Earlier this year, the Madagascar intervention site hosted none other than the famous Prof. J. Boone Kauffman, who’s also a member of the Blue Forests Carbon Science Advisory Panel. Boone visited us to help us refine our field protocols and provide advice on how we measure the amount of carbon lost from mangrove sediments following deforestation for charcoal production at our northwest pilot site. Accurately quantifying the amount of carbon sequestered by intact mangroves and the impact that ecosystem destruction has on this carbon is a critical element in the development of mangrove carbon projects. Mangroves store the bulk of their carbon in deep, organic-rich soils; 49-98% of total ecosystem carbon. Therefore it is vital that this soil organic carbon (SOC) is accounted for, if the true financial value of mangroves is to be realised.
Mangroves also sequester SOC at a significantly faster rate than terrestrial forest ecosystems, due to the way they dynamically accumulate sediment and carbon from surrounding systems, owing to frequent salt- and freshwater inundation. Mangrove deforestation and conversion brings about changes in the way inter-tidal wetlands function as carbon sinks, there and above the simple removal of tree biomass, adding a further level of complexity to carbon accounting in a mangrove environment.
While the loss of SOC due to mangrove deforestation for aquaculture ponds is relatively well established, not much is known about the loss of SOC following cutting for timber or charcoal, the predominant cause of mangrove deforestation both in Madagascar. In fact, it is estimated that 26% of mangrove forests worldwide are degraded due to over-exploitation for fuelwood and timber production. The lack of understanding of carbon dynamics in this setting is hindering the development of blue carbon projects worldwide.
Boone’s trip was incredibly useful and lead to a plan of action relating to how we estimate loss of SOC at our northwest pilot site. However, as with most mangrove research, it’s going to be neither quick nor easy. The processes occurring at our site are a complex mix of compaction and erosion. To definitively establish SOC loss requires another 2 years of fieldwork and research. But it’ll all be worth it in the end.
It was also a unique capacity building opportunity for our Malagasy scientists and conservationists. Ismael Ratefinjanahary, a recently graduated MSc student from the University of Antananarivo who joined the mission, says:
“Meeting Boone was amazing. Joining his field mission was a fantastic opportunity for me and I learnt a lot that will help me in my future research and career”
Lastly, this mission was a fantastic opportunity for Boone to see the context in which we work. He couldn’t quite get his head around the fact that the boats we use don’t have motors! For science protocols to be applicable in contexts like Madagascar’s, where blue carbon has the potential to have the greatest positive social impact, they must be pragmatic and relatively cost effective as well as robust.
By Leah Glass, Blue Ventures