Macroinvertebrate Diversity and Abundance as Key Determinants of Waterbird Foraging Habitats in Bagan Percut Mudflats, North Sumatra

Coastal mudflats play a critical role in supporting biodiversity, particularly for migratory waterbirds, by providing essential foraging habitats. Understanding the dynamics of macroinvertebrate communities in these areas is crucial, as they serve as the primary food source for many waterbird species. This study aims to assess the diversity, abundance, and vertical distribution of macroinvertebrates across sediment depths in the mudflats of Bagan Percut, North Sumatra, and evaluate their relationship with waterbird populations. Macroinvertebrate samples were collected from sediment layers (0–40 cm) using PVC core sampling. A total of 16 species from three phyla (Annelida, Arthropoda, and Mollusca) were identified, with Bivalvia being the dominant group, particularly in deeper sediments. Species richness and total abundance were highest at the surface layer (0–10 cm) and decreased with depth. Key indices, including Shannon's diversity index and Pielou's evenness, showed greater diversity and species evenness near the surface, which declined in deeper layers. A bird survey recorded 32 species of waterbirds, primarily from the Charadriiformes, Pelecaniformes, and Ciconiiformes orders. A significant and positive correlation (<img src=image/14039681_01.gif>, <img src=image/14039681_02.gif>) was found between the abundance of benthic macroinvertebrates and waterbird presence, highlighting the ecological importance of prey availability for waterbird foraging. This study contributes valuable insights into the conservation and management of coastal ecosystems, particularly for species that rely on mudflats for their survival.