ALLOCHTHONOUS COARSE PARTICULATE ORGANIC MATERIAL IN FOREST AND PASTURE REACHES OF 2 SOUTH-EASTERN AUSTRALIAN STREAMS .2. LITTER PROCESSING

1. Processing of five species of terrestrial leaves was compared in two summers and two winters at forest and pasture sites in each of two south-eastern Australian streams, using leaf packs fastened with plastic buttoneers and anchored to capping bricks. 2. Soluble carbohydrate and polyphenolics were rapidly lost from the leaves, mostly within 2 days. Total phosphorus and lipid contents remained constant, and nitrogen increased by about 50% over the period to 50% of leaf weight lost. 3. Processing rates, expressed in terms of the negative exponential decay coefficient varied widely for each leaf species, but the rank ordering was consistent with Pomaderris aspera and Eucalyptus viminalis processed at similar, rapid rates followed by Correa lawrenciana, Acacia melanoxylon and Blechnum nudum. Abscissed leaves were processed more slowly than fresh leaves. 4. Processing rates were significantly (P < 0.05) different between the two streams, and between leaf species, but there were no consistent differences between processing rates in winter and summer or between forest and pasture sites. 5. When decay coefficients were calculated on a degree day basis, Eucalyptus viminalis leaves were processed significantly faster (P < 0.05) in summer than in winter, whereas Pomaderris aspera leaves were processed significantly more rapidly in winter than summer (P < 0.05); processing rates of Acacia melanoxylon phyllodes were not significantly different between the two seasons