Carbon Storage Assessment under Mangrove Restoration of Dongzhai Harbor in Hainan Island, China

Abstract

Mangrove restoration is recognized as an effective strategy for enhancing the carbon storage capacity of natural ecosystems, advancing toward the “carbon neutrality” goal. The carbon storage effects of ecological restoration efforts remain insufficiently understood as previous studies have focused on carbon storage dynamics in ecosystems, yet the specific impacts of targeted mangrove restoration are less explored. This study utilizes multi-temporal remote sensing data and actual restoration data from Dongzhai Harbor Hainan Island to identify the mangrove wetland coverage and quantify the spatiotemporal evolution of carbon storage under various restoration efforts using the InVEST model. Additionally, we employed the PLUS model to simulate and compare carbon storage potential under multiple development goals. The findings reveal the following: (a) Mangrove restoration significantly increased the area of land with high carbon sink capability, resulting in a regional carbon storage increase of 210,001.68 tons from 2015 to 2021, with 97% of this increase attributable to ecological restoration. (b) Mangrove coverage is crucial for regional carbon storage, with an average of 443 tons of carbon stored per hectare. Decreases in carbon storage occurred mainly during the conversion of mangroves to aquaculture, and forests/agriculture to residential areas. Increases in carbon storage were seen in the reverse transitions. (c) Comparing the scenarios focused solely on mangrove protection with cultivated land protection, the carbon storage in Dongzhai Harbor is projected to reach its maximum by 2045 under the carbon storage priority scenario. Our findings build a scientific foundation for formulating effective mangrove conservation and restoration strategies.