea-level fluctuations had profound influence on population differentiation of the mangrove tree S. alba. Our study highlights the fragility of mangrove plants and offers a guide for the conservation of coastal mangrove communities experiencing ongoing changes in sea-level.

【 授权许可】

CC BY   
© The Author(s). 2017