Scientific Assessment of Mangrove Blue Carbon Stocks in Metinaro, Timor-leste: Establishing a Site-specific Baseline for Climate Action

Mangrove ecosystems play a vital role in global climate regulation through carbon sequestration, yet they are increasingly threatened by anthropogenic activities. Quantifying their blue-carbon potential is essential to support both conservation planning and international climate policy frameworks. Despite their ecological value, mangrove ecosystems in Timor-Leste remain underrepresented in blue-carbon research. The absence of site-specific baseline data, particularly in degraded and semi-arid regions such as Metinaro, limits their inclusion in global carbon accounting and restoration initiatives. This study aims to establish the first site-specific baseline of mangrove blue-carbon stocks in Metinaro, Timor-Leste, to contribute to international climate reporting and sustainable coastal management. Field data were collected using a stratified random sampling approach across thirteen plots to capture variability in disturbance intensity. Destructive sampling was applied to quantify five carbon pools: aboveground biomass (AGB), belowground biomass (BGB), necromass, litter, and soil organic carbon (SOC). Statistical analyses (ANOVA and Tukey’s HSD) were used to evaluate differences among carbon components. The total carbon stock was 132.94 Mg C ha⁻¹, dominated by SOC (71%), followed by necromass (20.46 Mg C ha⁻¹), AGB (13.10 Mg C ha⁻¹), BGB (2.88 Mg C ha⁻¹), and litter (1.57 Mg C ha⁻¹). Significant differences were observed among pools (F = 37.26, p < 0.001), confirming SOC as the primary and most stable carbon reservoir. These findings fill a critical data gap for global blue-carbon inventories and support the development of Tier-2 emission factors under IPCC guidelines. Incorporating mangrove carbon data into international frameworks such as the Paris Agreement enhances both climate mitigation and coastal resilience in small island nations.