Spatial Analysis of Mangrove Density and Carbon Stock Potential Estimation in Ambon Bay, Maluku

Abstract

Mangrove ecosystems function as blue carbon stores. Mangroves are capable of accumulating carbon in above-ground biomass, below-ground biomass, and sediments over long periods of time, making them one of the priority ecosystems in global climate change mitigation efforts. Ambon Bay is a coastal area in Maluku that possesses biophysical conditions conducive to mangrove growth; however, comprehensive spatial information regarding the distribution, density, and carbon stock potential of its mangroves remains very limited. This study aims to analyze the density and estimate the carbon stock potential of mangroves in Ambon Bay. Mangrove density analysis was conducted spatially using Sentinel-2A satellite imagery through the Normalized Difference Vegetation Index (NDVI) approach, with density classifications of low (NDVI ≤ 0.32), moderate (0.32–0.42), and high (0.43–1.00). Carbon stock estimation was calculated based on above-ground and below-ground biomass measurements using species-specific allometric equations with a diameter at breast height approach. Biomass was subsequently converted into carbon stock using a carbon fraction factor of 47% in accordance with the standards set by the National Standardization Agency of Indonesia. The results showed that the mangrove ecosystem in Ambon Bay has a total area of 29.62 hectares and estimated carbon stock potential of 904.51 tons/ha. Mangrove distribution is concentrated in the coastal areas of the inner bay, with varying density patterns across locations. The Nania and Passo areas are dominated by high-density mangroves, reflecting dense canopy cover and large stand biomass, whereas the Waiheru area tends to exhibit low density due to higher anthropogenic pressure. Field surveys identified 8 mangrove species from 4 families, including Avicennia officinalis, Rhizophora apiculata, Rhizophora mucronata, Sonneratia alba, and Xylocarpus moluccensis, indicating a vegetation zonation structure that remains relatively intact. The high carbon stock values found confirm the role of Ambon Bay's mangrove ecosystem as a significant blue carbon sink and store in the context of climate change mitigation. The spatial information generated is expected to serve as a scientific basis for the formulation of sustainable management, conservation, and mangrove rehabilitation policies, particularly through prioritizing rehabilitation in the Waiheru area and protecting high-density areas in Nania and Passo