Soil Health Recovery in Restored Mangroves

Mangroves are coastal ecosystems that provide essential ecosystem services, including carbon sequestration, nutrient cycling, coastal protection, and support for biodiversity, but are often threatened by agriculture, aquaculture, wastewater disposal, and deforestation. These disturbances compromise soil functions and reduce the capacity of mangroves to deliver ecosystem services. This study evaluates how mangrove restoration promotes organic matter accumulation and stabilization in soils and contributes to the recovery of soil health. A total of 75 soil samples were collected at depths of 0–5, 5–10, 10–20, 20–30, and 30–50 cm across three environmental conditions: degraded, restored, and preserved mangroves. Soil indicators related to organic carbon and biogeochemical processes were analyzed to assess soil health status. Restored mangroves played an important role in recovering organic carbon stocks and soil biogeochemical functioning, promoting reducing conditions that favor pyrite formation and organic matter stabilization. Preserved, mature mangroves showed the highest carbon contents (1.76±0.32% C), followed by reforested mangroves (0.40±0.10% C) and hypersaline tidal flats (0.18±0.10% C), indicating losses in carbon sequestration capacity under degraded conditions. Soil health was higher in mature areas, followed by restored and hypersaline tidal flat environments. Soil health was sensitive to changes in mangrove geochemical conditions, reflecting the impacts of degradation and restoration. Overall, the selected soil indicators were sufficient to identify soil health status in the analyzed mangroves.