Centuries of Evidence Confirming Mangroves’ Roles in Enhancing Coastal Resilience and Carbon Burial

Abstract Mangroves can adapt to sea-level rise (SLR) and help mitigate climate change through sedimentation processes, particularly by trapping and accumulating sediment inputs from upstream catchments, which drive surface elevation change (SEC), sediment accretion rates (SAR), and ultimately carbon burial. However, how these variables respond across different timescales — from millennial and centennial to contemporary periods — remains poorly understood, as SAR and carbon burial may vary considerably across historical and modern timeframes depending on sediment supply, and may be further intensified by land-use change over recent decades to centuries. Here, we evaluate mangrove response to SLR using Rod Surface Elevation Table–Marker Horizon (RSET–MH) measurements, supplemented by historical sedimentation rates and carbon burial assessments derived from 14 C and 210 Pb sediment dating from highly land use change-impacted mangroves in Pulau Dua Nature Reserve (PDNR), Banten, Indonesia. Our results show that mangroves in PDNR actively traps and retains sediment, supporting millennial-, centennial-, and contemporary-scale SAR of 0.68, 0.35, and 1.85 cm yr⁻¹ and associated carbon burial rates of 213, 105, and 556 g C m⁻² yr⁻¹, respectively. Further, the average SEC of the PDNR (1.84 cm yr⁻¹) indicates that mangroves at the study site are experiencing a surface elevation surplus and therefore keeping pace with relative SLR during the measurement period. Together, these findings highlight mangroves’ ability to build and maintain surface elevation over time, thereby enhancing their climate change mitigation capacity and resilience to SLR. Conserving mangrove ecosystems is therefore critical for sustaining long-term coastal resilience and both climate change mitigation and adaptation benefits.