The Effect of Substrate Variation on the Structure of Macrobenthic Communities in the Seagrass Beds of Tarahan Island

Abstract

Research on macrobenthic diversity in seagrass habitats in the waters of Tarahan Island highlights the important role of substrate variation in shaping benthic community structure. Comparisons between two stations with different substrate characteristics show that the dominance of seagrass and sand cover at Station 1 creates a more heterogeneous and stable environment, thereby supporting higher abundance and diversity of macrobenthos compared to Station 2, which is dominated by macroalgae and coral/rock. Gastropods emerged as the most dominant group, utilizing the complexity of seagrass habitats as a source of food, protection, and microhabitats. Additionally, Bivalvia and Malacostraca were more abundant in sandy-seagrass habitats, while Holothuroidea were only found in limited numbers on stable organic-sand substrates. Variations in community composition between stations underscore the importance of seagrass beds as hotspots of benthic biodiversity in coastal areas. These findings underscore the urgency of protecting and managing seagrass beds sustainably to maintain benthic ecosystem stability and support biodiversity in the coastal areas of Tarahan Island.