POLYPHENOLS, CONDENSED TANNINS, AND PROCESSING RATES OF TROPICAL AND TEMPERATE LEAVES IN AN AUSTRALIAN STREAM

We measured total polyphenol concentrations, condensed tannin levels, and processing rates in a temperate Australian stream for the leaves of 12 species of eucalypts, and six other species, of which six eucalypt species and two other species were tropical. Processing rates, polyphenol concentrations, and condensed tannin levels were not significantly different between the tropical and temperate species. There was a significant regression between tannin level and processing rate in degree days for the 12 eucalypt species; but no significant relationships between total polyphenol concentrations and processing rates, or tannin level and processing rate if the non-eucalypt species were included in the regression model. We suggest that the influence of tannin level on processing may only be apparent when the ''noise'' caused by variation in other aspects of leaf chemistry and between-site variability in overall processing rates is reduced.