As top of mangrove-rich country, Indonesia has experienced a long history in dynamic changes of mangrove forests, involving both increasing and decreasing area of mangroves. From our study on the east coast of North Sumatra Province, we found mangrove forests have been lost about 12,526 ha during 28 years between 1990-2018, of which conversion of mangroves into oil palm plantations and shrimp/fish ponds were the main drivers. As part of coastal wetlands, mangroves play a far-reaching role in providing ecosystem services, including land building through the trapping of sediment containing organic carbon. Estimating sedimentation rates in coastal ecosystems is necessary to evaluate how the ecosystems and associated low-lying coastal zones cope with the effects of climate change, including sea-level rise (SLR).We found that the rates of sedimentation or surface accretion rates were 5.62 ± 2.08 mm yr-1 in the mudflats, 7.99 ± 1.73 mm yr-1 in the fringe, and 10.55 ± 2.45 mm yr-1 in the interior mangroves.
This suggests that the protected coastal zone can survive the regional SLR trends of the Malacca Strait of 3.6 ± 1.6 mm yr–1 (from tide gauge records) and 4.1 ± 1.9 mm yr–1 (from satellite data). In general, they also keep pace with the