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Effects of plant invasion along a Spartina alterniflora chronosequence on organic carbon dynamics in coastal wetland in north Jiangsu |
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Abstract Spartina alterniflora, an invasive grass, had rapidly replaced native plant Suaeda salsa since its intentional introduction to the coastal wetlands in Eastern China. Impacts of plant invasion along a Spartina alterniflora chronosequence on soil organic carbon (SOC) dynamics were investigated. The concentrations of SOC in bulk soil increased 70% from 2.89g/kg soil in remnant Suaeda salsa-vegetated soil to 4.90g/kg in 14-year Spartina alterniflora soil, and these values enhanced significantly along its chronosequence. The increase mainly resulted from a high quantity of organic residues incorporated in the soil. Compared with Suaeda salsa-vegetated soil, The SOC concentration increased significantly in coarse fraction (>250mm and 53~250mm) of Spartina alterniflora-vegetated soil, while there was no obvious difference in fine fraction (2~53mm). The δ13C values of SOC for either bulk soil or particle-size fractions were evidently higher in Spartina alterniflora-vegetated soil than in Suaeda salsa-vegetated soil. There was Spartina alterniflora-derived C in all particle-size fraction, however 31%~43% of the Spartina alterniflora-derived C distributed in the coarse fraction (>250mm). It was concluded in this study that Spartina alterniflora invasion significantly promoted SOC accumulation of surface soil in coastal wetland, and new C accumulation profoundly resulted in increasing SOC concentration of the coarse fraction (>250mm).
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Received: 02 June 2010
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