Spatial and Temporal Variation in Macrophyte Litter Decomposition in a Rare Chain-of-ponds, an Intermittent Stream and Wetland System

Abstract Ponds and wetlands around the world face anthropogenic pressures that threaten key ecosystem processes such as nutrient organic matter cycling. Wetlands in arid semi-arid regions are particularly at risk from uncertainty of water availability competing for use. Such threats most acute non-perennial systems rely on occasional surface flows to maintain important ecological functions. This study investigates decomposition an endemic macrophyte Cycnogeton procerum (R.Br.) Buchenau a process chain-of-ponds wetland system, located intermittently flowing Mulwaree River, New South Wales, Australia. The aims this were identify spatial temporal patterns relative importance microbial activity improve our understanding these intermittent systems. Exponential rates (proportional mass loss (g)) highest during spring summer (0.07-0.10 kd -1 ) slower autumn winter (0.03-0.04 ), reflecting seasonal drivers. Decomposition was significantly different 9 mm 150 μm mesh bags only spring, suggesting mostly performed by microbes, with invertebrate herbivores possibly factor lotic conditions. Mesotrophic conditions, regulated flow internal algal dynamics appear highly productive, macrophyte-dominated aquatic system. Temperature major expected increases due climate change will accentuate pressure resilience community. Alterations caused changing land use place ponds high risk.