Methane emissions from small freshwater wetlands and ponds represent a significant but poorly constrained component of regional greenhouse gas budgets, particularly in restored swamp systems. In this study, we investigated methane dynamics in three adjacent ponds that differ in their hydrological connection to a freshwater spring in a restored wetland in Israel. The ponds span a gradient from direct spring connection to hydrologic isolation, allowing assessment of how groundwater influence regulates methane production.

Methane concentrations and fluxes differed consistently among ponds, with the lowest methane levels observed in the pond closest to the spring and progressively higher methane in more isolated ponds. This pattern suggests that continuous spring input suppresses methane accumulation, likely through enhanced oxygenation, dilution, or altered redox conditions. Within each pond, we further compared vegetated and non-vegetated zones to evaluate the role of macrophytes. Vegetated areas generally exhibited distinct methane signatures relative to bare sediments, indicating that plant presence modulates methane production and transport.

Our results demonstrate that hydrological connectivity to groundwater sources is a primary control on methane dynamics in restored swamp ponds, while vegetation exerts a secondary but measurable influence. These findings highlight the importance of maintaining spring connectivity and managing vegetation cover in wetland restoration projects aimed at minimizing methane emissions. The study provides practical guidance for the long-term maintenance and climate performance of restored swamps in Israel and similar semi-arid environments.