Production and litter processing by crayfish in an Appalachian mountain stream

SUMMARY 1. Mean annual density and biomass (B̄) of Cambarus bartonii in an Appalachian mountain stream (U.S.A.) was 12 individuals m−2 and 1669 mg (ash‐free dry weight) m−2. 2. Annual production (P) of C bartonii was 961 mg AFDW m−2. Despite high biomass, low growth rates resulted in low production and a low P/B̄ ratio of 0.58. 3. While C bartonii constituted 61% of the total macroinvertebrate biomass, it contributed only 13% of annual community secondary production. 4. Litter processing was positively related to temperature and crayfish size. Cambariis bartotnii was estimated to comminute 36 g m−2 y−1 of leaf litter (>1 mm2) to 24 g m−>2 y−1 fine particulate material (5()% of shredding activity by crayfish occurred from June to September which was also the period of lowest litter standing crops and activity of other shredding macroinvertebrates. 5. We speculate that during summer crayfish play an important role in temperate woodland streams by converting slowly processed leaf litter species (e.g. Rhododendron) to fine particles which are then available to collector‐gatherers (e.g. Chironomidae, Oligochaeta).