Genetic diversity of seagrass Thalassia hemprichii and Enhalus acoroides in coastal area of East Java

Seagrass degradation occurring worldwide in the last few decades led scientists and governments to take a role in saving this ecosystem. Seagrass transplantation is a direct action to increase seagrass density or recover damaged seagrass habitats. Regrettably, transplantation does not guarantee the success of coastal restoration. The transplants were not resistant against environmental stress at its new habitats. One factor that should be considered when sourcing plant donor materials is genetic diversity. In this paper, we assessed a donor site, Labuhan Beach, where the seagrass species of Thalassia hemprichii and Enhalus acoroides occur. RAPD (Random Amplified Polymorphism DNA) was performed to discover polymorphic fragments in order to interprete variation genetic of these species. Genetic diversity of the donor population was compared with the same species inhabiting an undisturbed conservation area (Baluran National Park). The data revealed that genetic diversity (allelic richness) of T. hemprichii of Labuhan population (0.19) was higher than the population in Baluran (0.15). Equally, for E. acoroides genetic diversity of the Labuhan population (0.21) was higher than at Baluran (0.16; t-test p=0.037). A phylogenetic analysis of the MatK region verified that the seagrass samples taken from Labuhan Beach were indeed T. hemprichii and E. acoroides based on identity with sequences in the GenBank database. This finding suggested that the seagrass population in Labuhan could be used as donor material; however, geographic distance and differing environmental conditions must also be considered.