Litter Decomposition Of Phragmites Australis, Cyperus Malaccensis And Spartina Alterniflora In The Wetland Of Minjiang River Estuary

Litter decompositions of Cyperus malaccensis,Phragmites australis and Spartina alterniflora (an exotic invasive species) were studied using mesh bags method in the Shanyutan tidal marsh in the Minjiang River estuary. We explored the influences of litter composition and tide on litter decomposition. Main results are as follows:1. The decreasing order of litter decomposition rate was Cyperus malaccensis, Spartina alterniflora and Phragmites australis. The decomposition rates ranged from 0.003166 to 0.005280 d^-1, and the time of 95% dry mass of litter loss ranged from 1.56 to 2.61a2. C concentrations had only a little change, and the major pathway of C release was mineralization during the 280 days. There was an upward trend in N concentrations .At the end of the experiment, N content had a net loss and the major pathwany of loss was mineralization. There was a fluctuating downward trend in P concentrations. At the end of the experiment, P content had also a net loss and leaching losses were responsible for much of P loss.3. The relationship between Calorific Power dynamics and C concerntration dynamics was significant. The initial Calorific Power is a good indication of litter decomposition rates. The energy declined with decreases of dry mass and C content, and the release rates of energy was closely related to decomposition rates.4. Litter quality is the main factor influencing the decomposition rates of plant litter. Frequent tidal flooding had accelerated the litter decomposition, however, the impact of tide on litter decomposition rate was not significant. Frequent tidal flooding had accelerated significantly the N release, and had also accelerated the P loss.