Wetland Restoration Is Effective but Insufficient to Compensate for Soil Organic Carbon Losses From Degradation

Aim

To assess the effectiveness of wetland restoration in reversing soil organic carbon (SOC) loss from degradation.

Location

Global.

Time Period

1996–2023.

Major Taxa Studied

Wetland.

Methods

We conducted a global meta-analysis to compare SOC levels in restored, degraded, and natural wetlands across different restoration approaches and wetland types and to examine the dynamic trajectories of SOC recovery and the influence of climatic and edaphic factors.

Results

We found that passive restoration increased SOC in degraded sites by 141%, compared to an 8% increase from active restoration. Restored inland wetlands showed an increase in SOC of 118%, while coastal wetlands showed a limited improvement of 5%, in comparison with degraded wetlands. Increases in SOC primarily occurred within the first 10 years after restoration and then levelled off. That being said, SOC accumulation in restored wetlands rarely approached the levels found in natural wetlands, highlighting the importance of protecting wetlands from degradation for SOC targets. Key factors for wetland SOC restoration were total soil nitrogen and mean annual temperature.

Main Conclusions

We conclude that wetland restoration is effective but insufficient to compensate for SOC losses from degradation. This study provides valuable insights for climate change mitigation through wetland restoration, supporting the goals of the United Nations Decade on Ecosystem Restoration and the Paris Agreement.