Ecosystem carbon and nitrogen recovery in restored coastal wetlands

Coastal wetland restoration is a nature-based solution to mitigate climate change and eutrophication through carbon and nitrogen storage. However, the effects of different restoration practices on ecosystem carbon and nitrogen dynamics remain unclear. Here we conducted a global meta-analysis on the recovery rates of soil carbon and nitrogen stocks and plant biomass carbon in 110 salt marsh and 190 mangrove sites under various restoration types. Restored coastal wetlands achieved 37–76% of soil carbon, 43–83% of soil nitrogen, and 34–119% of plant biomass carbon relative to natural wetlands, due to different practices. Plant biomass requires ~20 years to reach natural levels, whereas soil carbon and nitrogen stocks require ~40 years. Remediated wetlands have lower recovery resistance than created wetlands, and the recovery efficiency is influenced by engineering approaches, vegetation regrowth, soil properties, and hydrological conditions. These insights help optimize land-sea coordination projects for improving carbon and nitrogen recovery. Plant biomass carbon in restored wetlands requires about 20 years to reach natural levels while soil carbon and nitrogen stocks need 40 years to recover, suggests a meta-analysis of 110 salt marsh and 190 mangrove sites under various restoration types.