Effect of Tannins on Leaf Processing and Conditioning Rates in Aquatic Ecosystems: An Empirical Approach

Abstract

Tannin concentrations were determined in the autumn-shed leaves of 48 species of deciduous trees. Chemical measures of tannins (total phenolics and condensed tannins) were significantly correlated with protein-precipitating capacity. None of these measures of tannin concentration, however, were significantly related to published leaf processing rates, measured as weight loss versus time, or to microbial colonization, measured as rates of lipid synthesis on conditioned leaves. These data suggest that the large variation seen in leaf processing rates is due to factors other than tannin concentration and that much of this variation is due to abiotic factors such as leaching and physical fragmentation. Microbial activity on leaves showed much less variation than did processing rates.