[Changes of soil carbon, nitrogen and phosphorus and stoichiometry characteristics in marsh invaded by Spartina alterniflora].

To clarify the effect of invasive alien plants on ecosystem functions, soil total carbon (TC), total carbon (TN), and total phosphorus (TP) contents were studied in the exotic invasive plant Spartina alterniflora marsh with different durations and the native species Cyperus malaccensis marsh in the Minjiang River estuary. The results showed that there were different variations of TC, TN and TP at 0-50 cm soil layer in the C. malaccensis marsh invaded by S. alterniflora, but the changes of TC and TN were similar and the change of the TP lagged behind them. Soil C/N increased continually with the increase of TC. Soil TP was a key factor affecting soil C/P and N/P during the S. alterniflora invasion, and the change of C/P and N/P followed a similar trend. The changes of TC, TN and TP were influenced by abiotic factors such as soil salinity, bulk density, soil water content and clay composition. C, N and P stoichiometric ratios were influenced mainly by soil salinity and grain composition. C/N and C/P were the good indicators for soil carbon enrichment ability in S. alterniflora marsh. S. alterniflora invasion induced the change of biomass and marsh habitats. Soil carbon, nitrogen, phosphorus contents, and their ecological stoichiometric ratios changed significantly in the C. malaccensis marsh invaded by S. alterniflora and showed diffe-rent change characteristics with different invasion duration.