Decomposition rate of common reed leaves depends on litter origin and exposure location characteristics

Abstract

The decomposition process in wetlands is affected by various factors, among which hydrology and litter quality are very important. We studied the decomposition rate of Phragmites australis upper and lower leaf litter from the lake and the riparian sites at the intermittent Lake Cerknica (Slovenia), exposed to flooded and dry conditions. X-ray fluorescence spectrometry revealed that leaf litter element composition was related to soil element composition. Fresh leaves also differed according to their age, especially regarding leaf silicon, which ranged from 2.8% to 6.1% dry matter, and leaf phosphorus, which ranged from 0.12% to 0.17% dry matter for the different leaf groups. According to factorial ANOVA, leaf litter decomposition rate was significantly affected by sampling site, exposure location, and leaf age (p ≤ 0.01). Decomposition rate was significantly lower at the dry location compared to the flooded location, and was not related to leaf silicon content. However, leaf sulphur, chlorine, and calcium contents had a significant positive impact on leaf litter decomposition rate at both the dry and the flooded locations. Leaf phosphorus significantly positively affected leaf litter decomposition rate only at the dry location.