Foraminifera assemblages in Pulau Redang: Uncovering Discrepancies and the Importance of FoRAM Index Calibration for Precise Reef Monitoring

Abstract

Abstract To mitigate the adverse effects of ocean warming on coral reef degradation, resource managers increasingly explore the management and regulation of local stressors to bolster coral resilience and recovery. Comprehensive assessments and monitoring efforts offer a holistic understanding of reef dynamic ecosystems. Using the Foraminifera-based Reef Assessment (FoRAM) index, we documented the distribution of benthic foraminiferal assemblages surrounding Pulau Redang, Malaysia, and assessed their potential for monitoring coral reef health. Undeveloped (R1–R3) and developed (R4–R6) reef sites revealed distinct differences in reef conditions. The significant presence of dead corals in R4–R6 is linked to Tropical Storm Pabuk. Foraminiferal distribution showed Amphistegina lessonii (14–34%) as the dominant species, followed by Calcarina hispida (21%) and Calcarina mayori (19%). Surprisingly, FoRAM consistently yielded high values across the study area despite varying coral reef conditions, probably due to the prevalence of Calcarina mayori in mesotrophic reefs (R4, R5, and R6), potentially skewing FoRAM values and providing a misleading indicator of reef conditions. We recommend calibrating the FoRAM Index, particularly in mesotrophic reefs where calcarinids dominate foraminiferal assemblages, to enhance its precision and reliability for coral reef health monitoring and assessment within the region.