Abundance and diversity of gastropods in replanted and natural mangrove sites in Guang-guang, Dahican, Mati City, Philippines

This study compared gastropod abundance and biodiversity in naturally grown and replanted mangroves in Guang-guang, Dahican, Mati, Philippines. To do this, a total of 12 transects (50 m) were laid perpendicular to the shore, and vertical quadrats were used for mangrove trees assessed every 5 m along the line transects. Gastropods were identified and counted on the mangrove tree leaves, trunks, and roots found in the natural and replanted sites. A total of 16 gastropod species from four families (Littorinidae, Neritidae, Trochidae, and Siphonariidae) were found. All 16 species were found in the natural sites, whereas four species—Nerita albicilla Linnaeus, 1758, Nerita histrio Linnaeus, 1758, Siphonaria sirius Pilsbry, 1894, and Siphonaria atra Quoy & Gaimard, 1833 —were absent from the replanted sites. Overall, more gastropods found in the replanted sites compared with the naturally grown sites (t-tests, df = 166, mean difference = -0.463, t-value = -7.42, P = 0.000) although the natural sites hosted more diverse species (H’ = 2.41 vs 2.39). The results suggest the need to improve mangrove conservation, including planting more mangrove species suitable for these habitats as they act as refugia for gastropods, other invertebrates and marine organisms.