Effects of wetland disturbance on methane emissions and influential factors: A global meta-analysis of field studies

Wetlands, one of the largest source of methane (CH₄) on Earth, are undergoing extensive disturbance globally, resulting in profound impacts on global changes. This study conducted a comprehensive global meta-analysis of field studies to assess the effects of wetland disturbance on CH₄ emissions and the key factors influencing these changes. Our analysis indicates that while CH₄ emissions generally decrease following wetland disturbance, the global warming potential does not necessarily diminish compared to that of natural wetlands. Notably, wetlands with tidal hydrology, saline conditions, or those experiencing slight disturbance, increased water tables, or enhanced plant biomass post-disturbance showed elevated CH₄ emissions. The variations in CH₄ emissions were dominantly controlled by hydrology-related factors, including hydrologic type, water table variation, and drainage. Structural equation modeling analysis revealed that disturbed years, drainage, natural hydrology and soil pH exhibited direct negative effects on CH₄ emissions, while climate factors such as temperature and precipitation had indirect influences. These findings highlight the need for increased attention to wetlands in colder regions and saline wetlands due to their uniqueness and heightened sensitivity to global changes and disturbance. This study provides valuable insights into CH₄ emission dynamics following wetland disturbance, supporting the development of effective wetland management strategies and more accurate CH₄ emission assessments in the context of global change scenarios.