9317514 Parker This project investigates the effect of stream disturbance on the length of aquatic food chains. Ecological theory indicates that food chains should be shortened by disturbance, but preliminary observations suggest that periodic winter scouring in northern California rivers may actually lengthen food chains. The interplay of disturbance and trophic dynamics is investigated by laboratory trials to establish susceptibility of key invertebrate taxa to predation, field experiments to assess the effect of disturbance on the strength of species interactions and of artificial scouring on the benthos and feeding rates of predatory fish, and field surveys comparing the trophic structure of regulated (low disturbance) and natural (high-disturbance) rivers. %%% This research is important for several reasons. First, this is an ideal system for testing (and revising) fundamental theories on the stucture of food webs and the role of disturbance in community structure. The results of this study have important implications for the effects of dam-release schedules and flood control projects on the biodiversity and community ecology of rivers. Results from this research will provide important information for stream and river management and restoration. ***
