To more comprehensively evaluate the ecological impacts of Bt corn than did the EPA, the research team did the following:
Measured the entry of Bt plant parts--including pollen, leaves and cobs--in 12 streams in a heavily farmed Indiana region. The research team's results demonstrate that these plant parts are washing into local steams. Moreover, during storms, these plant parts are carried long distances and therefore could have ecological impacts on downstream water bodies, such as lakes and large rivers.
Collected field data indicating that Bt corn pollen is being eaten by caddisflies, which are close genetic relatives of the targeted Bt pests. Todd V. Royer, a member of the research team from Indiana University, says that caddisflies "provide a food resource for higher organisms like fish and amphibians." Conducted laboratory tests showing that consumption of Bt corn byproducts increased the mortality and reduced the growth of caddisflies. Together with field data indicating that the caddisflies are eating Bt corn pollen, these results "suggest that the toxin in Bt corn pollen and detritus can affect species of insects other than the targeted pest," Tank said.
Royer says that "if our goal is to have healthy, functioning ecosystems, we need to protect all the parts. Water resources are something we depend on greatly."
"Overall, our study points to the potential for unintended and unexpected consequences from the widespread planting of genetically engineered crops," Tank said. "The exact extent to which aquatic ecosystems are, or will be, impacted is still unknown and likely will depend on a variety of factors, such as current ecological conditions, agricultural practices and climate/weather patterns."
James Raich, a National Science Foundation program director, adds that "increased use of corn for ethanol is leading to increased demand for corn and increased acreage in corn production. Previous concerns about th
|Contact: Jennifer Tank|
National Science Foundation