Projections of Elevation and Mangrove Species Cover under Sea-Level Rise across Pohnpei, Federated States of Micronesia

Future sea-level rise poses a risk to mangrove forests. To better understand potential vulnerability, we developed a numerical model of soil elevation for mangrove forests. We used the model to generate projections of elevation and mangrove forest composition change under six sea-level rise scenarios from 2020 through 2150. We employed a data-driven modeling approach, utilizing new and existing data to inform model parameters. The model was calibrated using dated soil cores and used a spin-up period to establish the soil column prior to future projections. Additional field data, including water level monitoring and elevation surveys, were used to estimate the initial elevation of the mangrove forest relative to mean sea level, and forest inventory plots were used to estimate mangrove productivity. Finally, we used a Monte Carlo simulation to incorporate variation in annual sea level due to the El Nino-Southern Oscillation and uncertainty in sediment availability and rates of decomposition.