Influence of Exposure Technique on Leaf Breakdown Rates in Streams

Abstract

Breakdown rate of American sycamore Platanus occidentalis L. leaves in a river was investigated using 9 different exposure techniques in identical stream conditions. It was determined that large leaf packs and leaf disks broke down more slowly than small packs, and that processing coefficients ranged from fast to slow depending upon the exposure technique employed. It is hypothesized that species-specific breakdown rates may be modified when leaves aggregate in large packs and that pack size may constitute a major factor influencing the leaf breakdown rate in streams.