HR: 10:45h
AN: NB42A-02    [Abstracts]
TI: Twenty-eight Years of Stream Invertebrate Abundance, Biomass, and Secondary Production From Three Headwater Streams
AU: * Wallace, J
EM: bwallace@uga.edu
AF: Department of Entomology, University of Georgia, Athens, GA 30602 United States
AU: * Wallace, J
EM: bwallace@uga.edu
AF: Institute of Ecology, University of Georgia, Athens, GA 30602 United States
AU: Eggert, S L
AF: Department of Entomology, University of Georgia, Athens, GA 30602 United States
AU: Cross, W F
AF: Institute of Ecology, University of Georgia, Athens, GA 30602 United States
AU: Rosemond, A D
AF: Institute of Ecology, University of Georgia, Athens, GA 30602 United States
AU: Meyer, J L
AF: Institute of Ecology, University of Georgia, Athens, GA 30602 United States
AB: We analyzed 28 years of abundance, biomass and secondary production data from 3 headwater streams at the Coweeta Hydrologic Laboratory, NC, USA. These data include years of extreme drought and precipitation (78-y record) and 8 years of reduced litter inputs (litter exclusion) and wood removal for one stream. Analysis of functional feeding group (FFG) proportions revealed strong habitat-specific preferences for either mixed substrates or bedrock outcrop habitats, with remarkable between year similarities. For both reference streams and litter reduction streams there was a significant relationship between annual CPOM standing crop and secondary production for the dominant mixed substrate habitats. Habitat-weighted production across reference streams averaged 8.2 g AFDM/m²/y (range = 4.6 to 13.2) versus 1.7 g AFDM/m²/y (range = 0.9 to 3.5) for litter exclusion years. Predator production was strongly correlated (P<0.001) with total secondary production over all years, and based on known bioenergetic efficiencies, indicate the importance of predators in these streams. Our study suggests that trophic interactions, including standing crop of CPOM as a food source, strongly influence secondary production in these headwater streams.
DE: 9810 New fields (not classifiable under other headings)
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly