Etude du stock de carbone dans l’écosystème mangrove : cas du Parc National de Sahamalaza-île Radama (Nord-Ouest de Madagascar)

Abstract

Northern Madagascar is a world-renowned tourist attraction, and the majority of its
protected areas (Pas), including Sahamalaza/island Radama National Park, are maintained
in part by the access fees generated by visitors. However, sanitary restrictions during Covid-
19 make almost all Pas in strangle for financial support and finding another income activity
to maintain their protection becomes critical. With its 5,796ha of mangrove in the
Sahamalaza/Radama island National Park, this can be an opportunity for ecosystem service
payment especially through blue carbon. This study aims to quantify the carbon stock on
living mangrove and in soil on the park. Thus, from October to December 2021, an
estimation of the carbon in the above-ground biomass (AGB) by using a cluster of 10*10m.
And soil-core of 5cm was carried out from each layer of 0 to 200cm (0-15cm; 15-30cm; 30-
50cm; 50-100cm; 100-150cm and 150-200cm) for carbon quantification using Loss On
Ignition (LOI) method in center of each cluster. A total of 60 clusters is done in 3/5 of all
parcels (Maromandia, Ankitsika – Tanandava, Ampasimbezo). By using the linear equation
generated between NDVI and AGB, y =0.242x – 0.0224 with R² = 0.4749 and carbon factor,
a total of 34,463.3TC is stocked on AGB where Ampasimbezo represents 97.93%. Total
carbon on soil reaches 5,949,246.24TC where more than 70% is localized in the 3rd last deep
layers. Data shows that changes on area zonation and management are needed and an
ongoing change is engaged on the mangrove community. Carbon market can help the
ecotourism in conservation actions provided that those modifications are constructive.
KEYWORDS
Mangrove, Sahamalaza, AGB-NDVI interaction, carbon pool, conservation