A global map of mangrove forest soil carbon at 30 m spatial resolution

An international group led by researchers at the Woods Hole Research Center (WHRC) and ISRIC – World Soil Information have compiled a large geo-referenced database of mangrove soil carbon measurements and developed a global map of mangrove forest soil carbon at 30 m spatial resolution. The map can help nations seeking to include mangrove habitats in payment-for-ecosystem services projects and in designing effective mangrove conservation strategies. The map and model outputs are freely available from Harvard Dataverse.

Effective action on climate change will require a combination of emissions reductions and carbon sequestration, protecting, enhancing and restoring natural carbon sinks. Mangrove forests are considered some of the most carbon-dense ecosystems in the world with most of the carbon stored in the soil.  In order for these to be included in climate mitigation efforts, knowledge of the spatial distribution of mangrove soil carbon stocks is critical.

The develped global map of mangrove forest is produced using a novel machine-learning based statistical model of the distribution of carbon density using spatially comprehensive data at a resolution of 30 m. It has now been possible to capture enough of the finer scale variability that would be required to inform local decisions on siting protection and restoration projects. 

The model was able to capture 63% of the vertical and horizontal variability in soil organic carbon density. Of the local variables, total suspended sediment load and LANDSAT imagery were the most important explaining variables. Projecting the model across the global mangrove forest area for the year 2000 gave an estimate of 6.4 Pg C for the top meter of soil, with an 86-729 Mg C ha^-1 range across all pixels.

By utilizing remotely-sensed mangrove forest cover change data, loss of soil carbon due to mangrove habitat loss between 2000 and 2015 was estimated at 30-122 Tg C, with >75% of this loss attributable to Indonesia, Malaysia and Myanmar.

The map can help nations seeking to include mangrove habitats in payment-for-ecosystem services projects and in designing effective mangrove conservation strategies. The map and model outputs are freely available from Harvard Dataverse.