Carbon Stocks of Urban-Influenced Mangroves of Jamaica, West Indies

Mangroves are globally important coastal systems providing numerous ecosystem services. They store large amounts of carbon in their living and non-living parts. Mangroves associated with urbanised areas such as Kingston Harbour, Jamaica are exposed to threats that result in the loss of valuable ecosystem functions, including carbon sequestration. Quantifying carbon stocks is therefore essential both for their valuation and as a baseline for future comparative studies. This study was designed to determine the baseline above- and belowground carbon stocks within 300 hectares of mangrove forests associated with Kingston Harbour (Buccaneer Swamp, Port Royal Mangroves, and Hunts Bay Forest). Diameter at breast height and tree height were measured at 12 sites, and these measurements were converted to biomass using allometric equations. Forest structural variability among sites reflected differences in height and basal area driven by varying freshwater and nutrient influences. Carbon stocks also varied among forests and between sites, with the lowest soil carbon found in rehabilitated mangroves along the Portmore Toll road (Hunts Bay Forest) and the highest at Fort Rocky Lagoon 2 (Port Royal Mangroves). Belowground carbon pools dominated storage, contributing 92% of total carbon. Estimates from the top metre of soil and biomass of the 300 ha of forest, indicated carbon stores of 125,373 Mg C. Our study also showed that disturbed, urbanised forests store less carbon than adjacent undisturbed stands, highlighting the need for the protection and conservation of undisturbed mangroves in areas such as Kingston Harbour and by extension all of Jamaica’s mangroves.