A team of biologists, including a UC Davis plant scientist, is proposing that maps be created showing where all of the billion-plus acres of genetically engineered crops have been grown in the United States.

The comprehensive biotech mapping system, modeled after one now in use in Arizona, would permit much-needed studies of the positive or negative environmental impacts of genetically engineered crops, the researchers suggest in a Policy Forum piece published in the April 25 issue of the journal Science.

"Such maps would enable scientists to better analyze the effects of genetically modified crops on wildlife, water quality, insect pests and beneficial insects," said UC Davis Professor Paul Gepts, an expert on the evolutionary processes that have shaped the evolution of crop plants.

In Arizona, farmers routinely share maps of biotech cotton fields with scientists at the University of Arizona, enabling detailed analyses of the effects of this technology. That information is collected and stored in such a way that the privacy of the farmers is protected.

The U.S. Department of Agriculture already is collecting data at the individual farm level, but that information is only made available to researchers at the scale of entire states. In this forum piece, the authors maintain that such information needs to be made available at the county and township level in order to be useful in analyzing the impacts of biotech crops.

Lead author on this paper is Michelle Marvier of Santa Clara University. The other authors, in addition to Gepts, are Peter Kareiva of Santa Clara University and The Nature Conservancy, Norman Elstrand of UC Riverside, Yves Carrière and Bruce Tabashnik of the University of Arizona, Emma Rosi-Marshall of Loyola University Chicago, and L. LaReesa Wolfenbarger of the University of Nebraska at Omaha.