HR: 14:45h
AN: B13A-06    [Abstracts]
TI: Effects of Crayfish and Fish on Sediment Accumulation and Macroinvertebrate Community Structure in a Temperate Stream
AU: * Ewing, T D
EM: todd.ewing@ncwildlife.org
AF: North Carolina Wildlife Resources Commission, Division of Inland Fisheries 1721 Mail Service Center, Raleigh, NC 27699 United States
AU: Creed, R P
EM: creedrp@appstate.edu
AF: Appalachian State University, Department of Biology , Boone, NC 28608 United States
AB: A variety of large taxa can act as ecosystem engineers in stream communities. These taxa are often found in the same stream. We used an enclosure/exclosure experiment to evaluate the individual and combined effects of a crayfish and a benthic-feeding fish on sediment accumulation and macroinvertebrate abundance in a temperate stream. There were 5 treatments in the experiment: 1) central stoneroller enclosure, 2) crayfish enclosure, 3) crayfish plus central stoneroller enclosure, 4) manually brushing the substrate, and 5) a control. The brushed treatment allowed us to separate the consumptive effects of the crayfish and central stonerollers from the indirect effects resulting from their bioturbation. The control contained significantly more sediment than the other 4 treatments indicating that both crayfish and central stonerollers acted as ecosystem engineers. Reduction in sediment abundance had negative effects on the abundance of 2 genera while three taxa were more abundant in sediment-free substrata. Macroinvertebrate abundance in the brushed treatment was not different from the 3 treatments with crayfish or central stonerollers suggesting that the main effects of consumers in this experiment were indirect. Our results demonstrate that both crayfish and central stonerollers can influence lotic community structure by acting as ecosystem engineers.
DE: 4804 Benthic processes/benthos
SC: Biogeosciences [B]
MN: 2005 Joint Assembly