Decomposition and Carbon and Nitrogen Dynamics of Phragmites australis Litter as Affected by Flooding Periods in Coastal Wetlands

Abstract

To investigate the effects of flooding periods on decomposition and carbon and nitrogen return of Phragmites australis litter, we examined the dynamic of P. australis litter decomposition in short‐, medium‐, and long‐flooding coastal wetlands (HN, HS, and LL wetlands, respectively) in the Yellow River Delta, China. Our results showed that the percentage of dry weight loss of P. australis litter increased gradually as the decomposition proceeded and the percentage of dry weight loss was highest in LL wetland, followed by HS wetland, while the percentage of dry weight loss was lowest in HN wetland. Similar to the percentage of dry weight loss, the relative return indices (RRIs) of carbon of P. australis litter also increased with the increasing days of decomposition, following the order LL wetland > HS wetland > HN wetland. With the exception of little accumulation in both HS and HN wetlands in a certain period, the RRIs of nitrogen increased generally with increasing days of decomposition. However, the C/N ratios decreased rapidly in the first 40 days and retained steady after 40 days.