Decomposition of the common reed Phragmites australis in a Mediterranean stream pond

Abstract

In this study the dynamics of leaf fall, decomposition and nutrient dynamics of Phragmites australis was investigated beginning in the standing position and after leaves fall into the water. The study was conducted in a pond at the end of a temporary Mediterranean stream. The results showed that the decomposition rate was higher in the standing position (0.0098d -1 ) than after submergence of the detritus (0.0034-0.0042d -1 ). A significant variation in leaf nutrient content was observed during the standing dead phase, increasing during the first days and decreasing afterwards. After submergence, significant effects of macroinvertebrates, mainly gastropods, were observed on the nutrient content of the detritus after 60 days. The overall decomposition rate, considering the 184 days from the beginning of the experiment with emerged leaves, in the standing position, to the end of measurements with submerged leaves, was 0.0076d -1 . This rate is higher than values reported in the literature for P. australis leaves in submerged conditions, suggesting that decomposition takes place mostly in the standing position.