Abstract:To clarify variability in soil microbial respiration (SMR) and its influencing factors, characteristics of SMR and soil physical and biochemical factors under different successional stages were studied at the Jiuduansha Wetland, located at the Yangtze Estuary. Results indicate that SMR varies significantly among different successional stages of vegetation (P<005). SMR in the Phragmites australis district is lower than that in the Scirpus mariqueter district, and SMR of Spartina alterniflora dis trict (0.367 mg?g-1?(24 h)-1) is the highest among the five vegetation types. This implies that S. alterniflora can greatly enhance SMR. Considering both SMR and input of organic matter from decayed plant biomass of different vegetation types, wetlands composed of a P. australis community, in theory, have higher capability to accumulate carbon. Results from Path analysis show that the main biological factors influencing SMR include prokaryon microbial diversity (Shannon index) and soil microbial biomass (SMB). In addition, soil organic matter (SOM), nitrate nitrogen and soil water content significantly affect the above-mentioned biological factors, thereby also influence SMR.