Abstract: By using open-top growth chambers (OTC) to simulate short-term warming and mesh bags,the study was carried out in the reclaimed wetland in the east Chongming tidal flat. The effects of short-term simulated warming （1.984±0.7） ℃ on the decomposition of Phragmites australis litter were studied and the changes of correlations between decomposition rate and environmental parameters were analysed.The results are as follows: ① stem decomposition rates in OTC plots and CG plots are 49.20% and 45.11%, and leaves decomposition rates are 63.52% and 58.53%, respectively, which shows that warming has increased the decomposition rates; ② stems average decomposition coefficients (K) in OTC plots and CG plots are 0.028 and 0.027,while the average decomposition coefficients of leaves are 0.093 and 0.080, respectively, which shows that the increment of leaves K is bigger than stems K; ③ the order of correlation degree between environmental factors and decomposition rate is: 1.2 m air temperature> 0～5 cm soil temperature> 0～5 cm soil moisture,and the correlation coefficient between leaves decomposition rate and 1.2 m air temperature is biggest which is 6.43%. In summary, air temperature is the key factor affecting the Phragmites australis litter decomposition; meanwhile warming not only improves litters decomposition rates, but also changes the relevance between decomposition rate and environmental factors.

Key words: wetland, Phragmites australis, litter decomposition, temperature enhancement, open-top chambers (OTC)