摘要：Several studies have shown that lake littoral zones often support high methane (CH4) emissions. In this study, we measured CH4 emissions from two vegetation meadows in the littoral zone of Poyang Lake, China, from October 2014 to May 2015. CH4 emissions in the meadow dominated by Carex cinerascens were 11.27 ± 11.29 mg CH4 m−2 h−1, which were significantly higher than emissions in the meadow dominated by Artemisia selengensis (2.99 ± 1.67 mg CH4 m−2 h−1). Between-species differences in CH4 emission were caused by differences in belowground biomass. The results also showed distinct seasonal variation in CH4 emissions in this area; fluxes reached a maximum at the peak of the growing season and reached a minimum after the summer flood, when plants began to germinate. There were two peak values in the Carex meadow, and belowground biomass controlled the seasonality of CH4 emissions. Our results suggest that plant biomass may be a key factor controlling CH4 emissions in the littoral zone of Poyang Lake, highlighting that CH4 fluxes vary with vegetation type in littoral wetlands and demonstrating that spatial variation in CH4 emissions must be considered when estimating regional CH4 emissions in Poyang Lake. Considering climate change and the operations of a proposed hydraulic engineering project, changes to the hydrologic regime in this region may significantly affect CH4 emissions.
关键词：Poyang Lake;littoral wetlands;methane (CH4);subtropical;drawdown periods
