HR: 1330h
AN: NB33Q-06    [Abstracts]
TI: Do Brook Trout and Mottled Sculpin Cause Trophic Cascades in Appalachian Streams?
AU: * Cheever, B M
EM: cheevebm@jmu.edu
AF: Department of Biology, James Madison University, Harrisonburg, VA 22807 United States
AU: Taylor, L E
EM: taylore@jmu.edu
AF: Department of Biology, James Madison University, Harrisonburg, VA 22807 United States
AU: Simon, K S
EM: simonks@jmu.edu
AF: Department of Biology, James Madison University, Harrisonburg, VA 22807 United States
AB: The ability of fish to cause trophic cascades varies. The strength of the cascade may change depending on the foraging mode of the fish or interactions among coexisting fish species. We investigated the ability of brook trout (Salvelinus fontinalis) and mottled sculpin (Cottus bairdi) to cause trophic cascades individually and in tandem. Artificial channels (2.1m long and 38.5cm in diameter) constructed from PVC pipe were positioned in a stream to create enclosures. The channels were arranged in a randomized complete block design with blocks of four channels located in four different reaches. In each block channels were randomly assigned to one of the following treatments: (1) control (no fish added) (2) sculpin only (3) trout only (4) both sculpin and trout. We measured changes in invertebrate density, algal biomass, and leaf pack colonization and breakdown rate after three weeks. Compared to controls, algal biomass in channels with sculpin doubled. When trout were present alone or with sculpin, algal biomass was not significantly different from control channels. Our results suggest that sculpin and trout differ in their ability to cause trophic cascades, and that the effects of sculpin on lower trophic levels change when trout are present.
DE: 9810 New fields (not classifiable under other headings)
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly