Mangroves, salt marshes and seagrasses of international importance in Mozambique and Tanzania are currently not subject to the level of protection needed to ensure their long-term functioning.  This is one of the findings of a new IUCN report that provides an in-depth analysis of carbon-rich coastal ecosystems – also known as blue carbon - in the two countries. The report also observed that the mangroves found in the tropical regions of the study area store considerably higher amounts of organic carbon than do their subtropical counterparts.  This underlines their importance in the carbon cycle and highlights the extent of carbon emissions when they are destroyed or degraded.

The report confirmed previous studies in finding that the relatively understudied West Indian Ocean region hosts a unique distribution of blue carbon stocks in the sediments of mangrove forests and seagrass meadows. Through their primary production, these vegetated coastal habitats are amongst the most efficient natural carbon sinks due to their ability to store carbon in their sediments over long time scales. Their conservation is therefore key for implementing climate mitigation and adaptation and are crucial habitats hosting rich biodiversity and providing key ecosystem services.

The past designation of marine protected areas has clearly been made mainly based on biodiversity or ecosystem-service parameters and little importance has been given to protecting blue carbon stocks.  The report found that blue carbon hotspots – the areas of greatest importance – are located within areas of large, continuous and relatively sheltered blue carbon habitats.  Recognition of these can play an important role in future designation of protected areas and could preserve connectivity and avoid further degradation from the increasing pressures of fragmentation, over-exploitation and resource extraction.

Regional efforts to address climate change and protect carbon stores are governed through participating countries’ Nationally Determined Contributions (NDCs).  Among the report’s recommendations was the need to restore areas where blue carbon ecosystems have been degraded, fragmented or lost to secure and enhance the carbon storage capacity and the mitigation of climate change.  It also called for inclusion of multiple blue carbon ecosystems (where possible) in marine protected areas and other area-based conservation measures to enhance connectivity due to the transport of organic carbon and spill-over effects from one blue carbon habitat to another. Finally, the report also calls for integrated and coordinated strategies and plans for blue carbon ecosystems with other national planning processes in recognition that blue carbon ecosystems provide multiple benefits.

Coastal blue carbon stocks in Tanzania and Mozambique, Support for climate adaptation and mitigation actions is part of IUCN’s Oceans and Climate Change initiative funded by the Swedish Ministry of the Environment. It was a joint collaboration with Stockholm University, University of Dar es Salaam and Södertörn University. With this report, IUCN aims to inform coastal management and spatial planning efforts to ensure that carbon capture and storage together with other ecosystem services (e.g. biodiversity) are adequately protected and, where possible, enhanced. Read the full report in the PDF below.

Useful links: Save Our Mangroves Now project website