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Spartina alterniflora Loisel,a species vegetating in intertidal fiats along the eastern coast of the United States,was introduced in China almost 30 years ago and has become an urgent topic due to its invasiveness in the coastal zone of China.The impacts of this alien species S.alterniflora on intertidal ecosystem processes in the Jiangsu coastland were investigated by comparing the sediment nutrient availability and trace element concentration characteristics in a mudfiat and those of a four-year old Spartina salt marsh that had earlier been a mudflat.At each study site,fifteen plots were sampled in different seasons to determine the sediment characteristics along the tidal fiats.The results suggested that Spartina salt marsh sediments had significantly higher total N,available P,and water content,but lower pH and bulk density than mudfiat sediments.Sediment salinity,water content,total N,organic C,and available P decreased along a seaward gradient in the Spartina salt marsh and increased with vegetation biomass.Furthermore,the concentrations of trace elements and some metal elements in the sediment were higher under Spartina although these increases were not significant.Also,in the Spartina marsh,some heavy metals were concentrated in the surface layer of the sediment.The Spartina salt marsh in this study was only four years old;therefore,it is suggested that further study of this alien species on a longer time frame in the Jiangsu coastland should be carried out.
Spartina alterniflora Loisel, a species vegetating in intertidal fiats along the eastern coast of the United States, was introduced in China almost 30 years ago and has become an urgent topic due to its invasiveness in the coastal zone of China. These impacts of this alien species S.alterniflora on intertidal ecosystem processes in the Jiangsu coastland were investigated by comparing the sediment nutrient availability and trace element concentration characteristics in a mudfiat and those of a four-year old Spartina salt marsh that had earlier been a mudflat. At each study site, fifteen plots were sampled in different seasons to determine the sediment characteristics along the tidal fiats. the results suggested that spartina salt marsh sediments had significantly higher total N, available P, and water content, but lower pH and bulk density than mudfiat sediments. Sediment salinity , water content, total N, organic C, and available P decreased along a seaward gradient in the Spartina salt marsh and incre the concentration of trace elements and some metal elements in the sediment were higher under Spartina although these increases were not significant. Also, in the Spartina marsh, some heavy metals were concentrated in the surface layer of the sediment. The Spartina salt marsh in this study was only four years old; therefore, it is suggested that further study of this alien species on a longer time frame in the Jiangsu coastland should be carried out.