Deforestation, emissions, and carbon sequestration potential of Merlimau mangrove forest: A landscape-level analysis

The worldwide decline of mangroves, driven by land-use changes, contributes to global carbon emissions. Nevertheless, there is still uncertainty surrounding the effects of mangrove deforestation on carbon emissions. Only a few studies have attempted to quantify its implications for the carbon budget, especially at the landscape level. We conducted a field assessment of carbon stock, losses or emissions associated with the conversion of these ecosystems, along with quantifying the impact of this conversion on the carbon budget using carbon sequestration rates in various types of mangrove ecosystems, including intact and varying ages of naturally regenerated mangroves within the Merlimau–Kuala Sebatu landscape. Results show that the estimated total ecosystem carbon (TEC) stock for clear-cut sites was 149.06 ± 7.56 Mg C ha⁻¹, whereas the TEC stock for intact sites was 280.65 ± 16.92 Mg C ha⁻¹; however, no significant difference was observed (p > 0.05). Using a stock-change approach, the equivalent carbon emissions are 482.93 Mg ha⁻¹ CO₂e. This is among the lowest measured C emissions from land use in the tropics. Remarkably, the landscape-scale carbon budget remained favorable, with a net positive balance of 2835 Mg C yr⁻¹, mainly due to the carbon sink capacity and expansion of natural regeneration of the intact mangrove site (796 Mg C yr⁻¹). Our research identifies a deforestation threshold of 75%, at which the carbon budget approaches neutrality. These findings therefore emphasize the importance of protecting intact forests and managing regenerated mangroves sustainably, as younger mangroves help sequester carbon and reduce deforestation emissions.