This study observed the characteristics and influencing factors of the carbon fluxes of the Momoge salt marsh ecosystem over four years, which behaves as a CO2 sink. The daily, seasonal, and interannual variations in CO2 fluxes in the Momoge salt marshes were observed using the eddy covariance method and were compared with various environmental factors. An overall daily “U”-shaped distribution was observed, with uptake during the day (negative values) and release at night (positive values). Annually, the carbon fluxes in the study area roughly exhibited a “V” shape. The carbon fluxes during the non-growing season predominantly showed positive values, indicating the release of CO2 into the atmosphere. Photosynthetically active radiation was the primary influencing factor affecting the hourly and daytime variations in net ecosystem exchange (NEE) during the growing season, while temperature was the main factor influencing nighttime NEE dynamics. The air temperature, soil temperature, photosynthetically active radiation, precipitation, and water level all had significant impacts on the daily net CO2 exchange. At the monthly scale, larger values of soil temperature, air temperature, photosynthetically active radiation, and aboveground biomass corresponded to a stronger carbon absorption capacity of the ecosystem. Overall, temperature remains the primary factor for carbon fluxes in the Momoge wetlands.

Aims: Siberian crane (Grus leucogeranus) is a migratory, endangered species that uses the Songnen Plain as a main stopover area.Traditionally a wetland species, today most populations of Siberian cranes feed and rest during migratory stopovers in fields of corn (Zea mays).By examining the causes of this change in stopover habitat use, we can provide better protection for and potentially recovery of this declining species.Methods: We recorded the numbers of Siberian cranes and both food resource and habitat usage on stopover sites on the Songnen Plain from September 2020 to November 2021 in the study area.These data were collected and analyzed using Google Earth, ArcGIS 10.7.Results: Of the total number of Siberian cranes we observed, 72.7% were feeding on farmland, which was 2.66 times more than that of wetland habitats.Farmland has become the main feeding habitat for Siberian cranes.The total energy provided by farmland was 1.24-2.79times as much as that provided by wetlands based on different harvesting methods, and the energy intake of Siberian cranes in farmland was about 1.56 times that of wetland.The daily feeding budget of Siberian cranes in farmland was 53.5% of their total time, which was 1.67 times more than that in wetlands.The feeding