Genetic differentiation and phylogeography of partially sympatric species complex Rhizophora mucronata Lam. and R. stylosa Griff. using SSR markers

Mangrove forests are ecologically important but globally threatened intertidal plant communities. Effective mangrove conservation requires the determination of species identity management units and genetic structure. Here we investigate the genetic distinctiveness and genetic structure of an iconic but yet taxonomically confusing species complex Rhizophora mucronata and R. stylosa across their distributional range by employing a suite of 20 informative nuclear SSR markers. Our results demonstrated the general genetic distinctiveness of R. mucronata and R. stylosa and potential hybridization or introgression between them. We investigated the population genetics of each species without the putative hybrids and found strong genetic structure between oceanic regions in both R. mucronata and R. stylosa. In R. mucronata a strong divergence was detected between populations from the Indian Ocean region (Indian Ocean and Andaman Sea) and the Pacific Ocean region (Malacca Strait South China Sea ...