Biodiversity and Conservation of Marine Mollusks in the Indo-Pacific Convergence Zone.

The Indo-Pacific Convergence Zone (IPCZ), a global marine biodiversity hotspot, faces increasing threats from anthropogenic activities and climate change. This study presents the first comprehensive assessment of mollusk diversity, identifies conservation gaps, and prioritizes protection areas in the IPCZ. Using 47,097 occurrence records of 3215 mollusk species, along with habitat and environmental data, we mapped biodiversity indices and integrated Marine Protected Areas (MPAs) and fishing effort. The results revealed significant spatial variability, with 11 priority conservation areas located in the Philippines, Indonesia, Papua New Guinea, and Australia. These areas contained 47.9% of mollusk species and 58.9% of threatened taxa, yet only 18.7% overlapped with existing MPAs. High fishing pressure disproportionately affected priority zones, particularly near Australia's Great Barrier Reef and Indonesia's Papua Province. Environmental factors, especially primary productivity and bathymetry, were key drivers of biodiversity, while rising temperatures had negative effects. Biogenic habitats, which cover 28% of the IPCZ, strongly correlated with mollusk diversity, with multi-habitat zones supporting 42.3% of biodiversity. This study underscores the urgent need to expand protection in high-diversity habitats and reduce fisheries pressure, providing actionable insights to enhance conservation strategies and ecosystem resilience in the IPCZ.