Spatial ecological patterns of gastropods in relation to mangrove density in Kemujan Mangrove Forests, Karimunjawa National Park, Indonesia

Abstract

Mangrove ecosystems play a crucial role in supporting coastal biodiversity by providing vital habitats and ecological services for many marine organisms, including gastropods. Despite the extensive mangrove coverage in the Karimunjawa Islands, information on the composition, distribution, and ecological significance of gastropods in this region remains limited. This study investigates the diversity, abundance, and spatial distribution of gastropod species inhabiting the Kemujan mangrove forest in the Karimunjawa Islands. A total of eight gastropod species from six families were recorded across three sampling stations. The two most abundant species, Pirenella cingulata (Gmelin, 1791) and Terebralia sulcata (Born, 1778), both belonging to the Potamididae family, were widely distributed across all sites. Station 2, characterized by the lowest mangrove density, supported the highest gastropod abundance (80 Ind./5 m2), diversity (H’ = 1.73), and evenness (J’ = 0.83). In contrast, Station 1, with the highest mangrove density, exhibited the lowest abundance (53.6 ± 40 Ind./5 m2) and diversity (H’ = 1.05) and the highest dominance (D = 0.39). A strong negative correlation was observed between mangrove density and gastropod abundance. Denser mangrove stands are associated with increased shading, softer sediment, reduced food availability, and fewer habitat options—factors that may reduce habitat suitability for diverse gastropod communities. These findings underscore the influence of mangrove structure on gastropod assemblages and offer valuable insights for the conservation and management of mangrove ecosystems in the Karimunjawa Islands.