Processing of Leaf Litter by a Stream Detritivore: Effect on Nutrient Availability to Collectors

Abstract
An artificial stream containing alder (Alnus rubra) leaves labeled with radiophosphorus, a shredder (Pteronarcys californica), and two collectors (Hydropsyche californica and Simulium arcticum) was used to test the processing effect shredders have on nutrient availability to collectors. The radioactivity accrued by the collector species was significantly greater (P <.01 for H. californica and P <.005 for S. arcticum) when the shredder was present. This indicates the importance of the leaf—processing activities of shredders in enhancing nutrient availability for collectors.