Biodiversity and density of marine intertidal gastropods in tropical seagrass meadows on Gorom Island, East Seram, Maluku, Indonesia

Abstract

Gastropods are benthic invertebrates from the Mollusca phylum that live in association with seagrass meadows on various types of substrates in the intertidal zone. This study aims to analyze the species composition and density of gastropods in seagrass meadows. The study was carried out from November to December 2016 in Rarat Village, Gorom Island, East Seram, Maluku. Estimation of seagrass and gastropods was conducted using a systematic sampling method. Analysis of species composition, density, and regression analyses were carried out to determine the influence and relationship of seagrass communities with gastropods. There were 7 seagrass species from 2 families, including 4 species from the Potomogetonaceae family (Enhalus accoroides, Thalassia hemprichii, Halophila ovalis, Halophila spinulosa), and 3 species from the Cymodoceaceae family (Cymodocea rotundata, C. serrulata, Thalassodendron ciliatum). A total of 266 individual gastropods, representing 30 species, 13 families, and 4 orders were identified. The highest density was determined for Conus virgo (Conidae), the highest number of species was from the family Strombidae (7 species), and Neogastropods was the order that dominated the gastropod community, with a total of 16 species from 8 families. The density of the gastropod community was positively related to the density of seagrass vegetation (r=0.62), but seagrass vegetation only gave a 39% effect on the density of gastropods (R 2 =0.39). Important conservation efforts are carried out through monitoring and controlling the flow of rivers that lead to seagrass meadows to support the life of seagrass vegetation and gastropod communities.