HR: 11:30h
AN: NB42A-05    [Abstracts]
TI: Implications of Transgenic Corn Cultivation on the Ecology of Agricultural Streams
AU: * VanTull, L
EM: lv2@umbc.edu
AF: University of Maryland, Baltimore County, Department of Geography & Environmental Systems, Baltimore, MD 21250 United States
AU: Swan, C
EM: cmswan@umbc.edu
AF: University of Maryland, Baltimore County, Department of Geography & Environmental Systems, Baltimore, MD 21250 United States
AB: Corn has been genetically-modified by introducing a gene that codes for a toxic protein from a bacterium, Bacillus thuringiensis (Bt), into corn DNA. Genetically-modified crops provide internal resistance to herbivorous pests like the European Corn Borer (Ostrina nubilalis). With the use of transgenic crops on the rise, research is being done to consider its environmental effects on non-target taxa and ecosystems. Stream ecosystems occupy topographic low points in the landscape and thus are affected by agricultural land use. In many temperate streams, the main energy source is from terrestrial organic detritus, mostly in the form of dead leaves and wood, delivered via wind or natural leaf fall. Stream insects consume this material, contributing to organic matter breakdown and creating biomass for predators. With the heightened practice of no-till agriculture, crop detritus remaining on fields as a by-product of harvesting has been documented to enter adjacent streams. Given insect larvae are critical to the transformation of energy from detritus to higher trophic levels, we explored the implications of detritus containing Bt on both insect performance and litter decay in six streams. The presence of Bt in senesced corn leaf litter resulted in significant reductions in both insect feeding rate and organic matter breakdown. Furthermore, colonization of corn litter containing Bt by detritivorous insects was significantly reduced when compared to non-Bt isoline litter controls. We conclude that detritus generated from harvesting transgenic corn negatively impacts insect feeding behavior and colonization dynamics, and may contribute substantially to the reduction of organic matter breakdown rates in agricultural streams.
UR: http://userpages.umbc.edu/~cmswan
DE: 9810 New fields (not classifiable under other headings)
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly