HR: 08:45h
AN: B51A-02    [Abstracts]
TI: Effects of Patch Context on two Species of Invertivorous Fishes in a Riffle-Pool Stream
AU: * Gillette, D P
EM: dgillette@ou.edu
AF: Department of Zoology University of Oklahoma, 730 Van Vleet Oval Room 314 , Norman, OK 73019 United States
AB: Lotic systems with riffle-pool geomorphology can be conceptualized as chains of habitat patches connected by an aquatic medium. Patches receive input from upstream, as well as from the adjacent riparian zone. For organisms dependent on such input for food, context of an occupied patch may be a better determinant of patch quality than within-patch factors. I tested this hypothesis for two invertivorous stream fishes in a prairie-margin, riffle-pool stream. Notropis boops is a drift-feeder, trophically dependent on input of aquatic invertebrate drift and terrestrial invertebrate input from outside an occupied patch. Etheostoma spectabile is a benthic feeder, trophically dependent on the within-patch standing crop of invertebrates. I measured resource levels by quantifying benthic invertebrate density, invertebrate drift input, and terrestrial invertebrate input for ten pools riffles. I determined the number of N. boops in each pool, and E. spectabile in each riffle, and the number of predators. I asked if resource levels differed among patches and if these differences were a function of upstream or riparian patch characteristics. Effects of resource levels on fishes were determined by comparing fish distribution among patches to that of resources, and examining fish diets in patches with different resource levels.
DE: 1824 Geomorphology (1625)
SC: Biogeosciences [B]
MN: 2005 Joint Assembly