Influence of drought and abiotic factors on Phragmites australis leaf decomposition in the River Pula, Sardinia, Italy

Temporal and spatial patterns of Phragmites australis leaf decomposition and the relative influence of summer droughts and abiotic features were studied in a Mediterranean-type river basin, the River Pula. Reed processing rates varied among seasons and sites, being on average significantly faster in the cold season (i.e., winter-spring) than in the warm seasons (i.e., summer-fall) and in low rather than high stream order reaches. On the other hand, at sites protected from summer drought events (i.e., wet sites), decay rates were faster in the warm than in the cold season. Along stream order, leaf decay rates were significantly faster at wet sites than at sites suffering from summer droughts. Summer drought events explained 44% of reed decay rate spatial variability, and major water abiotic parameters explained an additional 8%.