Issues of Peatland Restoration Across Scales: A Review and Meta-Analysis

Although peatland restoration has been widely promoted as a strategy for reducing carbon emissions and restoring hydrological function, its effectiveness remains context-dependent and highly variable across regions and methods. This study presents a systematic review and meta-analysis of 52 peer-reviewed studies from 2014 to 2024, synthesizing the ecohydrological impacts of restoration across multiple spatial scales and implementation types. In tropical peatlands, restoration frequently reduced CO2 emissions by more than 65,000 kg·ha−1·yr−1 and increased carbon sequestration up to 39,700 kg·ha−1·yr−1, with moderate CH4 increases (~450 kg·ha−1·yr−1). In boreal sites, CO2 reductions were generally below 25,000 kg·ha−1·yr−1, with long-term carbon accumulation reported in other studies, typically around 2–3 tCO2·ha−1·yr−1. Higher values in our dataset likely reflect the limited number of boreal studies and the influence of short-term measurements. Across all regions, restoration was also associated with an average rise in WTD up to 10 cm. These averages were derived from studies conducted across diverse climatic zones, showing high standard deviations, indicating substantial inter-site heterogeneity. These differences emphasize the need for region-specific assessments rather than global generalizations, highlighting the importance of adaptive restoration strategies that balance carbon dynamics with hydrological resilience in the face of climate change.